From d2b5290dc4b4f7277e41f302f0893b0fb01c4850 Mon Sep 17 00:00:00 2001 From: Alexander Litus Date: Wed, 6 Apr 2016 17:08:39 +0300 Subject: [PATCH 01/26] Remove empty lines. --- .../org/spine3/server/command/CommandBus.java | 16 +--------------- 1 file changed, 1 insertion(+), 15 deletions(-) diff --git a/server/src/main/java/org/spine3/server/command/CommandBus.java b/server/src/main/java/org/spine3/server/command/CommandBus.java index b004d363cb8..c3057be9c14 100644 --- a/server/src/main/java/org/spine3/server/command/CommandBus.java +++ b/server/src/main/java/org/spine3/server/command/CommandBus.java @@ -131,19 +131,15 @@ public void unregister(CommandHandler handler) { public Response validate(Message command) { checkNotNull(command); final CommandClass commandClass = CommandClass.of(command); - if (dispatcherRegistered(commandClass)) { return Responses.ok(); } - if (handlerRegistered(commandClass)) { return Responses.ok(); } - //TODO:2015-12-16:alexander.yevsyukov: Implement command validation for completeness of commands. // Presumably, it would be CommandValidator which would be exposed by // corresponding Aggregates or ProcessManagers, and then contributed to validator registry. - return CommandValidation.unsupportedCommand(command); } @@ -156,25 +152,18 @@ public Response validate(Message command) { * the class of the passed command */ public List post(Command request) { - //TODO:2016-01-24:alexander.yevsyukov: Do not return value. - checkNotNull(request); - store(request); - final CommandClass commandClass = CommandClass.of(request); - if (dispatcherRegistered(commandClass)) { return dispatch(request); } - if (handlerRegistered(commandClass)) { final Message command = getMessage(request); final CommandContext context = request.getContext(); return invokeHandler(command, context); } - throw new UnsupportedCommandException(getMessage(request)); } @@ -197,9 +186,7 @@ private List invokeHandler(Message msg, CommandContext context) { List result = Collections.emptyList(); try { result = method.invoke(msg, context); - commandStatus.setOk(context.getCommandId()); - } catch (InvocationTargetException e) { final CommandId commandId = context.getCommandId(); final Throwable cause = e.getCause(); @@ -217,7 +204,6 @@ private List invokeHandler(Message msg, CommandContext context) { commandStatus.setToError(commandId, Errors.fromThrowable(cause)); } } - return result; } @@ -258,6 +244,7 @@ private List invokeHandler(Message msg, CommandContext context) { * The helper class for updating command status. */ private static class CommandStatusHelper { + private final CommandStore commandStore; private CommandStatusHelper(CommandStore commandStore) { @@ -312,7 +299,6 @@ public void close() throws Exception { private enum LogSingleton { INSTANCE; - @SuppressWarnings("NonSerializableFieldInSerializableClass") private final Logger value = LoggerFactory.getLogger(CommandBus.class); } From f4dc5ff0acc49e6c5f2cdc1a0a121ec21163aadb Mon Sep 17 00:00:00 2001 From: Alexander Litus Date: Wed, 6 Apr 2016 17:14:34 +0300 Subject: [PATCH 02/26] Use `checkNotDefault()` method. --- .../main/java/org/spine3/server/command/CommandBus.java | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/server/src/main/java/org/spine3/server/command/CommandBus.java b/server/src/main/java/org/spine3/server/command/CommandBus.java index c3057be9c14..5327f953221 100644 --- a/server/src/main/java/org/spine3/server/command/CommandBus.java +++ b/server/src/main/java/org/spine3/server/command/CommandBus.java @@ -44,6 +44,7 @@ import static com.google.common.base.Preconditions.checkNotNull; import static org.spine3.base.Commands.*; +import static org.spine3.validate.Validate.checkNotDefault; /** * Dispatches the incoming commands to the corresponding handler. @@ -129,7 +130,7 @@ public void unregister(CommandHandler handler) { * {@link CommandValidation#unsupportedCommand(Message)} otherwise */ public Response validate(Message command) { - checkNotNull(command); + checkNotDefault(command); final CommandClass commandClass = CommandClass.of(command); if (dispatcherRegistered(commandClass)) { return Responses.ok(); @@ -153,7 +154,9 @@ public Response validate(Message command) { */ public List post(Command request) { //TODO:2016-01-24:alexander.yevsyukov: Do not return value. - checkNotNull(request); + checkNotDefault(request); + + store(request); final CommandClass commandClass = CommandClass.of(request); if (dispatcherRegistered(commandClass)) { From 18b04beda80cf23dde7a839b07a0a6c9c7e07e45 Mon Sep 17 00:00:00 2001 From: Alexander Litus Date: Thu, 7 Apr 2016 13:50:08 +0300 Subject: [PATCH 03/26] Add command scheduler to command bus. --- .../main/java/org/spine3/base/Commands.java | 29 +++++ .../src/main/proto/spine/base/command.proto | 9 ++ .../java/org/spine3/base/CommandsShould.java | 28 +++++ .../org/spine3/server/command/CommandBus.java | 45 +++++--- .../server/command/CommandScheduler.java | 47 ++++++++ .../command/DefaultCommandScheduler.java | 103 ++++++++++++++++++ .../server/command/CommandBusShould.java | 41 ++++++- .../DefaultCommandSchedulerShould.java | 95 ++++++++++++++++ 8 files changed, 379 insertions(+), 18 deletions(-) create mode 100644 server/src/main/java/org/spine3/server/command/CommandScheduler.java create mode 100644 server/src/main/java/org/spine3/server/command/DefaultCommandScheduler.java create mode 100644 server/src/test/java/org/spine3/server/command/DefaultCommandSchedulerShould.java diff --git a/client/src/main/java/org/spine3/base/Commands.java b/client/src/main/java/org/spine3/base/Commands.java index 869ea079732..007d2560f9c 100644 --- a/client/src/main/java/org/spine3/base/Commands.java +++ b/client/src/main/java/org/spine3/base/Commands.java @@ -21,6 +21,7 @@ package org.spine3.base; import com.google.common.base.Predicate; +import com.google.protobuf.Duration; import com.google.protobuf.Message; import com.google.protobuf.Timestamp; import org.spine3.protobuf.Messages; @@ -37,6 +38,8 @@ import static com.google.common.base.Preconditions.checkArgument; import static com.google.common.base.Preconditions.checkNotNull; import static com.google.protobuf.util.TimeUtil.getCurrentTime; +import static org.spine3.protobuf.Timestamps.isAfter; +import static org.spine3.validate.Validate.isNotDefault; /** * Client-side utilities for working with commands. @@ -179,4 +182,30 @@ public static String formatMessageTypeAndId(String format, Message commandMessag final String result = String.format(format, commandType, id); return result; } + + /** + * Checks if the command is scheduled to be sent later. + * + * @param command a command to check + * @return {@code true} if the command context has valid delay or sending time set, {@code false} otherwise + */ + public static boolean isScheduled(Command command) { + final CommandContext context = command.getContext(); + final Duration delay = context.getDelay(); + if (isNotDefault(delay)) { + checkArgument(delay.getSeconds() > 0, "Command delay seconds must be a positive value."); + return true; + } + final Timestamp sendingTime = context.getSendingTime(); + if (isNotDefault(sendingTime)) { + checkIsAfterNow(sendingTime); + return true; + } + return false; + } + + private static void checkIsAfterNow(Timestamp sendingTime) { + final Timestamp now = getCurrentTime(); + checkArgument(isAfter(sendingTime, /*than*/ now), "Sending time must be after the current time."); + } } diff --git a/client/src/main/proto/spine/base/command.proto b/client/src/main/proto/spine/base/command.proto index 6c07c3a03cf..967890559b0 100644 --- a/client/src/main/proto/spine/base/command.proto +++ b/client/src/main/proto/spine/base/command.proto @@ -27,6 +27,7 @@ option java_multiple_files = true; option java_generate_equals_and_hash = true; import "google/protobuf/timestamp.proto"; +import "google/protobuf/duration.proto"; import "google/protobuf/any.proto"; import "spine/base/user_id.proto"; @@ -77,6 +78,14 @@ message CommandContext { // The `namespace` attribute must be defined for commands in multitenant applications. Namespace namespace = 5; + + oneof time_opts { + // The delay to wait before sending the command. + google.protobuf.Duration delay = 6; + + // The time when the command should be sent. + google.protobuf.Timestamp sending_time = 7; + } } // Enumeration of possible failures when validating a command. diff --git a/client/src/test/java/org/spine3/base/CommandsShould.java b/client/src/test/java/org/spine3/base/CommandsShould.java index 622fd107e33..f9d0bb8a3dd 100644 --- a/client/src/test/java/org/spine3/base/CommandsShould.java +++ b/client/src/test/java/org/spine3/base/CommandsShould.java @@ -36,7 +36,10 @@ import java.util.Collection; import java.util.List; +import static com.google.protobuf.util.TimeUtil.add; +import static com.google.protobuf.util.TimeUtil.getCurrentTime; import static org.junit.Assert.*; +import static org.spine3.protobuf.Durations.seconds; import static org.spine3.protobuf.Timestamps.minutesAgo; import static org.spine3.protobuf.Timestamps.secondsAgo; import static org.spine3.test.Tests.hasPrivateUtilityConstructor; @@ -120,4 +123,29 @@ public void create_logging_message_for_command_with_type_and_id() { assertTrue(string.contains(typeName)); assertTrue(string.contains(commandId)); } + + @Test + public void when_command_delay_is_set_then_return_true() { + final Command cmd = Commands.create(StringValue.getDefaultInstance(), CommandContext.newBuilder() + .setDelay(seconds(10)) + .build()); + + assertTrue(Commands.isScheduled(cmd)); + } + + @Test + public void when_command_sending_time_is_set_then_return_true() { + final Command cmd = Commands.create(StringValue.getDefaultInstance(), CommandContext.newBuilder() + .setSendingTime(add(getCurrentTime(), seconds(10))) + .build()); + + assertTrue(Commands.isScheduled(cmd)); + } + + @Test + public void when_command_is_not_scheduled_then_return_false() { + final Command cmd = Commands.create(StringValue.getDefaultInstance(), CommandContext.getDefaultInstance()); + + assertFalse(Commands.isScheduled(cmd)); + } } diff --git a/server/src/main/java/org/spine3/server/command/CommandBus.java b/server/src/main/java/org/spine3/server/command/CommandBus.java index 5327f953221..c36fefd45ce 100644 --- a/server/src/main/java/org/spine3/server/command/CommandBus.java +++ b/server/src/main/java/org/spine3/server/command/CommandBus.java @@ -39,10 +39,10 @@ import javax.annotation.CheckReturnValue; import java.lang.reflect.InvocationTargetException; -import java.util.Collections; import java.util.List; import static com.google.common.base.Preconditions.checkNotNull; +import static java.util.Collections.emptyList; import static org.spine3.base.Commands.*; import static org.spine3.validate.Validate.checkNotDefault; @@ -61,10 +61,13 @@ public class CommandBus implements AutoCloseable { private final CommandStatusHelper commandStatus; private final ProblemLog problemLog = new ProblemLog(); + private CommandScheduler scheduler; @CheckReturnValue public static CommandBus create(CommandStore store) { - return new CommandBus(checkNotNull(store)); + final CommandBus commandBus = new CommandBus(checkNotNull(store)); + commandBus.setScheduler(new DefaultCommandScheduler(commandBus)); + return commandBus; } protected CommandBus(CommandStore commandStore) { @@ -115,6 +118,13 @@ public void unregister(CommandHandler handler) { handlerRegistry.unregister(handler); } + /** + * Sets a command scheduler. + */ + public void setScheduler(CommandScheduler scheduler) { + this.scheduler = scheduler; + } + /** * Verifies if the command can be posted to this {@code CommandBus}. * @@ -147,33 +157,35 @@ public Response validate(Message command) { /** * Directs a command request to the corresponding handler. * - * @param request the command request to be processed + * @param command the command request to be processed * @return a list of the events as the result of handling the command * @throws UnsupportedCommandException if there is neither handler nor dispatcher registered for * the class of the passed command */ - public List post(Command request) { + public List post(Command command) { //TODO:2016-01-24:alexander.yevsyukov: Do not return value. - checkNotDefault(request); - - - store(request); - final CommandClass commandClass = CommandClass.of(request); + checkNotDefault(command); + store(command); + if (isScheduled(command)) { + scheduler.schedule(command); + return emptyList(); + } + final CommandClass commandClass = CommandClass.of(command); if (dispatcherRegistered(commandClass)) { - return dispatch(request); + return dispatch(command); } if (handlerRegistered(commandClass)) { - final Message command = getMessage(request); - final CommandContext context = request.getContext(); - return invokeHandler(command, context); + final Message message = getMessage(command); + final CommandContext context = command.getContext(); + return invokeHandler(message, context); } - throw new UnsupportedCommandException(getMessage(request)); + throw new UnsupportedCommandException(getMessage(command)); } private List dispatch(Command command) { final CommandClass commandClass = CommandClass.of(command); final CommandDispatcher dispatcher = getDispatcher(commandClass); - List result = Collections.emptyList(); + List result = emptyList(); try { result = dispatcher.dispatch(command); } catch (Exception e) { @@ -186,7 +198,7 @@ private List dispatch(Command command) { private List invokeHandler(Message msg, CommandContext context) { final CommandClass commandClass = CommandClass.of(msg); final CommandHandlerMethod method = getHandler(commandClass); - List result = Collections.emptyList(); + List result = emptyList(); try { result = method.invoke(msg, context); commandStatus.setOk(context.getCommandId()); @@ -298,6 +310,7 @@ public void close() throws Exception { dispatcherRegistry.unregisterAll(); handlerRegistry.unregisterAll(); commandStore.close(); + scheduler.shutdown(); } private enum LogSingleton { diff --git a/server/src/main/java/org/spine3/server/command/CommandScheduler.java b/server/src/main/java/org/spine3/server/command/CommandScheduler.java new file mode 100644 index 00000000000..3003ef96089 --- /dev/null +++ b/server/src/main/java/org/spine3/server/command/CommandScheduler.java @@ -0,0 +1,47 @@ +/* + * Copyright 2016, TeamDev Ltd. All rights reserved. + * + * Redistribution and use in source and/or binary forms, with or without + * modification, must retain the above copyright notice and the following + * disclaimer. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +package org.spine3.server.command; + +import org.spine3.base.Command; + +/** + * Schedules commands sending them after the given delay (or at the given time). + * + * @author Alexander Litus + */ +public interface CommandScheduler { + + /** + * Schedule a command and send it after the given delay (or at the given time). + * + * @param command a command to send later + * @throws IllegalStateException if the scheduler is shut down + */ + void schedule(Command command); + + /** + * Initiates an orderly shutdown in which previously scheduled commands will be sent later, + * but no new commands will be accepted. + * + *

Invocation has no effect if the scheduler is already shut down. + */ + void shutdown(); +} diff --git a/server/src/main/java/org/spine3/server/command/DefaultCommandScheduler.java b/server/src/main/java/org/spine3/server/command/DefaultCommandScheduler.java new file mode 100644 index 00000000000..6e227c95e71 --- /dev/null +++ b/server/src/main/java/org/spine3/server/command/DefaultCommandScheduler.java @@ -0,0 +1,103 @@ +/* + * Copyright 2016, TeamDev Ltd. All rights reserved. + * + * Redistribution and use in source and/or binary forms, with or without + * modification, must retain the above copyright notice and the following + * disclaimer. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +package org.spine3.server.command; + +import com.google.protobuf.Duration; +import com.google.protobuf.Timestamp; +import org.spine3.base.Command; +import org.spine3.base.CommandContext; + +import java.util.concurrent.Executors; +import java.util.concurrent.ScheduledExecutorService; + +import static com.google.common.base.Preconditions.checkState; +import static com.google.protobuf.util.TimeUtil.getCurrentTime; +import static java.util.concurrent.TimeUnit.SECONDS; +import static org.spine3.validate.Validate.isNotDefault; + +/** + * The default command scheduler implementation. + * + * @author Alexander Litus + */ +public class DefaultCommandScheduler implements CommandScheduler { + + private static final int MIN_THEAD_POOL_SIZE = 5; + + private final ScheduledExecutorService executorService = Executors.newScheduledThreadPool(MIN_THEAD_POOL_SIZE); + + private boolean isShutdown = false; + + private final CommandBus commandBus; + + /** + * Creates a new instance. + * + * @param commandBus a command bus used to send scheduled commands + */ + public DefaultCommandScheduler(CommandBus commandBus) { + this.commandBus = commandBus; + } + + @Override + public void schedule(Command command) { + checkState(!isShutdown, "Scheduler is shut down."); + final long delaySec = getDelaySeconds(command); + final Command commandUpdated = removeSchedulingOptions(command); + executorService.schedule(new Runnable() { + @Override + public void run() { + commandBus.post(commandUpdated); + } + }, delaySec, SECONDS); + } + + private static long getDelaySeconds(Command command) { + final CommandContext context = command.getContext(); + final long delaySec; + final Duration delay = context.getDelay(); + if (isNotDefault(delay)) { + delaySec = delay.getSeconds(); + } else { + final Timestamp sendingTime = context.getSendingTime(); + final Timestamp now = getCurrentTime(); + delaySec = sendingTime.getSeconds() - now.getSeconds(); + } + return delaySec; + } + + private static Command removeSchedulingOptions(Command command) { + final CommandContext contextUpdated = command.getContext().toBuilder() + .clearDelay() + .clearSendingTime() + .build(); + final Command result = command.toBuilder() + .setContext(contextUpdated) + .build(); + return result; + } + + @Override + public void shutdown() { + executorService.shutdown(); + isShutdown = true; + } +} diff --git a/server/src/test/java/org/spine3/server/command/CommandBusShould.java b/server/src/test/java/org/spine3/server/command/CommandBusShould.java index 4b59e2459f0..e2727a4f57c 100644 --- a/server/src/test/java/org/spine3/server/command/CommandBusShould.java +++ b/server/src/test/java/org/spine3/server/command/CommandBusShould.java @@ -49,9 +49,12 @@ import java.util.List; import java.util.Set; +import static com.google.protobuf.util.TimeUtil.add; +import static com.google.protobuf.util.TimeUtil.getCurrentTime; import static org.junit.Assert.*; import static org.mockito.Mockito.*; import static org.spine3.base.Identifiers.newUuid; +import static org.spine3.protobuf.Durations.minutes; import static org.spine3.server.command.CommandValidation.isUnsupportedCommand; import static org.spine3.testdata.TestCommands.*; @@ -61,12 +64,14 @@ public class CommandBusShould { private CommandBus commandBus; private CommandStore commandStore; private CommandFactory commandFactory; + private DefaultCommandScheduler scheduler; @Before public void setUp() { commandStore = mock(CommandStore.class); - + scheduler = mock(DefaultCommandScheduler.class); commandBus = CommandBus.create(commandStore); + commandBus.setScheduler(scheduler); commandFactory = TestCommandFactory.newInstance(CommandBusShould.class); } @@ -398,7 +403,7 @@ public void set_command_status_to_failure_when_handler_throws_failure() throws T // Verify we logged the failure. verify(log, atMost(1)).failureHandling(eq(failure), eq(commandMessage), eq(commandId)); } - +// TODO:2016-04-07:alexander.litus: check all atMost() @Test public void set_command_status_to_failure_when_handler_throws_exception() throws TestFailure, TestThrowable { final CreateProjectHandler handler = mock(CreateProjectHandler.class); @@ -444,4 +449,36 @@ public void set_command_status_to_failure_when_handler_throws_unknown_Throwable( // Verify we logged the failure. verify(log, atMost(1)).errorHandlingUnknown(eq(throwable), eq(commandMessage), eq(commandId)); } + + @Test + public void schedule_command_if_delay_is_set() { + final Command cmd = Commands.create(createProject(newUuid()), CommandContext.newBuilder() + .setDelay(minutes(1)) + .build()); + + commandBus.post(cmd); + + verify(scheduler, times(1)).schedule(cmd); + } + + @Test + public void schedule_command_if_sending_time_is_set() { + final Command cmd = Commands.create(createProject(newUuid()), CommandContext.newBuilder() + .setSendingTime(add(getCurrentTime(), minutes(1))) + .build()); + + commandBus.post(cmd); + + verify(scheduler, times(1)).schedule(cmd); + } + + @Test + public void do_not_schedule_command_if_no_scheduling_options_are_set() { + commandBus.register(new CreateProjectHandler()); + final Command cmd = commandFactory.create(createProject(newUuid())); + + commandBus.post(cmd); + + verify(scheduler, times(0)).schedule(cmd); + } } diff --git a/server/src/test/java/org/spine3/server/command/DefaultCommandSchedulerShould.java b/server/src/test/java/org/spine3/server/command/DefaultCommandSchedulerShould.java new file mode 100644 index 00000000000..aa07ebf91f8 --- /dev/null +++ b/server/src/test/java/org/spine3/server/command/DefaultCommandSchedulerShould.java @@ -0,0 +1,95 @@ +/* + * Copyright 2016, TeamDev Ltd. All rights reserved. + * + * Redistribution and use in source and/or binary forms, with or without + * modification, must retain the above copyright notice and the following + * disclaimer. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +package org.spine3.server.command; + +import com.google.protobuf.Duration; +import org.junit.After; +import org.junit.Before; +import org.junit.Test; +import org.spine3.base.Command; +import org.spine3.base.CommandContext; +import org.spine3.base.Commands; +import org.spine3.test.project.command.CreateProject; + +import static com.google.protobuf.util.TimeUtil.add; +import static com.google.protobuf.util.TimeUtil.getCurrentTime; +import static org.mockito.Mockito.*; +import static org.spine3.base.Identifiers.newUuid; +import static org.spine3.protobuf.Durations.seconds; +import static org.spine3.testdata.TestCommands.createProject; + +/** + * @author Alexander Litus + */ +@SuppressWarnings("InstanceMethodNamingConvention") +public class DefaultCommandSchedulerShould { + + private static final Duration DELAY = seconds(1); + private static final int CHECK_OFFSET_MS = 50; + + private CommandBus commandBus; + private CommandScheduler scheduler; + + @Before + public void setUpTest() { + this.commandBus = mock(CommandBus.class); + this.scheduler = new DefaultCommandScheduler(commandBus); + } + + @After + public void tearDownTest() { + scheduler.shutdown(); + } + + @Test + public void schedule_command_if_delay_is_set() throws InterruptedException { + final CreateProject msg = createProject(newUuid()); + final Command cmdPrimary = Commands.create(msg, CommandContext.newBuilder() + .setDelay(DELAY) + .build()); + final Command cmdExpected = Commands.create(msg, CommandContext.getDefaultInstance()); + + scheduler.schedule(cmdPrimary); + + assertCommandSent(cmdExpected, DELAY); + } + + @Test + public void schedule_command_if_sending_time_is_set() throws InterruptedException { + final CreateProject msg = createProject(newUuid()); + final Command cmdPrimary = Commands.create(msg, CommandContext.newBuilder() + .setSendingTime(add(getCurrentTime(), DELAY)) + .build()); + final Command cmdExpected = Commands.create(msg, CommandContext.getDefaultInstance()); + + scheduler.schedule(cmdPrimary); + + assertCommandSent(cmdExpected, DELAY); + } + + private void assertCommandSent(Command cmd, Duration delay) throws InterruptedException { + verify(commandBus, never()).post(any(Command.class)); + + Thread.sleep((delay.getSeconds() * 1000) + CHECK_OFFSET_MS); + + verify(commandBus, times(1)).post(cmd); + } +} From e0e8ecc6bfda431a4569f82a8f6022a88e2db97d Mon Sep 17 00:00:00 2001 From: Alexander Litus Date: Thu, 7 Apr 2016 16:03:25 +0300 Subject: [PATCH 04/26] Fix command bus tests. --- .../org/spine3/server/command/CommandBus.java | 6 +- .../server/command/CommandBusShould.java | 139 +++++++++--------- 2 files changed, 74 insertions(+), 71 deletions(-) diff --git a/server/src/main/java/org/spine3/server/command/CommandBus.java b/server/src/main/java/org/spine3/server/command/CommandBus.java index c36fefd45ce..f0a3b8d8d53 100644 --- a/server/src/main/java/org/spine3/server/command/CommandBus.java +++ b/server/src/main/java/org/spine3/server/command/CommandBus.java @@ -60,7 +60,7 @@ public class CommandBus implements AutoCloseable { private final CommandStore commandStore; private final CommandStatusHelper commandStatus; - private final ProblemLog problemLog = new ProblemLog(); + private ProblemLog problemLog = new ProblemLog(); private CommandScheduler scheduler; @CheckReturnValue @@ -251,8 +251,8 @@ private List invokeHandler(Message msg, CommandContext context) { } @VisibleForTesting - /* package */ ProblemLog getProblemLog() { - return problemLog; + /* package */ void setProblemLog(ProblemLog problemLog) { + this.problemLog = problemLog; } /** diff --git a/server/src/test/java/org/spine3/server/command/CommandBusShould.java b/server/src/test/java/org/spine3/server/command/CommandBusShould.java index e2727a4f57c..3592d8b32b2 100644 --- a/server/src/test/java/org/spine3/server/command/CommandBusShould.java +++ b/server/src/test/java/org/spine3/server/command/CommandBusShould.java @@ -65,13 +65,16 @@ public class CommandBusShould { private CommandStore commandStore; private CommandFactory commandFactory; private DefaultCommandScheduler scheduler; + private CommandBus.ProblemLog log; @Before public void setUp() { commandStore = mock(CommandStore.class); - scheduler = mock(DefaultCommandScheduler.class); commandBus = CommandBus.create(commandStore); + scheduler = mock(DefaultCommandScheduler.class); commandBus.setScheduler(scheduler); + log = mock(CommandBus.ProblemLog.class); + commandBus.setProblemLog(log); commandFactory = TestCommandFactory.newInstance(CommandBusShould.class); } @@ -216,8 +219,7 @@ private static class CreateProjectHandler implements CommandHandler { private boolean handlerInvoked = false; @Assign - public ProjectCreated handle(CreateProject command, CommandContext ctx) - throws TestFailure, TestThrowable { + public ProjectCreated handle(CreateProject command, CommandContext ctx) throws TestFailure, TestThrowable { handlerInvoked = true; return ProjectCreated.getDefaultInstance(); } @@ -242,7 +244,7 @@ public List dispatch(Command request) throws Exception { @Test public void unregister_handler() { - final CreateProjectHandler handler = new CreateProjectHandler(); + final CommandHandler handler = new CreateProjectHandler(); commandBus.register(handler); commandBus.unregister(handler); final String projectId = newUuid(); @@ -251,8 +253,8 @@ public void unregister_handler() { @Test public void validate_commands_both_dispatched_and_handled() { - final CreateProjectHandler handler = new CreateProjectHandler(); - final AddTaskDispatcher dispatcher = new AddTaskDispatcher(); + final CommandHandler handler = new CreateProjectHandler(); + final CommandDispatcher dispatcher = new AddTaskDispatcher(); commandBus.register(handler); commandBus.register(dispatcher); @@ -291,12 +293,19 @@ public void have_log() { public void close_CommandStore_when_closed() throws Exception { commandBus.close(); - verify(commandStore, atMost(1)).close(); + verify(commandStore, times(1)).close(); + } + + @Test + public void shutdown_CommandScheduler_when_closed() throws Exception { + commandBus.close(); + + verify(scheduler, times(1)).shutdown(); } @Test public void remove_all_handlers_on_close() throws Exception { - final CreateProjectHandler handler = new CreateProjectHandler(); + final CommandHandler handler = new CreateProjectHandler(); commandBus.register(handler); commandBus.close(); @@ -342,112 +351,92 @@ public void set_command_status_to_OK_when_handler_returns() { commandBus.post(command); // See that we called CommandStore only once with the right command ID. - verify(commandStore, atMost(1)).setCommandStatusOk(command.getContext() - .getCommandId()); + verify(commandStore, times(1)).setCommandStatusOk(command.getContext() + .getCommandId()); } @Test public void set_command_status_to_error_when_dispatcher_throws() throws Exception { - final CommandDispatcher throwingDispatcher = mock(CommandDispatcher.class); - when(throwingDispatcher.getCommandClasses()).thenReturn(CommandClass.setOf(CreateProject.class)); - final IOException exception = new IOException("Unable to dispatch"); - doThrow(exception).when(throwingDispatcher) - .dispatch(any(Command.class)); - final CommandBus.ProblemLog log = spy(commandBus.getProblemLog()); - - commandBus.register(throwingDispatcher); + final IOException exception = givenThrowingDispatcher(); final Command command = commandFactory.create(createProject(newUuid())); commandBus.post(command); // Verify we updated the status. - verify(commandStore, atMost(1)).updateStatus(eq(command.getContext() - .getCommandId()), eq(exception)); + verify(commandStore, times(1)).updateStatus(eq(command.getContext() + .getCommandId()), eq(exception)); // Verify we logged the error. verify(log, atMost(1)).errorDispatching(eq(exception), eq(command)); } - private static class TestFailure extends FailureThrowable { - private static final long serialVersionUID = 1L; - - private TestFailure() { - super(Failures.UnableToHandle.newBuilder() - .setMessage(TestFailure.class.getName()) - .build()); - } - } - - @SuppressWarnings("serial") - private static class TestThrowable extends Throwable { - } - @Test public void set_command_status_to_failure_when_handler_throws_failure() throws TestFailure, TestThrowable { - final CreateProjectHandler handler = mock(CreateProjectHandler.class); - final FailureThrowable failure = new TestFailure(); - doThrow(failure).when(handler) - .handle(any(CreateProject.class), any(CommandContext.class)); - final CommandBus.ProblemLog log = spy(commandBus.getProblemLog()); - - commandBus.register(handler); + final TestFailure failure = new TestFailure(); + givenThrowingHandler(failure); final Command command = commandFactory.create(createProject(newUuid())); - final CommandId commandId = command.getContext() - .getCommandId(); + final CommandId commandId = command.getContext().getCommandId(); final Message commandMessage = Commands.getMessage(command); commandBus.post(command); // Verify we updated the status. - verify(commandStore, atMost(1)).updateStatus(eq(commandId), eq(failure.toMessage())); + verify(commandStore, times(1)).updateStatus(eq(commandId), eq(failure.toMessage())); // Verify we logged the failure. - verify(log, atMost(1)).failureHandling(eq(failure), eq(commandMessage), eq(commandId)); + verify(log, times(1)).failureHandling(eq(failure), eq(commandMessage), eq(commandId)); } -// TODO:2016-04-07:alexander.litus: check all atMost() + @Test public void set_command_status_to_failure_when_handler_throws_exception() throws TestFailure, TestThrowable { - final CreateProjectHandler handler = mock(CreateProjectHandler.class); final RuntimeException exception = new IllegalStateException("handler throws"); - doThrow(exception).when(handler) - .handle(any(CreateProject.class), any(CommandContext.class)); - final CommandBus.ProblemLog log = spy(commandBus.getProblemLog()); - - commandBus.register(handler); + givenThrowingHandler(exception); final Command command = commandFactory.create(createProject(newUuid())); - final CommandId commandId = command.getContext() - .getCommandId(); + final CommandId commandId = command.getContext().getCommandId(); final Message commandMessage = Commands.getMessage(command); commandBus.post(command); // Verify we updated the status. - - verify(commandStore, atMost(1)).updateStatus(eq(commandId), eq(exception)); + verify(commandStore, times(1)).updateStatus(eq(commandId), eq(exception)); // Verify we logged the failure. - verify(log, atMost(1)).errorHandling(eq(exception), eq(commandMessage), eq(commandId)); + verify(log, times(1)).errorHandling(eq(exception), eq(commandMessage), eq(commandId)); } @Test public void set_command_status_to_failure_when_handler_throws_unknown_Throwable() throws TestFailure, TestThrowable { - final CreateProjectHandler handler = mock(CreateProjectHandler.class); final Throwable throwable = new TestThrowable(); - doThrow(throwable).when(handler) - .handle(any(CreateProject.class), any(CommandContext.class)); - final CommandBus.ProblemLog log = spy(commandBus.getProblemLog()); - - commandBus.register(handler); + givenThrowingHandler(throwable); final Command command = commandFactory.create(createProject(newUuid())); - final CommandId commandId = command.getContext() - .getCommandId(); + final CommandId commandId = command.getContext().getCommandId(); final Message commandMessage = Commands.getMessage(command); commandBus.post(command); // Verify we updated the status. - - verify(commandStore, atMost(1)).updateStatus(eq(commandId), eq(Errors.fromThrowable(throwable))); + verify(commandStore, times(1)).updateStatus(eq(commandId), eq(Errors.fromThrowable(throwable))); // Verify we logged the failure. - verify(log, atMost(1)).errorHandlingUnknown(eq(throwable), eq(commandMessage), eq(commandId)); + verify(log, times(1)).errorHandlingUnknown(eq(throwable), eq(commandMessage), eq(commandId)); + } + + private void givenThrowingHandler(E throwable) throws TestThrowable, TestFailure { + final CreateProjectHandler handler = mock(CreateProjectHandler.class); + doThrow(throwable) + .when(handler) + .handle(any(CreateProject.class), any(CommandContext.class)); + commandBus.register(handler); + } + + private E givenThrowingDispatcher() throws Exception { + final CommandDispatcher throwingDispatcher = mock(CommandDispatcher.class); + when(throwingDispatcher.getCommandClasses()).thenReturn(CommandClass.setOf(CreateProject.class)); + final IOException exception = new IOException("Unable to dispatch"); + doThrow(exception) + .when(throwingDispatcher) + .dispatch(any(Command.class)); + commandBus.register(throwingDispatcher); + @SuppressWarnings("unchecked") + final E throwable = (E) exception; + return throwable; } @Test @@ -481,4 +470,18 @@ public void do_not_schedule_command_if_no_scheduling_options_are_set() { verify(scheduler, times(0)).schedule(cmd); } + + private static class TestFailure extends FailureThrowable { + private static final long serialVersionUID = 1L; + + private TestFailure() { + super(Failures.UnableToHandle.newBuilder() + .setMessage(TestFailure.class.getName()) + .build()); + } + } + + @SuppressWarnings("serial") + private static class TestThrowable extends Throwable { + } } From c4a6e1bb1d8abe0d7a0b5dd66792f8f212c10508 Mon Sep 17 00:00:00 2001 From: Alexander Litus Date: Thu, 7 Apr 2016 16:20:12 +0300 Subject: [PATCH 05/26] Add more tests. --- .../java/org/spine3/base/CommandsShould.java | 23 +++++++++++++++++-- .../DefaultCommandSchedulerShould.java | 13 +++++++++++ 2 files changed, 34 insertions(+), 2 deletions(-) diff --git a/client/src/test/java/org/spine3/base/CommandsShould.java b/client/src/test/java/org/spine3/base/CommandsShould.java index f9d0bb8a3dd..0245f2faa62 100644 --- a/client/src/test/java/org/spine3/base/CommandsShould.java +++ b/client/src/test/java/org/spine3/base/CommandsShould.java @@ -29,6 +29,7 @@ import com.google.protobuf.StringValue; import org.junit.Test; import org.spine3.client.test.TestCommandFactory; +import org.spine3.protobuf.Timestamps; import org.spine3.test.RunTest; import org.spine3.type.TypeName; @@ -127,8 +128,8 @@ public void create_logging_message_for_command_with_type_and_id() { @Test public void when_command_delay_is_set_then_return_true() { final Command cmd = Commands.create(StringValue.getDefaultInstance(), CommandContext.newBuilder() - .setDelay(seconds(10)) - .build()); + .setDelay(seconds(10)) + .build()); assertTrue(Commands.isScheduled(cmd)); } @@ -148,4 +149,22 @@ public void when_command_is_not_scheduled_then_return_false() { assertFalse(Commands.isScheduled(cmd)); } + + @Test(expected = IllegalArgumentException.class) + public void when_set_negative_delay_then_throw_exception() { + final Command cmd = Commands.create(StringValue.getDefaultInstance(), CommandContext.newBuilder() + .setDelay(seconds(-10)) + .build()); + + Commands.isScheduled(cmd); + } + + @Test(expected = IllegalArgumentException.class) + public void when_set_past_sending_time_then_throw_exception() { + final Command cmd = Commands.create(StringValue.getDefaultInstance(), CommandContext.newBuilder() + .setSendingTime(Timestamps.secondsAgo(10)) + .build()); + + Commands.isScheduled(cmd); + } } diff --git a/server/src/test/java/org/spine3/server/command/DefaultCommandSchedulerShould.java b/server/src/test/java/org/spine3/server/command/DefaultCommandSchedulerShould.java index aa07ebf91f8..28229f2a89e 100644 --- a/server/src/test/java/org/spine3/server/command/DefaultCommandSchedulerShould.java +++ b/server/src/test/java/org/spine3/server/command/DefaultCommandSchedulerShould.java @@ -31,6 +31,7 @@ import static com.google.protobuf.util.TimeUtil.add; import static com.google.protobuf.util.TimeUtil.getCurrentTime; +import static org.junit.Assert.fail; import static org.mockito.Mockito.*; import static org.spine3.base.Identifiers.newUuid; import static org.spine3.protobuf.Durations.seconds; @@ -92,4 +93,16 @@ private void assertCommandSent(Command cmd, Duration delay) throws InterruptedEx verify(commandBus, times(1)).post(cmd); } + + @Test + public void throw_exception_if_is_shutdown() { + scheduler.shutdown(); + try { + scheduler.schedule(createProject()); + } catch (IllegalStateException expected) { + // is OK as it is shutdown + return; + } + fail("Must throw an exception as it is shutdown."); + } } From 637183f87d7ddcc434d364b97dc80732030265fa Mon Sep 17 00:00:00 2001 From: Alexander Litus Date: Thu, 7 Apr 2016 17:47:33 +0300 Subject: [PATCH 06/26] Update protobuf plugin dependency. --- client/build.gradle | 4 ++-- examples/build.gradle | 4 ++-- server/build.gradle | 4 ++-- values/build.gradle | 4 ++-- 4 files changed, 8 insertions(+), 8 deletions(-) diff --git a/client/build.gradle b/client/build.gradle index 3c9e14c1a9f..7491242a5e7 100644 --- a/client/build.gradle +++ b/client/build.gradle @@ -4,7 +4,7 @@ buildscript { resolutionStrategy.cacheChangingModulesFor 0, 'seconds' } dependencies { - classpath group: 'org.spine3.tools', name: 'proto-lookup-plugin', version: '1.1', changing: true + classpath group: 'org.spine3.tools', name: 'protobuf-plugin', version: '1.2', changing: true } } @@ -13,7 +13,7 @@ dependencies { testCompile project (path: ":testutil", configuration: 'testArtifacts') } -apply plugin: 'org.spine3.tools.protolookup'; +apply plugin: 'org.spine3.tools.protobuf-plugin'; sourceSets { main { diff --git a/examples/build.gradle b/examples/build.gradle index da482493b4d..9758e243473 100644 --- a/examples/build.gradle +++ b/examples/build.gradle @@ -1,6 +1,6 @@ buildscript { dependencies { - classpath "org.spine3.tools:proto-lookup-plugin:1.1" + classpath "org.spine3.tools:protobuf-plugin:1.2" } } @@ -13,5 +13,5 @@ dependencies { compile project(path: ':server'); } -apply plugin: 'org.spine3.tools.protolookup' +apply plugin: 'org.spine3.tools.protobuf-plugin' diff --git a/server/build.gradle b/server/build.gradle index f47f10080d7..1cf8134453f 100644 --- a/server/build.gradle +++ b/server/build.gradle @@ -3,7 +3,7 @@ buildscript { resolutionStrategy.cacheChangingModulesFor 0, 'seconds' } dependencies { - classpath group: 'org.spine3.tools', name: 'proto-lookup-plugin', version: '1.1', changing: true + classpath group: 'org.spine3.tools', name: 'protobuf-plugin', version: '1.2', changing: true } } @@ -14,7 +14,7 @@ dependencies { compile project(path: ':client'); } -apply plugin: 'org.spine3.tools.protolookup'; +apply plugin: 'org.spine3.tools.protobuf-plugin'; sourceSets { main { diff --git a/values/build.gradle b/values/build.gradle index 1083a42de55..205c7bd4370 100644 --- a/values/build.gradle +++ b/values/build.gradle @@ -4,7 +4,7 @@ buildscript { resolutionStrategy.cacheChangingModulesFor 0, 'seconds' } dependencies { - classpath group: 'org.spine3.tools', name: 'proto-lookup-plugin', version: '1.1', changing: true + classpath group: 'org.spine3.tools', name: 'protobuf-plugin', version: '1.2', changing: true } } @@ -14,7 +14,7 @@ dependencies { compile project(path: ':client'); } -apply plugin: 'org.spine3.tools.protolookup'; +apply plugin: 'org.spine3.tools.protobuf-plugin'; sourceSets { main { From 82894c4629cac8fd10816be82fbfc062bfacecc8 Mon Sep 17 00:00:00 2001 From: Alexander Litus Date: Fri, 8 Apr 2016 14:08:54 +0300 Subject: [PATCH 07/26] Make CommandScheduler an abstract class; add docs, tests; add a builder to CommandBus. --- .../main/java/org/spine3/base/Commands.java | 21 ++--- .../src/main/proto/spine/base/command.proto | 20 +++-- .../java/org/spine3/base/CommandsShould.java | 39 +++++---- .../spine3/testdata/TestContextFactory.java | 47 ++++++++++- .../aggregate/server/Application.java | 10 ++- .../org/spine3/server/command/CommandBus.java | 81 ++++++++++++++----- .../server/command/CommandScheduler.java | 63 +++++++++++++-- ...ler.java => ExecutorCommandScheduler.java} | 47 ++++------- .../server/BoundedContextBuilderShould.java | 25 +++--- .../spine3/server/BoundedContextShould.java | 6 -- .../server/BoundedContextTestStubs.java | 23 +++--- .../server/command/CommandBusShould.java | 51 +++++++++--- ...va => ExecutorCommandSchedulerShould.java} | 51 +++++++----- .../org/spine3/testdata/TestCommands.java | 22 ++++- 14 files changed, 344 insertions(+), 162 deletions(-) rename {server => client}/src/test/java/org/spine3/testdata/TestContextFactory.java (73%) rename server/src/main/java/org/spine3/server/command/{DefaultCommandScheduler.java => ExecutorCommandScheduler.java} (64%) rename server/src/test/java/org/spine3/server/command/{DefaultCommandSchedulerShould.java => ExecutorCommandSchedulerShould.java} (64%) diff --git a/client/src/main/java/org/spine3/base/Commands.java b/client/src/main/java/org/spine3/base/Commands.java index 549b9943dda..ca78ec9f9d4 100644 --- a/client/src/main/java/org/spine3/base/Commands.java +++ b/client/src/main/java/org/spine3/base/Commands.java @@ -221,28 +221,31 @@ public static boolean isEntityFile(FileDescriptor file) { } /** - * Checks if the command is scheduled to be sent later. + * Checks if the command is scheduled to be delivered later. * * @param command a command to check - * @return {@code true} if the command context has valid delay or sending time set, {@code false} otherwise + * @return {@code true} if the command context has scheduling options set, {@code false} otherwise */ public static boolean isScheduled(Command command) { - final CommandContext context = command.getContext(); - final Duration delay = context.getDelay(); + final Schedule schedule = command.getContext().getSchedule(); + if (schedule.getInTime()) { + return false; + } + final Duration delay = schedule.getDelay(); if (isNotDefault(delay)) { checkArgument(delay.getSeconds() > 0, "Command delay seconds must be a positive value."); return true; } - final Timestamp sendingTime = context.getSendingTime(); - if (isNotDefault(sendingTime)) { - checkIsAfterNow(sendingTime); + final Timestamp deliveryTime = schedule.getDeliveryTime(); + if (isNotDefault(deliveryTime)) { + checkIsAfterNow(deliveryTime); return true; } return false; } - private static void checkIsAfterNow(Timestamp sendingTime) { + private static void checkIsAfterNow(Timestamp deliveryTime) { final Timestamp now = getCurrentTime(); - checkArgument(isAfter(sendingTime, /*than*/ now), "Sending time must be after the current time."); + checkArgument(isAfter(deliveryTime, /*than*/ now), "Delivery time must be after the current time."); } } diff --git a/client/src/main/proto/spine/base/command.proto b/client/src/main/proto/spine/base/command.proto index 46b3565d9ca..45bb5757a55 100644 --- a/client/src/main/proto/spine/base/command.proto +++ b/client/src/main/proto/spine/base/command.proto @@ -79,13 +79,23 @@ message CommandContext { // The `namespace` attribute must be defined for commands in multitenant applications. Namespace namespace = 5; - oneof time_opts { - // The delay to wait before sending the command. - google.protobuf.Duration delay = 6; + // The command scheduling options. + Schedule schedule = 6; +} + +message Schedule { + oneof options { + // The amount of time between the current moment and a command delivering to the target. + google.protobuf.Duration delay = 1; - // The time when the command should be sent. - google.protobuf.Timestamp sending_time = 7; + // The time when the command should be delivered to the target. + google.protobuf.Timestamp delivery_time = 2; } + + // `true` if the command should be delivered to the target right now, despite the scheduling options set; + // `false` otherwise. + // This flag is needed to specify that a scheduled command arrived in time, and to retain the scheduling options. + bool in_time = 3; } // Enumeration of possible failures when validating a command. diff --git a/client/src/test/java/org/spine3/base/CommandsShould.java b/client/src/test/java/org/spine3/base/CommandsShould.java index 909dc544cda..55e6672cc64 100644 --- a/client/src/test/java/org/spine3/base/CommandsShould.java +++ b/client/src/test/java/org/spine3/base/CommandsShould.java @@ -27,9 +27,9 @@ import com.google.protobuf.Int64Value; import com.google.protobuf.Message; import com.google.protobuf.StringValue; +import com.google.protobuf.Timestamp; import org.junit.Test; import org.spine3.client.test.TestCommandFactory; -import org.spine3.protobuf.Timestamps; import org.spine3.test.RunTest; import org.spine3.test.TestCommand; import org.spine3.type.TypeName; @@ -38,15 +38,16 @@ import java.util.Collection; import java.util.List; +import static com.google.protobuf.Descriptors.FileDescriptor; import static com.google.protobuf.util.TimeUtil.add; import static com.google.protobuf.util.TimeUtil.getCurrentTime; -import static com.google.protobuf.Descriptors.FileDescriptor; import static org.junit.Assert.*; import static org.spine3.protobuf.Durations.seconds; import static org.spine3.protobuf.Timestamps.minutesAgo; import static org.spine3.protobuf.Timestamps.secondsAgo; import static org.spine3.protobuf.Values.newStringValue; import static org.spine3.test.Tests.hasPrivateUtilityConstructor; +import static org.spine3.testdata.TestContextFactory.createCommandContext; @SuppressWarnings({"InstanceMethodNamingConvention", "MagicNumber"}) public class CommandsShould { @@ -152,44 +153,48 @@ public void return_false_if_file_does_not_belong_to_entity() { } @Test - public void when_command_delay_is_set_then_return_true() { - final Command cmd = Commands.create(StringValue.getDefaultInstance(), CommandContext.newBuilder() - .setDelay(seconds(10)) - .build()); + public void when_command_delay_is_set_then_consider_it_scheduled() { + final CommandContext context = createCommandContext(/*delay=*/seconds(10)); + final Command cmd = Commands.create(StringValue.getDefaultInstance(), context); assertTrue(Commands.isScheduled(cmd)); } @Test - public void when_command_sending_time_is_set_then_return_true() { - final Command cmd = Commands.create(StringValue.getDefaultInstance(), CommandContext.newBuilder() - .setSendingTime(add(getCurrentTime(), seconds(10))) - .build()); + public void when_command_sending_time_is_set_then_consider_it_scheduled() { + final Timestamp deliveryTime = add(getCurrentTime(), seconds(10)); + final Command cmd = Commands.create(StringValue.getDefaultInstance(), createCommandContext(deliveryTime)); assertTrue(Commands.isScheduled(cmd)); } @Test - public void when_command_is_not_scheduled_then_return_false() { + public void when_no_scheduling_options_then_consider_command_not_scheduled() { final Command cmd = Commands.create(StringValue.getDefaultInstance(), CommandContext.getDefaultInstance()); assertFalse(Commands.isScheduled(cmd)); } + @Test + public void when_command_is_in_time_then_consider_it_not_scheduled() { + final CommandContext context = createCommandContext(/*delay=*/seconds(10), /*in time=*/true); + final Command cmd = Commands.create(StringValue.getDefaultInstance(), context); + + assertFalse(Commands.isScheduled(cmd)); + } + @Test(expected = IllegalArgumentException.class) public void when_set_negative_delay_then_throw_exception() { - final Command cmd = Commands.create(StringValue.getDefaultInstance(), CommandContext.newBuilder() - .setDelay(seconds(-10)) - .build()); + final CommandContext context = createCommandContext(/*delay=*/seconds(-10)); + final Command cmd = Commands.create(StringValue.getDefaultInstance(), context); Commands.isScheduled(cmd); } @Test(expected = IllegalArgumentException.class) public void when_set_past_sending_time_then_throw_exception() { - final Command cmd = Commands.create(StringValue.getDefaultInstance(), CommandContext.newBuilder() - .setSendingTime(Timestamps.secondsAgo(10)) - .build()); + final CommandContext context = createCommandContext(/*delivery time=*/secondsAgo(10)); + final Command cmd = Commands.create(StringValue.getDefaultInstance(), context); Commands.isScheduled(cmd); } diff --git a/server/src/test/java/org/spine3/testdata/TestContextFactory.java b/client/src/test/java/org/spine3/testdata/TestContextFactory.java similarity index 73% rename from server/src/test/java/org/spine3/testdata/TestContextFactory.java rename to client/src/test/java/org/spine3/testdata/TestContextFactory.java index e16bf6b3ccc..bc48315f2af 100644 --- a/server/src/test/java/org/spine3/testdata/TestContextFactory.java +++ b/client/src/test/java/org/spine3/testdata/TestContextFactory.java @@ -21,6 +21,7 @@ package org.spine3.testdata; import com.google.protobuf.Any; +import com.google.protobuf.Duration; import com.google.protobuf.Message; import com.google.protobuf.Timestamp; import org.spine3.base.CommandContext; @@ -29,6 +30,7 @@ import org.spine3.base.EventContext; import org.spine3.base.EventId; import org.spine3.base.Events; +import org.spine3.base.Schedule; import org.spine3.base.UserId; import org.spine3.time.ZoneOffset; @@ -36,7 +38,7 @@ import static org.spine3.base.Identifiers.newUuid; import static org.spine3.client.UserUtil.newUserId; import static org.spine3.protobuf.Messages.toAny; -import static org.spine3.testdata.TestAggregateIdFactory.newProjectId; +import static org.spine3.protobuf.Values.newStringValue; /** @@ -47,7 +49,7 @@ @SuppressWarnings({"UtilityClass", "OverloadedMethodsWithSameNumberOfParameters"}) public class TestContextFactory { - private static final Any AGGREGATE_ID = toAny(newProjectId()); + private static final Any AGGREGATE_ID = toAny(newStringValue(newUuid())); private TestContextFactory() { } @@ -74,6 +76,47 @@ public static CommandContext createCommandContext(UserId userId, CommandId comma return builder.build(); } + /** + * Creates a new context with the given delay before the delivery time. + */ + public static CommandContext createCommandContext(Duration delay) { + final Schedule schedule = Schedule.newBuilder() + .setDelay(delay) + .build(); + return createCommandContext(schedule); + } + + /** + * Creates a new context with the given scheduling options. + */ + public static CommandContext createCommandContext(Duration delay, boolean isInTime) { + final Schedule schedule = Schedule.newBuilder() + .setDelay(delay) + .setInTime(isInTime) + .build(); + return createCommandContext(schedule); + } + + /** + * Creates a new context with the given delivery time. + */ + public static CommandContext createCommandContext(Timestamp deliveryTime) { + final Schedule schedule = Schedule.newBuilder() + .setDeliveryTime(deliveryTime) + .build(); + return createCommandContext(schedule); + } + + public static CommandContext createCommandContext(Schedule schedule) { + final CommandContext.Builder builder = TestContextFactory.createCommandContext().toBuilder() + .setSchedule(schedule); + return builder.build(); + } + + /* + * Event context factory methods. + */ + /** * Creates a new {@link EventContext} with default properties. */ diff --git a/examples/src/main/java/org/spine3/examples/aggregate/server/Application.java b/examples/src/main/java/org/spine3/examples/aggregate/server/Application.java index 4da11e27229..dc54f547380 100644 --- a/examples/src/main/java/org/spine3/examples/aggregate/server/Application.java +++ b/examples/src/main/java/org/spine3/examples/aggregate/server/Application.java @@ -28,6 +28,7 @@ import org.spine3.examples.aggregate.Client; import org.spine3.examples.aggregate.OrderId; import org.spine3.server.BoundedContext; +import org.spine3.server.EventHandler; import org.spine3.server.command.CommandBus; import org.spine3.server.command.CommandStore; import org.spine3.server.event.EventBus; @@ -53,7 +54,7 @@ public class Application implements AutoCloseable { private final StorageFactory storageFactory; private final BoundedContext boundedContext; - private final EventLogger eventLogger = new EventLogger(); + private final EventHandler eventLogger = new EventLogger(); /** * Creates a new sample with the specified storage factory. @@ -70,7 +71,11 @@ public Application(StorageFactory storageFactory) { } private static CommandBus createCommandBus() { - return CommandBus.create(new CommandStore(InMemoryStorageFactory.getInstance().createCommandStorage())); + final CommandStore store = new CommandStore(InMemoryStorageFactory.getInstance().createCommandStorage()); + final CommandBus commandBus = CommandBus.newBuilder() + .setCommandStore(store) + .build(); + return commandBus; } private static EventBus createEventBus(StorageFactory storageFactory) { @@ -79,7 +84,6 @@ private static EventBus createEventBus(StorageFactory storageFactory) { .setStorage(storageFactory.createEventStorage()) .setLogger(EventStore.log()) .build(); - return EventBus.newInstance(eventStore); } diff --git a/server/src/main/java/org/spine3/server/command/CommandBus.java b/server/src/main/java/org/spine3/server/command/CommandBus.java index 9b5b45bb612..b980f86c67d 100644 --- a/server/src/main/java/org/spine3/server/command/CommandBus.java +++ b/server/src/main/java/org/spine3/server/command/CommandBus.java @@ -39,7 +39,7 @@ import org.spine3.type.CommandClass; import org.spine3.validation.options.ConstraintViolation; -import javax.annotation.CheckReturnValue; +import javax.annotation.Nullable; import java.lang.reflect.InvocationTargetException; import java.util.List; @@ -55,6 +55,7 @@ * * @author Alexander Yevsyukov * @author Mikhail Melnik + * @author Alexander Litus */ public class CommandBus implements AutoCloseable { @@ -63,20 +64,23 @@ public class CommandBus implements AutoCloseable { private final CommandStore commandStore; + @Nullable + private final CommandScheduler scheduler; + private final CommandStatusHelper commandStatus; private ProblemLog problemLog = new ProblemLog(); - private CommandScheduler scheduler; - @CheckReturnValue - public static CommandBus create(CommandStore store) { - final CommandBus commandBus = new CommandBus(checkNotNull(store)); - commandBus.setScheduler(new DefaultCommandScheduler(commandBus)); - return commandBus; + private CommandBus(Builder builder) { + this.commandStore = builder.getCommandStore(); + this.scheduler = builder.getScheduler(); + this.commandStatus = new CommandStatusHelper(commandStore); } - protected CommandBus(CommandStore commandStore) { - this.commandStore = commandStore; - this.commandStatus = new CommandStatusHelper(commandStore); + /** + * Creates a new builder for command bus. + */ + public static Builder newBuilder() { + return new Builder(); } /** @@ -122,13 +126,6 @@ public void unregister(CommandHandler handler) { handlerRegistry.unregister(handler); } - /** - * Sets a command scheduler. - */ - public void setScheduler(CommandScheduler scheduler) { - this.scheduler = scheduler; - } - /** * Verifies if the command can be posted to this {@code CommandBus}. * @@ -173,11 +170,11 @@ private boolean isUnsupportedCommand(CommandClass commandClass) { public List post(Command command) { //TODO:2016-01-24:alexander.yevsyukov: Do not return value. checkNotDefault(command); - store(command); if (isScheduled(command)) { - scheduler.schedule(command); + schedule(command); return emptyList(); } + store(command); final CommandClass commandClass = CommandClass.of(command); if (isDispatcherRegistered(commandClass)) { return dispatch(command); @@ -230,6 +227,15 @@ private List invokeHandler(Message msg, CommandContext context) { return result; } + private void schedule(Command command) { + if (scheduler != null) { + scheduler.schedule(command); + } else { + throw new IllegalStateException( + "Scheduled commands are not supported by this command bus (scheduler is not set)."); + } + } + /** * Convenience wrapper for logging errors and warnings. */ @@ -318,7 +324,9 @@ public void close() throws Exception { dispatcherRegistry.unregisterAll(); handlerRegistry.unregisterAll(); commandStore.close(); - scheduler.shutdown(); + if (scheduler != null) { + scheduler.shutdown(); + } } private enum LogSingleton { @@ -334,4 +342,37 @@ private enum LogSingleton { /* package */ static Logger log() { return LogSingleton.INSTANCE.value; } + + /** + * Constructs a command bus. + */ + public static class Builder { + + private CommandStore commandStore; + private CommandScheduler scheduler; + + public CommandBus build() { + checkNotNull(commandStore, "Command store must be set."); + final CommandBus commandBus = new CommandBus(this); + return commandBus; + } + + public Builder setCommandStore(CommandStore commandStore) { + this.commandStore = commandStore; + return this; + } + + public CommandStore getCommandStore() { + return commandStore; + } + + public Builder setScheduler(CommandScheduler scheduler) { + this.scheduler = scheduler; + return this; + } + + public CommandScheduler getScheduler() { + return scheduler; + } + } } diff --git a/server/src/main/java/org/spine3/server/command/CommandScheduler.java b/server/src/main/java/org/spine3/server/command/CommandScheduler.java index 3003ef96089..2dd74163fa6 100644 --- a/server/src/main/java/org/spine3/server/command/CommandScheduler.java +++ b/server/src/main/java/org/spine3/server/command/CommandScheduler.java @@ -20,28 +20,77 @@ package org.spine3.server.command; +import com.google.common.annotations.VisibleForTesting; import org.spine3.base.Command; +import org.spine3.base.CommandContext; +import org.spine3.base.Schedule; + +import static com.google.common.base.Preconditions.checkState; /** - * Schedules commands sending them after the given delay (or at the given time). + * Schedules commands delivering them to the target according to the scheduling options. * * @author Alexander Litus */ -public interface CommandScheduler { +public abstract class CommandScheduler { + + private final CommandBus commandBus; + + private boolean isActive = true; + + /** + * Creates a new instance. + * + * @param commandBus a command bus used to send scheduled commands + */ + protected CommandScheduler(CommandBus commandBus) { + this.commandBus = commandBus; + } /** - * Schedule a command and send it after the given delay (or at the given time). + * Schedule a command and deliver it to the target according to the scheduling options. * - * @param command a command to send later + * @param command a command to deliver later * @throws IllegalStateException if the scheduler is shut down + * @see #post(Command) */ - void schedule(Command command); + public void schedule(Command command) { + checkState(isActive, "Scheduler is shut down."); + } /** - * Initiates an orderly shutdown in which previously scheduled commands will be sent later, + * Initiates an orderly shutdown in which previously scheduled commands will be delivered later, * but no new commands will be accepted. * *

Invocation has no effect if the scheduler is already shut down. */ - void shutdown(); + public void shutdown() { + isActive = false; + } + + /** + * Delivers a scheduled command to a target. + * + * @param command a command to deliver + */ + protected void post(Command command) { + final Command commandUpdated = setIsInTime(command); + commandBus.post(commandUpdated); + } + + @VisibleForTesting + /* package */ static Command setIsInTime(Command command) { + final CommandContext contextPrimary = command.getContext(); + final Schedule scheduleUpdated = contextPrimary.getSchedule() + .toBuilder() + .setInTime(true) + .build(); + final CommandContext contextUpdated = contextPrimary.toBuilder() + .setSchedule(scheduleUpdated) + .build(); + final Command cmdUpdated = command.toBuilder() + .setContext(contextUpdated) + .build(); + return cmdUpdated; + } } diff --git a/server/src/main/java/org/spine3/server/command/DefaultCommandScheduler.java b/server/src/main/java/org/spine3/server/command/ExecutorCommandScheduler.java similarity index 64% rename from server/src/main/java/org/spine3/server/command/DefaultCommandScheduler.java rename to server/src/main/java/org/spine3/server/command/ExecutorCommandScheduler.java index 6e227c95e71..a38ae0768cf 100644 --- a/server/src/main/java/org/spine3/server/command/DefaultCommandScheduler.java +++ b/server/src/main/java/org/spine3/server/command/ExecutorCommandScheduler.java @@ -23,81 +23,68 @@ import com.google.protobuf.Duration; import com.google.protobuf.Timestamp; import org.spine3.base.Command; -import org.spine3.base.CommandContext; +import org.spine3.base.Schedule; import java.util.concurrent.Executors; import java.util.concurrent.ScheduledExecutorService; -import static com.google.common.base.Preconditions.checkState; import static com.google.protobuf.util.TimeUtil.getCurrentTime; import static java.util.concurrent.TimeUnit.SECONDS; import static org.spine3.validate.Validate.isNotDefault; /** - * The default command scheduler implementation. + * The command scheduler implementation which uses basic Java task scheduling features. * + *

NOTE: please use another implementation + * in applications running under the Google App Engine. + * + * @see ScheduledExecutorService * @author Alexander Litus */ -public class DefaultCommandScheduler implements CommandScheduler { +public class ExecutorCommandScheduler extends CommandScheduler { private static final int MIN_THEAD_POOL_SIZE = 5; private final ScheduledExecutorService executorService = Executors.newScheduledThreadPool(MIN_THEAD_POOL_SIZE); - private boolean isShutdown = false; - - private final CommandBus commandBus; - /** * Creates a new instance. * * @param commandBus a command bus used to send scheduled commands */ - public DefaultCommandScheduler(CommandBus commandBus) { - this.commandBus = commandBus; + public ExecutorCommandScheduler(CommandBus commandBus) { + super(commandBus); } @Override - public void schedule(Command command) { - checkState(!isShutdown, "Scheduler is shut down."); + public void schedule(final Command command) { + super.schedule(command); final long delaySec = getDelaySeconds(command); - final Command commandUpdated = removeSchedulingOptions(command); executorService.schedule(new Runnable() { @Override public void run() { - commandBus.post(commandUpdated); + post(command); } }, delaySec, SECONDS); } private static long getDelaySeconds(Command command) { - final CommandContext context = command.getContext(); + final Schedule schedule = command.getContext().getSchedule(); final long delaySec; - final Duration delay = context.getDelay(); + final Duration delay = schedule.getDelay(); if (isNotDefault(delay)) { delaySec = delay.getSeconds(); } else { - final Timestamp sendingTime = context.getSendingTime(); + final Timestamp deliveryTime = schedule.getDeliveryTime(); final Timestamp now = getCurrentTime(); - delaySec = sendingTime.getSeconds() - now.getSeconds(); + delaySec = deliveryTime.getSeconds() - now.getSeconds(); } return delaySec; } - private static Command removeSchedulingOptions(Command command) { - final CommandContext contextUpdated = command.getContext().toBuilder() - .clearDelay() - .clearSendingTime() - .build(); - final Command result = command.toBuilder() - .setContext(contextUpdated) - .build(); - return result; - } - @Override public void shutdown() { + super.shutdown(); executorService.shutdown(); - isShutdown = true; } } diff --git a/server/src/test/java/org/spine3/server/BoundedContextBuilderShould.java b/server/src/test/java/org/spine3/server/BoundedContextBuilderShould.java index 8ca78e80a7e..173412cbd5e 100644 --- a/server/src/test/java/org/spine3/server/BoundedContextBuilderShould.java +++ b/server/src/test/java/org/spine3/server/BoundedContextBuilderShould.java @@ -25,13 +25,13 @@ import org.junit.Before; import org.junit.Test; import org.spine3.server.command.CommandBus; -import org.spine3.server.command.CommandStore; import org.spine3.server.event.EventBus; import org.spine3.server.event.EventStore; import org.spine3.server.storage.StorageFactory; import org.spine3.server.storage.memory.InMemoryStorageFactory; import static org.junit.Assert.*; +import static org.spine3.testdata.TestCommands.newCommandBus; @SuppressWarnings("InstanceMethodNamingConvention") public class BoundedContextBuilderShould { @@ -48,17 +48,6 @@ public void tearDown() throws Exception { storageFactory.close(); } - private static CommandBus newCommandDispatcher(StorageFactory storageFactory) { - return CommandBus.create(new CommandStore(storageFactory.createCommandStorage())); - } - - private static EventBus newEventBus(StorageFactory storageFactory) { - return EventBus.newInstance(EventStore.newBuilder() - .setStreamExecutor(MoreExecutors.directExecutor()) - .setStorage(storageFactory.createEventStorage()) - .build()); - } - @Test(expected = NullPointerException.class) public void do_not_accept_null_StorageFactory() { //noinspection ConstantConditions @@ -80,7 +69,7 @@ public void do_not_accept_null_CommandDispatcher() { @Test public void return_CommandDispatcher_from_builder() { - final CommandBus expected = newCommandDispatcher(storageFactory); + final CommandBus expected = newCommandBus(storageFactory); final BoundedContext.Builder builder = BoundedContext.newBuilder().setCommandBus(expected); assertEquals(expected, builder.getCommandBus()); } @@ -101,7 +90,8 @@ public void return_if_multitenant_from_builder() { @Test public void be_not_multitenant_by_default() { - assertFalse(BoundedContext.newBuilder().isMultitenant()); + assertFalse(BoundedContext.newBuilder() + .isMultitenant()); } @Test(expected = NullPointerException.class) @@ -109,4 +99,11 @@ public void do_not_accept_null_EventBus() { //noinspection ConstantConditions BoundedContext.newBuilder().setEventBus(null); } + + private static EventBus newEventBus(StorageFactory storageFactory) { + return EventBus.newInstance(EventStore.newBuilder() + .setStreamExecutor(MoreExecutors.directExecutor()) + .setStorage(storageFactory.createEventStorage()) + .build()); + } } diff --git a/server/src/test/java/org/spine3/server/BoundedContextShould.java b/server/src/test/java/org/spine3/server/BoundedContextShould.java index 1c2f382d7df..390458b1fea 100644 --- a/server/src/test/java/org/spine3/server/BoundedContextShould.java +++ b/server/src/test/java/org/spine3/server/BoundedContextShould.java @@ -41,8 +41,6 @@ import org.spine3.server.aggregate.Aggregate; import org.spine3.server.aggregate.AggregateRepository; import org.spine3.server.aggregate.Apply; -import org.spine3.server.command.CommandBus; -import org.spine3.server.command.CommandStore; import org.spine3.server.entity.IdFunction; import org.spine3.server.error.UnsupportedCommandException; import org.spine3.server.event.EventBus; @@ -108,10 +106,6 @@ private static EventBus newEventBus(StorageFactory storageFactory) { .build()); } - private static CommandBus newCommandBus(StorageFactory storageFactory) { - return CommandBus.create(new CommandStore(storageFactory.createCommandStorage())); - } - @After public void tearDown() throws Exception { if (handlersRegistered) { diff --git a/server/src/test/java/org/spine3/server/BoundedContextTestStubs.java b/server/src/test/java/org/spine3/server/BoundedContextTestStubs.java index 28a7b9971cc..37a4ed47157 100644 --- a/server/src/test/java/org/spine3/server/BoundedContextTestStubs.java +++ b/server/src/test/java/org/spine3/server/BoundedContextTestStubs.java @@ -22,12 +22,13 @@ import com.google.common.util.concurrent.MoreExecutors; import org.spine3.server.command.CommandBus; -import org.spine3.server.command.CommandStore; import org.spine3.server.event.EventBus; import org.spine3.server.event.EventStore; import org.spine3.server.storage.StorageFactory; import org.spine3.server.storage.memory.InMemoryStorageFactory; +import static org.spine3.testdata.TestCommands.newCommandBus; + /** * Creates stubs with instances of {@link BoundedContext} for testing purposes. * @@ -41,21 +42,17 @@ public static BoundedContext create() { } public static BoundedContext create(StorageFactory storageFactory) { - final CommandBus commandBus = CommandBus.create( - new CommandStore(storageFactory.createCommandStorage())); - + final CommandBus commandBus = newCommandBus(storageFactory); final EventBus eventBus = EventBus.newInstance(EventStore.newBuilder() - .setStreamExecutor(MoreExecutors.directExecutor()) - .setStorage(storageFactory.createEventStorage()) - .build()); - - return BoundedContext.newBuilder() + .setStreamExecutor(MoreExecutors.directExecutor()) + .setStorage(storageFactory.createEventStorage()) + .build()); + final BoundedContext.Builder builder = BoundedContext.newBuilder() .setStorageFactory(storageFactory) .setCommandBus(commandBus) - .setEventBus(eventBus) - .build(); + .setEventBus(eventBus); + return builder.build(); } - private BoundedContextTestStubs() { - } + private BoundedContextTestStubs() {} } diff --git a/server/src/test/java/org/spine3/server/command/CommandBusShould.java b/server/src/test/java/org/spine3/server/command/CommandBusShould.java index 3592d8b32b2..83e936a9299 100644 --- a/server/src/test/java/org/spine3/server/command/CommandBusShould.java +++ b/server/src/test/java/org/spine3/server/command/CommandBusShould.java @@ -20,6 +20,7 @@ package org.spine3.server.command; +import com.google.protobuf.Duration; import com.google.protobuf.Message; import org.junit.Before; import org.junit.Test; @@ -57,6 +58,7 @@ import static org.spine3.protobuf.Durations.minutes; import static org.spine3.server.command.CommandValidation.isUnsupportedCommand; import static org.spine3.testdata.TestCommands.*; +import static org.spine3.testdata.TestContextFactory.createCommandContext; @SuppressWarnings({"InstanceMethodNamingConvention", "ClassWithTooManyMethods"}) public class CommandBusShould { @@ -64,15 +66,17 @@ public class CommandBusShould { private CommandBus commandBus; private CommandStore commandStore; private CommandFactory commandFactory; - private DefaultCommandScheduler scheduler; + private ExecutorCommandScheduler scheduler; private CommandBus.ProblemLog log; @Before public void setUp() { commandStore = mock(CommandStore.class); - commandBus = CommandBus.create(commandStore); - scheduler = mock(DefaultCommandScheduler.class); - commandBus.setScheduler(scheduler); + scheduler = mock(ExecutorCommandScheduler.class); + commandBus = CommandBus.newBuilder() + .setCommandStore(commandStore) + .setScheduler(scheduler) + .build(); log = mock(CommandBus.ProblemLog.class); commandBus.setProblemLog(log); commandFactory = TestCommandFactory.newInstance(CommandBusShould.class); @@ -81,7 +85,9 @@ public void setUp() { @Test(expected = NullPointerException.class) public void do_not_accept_null_CommandStore_on_construction() { //noinspection ConstantConditions,ResultOfMethodCallIgnored - CommandBus.create(null); + CommandBus.newBuilder() + .setCommandStore(null) + .build(); } // @@ -441,9 +447,7 @@ private E givenThrowingDispatcher() throws Exception { @Test public void schedule_command_if_delay_is_set() { - final Command cmd = Commands.create(createProject(newUuid()), CommandContext.newBuilder() - .setDelay(minutes(1)) - .build()); + final Command cmd = newCommand(/*delay=*/minutes(1)); commandBus.post(cmd); @@ -452,9 +456,8 @@ public void schedule_command_if_delay_is_set() { @Test public void schedule_command_if_sending_time_is_set() { - final Command cmd = Commands.create(createProject(newUuid()), CommandContext.newBuilder() - .setSendingTime(add(getCurrentTime(), minutes(1))) - .build()); + final CommandContext context = createCommandContext(/*delivery time=*/add(getCurrentTime(), minutes(1))); + final Command cmd = Commands.create(createProject(newUuid()), context); commandBus.post(cmd); @@ -468,7 +471,31 @@ public void do_not_schedule_command_if_no_scheduling_options_are_set() { commandBus.post(cmd); - verify(scheduler, times(0)).schedule(cmd); + verify(scheduler, never()).schedule(cmd); + } + + @Test + public void do_not_store_command_if_command_is_scheduled() { + final Command cmd = newCommand(/*delay=*/minutes(1)); + + commandBus.post(cmd); + + verify(commandStore, never()).store(cmd); + } + + @Test(expected = IllegalStateException.class) + public void throw_exception_if_post_scheduled_cmd_and_no_scheduler_is_set() { + final CommandBus commandBus = CommandBus.newBuilder() + .setCommandStore(commandStore) + .build(); + final Command cmd = newCommand(/*delay=*/minutes(1)); + + commandBus.post(cmd); + } + + private static Command newCommand(Duration delay) { + final CommandContext context = createCommandContext(delay); + return Commands.create(createProject(newUuid()), context); } private static class TestFailure extends FailureThrowable { diff --git a/server/src/test/java/org/spine3/server/command/DefaultCommandSchedulerShould.java b/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java similarity index 64% rename from server/src/test/java/org/spine3/server/command/DefaultCommandSchedulerShould.java rename to server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java index 28229f2a89e..e0caa79b580 100644 --- a/server/src/test/java/org/spine3/server/command/DefaultCommandSchedulerShould.java +++ b/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java @@ -27,21 +27,23 @@ import org.spine3.base.Command; import org.spine3.base.CommandContext; import org.spine3.base.Commands; -import org.spine3.test.project.command.CreateProject; import static com.google.protobuf.util.TimeUtil.add; import static com.google.protobuf.util.TimeUtil.getCurrentTime; +import static org.junit.Assert.assertFalse; +import static org.junit.Assert.assertTrue; import static org.junit.Assert.fail; import static org.mockito.Mockito.*; import static org.spine3.base.Identifiers.newUuid; import static org.spine3.protobuf.Durations.seconds; import static org.spine3.testdata.TestCommands.createProject; +import static org.spine3.testdata.TestContextFactory.createCommandContext; /** * @author Alexander Litus */ @SuppressWarnings("InstanceMethodNamingConvention") -public class DefaultCommandSchedulerShould { +public class ExecutorCommandSchedulerShould { private static final Duration DELAY = seconds(1); private static final int CHECK_OFFSET_MS = 50; @@ -52,7 +54,7 @@ public class DefaultCommandSchedulerShould { @Before public void setUpTest() { this.commandBus = mock(CommandBus.class); - this.scheduler = new DefaultCommandScheduler(commandBus); + this.scheduler = new ExecutorCommandScheduler(commandBus); } @After @@ -62,36 +64,45 @@ public void tearDownTest() { @Test public void schedule_command_if_delay_is_set() throws InterruptedException { - final CreateProject msg = createProject(newUuid()); - final Command cmdPrimary = Commands.create(msg, CommandContext.newBuilder() - .setDelay(DELAY) - .build()); - final Command cmdExpected = Commands.create(msg, CommandContext.getDefaultInstance()); + final CommandContext context = createCommandContext(DELAY); + final Command cmd = Commands.create(createProject(newUuid()), context); - scheduler.schedule(cmdPrimary); + scheduler.schedule(cmd); - assertCommandSent(cmdExpected, DELAY); + assertCommandSent(cmd, DELAY); } @Test public void schedule_command_if_sending_time_is_set() throws InterruptedException { - final CreateProject msg = createProject(newUuid()); - final Command cmdPrimary = Commands.create(msg, CommandContext.newBuilder() - .setSendingTime(add(getCurrentTime(), DELAY)) - .build()); - final Command cmdExpected = Commands.create(msg, CommandContext.getDefaultInstance()); + final CommandContext context = createCommandContext(/*delivery time=*/add(getCurrentTime(), DELAY)); + final Command cmd = Commands.create(createProject(newUuid()), context); - scheduler.schedule(cmdPrimary); + scheduler.schedule(cmd); - assertCommandSent(cmdExpected, DELAY); + assertCommandSent(cmd, DELAY); + } + + @Test + public void set_command_is_in_time() { + final Command cmd = createProject(); + assertFalse(cmd.getContext() + .getSchedule() + .getInTime()); + + final Command updatedCmd = CommandScheduler.setIsInTime(cmd); + assertTrue(updatedCmd.getContext() + .getSchedule() + .getInTime()); } private void assertCommandSent(Command cmd, Duration delay) throws InterruptedException { - verify(commandBus, never()).post(any(Command.class)); + verify(commandBus, times(0)).post(any(Command.class)); - Thread.sleep((delay.getSeconds() * 1000) + CHECK_OFFSET_MS); + final long delayMs = delay.getSeconds() * 1000; + Thread.sleep(delayMs + CHECK_OFFSET_MS); - verify(commandBus, times(1)).post(cmd); + final Command updatedCmd = CommandScheduler.setIsInTime(cmd); + verify(commandBus, times(1)).post(updatedCmd); } @Test diff --git a/server/src/test/java/org/spine3/testdata/TestCommands.java b/server/src/test/java/org/spine3/testdata/TestCommands.java index 3380aa76067..dcfaba22832 100644 --- a/server/src/test/java/org/spine3/testdata/TestCommands.java +++ b/server/src/test/java/org/spine3/testdata/TestCommands.java @@ -28,6 +28,9 @@ import org.spine3.base.CommandId; import org.spine3.base.Commands; import org.spine3.base.UserId; +import org.spine3.server.command.CommandBus; +import org.spine3.server.command.CommandStore; +import org.spine3.server.storage.StorageFactory; import org.spine3.test.project.ProjectId; import org.spine3.test.project.command.AddTask; import org.spine3.test.project.command.CreateProject; @@ -112,8 +115,8 @@ public static CreateProject createProject(String projectId) { return CreateProject.newBuilder() .setProjectId( ProjectId.newBuilder() - .setId(projectId) - .build()) + .setId(projectId) + .build()) .build(); } @@ -148,8 +151,19 @@ public static StartProject startProject(ProjectId id) { public static StartProject startProject(String projectId) { return StartProject.newBuilder() .setProjectId(ProjectId.newBuilder() - .setId(projectId) - .build()) + .setId(projectId) + .build()) + .build(); + } + + /** + * Creates a new command bus. + */ + public static CommandBus newCommandBus(StorageFactory storageFactory) { + final CommandStore store = new CommandStore(storageFactory.createCommandStorage()); + final CommandBus commandBus = CommandBus.newBuilder() + .setCommandStore(store) .build(); + return commandBus; } } From 35984074ff449ab97c01cce1a6f6d0ed9ba23d99 Mon Sep 17 00:00:00 2001 From: Alexander Litus Date: Mon, 18 Apr 2016 11:51:21 +0300 Subject: [PATCH 08/26] Remove `delivery_time` field in command Schedule options, rename other fields. --- .../main/java/org/spine3/base/Commands.java | 17 +++--------- .../src/main/proto/spine/base/command.proto | 15 ++++------- .../java/org/spine3/base/CommandsShould.java | 19 -------------- .../spine3/testdata/TestContextFactory.java | 18 +++---------- .../server/command/CommandScheduler.java | 12 ++++++--- .../command/ExecutorCommandScheduler.java | 14 +--------- .../server/command/CommandBusShould.java | 10 ------- .../ExecutorCommandSchedulerShould.java | 26 +++++-------------- 8 files changed, 28 insertions(+), 103 deletions(-) diff --git a/client/src/main/java/org/spine3/base/Commands.java b/client/src/main/java/org/spine3/base/Commands.java index ca78ec9f9d4..fac0493944b 100644 --- a/client/src/main/java/org/spine3/base/Commands.java +++ b/client/src/main/java/org/spine3/base/Commands.java @@ -21,8 +21,8 @@ package org.spine3.base; import com.google.common.base.Predicate; -import com.google.protobuf.Duration; import com.google.protobuf.Descriptors.FileDescriptor; +import com.google.protobuf.Duration; import com.google.protobuf.Message; import com.google.protobuf.Timestamp; import org.spine3.protobuf.EntityPackagesMap; @@ -40,7 +40,6 @@ import static com.google.common.base.Preconditions.checkArgument; import static com.google.common.base.Preconditions.checkNotNull; import static com.google.protobuf.util.TimeUtil.getCurrentTime; -import static org.spine3.protobuf.Timestamps.isAfter; import static org.spine3.validate.Validate.isNotDefault; /** @@ -228,24 +227,14 @@ public static boolean isEntityFile(FileDescriptor file) { */ public static boolean isScheduled(Command command) { final Schedule schedule = command.getContext().getSchedule(); - if (schedule.getInTime()) { + if (schedule.getIgnoreDelay()) { return false; } - final Duration delay = schedule.getDelay(); + final Duration delay = schedule.getAfter(); if (isNotDefault(delay)) { checkArgument(delay.getSeconds() > 0, "Command delay seconds must be a positive value."); return true; } - final Timestamp deliveryTime = schedule.getDeliveryTime(); - if (isNotDefault(deliveryTime)) { - checkIsAfterNow(deliveryTime); - return true; - } return false; } - - private static void checkIsAfterNow(Timestamp deliveryTime) { - final Timestamp now = getCurrentTime(); - checkArgument(isAfter(deliveryTime, /*than*/ now), "Delivery time must be after the current time."); - } } diff --git a/client/src/main/proto/spine/base/command.proto b/client/src/main/proto/spine/base/command.proto index 45bb5757a55..3c785dcb9a0 100644 --- a/client/src/main/proto/spine/base/command.proto +++ b/client/src/main/proto/spine/base/command.proto @@ -84,18 +84,13 @@ message CommandContext { } message Schedule { - oneof options { - // The amount of time between the current moment and a command delivering to the target. - google.protobuf.Duration delay = 1; + // The delay between the moment of receiving a command at the server and its delivery to the target. + google.protobuf.Duration after = 1; - // The time when the command should be delivered to the target. - google.protobuf.Timestamp delivery_time = 2; - } - - // `true` if the command should be delivered to the target right now, despite the scheduling options set; + // `true` if the command should be delivered to the target right now, despite the delay set; // `false` otherwise. - // This flag is needed to specify that a scheduled command arrived in time, and to retain the scheduling options. - bool in_time = 3; + // This flag is needed to specify that the delay is passed, and to retain the info about the delay. + bool ignore_delay = 2; } // Enumeration of possible failures when validating a command. diff --git a/client/src/test/java/org/spine3/base/CommandsShould.java b/client/src/test/java/org/spine3/base/CommandsShould.java index 55e6672cc64..87e9b097875 100644 --- a/client/src/test/java/org/spine3/base/CommandsShould.java +++ b/client/src/test/java/org/spine3/base/CommandsShould.java @@ -27,7 +27,6 @@ import com.google.protobuf.Int64Value; import com.google.protobuf.Message; import com.google.protobuf.StringValue; -import com.google.protobuf.Timestamp; import org.junit.Test; import org.spine3.client.test.TestCommandFactory; import org.spine3.test.RunTest; @@ -39,8 +38,6 @@ import java.util.List; import static com.google.protobuf.Descriptors.FileDescriptor; -import static com.google.protobuf.util.TimeUtil.add; -import static com.google.protobuf.util.TimeUtil.getCurrentTime; import static org.junit.Assert.*; import static org.spine3.protobuf.Durations.seconds; import static org.spine3.protobuf.Timestamps.minutesAgo; @@ -160,14 +157,6 @@ public void when_command_delay_is_set_then_consider_it_scheduled() { assertTrue(Commands.isScheduled(cmd)); } - @Test - public void when_command_sending_time_is_set_then_consider_it_scheduled() { - final Timestamp deliveryTime = add(getCurrentTime(), seconds(10)); - final Command cmd = Commands.create(StringValue.getDefaultInstance(), createCommandContext(deliveryTime)); - - assertTrue(Commands.isScheduled(cmd)); - } - @Test public void when_no_scheduling_options_then_consider_command_not_scheduled() { final Command cmd = Commands.create(StringValue.getDefaultInstance(), CommandContext.getDefaultInstance()); @@ -190,12 +179,4 @@ public void when_set_negative_delay_then_throw_exception() { Commands.isScheduled(cmd); } - - @Test(expected = IllegalArgumentException.class) - public void when_set_past_sending_time_then_throw_exception() { - final CommandContext context = createCommandContext(/*delivery time=*/secondsAgo(10)); - final Command cmd = Commands.create(StringValue.getDefaultInstance(), context); - - Commands.isScheduled(cmd); - } } diff --git a/client/src/test/java/org/spine3/testdata/TestContextFactory.java b/client/src/test/java/org/spine3/testdata/TestContextFactory.java index bc48315f2af..3fe63a99d76 100644 --- a/client/src/test/java/org/spine3/testdata/TestContextFactory.java +++ b/client/src/test/java/org/spine3/testdata/TestContextFactory.java @@ -81,7 +81,7 @@ public static CommandContext createCommandContext(UserId userId, CommandId comma */ public static CommandContext createCommandContext(Duration delay) { final Schedule schedule = Schedule.newBuilder() - .setDelay(delay) + .setAfter(delay) .build(); return createCommandContext(schedule); } @@ -89,20 +89,10 @@ public static CommandContext createCommandContext(Duration delay) { /** * Creates a new context with the given scheduling options. */ - public static CommandContext createCommandContext(Duration delay, boolean isInTime) { + public static CommandContext createCommandContext(Duration delay, boolean ignoreDelay) { final Schedule schedule = Schedule.newBuilder() - .setDelay(delay) - .setInTime(isInTime) - .build(); - return createCommandContext(schedule); - } - - /** - * Creates a new context with the given delivery time. - */ - public static CommandContext createCommandContext(Timestamp deliveryTime) { - final Schedule schedule = Schedule.newBuilder() - .setDeliveryTime(deliveryTime) + .setAfter(delay) + .setIgnoreDelay(ignoreDelay) .build(); return createCommandContext(schedule); } diff --git a/server/src/main/java/org/spine3/server/command/CommandScheduler.java b/server/src/main/java/org/spine3/server/command/CommandScheduler.java index 2dd74163fa6..681da86ca62 100644 --- a/server/src/main/java/org/spine3/server/command/CommandScheduler.java +++ b/server/src/main/java/org/spine3/server/command/CommandScheduler.java @@ -74,16 +74,22 @@ public void shutdown() { * @param command a command to deliver */ protected void post(Command command) { - final Command commandUpdated = setIsInTime(command); + final Command commandUpdated = setIgnoreDelay(command); commandBus.post(commandUpdated); } + /** + * Sets {@code ignoreDelay} option to true in {@link Schedule} command option. + * + * @param command the command to update + * @return the updated command + */ @VisibleForTesting - /* package */ static Command setIsInTime(Command command) { + /* package */ static Command setIgnoreDelay(Command command) { final CommandContext contextPrimary = command.getContext(); final Schedule scheduleUpdated = contextPrimary.getSchedule() .toBuilder() - .setInTime(true) + .setIgnoreDelay(true) .build(); final CommandContext contextUpdated = contextPrimary.toBuilder() .setSchedule(scheduleUpdated) diff --git a/server/src/main/java/org/spine3/server/command/ExecutorCommandScheduler.java b/server/src/main/java/org/spine3/server/command/ExecutorCommandScheduler.java index a38ae0768cf..59c249c5e6c 100644 --- a/server/src/main/java/org/spine3/server/command/ExecutorCommandScheduler.java +++ b/server/src/main/java/org/spine3/server/command/ExecutorCommandScheduler.java @@ -20,17 +20,13 @@ package org.spine3.server.command; -import com.google.protobuf.Duration; -import com.google.protobuf.Timestamp; import org.spine3.base.Command; import org.spine3.base.Schedule; import java.util.concurrent.Executors; import java.util.concurrent.ScheduledExecutorService; -import static com.google.protobuf.util.TimeUtil.getCurrentTime; import static java.util.concurrent.TimeUnit.SECONDS; -import static org.spine3.validate.Validate.isNotDefault; /** * The command scheduler implementation which uses basic Java task scheduling features. @@ -70,15 +66,7 @@ public void run() { private static long getDelaySeconds(Command command) { final Schedule schedule = command.getContext().getSchedule(); - final long delaySec; - final Duration delay = schedule.getDelay(); - if (isNotDefault(delay)) { - delaySec = delay.getSeconds(); - } else { - final Timestamp deliveryTime = schedule.getDeliveryTime(); - final Timestamp now = getCurrentTime(); - delaySec = deliveryTime.getSeconds() - now.getSeconds(); - } + final long delaySec = schedule.getAfter().getSeconds(); return delaySec; } diff --git a/server/src/test/java/org/spine3/server/command/CommandBusShould.java b/server/src/test/java/org/spine3/server/command/CommandBusShould.java index 83e936a9299..ff7a75449d8 100644 --- a/server/src/test/java/org/spine3/server/command/CommandBusShould.java +++ b/server/src/test/java/org/spine3/server/command/CommandBusShould.java @@ -454,16 +454,6 @@ public void schedule_command_if_delay_is_set() { verify(scheduler, times(1)).schedule(cmd); } - @Test - public void schedule_command_if_sending_time_is_set() { - final CommandContext context = createCommandContext(/*delivery time=*/add(getCurrentTime(), minutes(1))); - final Command cmd = Commands.create(createProject(newUuid()), context); - - commandBus.post(cmd); - - verify(scheduler, times(1)).schedule(cmd); - } - @Test public void do_not_schedule_command_if_no_scheduling_options_are_set() { commandBus.register(new CreateProjectHandler()); diff --git a/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java b/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java index e0caa79b580..742b9bedad0 100644 --- a/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java +++ b/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java @@ -28,11 +28,7 @@ import org.spine3.base.CommandContext; import org.spine3.base.Commands; -import static com.google.protobuf.util.TimeUtil.add; -import static com.google.protobuf.util.TimeUtil.getCurrentTime; -import static org.junit.Assert.assertFalse; -import static org.junit.Assert.assertTrue; -import static org.junit.Assert.fail; +import static org.junit.Assert.*; import static org.mockito.Mockito.*; import static org.spine3.base.Identifiers.newUuid; import static org.spine3.protobuf.Durations.seconds; @@ -73,26 +69,16 @@ public void schedule_command_if_delay_is_set() throws InterruptedException { } @Test - public void schedule_command_if_sending_time_is_set() throws InterruptedException { - final CommandContext context = createCommandContext(/*delivery time=*/add(getCurrentTime(), DELAY)); - final Command cmd = Commands.create(createProject(newUuid()), context); - - scheduler.schedule(cmd); - - assertCommandSent(cmd, DELAY); - } - - @Test - public void set_command_is_in_time() { + public void set_ignore_command_delay_to_true() { final Command cmd = createProject(); assertFalse(cmd.getContext() .getSchedule() - .getInTime()); + .getIgnoreDelay()); - final Command updatedCmd = CommandScheduler.setIsInTime(cmd); + final Command updatedCmd = CommandScheduler.setIgnoreDelay(cmd); assertTrue(updatedCmd.getContext() .getSchedule() - .getInTime()); + .getIgnoreDelay()); } private void assertCommandSent(Command cmd, Duration delay) throws InterruptedException { @@ -101,7 +87,7 @@ private void assertCommandSent(Command cmd, Duration delay) throws InterruptedEx final long delayMs = delay.getSeconds() * 1000; Thread.sleep(delayMs + CHECK_OFFSET_MS); - final Command updatedCmd = CommandScheduler.setIsInTime(cmd); + final Command updatedCmd = CommandScheduler.setIgnoreDelay(cmd); verify(commandBus, times(1)).post(updatedCmd); } From 970ff8f1c1068f4e9c9270c3341f8a34739d8353 Mon Sep 17 00:00:00 2001 From: Alexander Litus Date: Mon, 18 Apr 2016 11:57:22 +0300 Subject: [PATCH 09/26] Improve an error msg. --- server/src/main/java/org/spine3/server/command/CommandBus.java | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/server/src/main/java/org/spine3/server/command/CommandBus.java b/server/src/main/java/org/spine3/server/command/CommandBus.java index b980f86c67d..784ac011e11 100644 --- a/server/src/main/java/org/spine3/server/command/CommandBus.java +++ b/server/src/main/java/org/spine3/server/command/CommandBus.java @@ -232,7 +232,7 @@ private void schedule(Command command) { scheduler.schedule(command); } else { throw new IllegalStateException( - "Scheduled commands are not supported by this command bus (scheduler is not set)."); + "Scheduled commands are not supported by this command bus: scheduler is not set."); } } From 292f893b103be75ffdd1e94a92e36a12cad88ba8 Mon Sep 17 00:00:00 2001 From: Alexander Litus Date: Mon, 18 Apr 2016 12:02:21 +0300 Subject: [PATCH 10/26] Rename a constant. --- client/src/main/java/org/spine3/base/Commands.java | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/client/src/main/java/org/spine3/base/Commands.java b/client/src/main/java/org/spine3/base/Commands.java index fac0493944b..73dfee958c2 100644 --- a/client/src/main/java/org/spine3/base/Commands.java +++ b/client/src/main/java/org/spine3/base/Commands.java @@ -52,7 +52,7 @@ public class Commands { /** * A substring which the {@code .proto} file containing commands must have in its name. */ - public static final String COMMANDS_FILE_SUBSTRING = "commands"; + public static final String COMMANDS = "commands"; private static final char PROTO_FILE_SEPARATOR = '/'; @@ -195,13 +195,13 @@ public static String formatMessageTypeAndId(String format, Message commandMessag * Checks if the file is for commands. * * @param file a descriptor of a {@code .proto} file to check - * @return {@code true} if the file name contains {@link #COMMANDS_FILE_SUBSTRING} substring, {@code false} otherwise + * @return {@code true} if the file name contains {@link #COMMANDS} substring, {@code false} otherwise */ public static boolean isCommandsFile(FileDescriptor file) { final String fqn = file.getName(); final int startIndexOfFileName = fqn.lastIndexOf(PROTO_FILE_SEPARATOR) + 1; final String fileName = fqn.substring(startIndexOfFileName); - final boolean isCommandsFile = fileName.contains(COMMANDS_FILE_SUBSTRING); + final boolean isCommandsFile = fileName.contains(COMMANDS); return isCommandsFile; } From 96ade6ed5ae9bf1f4c412e66d1e6f3ce6c1d2092 Mon Sep 17 00:00:00 2001 From: Alexander Litus Date: Mon, 18 Apr 2016 12:36:25 +0300 Subject: [PATCH 11/26] Avoid circular dependency between CommandBus and CommandScheduler. --- .../org/spine3/server/command/CommandBus.java | 26 ++++++++++++++++--- .../server/command/CommandScheduler.java | 21 +++++++-------- .../command/ExecutorCommandScheduler.java | 9 ------- .../ExecutorCommandSchedulerShould.java | 24 ++++++++++++----- 4 files changed, 50 insertions(+), 30 deletions(-) diff --git a/server/src/main/java/org/spine3/server/command/CommandBus.java b/server/src/main/java/org/spine3/server/command/CommandBus.java index 784ac011e11..002d65f2fdf 100644 --- a/server/src/main/java/org/spine3/server/command/CommandBus.java +++ b/server/src/main/java/org/spine3/server/command/CommandBus.java @@ -20,6 +20,7 @@ package org.spine3.server.command; import com.google.common.annotations.VisibleForTesting; +import com.google.common.base.Function; import com.google.protobuf.Message; import org.slf4j.Logger; import org.slf4j.LoggerFactory; @@ -71,9 +72,12 @@ public class CommandBus implements AutoCloseable { private ProblemLog problemLog = new ProblemLog(); private CommandBus(Builder builder) { - this.commandStore = builder.getCommandStore(); - this.scheduler = builder.getScheduler(); - this.commandStatus = new CommandStatusHelper(commandStore); + commandStore = builder.getCommandStore(); + scheduler = builder.getScheduler(); + if (scheduler != null) { + scheduler.setPostFunction(newPostFunction()); + } + commandStatus = new CommandStatusHelper(commandStore); } /** @@ -319,6 +323,21 @@ private CommandHandlerMethod getHandler(CommandClass cls) { return handlerRegistry.getHandler(cls); } + private Function newPostFunction() { + final Function function = new Function() { + @Nullable + @Override + public Command apply(@Nullable Command command) { + if (command == null) { + return null; + } + post(command); + return command; + } + }; + return function; + } + @Override public void close() throws Exception { dispatcherRegistry.unregisterAll(); @@ -371,6 +390,7 @@ public Builder setScheduler(CommandScheduler scheduler) { return this; } + @Nullable public CommandScheduler getScheduler() { return scheduler; } diff --git a/server/src/main/java/org/spine3/server/command/CommandScheduler.java b/server/src/main/java/org/spine3/server/command/CommandScheduler.java index 681da86ca62..c7e07beee65 100644 --- a/server/src/main/java/org/spine3/server/command/CommandScheduler.java +++ b/server/src/main/java/org/spine3/server/command/CommandScheduler.java @@ -21,6 +21,7 @@ package org.spine3.server.command; import com.google.common.annotations.VisibleForTesting; +import com.google.common.base.Function; import org.spine3.base.Command; import org.spine3.base.CommandContext; import org.spine3.base.Schedule; @@ -34,18 +35,9 @@ */ public abstract class CommandScheduler { - private final CommandBus commandBus; - private boolean isActive = true; - /** - * Creates a new instance. - * - * @param commandBus a command bus used to send scheduled commands - */ - protected CommandScheduler(CommandBus commandBus) { - this.commandBus = commandBus; - } + private Function postFunction; /** * Schedule a command and deliver it to the target according to the scheduling options. @@ -75,7 +67,14 @@ public void shutdown() { */ protected void post(Command command) { final Command commandUpdated = setIgnoreDelay(command); - commandBus.post(commandUpdated); + postFunction.apply(commandUpdated); + } + + /** + * Sets a function used to post scheduled commands. + */ + /* package */ void setPostFunction(Function postFunction) { + this.postFunction = postFunction; } /** diff --git a/server/src/main/java/org/spine3/server/command/ExecutorCommandScheduler.java b/server/src/main/java/org/spine3/server/command/ExecutorCommandScheduler.java index 59c249c5e6c..17d1082b25f 100644 --- a/server/src/main/java/org/spine3/server/command/ExecutorCommandScheduler.java +++ b/server/src/main/java/org/spine3/server/command/ExecutorCommandScheduler.java @@ -43,15 +43,6 @@ public class ExecutorCommandScheduler extends CommandScheduler { private final ScheduledExecutorService executorService = Executors.newScheduledThreadPool(MIN_THEAD_POOL_SIZE); - /** - * Creates a new instance. - * - * @param commandBus a command bus used to send scheduled commands - */ - public ExecutorCommandScheduler(CommandBus commandBus) { - super(commandBus); - } - @Override public void schedule(final Command command) { super.schedule(command); diff --git a/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java b/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java index 742b9bedad0..3a18664fd55 100644 --- a/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java +++ b/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java @@ -20,6 +20,7 @@ package org.spine3.server.command; +import com.google.common.base.Function; import com.google.protobuf.Duration; import org.junit.After; import org.junit.Before; @@ -28,8 +29,9 @@ import org.spine3.base.CommandContext; import org.spine3.base.Commands; +import javax.annotation.Nullable; + import static org.junit.Assert.*; -import static org.mockito.Mockito.*; import static org.spine3.base.Identifiers.newUuid; import static org.spine3.protobuf.Durations.seconds; import static org.spine3.testdata.TestCommands.createProject; @@ -44,13 +46,21 @@ public class ExecutorCommandSchedulerShould { private static final Duration DELAY = seconds(1); private static final int CHECK_OFFSET_MS = 50; - private CommandBus commandBus; private CommandScheduler scheduler; + private Command postedCommand; + @Before public void setUpTest() { - this.commandBus = mock(CommandBus.class); - this.scheduler = new ExecutorCommandScheduler(commandBus); + this.scheduler = new ExecutorCommandScheduler(); + scheduler.setPostFunction(new Function() { + @Nullable + @Override + public Command apply(@Nullable Command input) { + postedCommand = input; + return input; + } + }); } @After @@ -82,13 +92,13 @@ public void set_ignore_command_delay_to_true() { } private void assertCommandSent(Command cmd, Duration delay) throws InterruptedException { - verify(commandBus, times(0)).post(any(Command.class)); + assertNull(postedCommand); final long delayMs = delay.getSeconds() * 1000; Thread.sleep(delayMs + CHECK_OFFSET_MS); - final Command updatedCmd = CommandScheduler.setIgnoreDelay(cmd); - verify(commandBus, times(1)).post(updatedCmd); + final Command expectedCommand = CommandScheduler.setIgnoreDelay(cmd); + assertEquals(expectedCommand, postedCommand); } @Test From bfdcb38d63dbe6812933d03195ffabf74aad2dcb Mon Sep 17 00:00:00 2001 From: Alexander Litus Date: Mon, 18 Apr 2016 13:35:33 +0300 Subject: [PATCH 12/26] Use mockito spy instead of mock to improve code coverage. --- .../java/org/spine3/server/command/CommandBusShould.java | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/server/src/test/java/org/spine3/server/command/CommandBusShould.java b/server/src/test/java/org/spine3/server/command/CommandBusShould.java index ff7a75449d8..b2d3368039c 100644 --- a/server/src/test/java/org/spine3/server/command/CommandBusShould.java +++ b/server/src/test/java/org/spine3/server/command/CommandBusShould.java @@ -50,8 +50,6 @@ import java.util.List; import java.util.Set; -import static com.google.protobuf.util.TimeUtil.add; -import static com.google.protobuf.util.TimeUtil.getCurrentTime; import static org.junit.Assert.*; import static org.mockito.Mockito.*; import static org.spine3.base.Identifiers.newUuid; @@ -77,7 +75,7 @@ public void setUp() { .setCommandStore(commandStore) .setScheduler(scheduler) .build(); - log = mock(CommandBus.ProblemLog.class); + log = spy(CommandBus.ProblemLog.class); commandBus.setProblemLog(log); commandFactory = TestCommandFactory.newInstance(CommandBusShould.class); } @@ -372,7 +370,7 @@ public void set_command_status_to_error_when_dispatcher_throws() throws Exceptio verify(commandStore, times(1)).updateStatus(eq(command.getContext() .getCommandId()), eq(exception)); // Verify we logged the error. - verify(log, atMost(1)).errorDispatching(eq(exception), eq(command)); + verify(log, times(1)).errorDispatching(eq(exception), eq(command)); } @Test From 2b42bcfebc7c3aef54b786132b9386ea96d43019 Mon Sep 17 00:00:00 2001 From: Alexander Litus Date: Mon, 18 Apr 2016 16:34:59 +0300 Subject: [PATCH 13/26] Add test API to aggregate. --- .../spine3/server/aggregate/Aggregate.java | 30 ++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-) diff --git a/server/src/main/java/org/spine3/server/aggregate/Aggregate.java b/server/src/main/java/org/spine3/server/aggregate/Aggregate.java index 70412bbb85a..598fa72037b 100644 --- a/server/src/main/java/org/spine3/server/aggregate/Aggregate.java +++ b/server/src/main/java/org/spine3/server/aggregate/Aggregate.java @@ -48,6 +48,7 @@ import static com.google.common.base.Preconditions.checkNotNull; import static com.google.common.base.Throwables.propagate; +import static java.util.Collections.singletonList; import static org.spine3.base.Identifiers.idToAny; /** @@ -276,7 +277,7 @@ private void updateState() { * which is called automatically by {@link AggregateRepository}. */ @VisibleForTesting - protected final void testDispatch(Message command, CommandContext context) { + public final void testDispatch(Message command, CommandContext context) { dispatch(command, context); } @@ -365,6 +366,33 @@ private void apply(Iterable messages, CommandContext commandC } } + /** + * This method is provided only for the purpose of testing event appliers + * of an aggregate and must not be called from the production code. + * + *

Calls {@link #apply(Iterable, CommandContext)}. + */ + @VisibleForTesting + public final void testApply(Message message, CommandContext commandContext) { + init(); + try { + apply(singletonList(message), commandContext); + } catch (InvocationTargetException e) { + throw propagate(e); + } + } + + /** + * This method is provided only for the purpose of testing an aggregate and + * must not be called from the production code. + * + *

Calls {@link #incrementState(Message)}. + */ + @VisibleForTesting + public final void testIncrementState(S newState) { + incrementState(newState); + } + /** * Applies an event to the aggregate. * From 754a16114faf922e17be25e9599d05a3ecb18cab Mon Sep 17 00:00:00 2001 From: Alexander Litus Date: Mon, 18 Apr 2016 17:55:54 +0300 Subject: [PATCH 14/26] Track commands which are scheduled already in scheduler. --- .../main/java/org/spine3/base/Commands.java | 21 +++++---- .../src/main/proto/spine/base/command.proto | 5 --- .../java/org/spine3/base/CommandsShould.java | 8 ---- .../spine3/testdata/TestContextFactory.java | 12 +---- .../server/command/CommandScheduler.java | 30 ++----------- .../command/ExecutorCommandScheduler.java | 15 +++++++ .../ExecutorCommandSchedulerShould.java | 44 ++++++++++--------- 7 files changed, 54 insertions(+), 81 deletions(-) diff --git a/client/src/main/java/org/spine3/base/Commands.java b/client/src/main/java/org/spine3/base/Commands.java index 73dfee958c2..561e2d858cd 100644 --- a/client/src/main/java/org/spine3/base/Commands.java +++ b/client/src/main/java/org/spine3/base/Commands.java @@ -50,11 +50,12 @@ public class Commands { /** - * A substring which the {@code .proto} file containing commands must have in its name. + * A suffix which the {@code .proto} file containing commands must have in its name. */ - public static final String COMMANDS = "commands"; + public static final String FILE_NAME_SUFFIX = "commands"; - private static final char PROTO_FILE_SEPARATOR = '/'; + private static final char FILE_PATH_SEPARATOR = '/'; + private static final char FILE_EXTENSION_SEPARATOR = '.'; private Commands() {} @@ -195,13 +196,14 @@ public static String formatMessageTypeAndId(String format, Message commandMessag * Checks if the file is for commands. * * @param file a descriptor of a {@code .proto} file to check - * @return {@code true} if the file name contains {@link #COMMANDS} substring, {@code false} otherwise + * @return {@code true} if the file name ends with the {@link #FILE_NAME_SUFFIX}, {@code false} otherwise */ public static boolean isCommandsFile(FileDescriptor file) { final String fqn = file.getName(); - final int startIndexOfFileName = fqn.lastIndexOf(PROTO_FILE_SEPARATOR) + 1; - final String fileName = fqn.substring(startIndexOfFileName); - final boolean isCommandsFile = fileName.contains(COMMANDS); + final int startIndexOfFileName = fqn.lastIndexOf(FILE_PATH_SEPARATOR) + 1; + final int endIndexOfFileName = fqn.lastIndexOf(FILE_EXTENSION_SEPARATOR); + final String fileName = fqn.substring(startIndexOfFileName, endIndexOfFileName); + final boolean isCommandsFile = fileName.endsWith(FILE_NAME_SUFFIX); return isCommandsFile; } @@ -223,13 +225,10 @@ public static boolean isEntityFile(FileDescriptor file) { * Checks if the command is scheduled to be delivered later. * * @param command a command to check - * @return {@code true} if the command context has scheduling options set, {@code false} otherwise + * @return {@code true} if the command context has a scheduling option set, {@code false} otherwise */ public static boolean isScheduled(Command command) { final Schedule schedule = command.getContext().getSchedule(); - if (schedule.getIgnoreDelay()) { - return false; - } final Duration delay = schedule.getAfter(); if (isNotDefault(delay)) { checkArgument(delay.getSeconds() > 0, "Command delay seconds must be a positive value."); diff --git a/client/src/main/proto/spine/base/command.proto b/client/src/main/proto/spine/base/command.proto index 3c785dcb9a0..87289eaff88 100644 --- a/client/src/main/proto/spine/base/command.proto +++ b/client/src/main/proto/spine/base/command.proto @@ -86,11 +86,6 @@ message CommandContext { message Schedule { // The delay between the moment of receiving a command at the server and its delivery to the target. google.protobuf.Duration after = 1; - - // `true` if the command should be delivered to the target right now, despite the delay set; - // `false` otherwise. - // This flag is needed to specify that the delay is passed, and to retain the info about the delay. - bool ignore_delay = 2; } // Enumeration of possible failures when validating a command. diff --git a/client/src/test/java/org/spine3/base/CommandsShould.java b/client/src/test/java/org/spine3/base/CommandsShould.java index 87e9b097875..cdf2333d00a 100644 --- a/client/src/test/java/org/spine3/base/CommandsShould.java +++ b/client/src/test/java/org/spine3/base/CommandsShould.java @@ -164,14 +164,6 @@ public void when_no_scheduling_options_then_consider_command_not_scheduled() { assertFalse(Commands.isScheduled(cmd)); } - @Test - public void when_command_is_in_time_then_consider_it_not_scheduled() { - final CommandContext context = createCommandContext(/*delay=*/seconds(10), /*in time=*/true); - final Command cmd = Commands.create(StringValue.getDefaultInstance(), context); - - assertFalse(Commands.isScheduled(cmd)); - } - @Test(expected = IllegalArgumentException.class) public void when_set_negative_delay_then_throw_exception() { final CommandContext context = createCommandContext(/*delay=*/seconds(-10)); diff --git a/client/src/test/java/org/spine3/testdata/TestContextFactory.java b/client/src/test/java/org/spine3/testdata/TestContextFactory.java index 3fe63a99d76..370e15000ab 100644 --- a/client/src/test/java/org/spine3/testdata/TestContextFactory.java +++ b/client/src/test/java/org/spine3/testdata/TestContextFactory.java @@ -89,17 +89,9 @@ public static CommandContext createCommandContext(Duration delay) { /** * Creates a new context with the given scheduling options. */ - public static CommandContext createCommandContext(Duration delay, boolean ignoreDelay) { - final Schedule schedule = Schedule.newBuilder() - .setAfter(delay) - .setIgnoreDelay(ignoreDelay) - .build(); - return createCommandContext(schedule); - } - public static CommandContext createCommandContext(Schedule schedule) { - final CommandContext.Builder builder = TestContextFactory.createCommandContext().toBuilder() - .setSchedule(schedule); + final CommandContext.Builder builder = createCommandContext().toBuilder() + .setSchedule(schedule); return builder.build(); } diff --git a/server/src/main/java/org/spine3/server/command/CommandScheduler.java b/server/src/main/java/org/spine3/server/command/CommandScheduler.java index c7e07beee65..45d4d23d4a5 100644 --- a/server/src/main/java/org/spine3/server/command/CommandScheduler.java +++ b/server/src/main/java/org/spine3/server/command/CommandScheduler.java @@ -20,11 +20,8 @@ package org.spine3.server.command; -import com.google.common.annotations.VisibleForTesting; import com.google.common.base.Function; import org.spine3.base.Command; -import org.spine3.base.CommandContext; -import org.spine3.base.Schedule; import static com.google.common.base.Preconditions.checkState; @@ -42,6 +39,8 @@ public abstract class CommandScheduler { /** * Schedule a command and deliver it to the target according to the scheduling options. * + *

NOTE: check if the command is scheduled already. + * * @param command a command to deliver later * @throws IllegalStateException if the scheduler is shut down * @see #post(Command) @@ -66,8 +65,7 @@ public void shutdown() { * @param command a command to deliver */ protected void post(Command command) { - final Command commandUpdated = setIgnoreDelay(command); - postFunction.apply(commandUpdated); + postFunction.apply(command); } /** @@ -76,26 +74,4 @@ protected void post(Command command) { /* package */ void setPostFunction(Function postFunction) { this.postFunction = postFunction; } - - /** - * Sets {@code ignoreDelay} option to true in {@link Schedule} command option. - * - * @param command the command to update - * @return the updated command - */ - @VisibleForTesting - /* package */ static Command setIgnoreDelay(Command command) { - final CommandContext contextPrimary = command.getContext(); - final Schedule scheduleUpdated = contextPrimary.getSchedule() - .toBuilder() - .setIgnoreDelay(true) - .build(); - final CommandContext contextUpdated = contextPrimary.toBuilder() - .setSchedule(scheduleUpdated) - .build(); - final Command cmdUpdated = command.toBuilder() - .setContext(contextUpdated) - .build(); - return cmdUpdated; - } } diff --git a/server/src/main/java/org/spine3/server/command/ExecutorCommandScheduler.java b/server/src/main/java/org/spine3/server/command/ExecutorCommandScheduler.java index 17d1082b25f..21c2fcde3c2 100644 --- a/server/src/main/java/org/spine3/server/command/ExecutorCommandScheduler.java +++ b/server/src/main/java/org/spine3/server/command/ExecutorCommandScheduler.java @@ -21,11 +21,14 @@ package org.spine3.server.command; import org.spine3.base.Command; +import org.spine3.base.CommandId; import org.spine3.base.Schedule; +import java.util.Set; import java.util.concurrent.Executors; import java.util.concurrent.ScheduledExecutorService; +import static com.google.common.collect.Sets.newHashSet; import static java.util.concurrent.TimeUnit.SECONDS; /** @@ -41,11 +44,16 @@ public class ExecutorCommandScheduler extends CommandScheduler { private static final int MIN_THEAD_POOL_SIZE = 5; + private static final Set SCHEDULED_COMMAND_IDS = newHashSet(); + private final ScheduledExecutorService executorService = Executors.newScheduledThreadPool(MIN_THEAD_POOL_SIZE); @Override public void schedule(final Command command) { super.schedule(command); + if (isScheduledAlready(command)) { + return; + } final long delaySec = getDelaySeconds(command); executorService.schedule(new Runnable() { @Override @@ -53,6 +61,13 @@ public void run() { post(command); } }, delaySec, SECONDS); + SCHEDULED_COMMAND_IDS.add(command.getContext().getCommandId()); + } + + private static boolean isScheduledAlready(Command command) { + final CommandId id = command.getContext().getCommandId(); + final boolean isScheduledAlready = SCHEDULED_COMMAND_IDS.contains(id); + return isScheduledAlready; } private static long getDelaySeconds(Command command) { diff --git a/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java b/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java index 3a18664fd55..b64b328a988 100644 --- a/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java +++ b/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java @@ -31,9 +31,11 @@ import javax.annotation.Nullable; +import static com.google.common.base.Throwables.propagate; import static org.junit.Assert.*; import static org.spine3.base.Identifiers.newUuid; import static org.spine3.protobuf.Durations.seconds; +import static org.spine3.testdata.TestCommands.addTask; import static org.spine3.testdata.TestCommands.createProject; import static org.spine3.testdata.TestContextFactory.createCommandContext; @@ -44,6 +46,7 @@ public class ExecutorCommandSchedulerShould { private static final Duration DELAY = seconds(1); + private static final long DELAY_MS = DELAY.getSeconds() * 1000; private static final int CHECK_OFFSET_MS = 50; private CommandScheduler scheduler; @@ -69,36 +72,29 @@ public void tearDownTest() { } @Test - public void schedule_command_if_delay_is_set() throws InterruptedException { + public void schedule_command_if_delay_is_set() { final CommandContext context = createCommandContext(DELAY); final Command cmd = Commands.create(createProject(newUuid()), context); scheduler.schedule(cmd); - assertCommandSent(cmd, DELAY); + assertNull(postedCommand); + sleep(DELAY_MS + CHECK_OFFSET_MS); + assertEquals(cmd, postedCommand); } @Test - public void set_ignore_command_delay_to_true() { - final Command cmd = createProject(); - assertFalse(cmd.getContext() - .getSchedule() - .getIgnoreDelay()); - - final Command updatedCmd = CommandScheduler.setIgnoreDelay(cmd); - assertTrue(updatedCmd.getContext() - .getSchedule() - .getIgnoreDelay()); - } - - private void assertCommandSent(Command cmd, Duration delay) throws InterruptedException { - assertNull(postedCommand); + public void not_schedule_command_with_same_id_twice() { + final CommandContext context = createCommandContext(DELAY); + final String id = newUuid(); + final Command expectedCmd = Commands.create(createProject(id), context); + final Command extraCmd = Commands.create(addTask(id), context); - final long delayMs = delay.getSeconds() * 1000; - Thread.sleep(delayMs + CHECK_OFFSET_MS); + scheduler.schedule(expectedCmd); + scheduler.schedule(extraCmd); - final Command expectedCommand = CommandScheduler.setIgnoreDelay(cmd); - assertEquals(expectedCommand, postedCommand); + sleep(DELAY_MS + CHECK_OFFSET_MS); + assertEquals(expectedCmd, postedCommand); } @Test @@ -112,4 +108,12 @@ public void throw_exception_if_is_shutdown() { } fail("Must throw an exception as it is shutdown."); } + + private static void sleep(long delayMs) { + try { + Thread.sleep(delayMs); + } catch (InterruptedException e) { + throw propagate(e); + } + } } From b1f115d3aab9e6abe5ea6b2ba756509b79b75378 Mon Sep 17 00:00:00 2001 From: Alexander Litus Date: Tue, 19 Apr 2016 13:14:58 +0300 Subject: [PATCH 15/26] Improve command schedule tests. --- .../java/org/spine3/protobuf/Durations.java | 106 ++++++++++++------ .../org/spine3/protobuf/DurationsShould.java | 23 +++- .../ExecutorCommandSchedulerShould.java | 48 +++----- 3 files changed, 108 insertions(+), 69 deletions(-) diff --git a/client/src/main/java/org/spine3/protobuf/Durations.java b/client/src/main/java/org/spine3/protobuf/Durations.java index 27ea85ce63e..6556e08e8d1 100644 --- a/client/src/main/java/org/spine3/protobuf/Durations.java +++ b/client/src/main/java/org/spine3/protobuf/Durations.java @@ -19,7 +19,7 @@ /** * Utility class for working with durations in addition to those available from {@link TimeUtil}. - * + *

*

Use {@code import static org.spine3.protobuf.Durations.*} for compact initialization like this: * 

  *      Duration d = add(hours(2), minutes(30));
@@ -41,6 +41,17 @@ private Durations() {}
      * using com.google.protobuf.Duration just by adding 's' before the dot.
      */
 
+    /**
+     * Obtains an instance of {@code Duration} representing the passed number of milliseconds.
+     *
+     * @param milliseconds the number of milliseconds, positive or negative
+     * @return a non-null {@code Duration}
+     */
+    public static Duration ofMilliseconds(long milliseconds) {
+        final Duration result = createDurationFromMillis(milliseconds);
+        return result;
+    }
+
     /**
      * Obtains an instance of {@code Duration} from the number of seconds.
      *
@@ -48,10 +59,10 @@ private Durations() {}
      * @return a non-null {@code Duration}
      */
     public static Duration ofSeconds(long seconds) {
-        return createDurationFromMillis(safeMultiply(seconds, MILLIS_PER_SECOND));
+        final Duration result = createDurationFromMillis(safeMultiply(seconds, MILLIS_PER_SECOND));
+        return result;
     }
 
-
     /**
      * Obtains an instance of {@code Duration} representing the passed number of minutes.
      *
@@ -59,29 +70,48 @@ public static Duration ofSeconds(long seconds) {
      * @return a non-null {@code Duration}
      */
     public static Duration ofMinutes(long minutes) {
-        return ofSeconds(safeMultiply(minutes, SECONDS_PER_MINUTE));
+        final Duration duration = ofSeconds(safeMultiply(minutes, SECONDS_PER_MINUTE));
+        return duration;
     }
 
     /**
      * Obtains an instance of {@code Duration} representing the passed number of hours.
+     *
      * @param hours the number of hours, positive or negative
      * @return a non-null {@code Duration}
      */
     public static Duration ofHours(long hours) {
-        return ofMinutes(safeMultiply(hours, MINUTES_PER_HOUR));
+        final Duration duration = ofMinutes(safeMultiply(hours, MINUTES_PER_HOUR));
+        return duration;
     }
 
+    // Methods for brief computations with Durations like
+    //       add(hours(2), minutes(30));
+
     /**
      * Obtains an instance of {@code Duration} representing the passed number of nanoseconds.
+     *
      * @param nanos the number of nanoseconds, positive or negative
      * @return a non-null {@code Duration}
      */
     public static Duration nanos(long nanos) {
-        return TimeUtil.createDurationFromNanos(nanos);
+        final Duration duration = TimeUtil.createDurationFromNanos(nanos);
+        return duration;
+    }
+
+    /**
+     * Obtains an instance of {@code Duration} representing the passed number of milliseconds.
+     *
+     * @param milliseconds the number of milliseconds, positive or negative
+     * @return a non-null {@code Duration}
+     */
+    public static Duration milliseconds(long milliseconds) {
+        return ofMilliseconds(milliseconds);
     }
 
     /**
      * Obtains an instance of {@code Duration} representing the passed number of seconds.
+     *
      * @param seconds the number of seconds, positive or negative
      * @return a non-null {@code Duration}
      */
@@ -89,9 +119,6 @@ public static Duration seconds(long seconds) {
         return ofSeconds(seconds);
     }
 
-    // Methods for brief computations with Durations like
-    //       add(hours(2), minutes(30));
-
     /**
      * This method allows for more compact code of creation of {@code Duration} instance with minutes.
      */
@@ -108,30 +135,27 @@ public static Duration hours(long hours) {
 
     /**
      * Adds two durations one of which or both can be {@code null}.
+     *
      * @param d1 a duration to add, could be {@code null}
      * @param d2 another duration to add, could be {@code null}
-     * @return
-     *      
    
-     *          
  • sum of two durations if both of them are {@code non-null}
    • 
-     *          
  • another {@code non-null} value, if one is {@code null}
    • 
-     *          
  • {@link #ZERO} if both values are {@code null}
    • 
-     *      

-     *
+     * @return 
    
+     * 
  • sum of two durations if both of them are {@code non-null}
    • 
+     * 
  • another {@code non-null} value, if one is {@code null}
    • 
+     * 
  • {@link #ZERO} if both values are {@code null}
    • 
+     * 

      */
     public static Duration add(@Nullable Duration d1, @Nullable Duration d2) {
         if (d1 == null && d2 == null) {
             return ZERO;
         }
-
         if (d1 == null) {
             return d2;
         }
-
         if (d2 == null) {
             return d1;
         }
-
-        return TimeUtil.add(d1, d2);
+        final Duration result = TimeUtil.add(d1, d2);
+        return result;
     }
 
 
@@ -141,14 +165,16 @@ public static Duration add(@Nullable Duration d1, @Nullable Duration d2) {
     public static Duration subtract(Duration d1, Duration d2) {
         /* The sole purpose of this method is minimize the dependencies of the classes
            working with durations. */
-        return TimeUtil.subtract(d1, d2);
+        final Duration result = TimeUtil.subtract(d1, d2);
+        return result;
     }
 
     /**
      * This method allows for more compact code of creation of {@code Duration} instance with hours and minutes.
      */
     public static Duration hoursAndMinutes(long hours, long minutes) {
-        return add(hours(hours), minutes(minutes));
+        final Duration result = add(hours(hours), minutes(minutes));
+        return result;
     }
 
     /**
@@ -157,14 +183,17 @@ public static Duration hoursAndMinutes(long hours, long minutes) {
     public static long toNanos(Duration duration) {
         /* The sole purpose of this method is minimize the dependencies of the classes
            working with durations. */
-        return TimeUtil.toNanos(duration);
+        final long result = TimeUtil.toNanos(duration);
+        return result;
     }
 
     /**
      * Convert a duration to the number of seconds.
      */
     public static long toSeconds(Duration duration) {
-        return floorDiv(TimeUtil.toMillis(duration), MILLIS_PER_SECOND);
+        final long millis = TimeUtil.toMillis(duration);
+        final long seconds = floorDiv(millis, MILLIS_PER_SECOND);
+        return seconds;
     }
 
     /**
@@ -201,7 +230,9 @@ public static long getHours(Duration value) {
     public static int getMinutes(Duration value) {
         final long allMinutes = toMinutes(value);
         final long remainder = allMinutes % MINUTES_PER_HOUR;
-        return Long.valueOf(remainder).intValue();
+        final int result = Long.valueOf(remainder)
+                               .intValue();
+        return result;
     }
 
     /**
@@ -209,14 +240,18 @@ public static int getMinutes(Duration value) {
      */
     public static boolean isPositiveOrZero(Duration value) {
         final long millis = toMillis(value);
-        return millis >= 0;
+        final boolean result = millis >= 0;
+        return result;
     }
 
     /**
      * @return {@code true} if the passed value is greater than zero, {@code false} otherwise
      */
     public static boolean isPositive(DurationOrBuilder value) {
-        return value.getSeconds() > 0 || value.getNanos() > 0;
+        final boolean secondsPositive = value.getSeconds() > 0;
+        final boolean nanosPositive = value.getNanos() > 0;
+        final boolean result = secondsPositive || nanosPositive;
+        return result;
 
     }
 
@@ -224,7 +259,10 @@ public static boolean isPositive(DurationOrBuilder value) {
      * @return {@code true} if the passed value is zero, {@code false} otherwise
      */
     public static boolean isZero(DurationOrBuilder value) {
-        return value.getSeconds() == 0 && value.getNanos() == 0;
+        final boolean noSeconds = value.getSeconds() == 0;
+        final boolean noNanos = value.getNanos() == 0;
+        final boolean result = noSeconds && noNanos;
+        return result;
     }
 
     /**
@@ -233,7 +271,8 @@ public static boolean isZero(DurationOrBuilder value) {
     public static boolean isGreaterThan(Duration value, Duration another) {
         final long nanos = toNanos(value);
         final long anotherNanos = toNanos(another);
-        return nanos > anotherNanos;
+        final boolean isGreater = nanos > anotherNanos;
+        return isGreater;
     }
 
     /**
@@ -242,7 +281,8 @@ public static boolean isGreaterThan(Duration value, Duration another) {
     public static boolean isLessThan(Duration value, Duration another) {
         final long nanos = toNanos(value);
         final long anotherNanos = toNanos(another);
-        return nanos < anotherNanos;
+        final boolean isLessThan = nanos < anotherNanos;
+        return isLessThan;
     }
 
     /**
@@ -251,7 +291,8 @@ public static boolean isLessThan(Duration value, Duration another) {
     public static int compare(Duration d1, Duration d2) {
         final long nanos = toNanos(d1);
         final long otherNanos = toNanos(d2);
-        return Long.compare(nanos, otherNanos);
+        final int result = Long.compare(nanos, otherNanos);
+        return result;
     }
 
     /**
@@ -259,6 +300,7 @@ public static int compare(Duration d1, Duration d2) {
      */
     public static boolean isNegative(Duration value) {
         final long nanos = toNanos(value);
-        return nanos < 0;
+        final boolean isNegative = nanos < 0;
+        return isNegative;
     }
 }
diff --git a/client/src/test/java/org/spine3/protobuf/DurationsShould.java b/client/src/test/java/org/spine3/protobuf/DurationsShould.java
index dad06a894b1..34eb0fa4624 100644
--- a/client/src/test/java/org/spine3/protobuf/DurationsShould.java
+++ b/client/src/test/java/org/spine3/protobuf/DurationsShould.java
@@ -21,9 +21,9 @@
 
 
 import com.google.protobuf.Duration;
+import com.google.protobuf.util.TimeUtil;
 import org.junit.Test;
 
-import static com.google.protobuf.Duration.newBuilder;
 import static org.junit.Assert.*;
 import static org.spine3.protobuf.Durations.*;
 import static org.spine3.test.Tests.hasPrivateUtilityConstructor;
@@ -46,6 +46,25 @@ public void have_ZERO_constant() {
     }
 
 
+    @Test
+    public void convert_milliseconds_to_duration() {
+        convertMillisecondsToDurationTest(0);
+        convertMillisecondsToDurationTest(27);
+        convertMillisecondsToDurationTest(-384);
+    }
+
+    private static void convertMillisecondsToDurationTest(long millis) {
+        final Duration expected = TimeUtil.createDurationFromMillis(millis);
+        assertEquals(expected, ofMilliseconds(millis));
+        assertEquals(expected, milliseconds(millis));
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void fail_to_convert_milliseconds_to_duration_if_input_is_too_big() {
+        ofMilliseconds(Long.MAX_VALUE);
+    }
+
+
     @Test
     public void convert_seconds_to_duration() {
         convertSecondsToDurationTest(0);
@@ -384,6 +403,6 @@ private static long minutesToSeconds(long minutes) {
     }
 
     private static Duration durationFromSec(long seconds) {
-        return newBuilder().setSeconds(seconds).build();
+        return Duration.newBuilder().setSeconds(seconds).build();
     }
 }
diff --git a/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java b/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java
index b64b328a988..deac3a17df0 100644
--- a/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java
+++ b/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java
@@ -20,7 +20,6 @@
 
 package org.spine3.server.command;
 
-import com.google.common.base.Function;
 import com.google.protobuf.Duration;
 import org.junit.After;
 import org.junit.Before;
@@ -29,12 +28,10 @@
 import org.spine3.base.CommandContext;
 import org.spine3.base.Commands;
 
-import javax.annotation.Nullable;
-
-import static com.google.common.base.Throwables.propagate;
-import static org.junit.Assert.*;
+import static org.junit.Assert.fail;
+import static org.mockito.Mockito.*;
 import static org.spine3.base.Identifiers.newUuid;
-import static org.spine3.protobuf.Durations.seconds;
+import static org.spine3.protobuf.Durations.milliseconds;
 import static org.spine3.testdata.TestCommands.addTask;
 import static org.spine3.testdata.TestCommands.createProject;
 import static org.spine3.testdata.TestContextFactory.createCommandContext;
@@ -45,25 +42,17 @@
 @SuppressWarnings("InstanceMethodNamingConvention")
 public class ExecutorCommandSchedulerShould {
 
-    private static final Duration DELAY = seconds(1);
-    private static final long DELAY_MS = DELAY.getSeconds() * 1000;
-    private static final int CHECK_OFFSET_MS = 50;
+    private static final long DELAY_MS = 1100;
 
-    private CommandScheduler scheduler;
+    private static final Duration DELAY = milliseconds(DELAY_MS);
 
-    private Command postedCommand;
+    private CommandScheduler scheduler;
+    private CommandContext context;
 
     @Before
     public void setUpTest() {
-        this.scheduler = new ExecutorCommandScheduler();
-        scheduler.setPostFunction(new Function() {
-            @Nullable
-            @Override
-            public Command apply(@Nullable Command input) {
-                postedCommand = input;
-                return input;
-            }
-        });
+        this.scheduler = spy(ExecutorCommandScheduler.class);
+        this.context = createCommandContext(DELAY);
     }
 
     @After
@@ -73,19 +62,16 @@ public void tearDownTest() {
 
     @Test
     public void schedule_command_if_delay_is_set() {
-        final CommandContext context = createCommandContext(DELAY);
         final Command cmd = Commands.create(createProject(newUuid()), context);
 
         scheduler.schedule(cmd);
 
-        assertNull(postedCommand);
-        sleep(DELAY_MS + CHECK_OFFSET_MS);
-        assertEquals(cmd, postedCommand);
+        verify(scheduler, never()).post(cmd);
+        verify(scheduler, after(DELAY_MS).times(1)).post(cmd);
     }
 
     @Test
     public void not_schedule_command_with_same_id_twice() {
-        final CommandContext context = createCommandContext(DELAY);
         final String id = newUuid();
         final Command expectedCmd = Commands.create(createProject(id), context);
         final Command extraCmd = Commands.create(addTask(id), context);
@@ -93,8 +79,8 @@ public void not_schedule_command_with_same_id_twice() {
         scheduler.schedule(expectedCmd);
         scheduler.schedule(extraCmd);
 
-        sleep(DELAY_MS + CHECK_OFFSET_MS);
-        assertEquals(expectedCmd, postedCommand);
+        verify(scheduler, after(DELAY_MS).times(1)).post(expectedCmd);
+        verify(scheduler, never()).post(extraCmd);
     }
 
     @Test
@@ -108,12 +94,4 @@ public void throw_exception_if_is_shutdown() {
         }
         fail("Must throw an exception as it is shutdown.");
     }
-
-    private static void sleep(long delayMs) {
-        try {
-            Thread.sleep(delayMs);
-        } catch (InterruptedException e) {
-            throw propagate(e);
-        }
-    }
 }

From 951b8b52ba0436358b32cea38fb3c13289651473 Mon Sep 17 00:00:00 2001
From: Alexander Litus 
Date: Tue, 19 Apr 2016 13:15:17 +0300
Subject: [PATCH 16/26] Rename aggregate methods for tests.

---
 .../spine3/server/aggregate/Aggregate.java    |  6 +--
 .../server/aggregate/AggregateShould.java     | 38 +++++++++----------
 2 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/server/src/main/java/org/spine3/server/aggregate/Aggregate.java b/server/src/main/java/org/spine3/server/aggregate/Aggregate.java
index 598fa72037b..d05f9c1d684 100644
--- a/server/src/main/java/org/spine3/server/aggregate/Aggregate.java
+++ b/server/src/main/java/org/spine3/server/aggregate/Aggregate.java
@@ -277,7 +277,7 @@ private void updateState() {
      * which is called automatically by {@link AggregateRepository}.
      */
     @VisibleForTesting
-    public final void testDispatch(Message command, CommandContext context) {
+    public final void dispatchForTest(Message command, CommandContext context) {
         dispatch(command, context);
     }
 
@@ -373,7 +373,7 @@ private void apply(Iterable messages, CommandContext commandC
      * 
Calls {@link #apply(Iterable, CommandContext)}.
      */
     @VisibleForTesting
-    public final void testApply(Message message, CommandContext commandContext) {
+    public final void applyForTest(Message message, CommandContext commandContext) {
         init();
         try {
             apply(singletonList(message), commandContext);
@@ -389,7 +389,7 @@ public final void testApply(Message message, CommandContext commandContext) {
      * 
Calls {@link #incrementState(Message)}.
      */
     @VisibleForTesting
-    public final void testIncrementState(S newState) {
+    public final void incrementStateForTest(S newState) {
         incrementState(newState);
     }
 
diff --git a/server/src/test/java/org/spine3/server/aggregate/AggregateShould.java b/server/src/test/java/org/spine3/server/aggregate/AggregateShould.java
index 205f3af2525..a1e5b485cb9 100644
--- a/server/src/test/java/org/spine3/server/aggregate/AggregateShould.java
+++ b/server/src/test/java/org/spine3/server/aggregate/AggregateShould.java
@@ -146,7 +146,7 @@ public void not_accept_to_constructor_id_of_unsupported_type() {
 
     @Test
     public void handle_one_command_and_apply_appropriate_event() {
-        aggregate.testDispatch(createProject, COMMAND_CONTEXT);
+        aggregate.dispatchForTest(createProject, COMMAND_CONTEXT);
 
         assertTrue(aggregate.isCreateProjectCommandHandled);
         assertTrue(aggregate.isProjectCreatedEventApplied);
@@ -154,7 +154,7 @@ public void handle_one_command_and_apply_appropriate_event() {
 
     @Test
     public void handle_only_appropriate_command() {
-        aggregate.testDispatch(createProject, COMMAND_CONTEXT);
+        aggregate.dispatchForTest(createProject, COMMAND_CONTEXT);
 
         assertTrue(aggregate.isCreateProjectCommandHandled);
         assertTrue(aggregate.isProjectCreatedEventApplied);
@@ -168,15 +168,15 @@ public void handle_only_appropriate_command() {
 
     @Test
     public void handle_appropriate_commands_sequentially() {
-        aggregate.testDispatch(createProject, COMMAND_CONTEXT);
+        aggregate.dispatchForTest(createProject, COMMAND_CONTEXT);
         assertTrue(aggregate.isCreateProjectCommandHandled);
         assertTrue(aggregate.isProjectCreatedEventApplied);
 
-        aggregate.testDispatch(addTask, COMMAND_CONTEXT);
+        aggregate.dispatchForTest(addTask, COMMAND_CONTEXT);
         assertTrue(aggregate.isAddTaskCommandHandled);
         assertTrue(aggregate.isTaskAddedEventApplied);
 
-        aggregate.testDispatch(startProject, COMMAND_CONTEXT);
+        aggregate.dispatchForTest(startProject, COMMAND_CONTEXT);
         assertTrue(aggregate.isStartProjectCommandHandled);
         assertTrue(aggregate.isProjectStartedEventApplied);
     }
@@ -186,7 +186,7 @@ public void throw_exception_if_missing_command_handler() {
         final TestAggregateForCaseMissingHandlerOrApplier aggregate =
                 new TestAggregateForCaseMissingHandlerOrApplier(ID);
         
-        aggregate.testDispatch(addTask, COMMAND_CONTEXT);
+        aggregate.dispatchForTest(addTask, COMMAND_CONTEXT);
     }
 
     @Test(expected = IllegalStateException.class)
@@ -194,7 +194,7 @@ public void throw_exception_if_missing_event_applier_for_non_state_neutral_event
         final TestAggregateForCaseMissingHandlerOrApplier aggregate =
                 new TestAggregateForCaseMissingHandlerOrApplier(ID);
         try {
-            aggregate.testDispatch(createProject, COMMAND_CONTEXT);
+            aggregate.dispatchForTest(createProject, COMMAND_CONTEXT);
         } catch (IllegalStateException e) { // expected exception
             assertTrue(aggregate.isCreateProjectCommandHandled);
             throw e;
@@ -228,7 +228,7 @@ public void return_default_state_by_default() {
 
     @Test
     public void return_current_state_after_dispatch() {
-        aggregate.testDispatch(createProject, COMMAND_CONTEXT);
+        aggregate.dispatchForTest(createProject, COMMAND_CONTEXT);
 
         final Project state = aggregate.getState();
 
@@ -238,10 +238,10 @@ public void return_current_state_after_dispatch() {
 
     @Test
     public void return_current_state_after_several_dispatches() {
-        aggregate.testDispatch(createProject, COMMAND_CONTEXT);
+        aggregate.dispatchForTest(createProject, COMMAND_CONTEXT);
         assertEquals(TestAggregate.STATUS_NEW, aggregate.getState().getStatus());
 
-        aggregate.testDispatch(startProject, COMMAND_CONTEXT);
+        aggregate.dispatchForTest(startProject, COMMAND_CONTEXT);
         assertEquals(TestAggregate.STATUS_STARTED, aggregate.getState().getStatus());
     }
 
@@ -253,7 +253,7 @@ public void return_non_null_time_when_was_last_modified() {
 
     @Test
     public void return_time_when_was_last_modified() {
-        aggregate.testDispatch(createProject, COMMAND_CONTEXT);
+        aggregate.dispatchForTest(createProject, COMMAND_CONTEXT);
         final long expectedTimeSec = currentTimeSeconds();
 
         final Timestamp whenLastModified = aggregate.whenModified();
@@ -272,11 +272,11 @@ public void play_events() {
 
     @Test
     public void play_snapshot_event_and_restore_state() {
-        aggregate.testDispatch(createProject, COMMAND_CONTEXT);
+        aggregate.dispatchForTest(createProject, COMMAND_CONTEXT);
 
         final Snapshot snapshotNewProject = aggregate.toSnapshot();
 
-        aggregate.testDispatch(startProject, COMMAND_CONTEXT);
+        aggregate.dispatchForTest(startProject, COMMAND_CONTEXT);
         assertEquals(TestAggregate.STATUS_STARTED, aggregate.getState().getStatus());
 
         final List events = newArrayList(snapshotToEvent(snapshotNewProject));
@@ -332,7 +332,7 @@ public void clear_event_records_when_commit_after_dispatch() {
     @Test
     public void transform_current_state_to_snapshot_event() {
 
-        aggregate.testDispatch(createProject, COMMAND_CONTEXT);
+        aggregate.dispatchForTest(createProject, COMMAND_CONTEXT);
 
         final Snapshot snapshot = aggregate.toSnapshot();
         final Project state = fromAny(snapshot.getState());
@@ -344,11 +344,11 @@ public void transform_current_state_to_snapshot_event() {
     @Test
     public void restore_state_from_snapshot() {
 
-        aggregate.testDispatch(createProject, COMMAND_CONTEXT);
+        aggregate.dispatchForTest(createProject, COMMAND_CONTEXT);
 
         final Snapshot snapshotNewProject = aggregate.toSnapshot();
 
-        aggregate.testDispatch(startProject, COMMAND_CONTEXT);
+        aggregate.dispatchForTest(startProject, COMMAND_CONTEXT);
         assertEquals(TestAggregate.STATUS_STARTED, aggregate.getState().getStatus());
 
         aggregate.restore(snapshotNewProject);
@@ -460,7 +460,7 @@ public void dispatchCommands(Message... commands) {
             final UserId userId = UserUtil.newUserId("aggregate_should@spine3.org");
             for (Message cmd : commands) {
                 final CommandContext ctx = Commands.createContext(userId, ZoneOffsets.UTC);
-                testDispatch(cmd, ctx);
+                dispatchForTest(cmd, ctx);
             }
         }
     }
@@ -582,7 +582,7 @@ public void propagate_RuntimeException_when_handler_throws() {
 
         final Command command = createProject();
         try {
-            faultyAggregate.testDispatch(command.getMessage(), command.getContext());
+            faultyAggregate.dispatchForTest(command.getMessage(), command.getContext());
         } catch (RuntimeException e) {
             @SuppressWarnings("ThrowableResultOfMethodCallIgnored") // We need it for checking.
             final Throwable cause = Throwables.getRootCause(e);
@@ -597,7 +597,7 @@ public void propagate_RuntimeException_when_applier_throws() {
 
         final Command command = createProject();
         try {
-            faultyAggregate.testDispatch(command.getMessage(), command.getContext());
+            faultyAggregate.dispatchForTest(command.getMessage(), command.getContext());
         } catch (RuntimeException e) {
             @SuppressWarnings("ThrowableResultOfMethodCallIgnored") // ... because we need it for checking.
             final Throwable cause = Throwables.getRootCause(e);

From 4aeca107fd421000c3aaaac7fb383005f2b8736f Mon Sep 17 00:00:00 2001
From: Alexander Litus 
Date: Tue, 19 Apr 2016 13:33:07 +0300
Subject: [PATCH 17/26] Fix tests.

---
 .../ExecutorCommandSchedulerShould.java        | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java b/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java
index deac3a17df0..e325da9cab7 100644
--- a/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java
+++ b/server/src/test/java/org/spine3/server/command/ExecutorCommandSchedulerShould.java
@@ -20,6 +20,7 @@
 
 package org.spine3.server.command;
 
+import com.google.common.base.Function;
 import com.google.protobuf.Duration;
 import org.junit.After;
 import org.junit.Before;
@@ -28,6 +29,8 @@
 import org.spine3.base.CommandContext;
 import org.spine3.base.Commands;
 
+import javax.annotation.Nullable;
+
 import static org.junit.Assert.fail;
 import static org.mockito.Mockito.*;
 import static org.spine3.base.Identifiers.newUuid;
@@ -51,8 +54,9 @@ public class ExecutorCommandSchedulerShould {
 
     @Before
     public void setUpTest() {
-        this.scheduler = spy(ExecutorCommandScheduler.class);
-        this.context = createCommandContext(DELAY);
+        scheduler = spy(ExecutorCommandScheduler.class);
+        scheduler.setPostFunction(newStubPostFunction());
+        context = createCommandContext(DELAY);
     }
 
     @After
@@ -94,4 +98,14 @@ public void throw_exception_if_is_shutdown() {
         }
         fail("Must throw an exception as it is shutdown.");
     }
+
+    private static Function newStubPostFunction() {
+        return new Function() {
+            @Nullable
+            @Override
+            public Command apply(@Nullable Command input) {
+                return input;
+            }
+        };
+    }
 }

From 1b2ecf69f576f9d3532284cc91752b15f3f261ad Mon Sep 17 00:00:00 2001
From: Alexander Litus 
Date: Tue, 19 Apr 2016 17:29:22 +0300
Subject: [PATCH 18/26] Merge branch 'repos-post-events' into schedule-commands

Conflicts:
	server/src/main/java/org/spine3/server/command/CommandBus.java
	server/src/test/java/org/spine3/server/BoundedContextShould.java
	server/src/test/java/org/spine3/server/BoundedContextTestStubs.java
	server/src/test/java/org/spine3/server/command/CommandBusShould.java
---
 .idea/codeStyleSettings.xml                   |   3 +-
 .../src/main/java/org/spine3/base/Events.java |  10 --
 .../main/java/org/spine3/base/Responses.java  |  16 ++-
 .../java/org/spine3/validate/Validate.java    |   2 +-
 client/src/main/proto/spine/validation.proto  |  20 +--
 .../java/org/spine3/base/ResponsesShould.java |  24 +++-
 .../org/spine3/validate/ValidateShould.java   |   2 +-
 examples/build.gradle                         |  14 +-
 .../aggregate/server/Application.java         |  46 +++----
 .../aggregate/server/EventLogger.java         |   6 +-
 .../aggregate/server/OrderAggregate.java      |   2 +-
 .../aggregate/server/OrderRepository.java     |  25 ++++
 .../examples/failure/TaskAggregate.java       |   2 +-
 .../failures/CannotCancelTaskInProgress.java  |   2 +-
 server/build.gradle                           |   9 +-
 .../org/spine3/server/BoundedContext.java     |  79 ++---------
 .../spine3/server/aggregate/Aggregate.java    |  74 ++---------
 .../server/aggregate/AggregateRepository.java |  54 +++++---
 .../spine3/server/aggregate/EventApplier.java |  50 +++++--
 .../org/spine3/server/aggregate/Registry.java |  79 -----------
 .../error/DuplicateApplierException.java      |   2 +-
 .../spine3/server/{ => command}/Assign.java   |   4 +-
 .../org/spine3/server/command/CommandBus.java | 102 ++++++--------
 .../{ => command}/CommandDispatcher.java      |  11 +-
 .../spine3/server/command/CommandHandler.java | 125 ++++++++++++++++++
 .../CommandStatusService.java}                |  51 +++----
 .../server/command/CommandValidation.java     |  10 +-
 .../server/command/DispatcherRegistry.java    |   6 +-
 .../server/command/HandlerRegistry.java       |  57 ++++----
 .../spine3/server/command/RegistryUtil.java   |   2 +-
 .../server/entity/EntityEventDispatcher.java  |   4 +-
 .../GetTargetIdFromCommand.java               |   4 +-
 ...mandHandlerAlreadyRegisteredException.java |   2 +-
 .../server/event/DispatcherRegistry.java      |   3 +-
 .../org/spine3/server/event/EventBus.java     |  80 ++++-------
 .../server/{ => event}/EventDispatcher.java   |   4 +-
 .../org/spine3/server/event/EventHandler.java |  50 +++++++
 .../spine3/server/event/HandlerRegistry.java  |  61 ++++-----
 .../spine3/server/{ => event}/Subscribe.java  |   4 +-
 .../{ => failure}/FailureThrowable.java       |   3 +-
 .../package-info.java}                        |  19 +--
 .../spine3/server/procman/ProcessManager.java | 115 +++-------------
 .../procman/ProcessManagerRepository.java     |  23 +++-
 .../spine3/server/projection/Projection.java  |  63 +--------
 .../projection/ProjectionRepository.java      |   4 +-
 .../org/spine3/server/reflect/Classes.java    |   2 +-
 .../CommandHandlerMethod.java                 |  90 +++++++------
 .../EventHandlerMethod.java                   |  74 ++++++-----
 .../HandlerMethod.java}                       | 102 +++++++++-----
 .../org/spine3/server/reflect/MethodMap.java  | 115 ++++++++--------
 .../spine3/server/reflect/MethodRegistry.java | 114 ++++++++++++++++
 .../org/spine3/server/reflect/Methods.java    |  96 --------------
 .../spine3/server/storage/CommandStorage.java |   3 +-
 .../org/spine3/server}/type/CommandClass.java |   4 +-
 .../org/spine3/server}/type/EventClass.java   |   4 +-
 .../org/spine3/server/type/MessageClass.java  |  10 +-
 .../org/spine3/server/type/package-info.java  |  28 ++++
 .../validate/ByteStringFieldValidator.java    |   2 +-
 .../server/validate/FieldValidator.java       |   8 +-
 .../validate/FloatFieldValidatorBase.java     |   2 +-
 .../validate/MessageFieldValidator.java       |  18 +--
 .../server/validate/MessageValidator.java     |   2 +-
 .../server/validate/NumberFieldValidator.java |  24 ++--
 .../server/validate/StringFieldValidator.java |   8 +-
 .../spine3/server/BoundedContextShould.java   | 114 +++++++---------
 .../server/BoundedContextTestStubs.java       |  10 +-
 .../aggregate/AggregateRepositoryShould.java  |  11 +-
 .../server/aggregate/AggregateShould.java     |   2 +-
 .../server/command/CommandBusShould.java      | 100 +++++++-------
 .../spine3/server/event/EventBusShould.java   |  14 +-
 .../ProcessManagerRepositoryShould.java       |  40 +++---
 .../server/procman/ProcessManagerShould.java  |   4 +-
 .../ProjectionRepositoryShould.java           |   4 +-
 .../server/projection/ProjectionShould.java   |   2 +-
 .../MessageHandlerMethodShould.java           |  43 +++---
 .../server/reflect/MethodMapShould.java       |   5 +-
 .../server/reflect/UtilitiesShould.java       |   1 -
 .../spine3/server}/type/EventClassShould.java |   2 +-
 .../server/type/MessageClassShould.java       |  16 ++-
 .../validate/FieldValidatorFactoryShould.java |   6 +-
 .../validate/MessageValidatorShould.java      |  54 ++++----
 .../org/spine3/testdata/ProjectAggregate.java |   2 +-
 .../msg/commands.proto                        |   4 +-
 .../msg/messages.proto                        |   4 +-
 .../msg/stub_aggregate.proto                  |   4 +-
 values/build.gradle                           |   9 +-
 86 files changed, 1220 insertions(+), 1265 deletions(-)
 delete mode 100644 server/src/main/java/org/spine3/server/aggregate/Registry.java
 rename server/src/main/java/org/spine3/server/{ => command}/Assign.java (96%)
 rename server/src/main/java/org/spine3/server/{ => command}/CommandDispatcher.java (82%)
 create mode 100644 server/src/main/java/org/spine3/server/command/CommandHandler.java
 rename server/src/main/java/org/spine3/server/{CommandHandler.java => command/CommandStatusService.java} (51%)
 rename server/src/main/java/org/spine3/server/{command => entity}/GetTargetIdFromCommand.java (93%)
 rename server/src/main/java/org/spine3/server/{ => event}/EventDispatcher.java (95%)
 create mode 100644 server/src/main/java/org/spine3/server/event/EventHandler.java
 rename server/src/main/java/org/spine3/server/{ => event}/Subscribe.java (96%)
 rename server/src/main/java/org/spine3/server/{ => failure}/FailureThrowable.java (96%)
 rename server/src/main/java/org/spine3/server/{EventHandler.java => failure/package-info.java} (70%)
 rename server/src/main/java/org/spine3/server/{internal => reflect}/CommandHandlerMethod.java (74%)
 rename server/src/main/java/org/spine3/server/{internal => reflect}/EventHandlerMethod.java (73%)
 rename server/src/main/java/org/spine3/server/{internal/MessageHandlerMethod.java => reflect/HandlerMethod.java} (64%)
 create mode 100644 server/src/main/java/org/spine3/server/reflect/MethodRegistry.java
 delete mode 100644 server/src/main/java/org/spine3/server/reflect/Methods.java
 rename {client/src/main/java/org/spine3 => server/src/main/java/org/spine3/server}/type/CommandClass.java (97%)
 rename {client/src/main/java/org/spine3 => server/src/main/java/org/spine3/server}/type/EventClass.java (96%)
 rename client/src/main/java/org/spine3/type/ClassTypeValue.java => server/src/main/java/org/spine3/server/type/MessageClass.java (84%)
 create mode 100644 server/src/main/java/org/spine3/server/type/package-info.java
 rename server/src/test/java/org/spine3/server/{internal => reflect}/MessageHandlerMethodShould.java (76%)
 rename {client/src/test/java/org/spine3 => server/src/test/java/org/spine3/server}/type/EventClassShould.java (97%)
 rename client/src/test/java/org/spine3/type/ClassTypeValueShould.java => server/src/test/java/org/spine3/server/type/MessageClassShould.java (77%)
 rename server/src/test/proto/spine/test/{validation => validate}/msg/commands.proto (95%)
 rename server/src/test/proto/spine/test/{validation => validate}/msg/messages.proto (97%)
 rename server/src/test/proto/spine/test/{validation => validate}/msg/stub_aggregate.proto (93%)

diff --git a/.idea/codeStyleSettings.xml b/.idea/codeStyleSettings.xml
index a422528b53a..258e4a12c25 100644
--- a/.idea/codeStyleSettings.xml
+++ b/.idea/codeStyleSettings.xml
@@ -9,11 +9,12 @@
         
         
           
Logs warning for the methods with a non-private modifier.
      *
      * @param methods the map of methods to check
-     * @see MessageHandlerMethod#log()
+     * @see HandlerMethod#log()
      */
     /* package */ static void checkModifiers(Iterable methods) {
         for (Method method : methods) {
@@ -76,6 +75,41 @@ protected  R invoke(Message message) throws InvocationTargetException {
         }
     }
 
+    public static HandlerMethod.Factory factory() {
+        return Factory.instance();
+    }
+
+    /**
+     * The factory for filtering methods that match {@code EventApplier} specification.
+     */
+    private static class Factory implements HandlerMethod.Factory {
+
+        @Override
+        public Class getMethodClass() {
+            return EventApplier.class;
+        }
+
+        @Override
+        public EventApplier create(Method method) {
+            return new EventApplier(method);
+        }
+
+        @Override
+        public Predicate getPredicate() {
+            return PREDICATE;
+        }
+
+        private enum Singleton {
+            INSTANCE;
+            @SuppressWarnings("NonSerializableFieldInSerializableClass")
+            private final Factory value = new Factory();
+        }
+
+        private static Factory instance() {
+            return Singleton.INSTANCE.value;
+        }
+    }
+
     /**
      * The predicate for filtering event applier methods.
      */
diff --git a/server/src/main/java/org/spine3/server/aggregate/Registry.java b/server/src/main/java/org/spine3/server/aggregate/Registry.java
deleted file mode 100644
index 17520909e97..00000000000
--- a/server/src/main/java/org/spine3/server/aggregate/Registry.java
+++ /dev/null
@@ -1,79 +0,0 @@
-/*
- * Copyright 2016, TeamDev Ltd. All rights reserved.
- *
- * Redistribution and use in source and/or binary forms, with or without
- * modification, must retain the above copyright notice and the following
- * disclaimer.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-package org.spine3.server.aggregate;
-
-import org.spine3.server.internal.CommandHandlerMethod;
-import org.spine3.server.reflect.MethodMap;
-
-import javax.annotation.CheckReturnValue;
-
-/**
- * The registry of method maps for all aggregate classes.
- *
- * 
This registry is used for caching command handlers and event appliers.
- * Aggregates register their classes in {@link Aggregate#init()} method.
- *
- * @author Alexander Yevsyukov
- */
-/* package */ class Registry {
-
-    private final MethodMap.Registry commandHandlers = new MethodMap.Registry<>();
-
-    private final MethodMap.Registry eventAppliers = new MethodMap.Registry<>();
-
-    /* package */ void register(Class clazz) {
-        commandHandlers.register(clazz, CommandHandlerMethod.PREDICATE);
-        CommandHandlerMethod.checkModifiers(commandHandlers.get(clazz).values());
-
-        eventAppliers.register(clazz, EventApplier.PREDICATE);
-        EventApplier.checkModifiers(eventAppliers.get(clazz).values());
-    }
-
-    @CheckReturnValue
-    /* package */ boolean contains(Class clazz) {
-        final boolean result = commandHandlers.contains(clazz);
-        return result;
-    }
-
-    @CheckReturnValue
-    /* package */ MethodMap getCommandHandlers(Class clazz) {
-        final MethodMap result = commandHandlers.get(clazz);
-        return result;
-    }
-
-    @CheckReturnValue
-    /* package */ MethodMap getEventAppliers(Class clazz) {
-        final MethodMap result = eventAppliers.get(clazz);
-        return result;
-    }
-
-    @CheckReturnValue
-    /* package */ static Registry getInstance() {
-        return Singleton.INSTANCE.value;
-    }
-
-    private enum Singleton {
-        INSTANCE;
-        @SuppressWarnings("NonSerializableFieldInSerializableClass")
-        private final Registry value = new Registry();
-    }
-}
-
diff --git a/server/src/main/java/org/spine3/server/aggregate/error/DuplicateApplierException.java b/server/src/main/java/org/spine3/server/aggregate/error/DuplicateApplierException.java
index f48f7f70488..98470039e9d 100644
--- a/server/src/main/java/org/spine3/server/aggregate/error/DuplicateApplierException.java
+++ b/server/src/main/java/org/spine3/server/aggregate/error/DuplicateApplierException.java
@@ -19,7 +19,7 @@
  */
 package org.spine3.server.aggregate.error;
 
-import org.spine3.type.EventClass;
+import org.spine3.server.type.EventClass;
 
 /**
  * Exception that is thrown when more than one applier
diff --git a/server/src/main/java/org/spine3/server/Assign.java b/server/src/main/java/org/spine3/server/command/Assign.java
similarity index 96%
rename from server/src/main/java/org/spine3/server/Assign.java
rename to server/src/main/java/org/spine3/server/command/Assign.java
index d1f1a194c01..574cb631ac2 100644
--- a/server/src/main/java/org/spine3/server/Assign.java
+++ b/server/src/main/java/org/spine3/server/command/Assign.java
@@ -18,9 +18,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package org.spine3.server;
-
-import org.spine3.server.command.CommandBus;
+package org.spine3.server.command;
 
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
diff --git a/server/src/main/java/org/spine3/server/command/CommandBus.java b/server/src/main/java/org/spine3/server/command/CommandBus.java
index 002d65f2fdf..646a2c1e96c 100644
--- a/server/src/main/java/org/spine3/server/command/CommandBus.java
+++ b/server/src/main/java/org/spine3/server/command/CommandBus.java
@@ -28,24 +28,19 @@
 import org.spine3.base.CommandContext;
 import org.spine3.base.CommandId;
 import org.spine3.base.Errors;
-import org.spine3.base.Event;
 import org.spine3.base.Response;
 import org.spine3.base.Responses;
-import org.spine3.server.CommandDispatcher;
-import org.spine3.server.CommandHandler;
-import org.spine3.server.FailureThrowable;
 import org.spine3.server.error.UnsupportedCommandException;
-import org.spine3.server.internal.CommandHandlerMethod;
+import org.spine3.server.failure.FailureThrowable;
+import org.spine3.server.type.CommandClass;
 import org.spine3.server.validate.MessageValidator;
-import org.spine3.type.CommandClass;
-import org.spine3.validation.options.ConstraintViolation;
+import org.spine3.validate.options.ConstraintViolation;
 
 import javax.annotation.Nullable;
 import java.lang.reflect.InvocationTargetException;
 import java.util.List;
 
 import static com.google.common.base.Preconditions.checkNotNull;
-import static java.util.Collections.emptyList;
 import static org.spine3.base.Commands.*;
 import static org.spine3.server.command.CommandValidation.invalidCommand;
 import static org.spine3.server.command.CommandValidation.unsupportedCommand;
@@ -67,9 +62,9 @@ public class CommandBus implements AutoCloseable {
 
     @Nullable
     private final CommandScheduler scheduler;
-
-    private final CommandStatusHelper commandStatus;
+    
     private ProblemLog problemLog = new ProblemLog();
+    private final CommandStatusService commandStatusService;
 
     private CommandBus(Builder builder) {
         commandStore = builder.getCommandStore();
@@ -77,7 +72,7 @@ private CommandBus(Builder builder) {
         if (scheduler != null) {
             scheduler.setPostFunction(newPostFunction());
         }
-        commandStatus = new CommandStatusHelper(commandStore);
+        commandStatusService = new CommandStatusService(commandStore);
     }
 
     /**
@@ -166,69 +161,78 @@ private boolean isUnsupportedCommand(CommandClass commandClass) {
     /**
      * Directs a command request to the corresponding handler.
      *
-     * @param command the command request to be processed
-     * @return a list of the events as the result of handling the command
+     * @param command the command to be processed
      * @throws UnsupportedCommandException if there is neither handler nor dispatcher registered for
      *                                     the class of the passed command
      */
-    public List post(Command command) {
-        //TODO:2016-01-24:alexander.yevsyukov: Do not return value.
+    public void post(Command command) {
         checkNotDefault(command);
         if (isScheduled(command)) {
             schedule(command);
-            return emptyList();
+            return;
         }
         store(command);
         final CommandClass commandClass = CommandClass.of(command);
         if (isDispatcherRegistered(commandClass)) {
-            return dispatch(command);
+            dispatch(command);
+            return;
         }
         if (isHandlerRegistered(commandClass)) {
             final Message message = getMessage(command);
             final CommandContext context = command.getContext();
-            return invokeHandler(message, context);
+            invokeHandler(message, context);
+            return;
         }
         throw new UnsupportedCommandException(getMessage(command));
     }
 
-    private List dispatch(Command command) {
+    /**
+     * Obtains the instance of the {@link CommandStatusService} associated with this command bus.
+     */
+    public CommandStatusService getCommandStatusService() {
+        return commandStatusService;
+    }
+
+    private void dispatch(Command command) {
         final CommandClass commandClass = CommandClass.of(command);
         final CommandDispatcher dispatcher = getDispatcher(commandClass);
-        List result = emptyList();
+        final CommandId commandId = command.getContext().getCommandId();
         try {
-            result = dispatcher.dispatch(command);
+            dispatcher.dispatch(command);
         } catch (Exception e) {
             problemLog.errorDispatching(e, command);
-            commandStatus.setToError(command.getContext().getCommandId(), e);
+            commandStatusService.setToError(commandId, e);
         }
-        return result;
     }
 
-    private List invokeHandler(Message msg, CommandContext context) {
+    private void invokeHandler(Message msg, CommandContext context) {
         final CommandClass commandClass = CommandClass.of(msg);
-        final CommandHandlerMethod method = getHandler(commandClass);
-        List result = emptyList();
+        final CommandHandler handler = getHandler(commandClass);
+        final CommandId commandId = context.getCommandId();
         try {
-            result = method.invoke(msg, context);
-            commandStatus.setOk(context.getCommandId());
+            handler.handle(msg, context);
+            commandStatusService.setOk(commandId);
         } catch (InvocationTargetException e) {
-            final CommandId commandId = context.getCommandId();
             final Throwable cause = e.getCause();
             //noinspection ChainOfInstanceofChecks
             if (cause instanceof Exception) {
                 final Exception exception = (Exception) cause;
                 problemLog.errorHandling(exception, msg, commandId);
-                commandStatus.setToError(commandId, exception);
+                commandStatusService.setToError(commandId, exception);
             } else if (cause instanceof FailureThrowable){
                 final FailureThrowable failure = (FailureThrowable) cause;
                 problemLog.failureHandling(failure, msg, commandId);
-                commandStatus.setToFailure(commandId, failure);
+                commandStatusService.setToFailure(commandId, failure);
             } else {
                 problemLog.errorHandlingUnknown(cause, msg, commandId);
-                commandStatus.setToError(commandId, Errors.fromThrowable(cause));
+                commandStatusService.setToError(commandId, Errors.fromThrowable(cause));
             }
         }
-        return result;
+    }
+
+    private CommandHandler getHandler(CommandClass commandClass) {
+        final CommandHandler handler = handlerRegistry.getHandler(commandClass);
+        return handler;
     }
 
     private void schedule(Command command) {
@@ -273,34 +277,6 @@ private void schedule(Command command) {
         this.problemLog = problemLog;
     }
 
-    /**
-     * The helper class for updating command status.
-     */
-    private static class CommandStatusHelper {
-
-        private final CommandStore commandStore;
-
-        private CommandStatusHelper(CommandStore commandStore) {
-            this.commandStore = commandStore;
-        }
-
-        private void setOk(CommandId commandId) {
-            commandStore.setCommandStatusOk(commandId);
-        }
-
-        private void setToError(CommandId commandId, Exception exception) {
-            commandStore.updateStatus(commandId, exception);
-        }
-
-        private void setToFailure(CommandId commandId, FailureThrowable failure) {
-            commandStore.updateStatus(commandId, failure.toMessage());
-        }
-
-        private void setToError(CommandId commandId, org.spine3.base.Error error) {
-            commandStore.updateStatus(commandId, error);
-        }
-    }
-
     private void store(Command request) {
         commandStore.store(request);
     }
@@ -319,10 +295,6 @@ private CommandDispatcher getDispatcher(CommandClass commandClass) {
         return dispatcherRegistry.getDispatcher(commandClass);
     }
 
-    private CommandHandlerMethod getHandler(CommandClass cls) {
-        return handlerRegistry.getHandler(cls);
-    }
-
     private Function newPostFunction() {
         final Function function = new Function() {
             @Nullable
diff --git a/server/src/main/java/org/spine3/server/CommandDispatcher.java b/server/src/main/java/org/spine3/server/command/CommandDispatcher.java
similarity index 82%
rename from server/src/main/java/org/spine3/server/CommandDispatcher.java
rename to server/src/main/java/org/spine3/server/command/CommandDispatcher.java
index 48f1d630cdf..90863cfbaf8 100644
--- a/server/src/main/java/org/spine3/server/CommandDispatcher.java
+++ b/server/src/main/java/org/spine3/server/command/CommandDispatcher.java
@@ -18,13 +18,11 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package org.spine3.server;
+package org.spine3.server.command;
 
 import org.spine3.base.Command;
-import org.spine3.base.Event;
-import org.spine3.type.CommandClass;
+import org.spine3.server.type.CommandClass;
 
-import java.util.List;
 import java.util.Set;
 
 /**
@@ -50,9 +48,6 @@ public interface CommandDispatcher {
     /**
      * Dispatches the command to its handler.
      */
-    List dispatch(Command request) throws Exception;
-    //TODO:2016-01-24:alexander.yevsyukov: Do not return results to the CommandBus.
-
-    //TODO:2016-01-24:alexander.yevsyukov: Do handle exceptions that can be thrown at CommandBus side.
+    void dispatch(Command request) throws Exception;
 
 }
diff --git a/server/src/main/java/org/spine3/server/command/CommandHandler.java b/server/src/main/java/org/spine3/server/command/CommandHandler.java
new file mode 100644
index 00000000000..a9b2406e52d
--- /dev/null
+++ b/server/src/main/java/org/spine3/server/command/CommandHandler.java
@@ -0,0 +1,125 @@
+/*
+ * Copyright 2016, TeamDev Ltd. All rights reserved.
+ *
+ * Redistribution and use in source and/or binary forms, with or without
+ * modification, must retain the above copyright notice and the following
+ * disclaimer.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.spine3.server.command;
+
+import com.google.common.collect.ImmutableList;
+import com.google.protobuf.Empty;
+import com.google.protobuf.Message;
+import com.google.protobuf.util.TimeUtil;
+import org.spine3.base.CommandContext;
+import org.spine3.base.Event;
+import org.spine3.base.EventContext;
+import org.spine3.base.EventId;
+import org.spine3.base.Events;
+import org.spine3.base.Identifiers;
+import org.spine3.server.entity.Entity;
+import org.spine3.server.event.EventBus;
+import org.spine3.server.failure.FailureThrowable;
+import org.spine3.server.reflect.CommandHandlerMethod;
+import org.spine3.server.reflect.MethodRegistry;
+
+import java.lang.reflect.InvocationTargetException;
+import java.util.List;
+
+/**
+ * The abstract base for classes that expose command handling methods
+ * and post their results to {@link EventBus}.
+ *
+ * 
A command handler is responsible for:
+ * 
    
+ *     
  1. Changing the state of the business model
    2. 
+ *     
  2. Producing corresponding events.
    3. 
+ *     
  3. Posting events to {@code EventBus}.
    4. 
+ * 

+ *
+ * 
Event messages are returned as values of command handling methods.
+ *
+ * 
Command handling methods

+ * 
A command handling method is a {@code public} method that accepts two parameters.
+ * The first parameter is a command message. The second parameter is {@link CommandContext}.
+ *
+ * 
The method returns an event message of the specific type, or {@code List} of messages
+ * if it produces more than one event.
+ *
+ * 
The method may throw one or more throwables derived from {@link FailureThrowable}.
+ * Throwing a {@code FailureThrowable} indicates that the passed command cannot be handled
+ * because of a business failure, which can be obtained via {@link FailureThrowable#getFailure()}.
+ *
+ * @author Alexander Yevsyukov
+ * @see CommandDispatcher
+ */
+public abstract class CommandHandler extends Entity {
+
+    private final EventBus eventBus;
+
+    /**
+     * Creates a new instance of the command handler.
+     *
+     * @param id the identifier, which will be used for recognizing events produced by this handler
+     * @param eventBus the Event Bus to post events generated by this handler
+     */
+    protected CommandHandler(String id, EventBus eventBus) {
+        super(id);
+        this.eventBus = eventBus;
+    }
+
+    public void handle(Message commandMessage, CommandContext context) throws InvocationTargetException {
+        final CommandHandlerMethod method = getHandlerMethod(commandMessage.getClass());
+
+        final List eventMessages = method.invoke(this, commandMessage, context);
+
+        final List events = toEvents(eventMessages, context);
+        postEvents(events);
+    }
+
+    /* package */ CommandHandlerMethod getHandlerMethod(Class commandClass) {
+        return MethodRegistry.getInstance().get(getClass(), commandClass, CommandHandlerMethod.factory());
+    }
+
+    private List toEvents(Iterable eventMessages, CommandContext context) {
+        final ImmutableList.Builder builder = ImmutableList.builder();
+        for (Message eventMessage : eventMessages) {
+            final EventContext eventContext = createEventContext(context);
+            final Event event = Events.createEvent(eventMessage, eventContext);
+            builder.add(event);
+        }
+        return builder.build();
+    }
+
+    private EventContext createEventContext(CommandContext commandContext) {
+        final EventId eventId = Events.generateId();
+        final EventContext.Builder builder = EventContext.newBuilder()
+                                                         .setEventId(eventId)
+                                                         .setCommandContext(commandContext)
+                                                         .setTimestamp(TimeUtil.getCurrentTime())
+                                                         .setProducerId(Identifiers.idToAny(getId()));
+        return builder.build();
+    }
+
+    /**
+     * Posts passed events to {@link EventBus}.
+     */
+    private void postEvents(Iterable events) {
+        for (Event event : events) {
+            eventBus.post(event);
+        }
+    }
+}
diff --git a/server/src/main/java/org/spine3/server/CommandHandler.java b/server/src/main/java/org/spine3/server/command/CommandStatusService.java
similarity index 51%
rename from server/src/main/java/org/spine3/server/CommandHandler.java
rename to server/src/main/java/org/spine3/server/command/CommandStatusService.java
index e6e43f42750..1e8e150f1cb 100644
--- a/server/src/main/java/org/spine3/server/CommandHandler.java
+++ b/server/src/main/java/org/spine3/server/command/CommandStatusService.java
@@ -18,34 +18,37 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package org.spine3.server;
+package org.spine3.server.command;
 
-import org.spine3.base.CommandContext;
+import org.spine3.base.CommandId;
+import org.spine3.server.failure.FailureThrowable;
 
 /**
- * The marker interface for classes that expose command handling methods.
- *
- * 
A command handler is responsible for:
- * 
    
- *     
  1. Changing the state of the business model
    2. 
- *     
  2. Producing corresponding events.
    3. 
- * 

- *
- * 
Events are returned as values of command handling methods.
- *
- * 
Command handling methods

- * 
A command handling method is a {@code public} method that accepts two parameters.
- * The first parameter is a command message. The second parameter is {@link CommandContext}.
- *
- * 
The method returns an event message of the specific type, or {@code List} of messages
- * if it produces more than one event.
- *
- * 
The method may throw one or more throwables derived from {@link FailureThrowable}.
- * Throwing a {@code FailureThrowable} indicates that the passed command cannot be handled
- * because of a business failure.
+ * The service for updating a status of a command.
  *
  * @author Alexander Yevsyukov
- * @see CommandDispatcher
  */
-public interface CommandHandler {
+public class CommandStatusService {
+
+    private final CommandStore commandStore;
+
+    /* package */ CommandStatusService(CommandStore commandStore) {
+        this.commandStore = commandStore;
+    }
+
+    public void setOk(CommandId commandId) {
+        commandStore.setCommandStatusOk(commandId);
+    }
+
+    public void setToError(CommandId commandId, Exception exception) {
+        commandStore.updateStatus(commandId, exception);
+    }
+
+    public void setToFailure(CommandId commandId, FailureThrowable failure) {
+        commandStore.updateStatus(commandId, failure.toMessage());
+    }
+
+    public void setToError(CommandId commandId, org.spine3.base.Error error) {
+        commandStore.updateStatus(commandId, error);
+    }
 }
diff --git a/server/src/main/java/org/spine3/server/command/CommandValidation.java b/server/src/main/java/org/spine3/server/command/CommandValidation.java
index 08851323940..a20af63db79 100644
--- a/server/src/main/java/org/spine3/server/command/CommandValidation.java
+++ b/server/src/main/java/org/spine3/server/command/CommandValidation.java
@@ -29,7 +29,7 @@
 import org.spine3.base.Failure;
 import org.spine3.base.Response;
 import org.spine3.base.ValidationFailure;
-import org.spine3.validation.options.ConstraintViolation;
+import org.spine3.validate.options.ConstraintViolation;
 
 import java.util.List;
 import java.util.Map;
@@ -70,14 +70,6 @@ public static Response unsupportedCommand(Message command) {
         return response;
     }
 
-    public static boolean isUnsupportedCommand(Response response) {
-        if (response.getStatusCase() == Response.StatusCase.ERROR) {
-            final Error error = response.getError();
-            return error.getCode() == CommandValidationError.UNSUPPORTED_COMMAND.getNumber();
-        }
-        return false;
-    }
-
     /**
      * Creates a {@code Response} for getting a command with invalid fields (e.g., marked as "required" but not set).
      *
diff --git a/server/src/main/java/org/spine3/server/command/DispatcherRegistry.java b/server/src/main/java/org/spine3/server/command/DispatcherRegistry.java
index 95ab446a29c..525a49d9db4 100644
--- a/server/src/main/java/org/spine3/server/command/DispatcherRegistry.java
+++ b/server/src/main/java/org/spine3/server/command/DispatcherRegistry.java
@@ -24,11 +24,9 @@
 import com.google.common.collect.Maps;
 import com.google.common.collect.Sets;
 import com.google.protobuf.Message;
-import org.spine3.server.CommandDispatcher;
-import org.spine3.server.CommandHandler;
-import org.spine3.server.internal.CommandHandlerMethod;
 import org.spine3.server.reflect.Classes;
-import org.spine3.type.CommandClass;
+import org.spine3.server.reflect.CommandHandlerMethod;
+import org.spine3.server.type.CommandClass;
 
 import java.util.Map;
 import java.util.Set;
diff --git a/server/src/main/java/org/spine3/server/command/HandlerRegistry.java b/server/src/main/java/org/spine3/server/command/HandlerRegistry.java
index b92d45c2b08..d730e4fc766 100644
--- a/server/src/main/java/org/spine3/server/command/HandlerRegistry.java
+++ b/server/src/main/java/org/spine3/server/command/HandlerRegistry.java
@@ -23,12 +23,11 @@
 import com.google.common.collect.Maps;
 import com.google.common.collect.Sets;
 import com.google.protobuf.Message;
-import org.spine3.server.CommandDispatcher;
-import org.spine3.server.CommandHandler;
 import org.spine3.server.error.CommandHandlerAlreadyRegisteredException;
-import org.spine3.server.internal.CommandHandlerMethod;
-import org.spine3.server.internal.MessageHandlerMethod;
-import org.spine3.type.CommandClass;
+import org.spine3.server.reflect.CommandHandlerMethod;
+import org.spine3.server.reflect.HandlerMethod;
+import org.spine3.server.reflect.MethodMap;
+import org.spine3.server.type.CommandClass;
 
 import javax.annotation.CheckReturnValue;
 import java.util.Map;
@@ -45,42 +44,43 @@
  */
 /* package */ class HandlerRegistry {
 
-    private final Map handlersByClass = Maps.newConcurrentMap();
+    private final Map handlersByClass = Maps.newConcurrentMap();
 
     /* package */ void register(CommandHandler object) {
         checkNotNull(object);
 
-        final Map handlers = CommandHandlerMethod.scan(object);
+        final MethodMap handlers = CommandHandlerMethod.scan(object);
 
         if (handlers.isEmpty()) {
             throw new IllegalArgumentException("No command handler methods found in :" + object);
         }
 
-        registerMap(handlers);
+        registerMap(object, handlers);
     }
 
     /* package */ void unregister(CommandHandler object) {
         checkNotNull(object);
 
-        final Map subscribers = CommandHandlerMethod.scan(object);
-        unregisterMap(subscribers);
+        final MethodMap handlers = CommandHandlerMethod.scan(object);
+        unregisterMap(handlers);
     }
 
     /**
      * Registers the passed handlers with the dispatcher.
      *
-     * @param handlers map from command classes to corresponding handlers
+     * @param object the command handler
+     * @param methods map from command classes to corresponding handlers
      */
-    private void registerMap(Map handlers) {
-        checkDuplicates(handlers);
-        putAll(handlers);
+    private void registerMap(CommandHandler object, MethodMap methods) {
+        checkDuplicates(methods);
+        putAll(object, methods);
     }
 
-    private void unregisterMap(Map handlers) {
-        for (Map.Entry entry : handlers.entrySet()) {
-            final CommandClass commandClass = entry.getKey();
+    private void unregisterMap(MethodMap methods) {
+        for (Map.Entry, CommandHandlerMethod> entry : methods.entrySet()) {
+            final CommandClass commandClass = CommandClass.of(entry.getKey());
             if (handlerRegistered(commandClass)) {
-                final CommandHandlerMethod registered = getHandler(commandClass);
+                final CommandHandlerMethod registered = getHandler(commandClass).getHandlerMethod(commandClass.value());
                 final CommandHandlerMethod passed = entry.getValue();
                 if (registered.equals(passed)) {
                     removeFor(commandClass);
@@ -93,12 +93,12 @@ private void removeFor(CommandClass commandClass) {
         handlersByClass.remove(commandClass);
     }
 
-    private void checkDuplicates(Map handlers) {
-        for (Map.Entry entry : handlers.entrySet()) {
-            final CommandClass commandClass = entry.getKey();
+    private void checkDuplicates(MethodMap handlers) {
+        for (Map.Entry, CommandHandlerMethod> entry : handlers.entrySet()) {
+            final CommandClass commandClass = CommandClass.of(entry.getKey());
 
             if (handlerRegistered(commandClass)) {
-                final MessageHandlerMethod alreadyRegistered = getHandler(commandClass);
+                final HandlerMethod alreadyRegistered = getHandler(commandClass).getHandlerMethod(commandClass.value());
                 throw new CommandHandlerAlreadyRegisteredException(commandClass,
                         alreadyRegistered.getFullName(),
                         entry.getValue().getFullName());
@@ -111,12 +111,14 @@ private void checkDuplicates(Map handlers) {
         return handlersByClass.containsKey(cls);
     }
 
-    /* package */ CommandHandlerMethod getHandler(CommandClass cls) {
+    /* package */ CommandHandler getHandler(CommandClass cls) {
         return handlersByClass.get(cls);
     }
 
-    private void putAll(Map subscribers) {
-        handlersByClass.putAll(subscribers);
+    private void putAll(CommandHandler object, MethodMap methods) {
+        for (Class commandClass : methods.keySet()) {
+            handlersByClass.put(CommandClass.of(commandClass), object);
+        }
     }
 
     /* package */ void unregisterAll() {
@@ -125,11 +127,6 @@ private void putAll(Map subscribers) {
         }
     }
 
-    /* package */ boolean hasHandlerFor(Message command) {
-        final CommandHandlerMethod method = getHandler(CommandClass.of(command));
-        return method != null;
-    }
-
     /**
      * Ensures that no handlers already registered for the command classes of the passed dispatcher.
      *
diff --git a/server/src/main/java/org/spine3/server/command/RegistryUtil.java b/server/src/main/java/org/spine3/server/command/RegistryUtil.java
index b6930d9aa4e..4fb9b849a3b 100644
--- a/server/src/main/java/org/spine3/server/command/RegistryUtil.java
+++ b/server/src/main/java/org/spine3/server/command/RegistryUtil.java
@@ -21,7 +21,7 @@
 package org.spine3.server.command;
 
 import com.google.common.base.Joiner;
-import org.spine3.type.CommandClass;
+import org.spine3.server.type.CommandClass;
 
 import java.util.Set;
 
diff --git a/server/src/main/java/org/spine3/server/entity/EntityEventDispatcher.java b/server/src/main/java/org/spine3/server/entity/EntityEventDispatcher.java
index d087a43d8f6..994d7441cf0 100644
--- a/server/src/main/java/org/spine3/server/entity/EntityEventDispatcher.java
+++ b/server/src/main/java/org/spine3/server/entity/EntityEventDispatcher.java
@@ -22,8 +22,8 @@
 
 import com.google.protobuf.Message;
 import org.spine3.base.EventContext;
-import org.spine3.server.EventDispatcher;
-import org.spine3.type.EventClass;
+import org.spine3.server.event.EventDispatcher;
+import org.spine3.server.type.EventClass;
 
 /**
  * Delivers events to handlers (which are supposed to be entities).
diff --git a/server/src/main/java/org/spine3/server/command/GetTargetIdFromCommand.java b/server/src/main/java/org/spine3/server/entity/GetTargetIdFromCommand.java
similarity index 93%
rename from server/src/main/java/org/spine3/server/command/GetTargetIdFromCommand.java
rename to server/src/main/java/org/spine3/server/entity/GetTargetIdFromCommand.java
index cadceab3fe7..c40a3c67d72 100644
--- a/server/src/main/java/org/spine3/server/command/GetTargetIdFromCommand.java
+++ b/server/src/main/java/org/spine3/server/entity/GetTargetIdFromCommand.java
@@ -18,13 +18,11 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package org.spine3.server.command;
+package org.spine3.server.entity;
 
 import com.google.protobuf.Message;
 import org.spine3.base.CommandContext;
 import org.spine3.base.Identifiers;
-import org.spine3.server.entity.Entity;
-import org.spine3.server.entity.GetIdByFieldIndex;
 
 /**
  * Obtains a command target {@link Entity} ID based on a command {@link Message} and context.
diff --git a/server/src/main/java/org/spine3/server/error/CommandHandlerAlreadyRegisteredException.java b/server/src/main/java/org/spine3/server/error/CommandHandlerAlreadyRegisteredException.java
index 01f5a0c8c16..74e8c04fac5 100644
--- a/server/src/main/java/org/spine3/server/error/CommandHandlerAlreadyRegisteredException.java
+++ b/server/src/main/java/org/spine3/server/error/CommandHandlerAlreadyRegisteredException.java
@@ -19,7 +19,7 @@
  */
 package org.spine3.server.error;
 
-import org.spine3.type.CommandClass;
+import org.spine3.server.type.CommandClass;
 
 /**
  * Exception that is thrown when more than one handler
diff --git a/server/src/main/java/org/spine3/server/event/DispatcherRegistry.java b/server/src/main/java/org/spine3/server/event/DispatcherRegistry.java
index 8a50a9ec8a5..2ae5e814e26 100644
--- a/server/src/main/java/org/spine3/server/event/DispatcherRegistry.java
+++ b/server/src/main/java/org/spine3/server/event/DispatcherRegistry.java
@@ -21,8 +21,7 @@
 package org.spine3.server.event;
 
 import com.google.common.collect.HashMultimap;
-import org.spine3.server.EventDispatcher;
-import org.spine3.type.EventClass;
+import org.spine3.server.type.EventClass;
 
 import java.util.Set;
 
diff --git a/server/src/main/java/org/spine3/server/event/EventBus.java b/server/src/main/java/org/spine3/server/event/EventBus.java
index 1b3c6b2560a..9240794612e 100644
--- a/server/src/main/java/org/spine3/server/event/EventBus.java
+++ b/server/src/main/java/org/spine3/server/event/EventBus.java
@@ -20,7 +20,6 @@
 package org.spine3.server.event;
 
 import com.google.common.annotations.VisibleForTesting;
-import com.google.common.collect.ImmutableSet;
 import com.google.common.util.concurrent.MoreExecutors;
 import com.google.protobuf.Message;
 import org.slf4j.Logger;
@@ -28,21 +27,15 @@
 import org.spine3.base.Event;
 import org.spine3.base.EventContext;
 import org.spine3.base.Events;
-import org.spine3.server.EventDispatcher;
-import org.spine3.server.EventHandler;
-import org.spine3.server.Subscribe;
 import org.spine3.server.aggregate.AggregateRepository;
-import org.spine3.server.internal.EventHandlerMethod;
 import org.spine3.server.procman.ProcessManager;
-import org.spine3.type.EventClass;
+import org.spine3.server.type.EventClass;
 
 import java.lang.reflect.InvocationTargetException;
 import java.util.Collection;
-import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.Executor;
 
-import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
 
 /**
@@ -133,6 +126,15 @@ public static EventBus newInstance(EventStore eventStore, Executor executor) {
         return result;
     }
 
+    /**
+     * Determines the class of the event from the passed event record.
+     */
+    public static EventClass getEventClass(Event event) {
+        final Message message = Events.getMessage(event);
+        final EventClass result = EventClass.of(message);
+        return result;
+    }
+
     /**
      * Subscribes the event handler to receive events from the bus.
      *
@@ -144,17 +146,7 @@ public static EventBus newInstance(EventStore eventStore, Executor executor) {
      */
     public void subscribe(EventHandler object) {
         checkNotNull(object);
-
-        final Map handlers = EventHandlerMethod.scan(object);
-        final boolean handlersEmpty = handlers.isEmpty();
-        checkHandlersNotEmpty(object, handlersEmpty);
-        if (!handlersEmpty) {
-            handlerRegistry.subscribe(handlers);
-        }
-    }
-
-    private static void checkHandlersNotEmpty(Object object, boolean handlersEmpty) {
-        checkArgument(!handlersEmpty, "No event subscriber methods found in %s", object);
+        handlerRegistry.subscribe(object);
     }
 
     /**
@@ -171,13 +163,9 @@ public void register(EventDispatcher dispatcher) {
     }
 
     @VisibleForTesting
-    /* package */ Set getHandlers(EventClass eventClass) {
-        final Collection handlers = handlerRegistry.getSubscribers(eventClass);
-        final ImmutableSet.Builder result = ImmutableSet.builder();
-        for (EventHandlerMethod handler : handlers) {
-            result.add(handler.getTarget());
-        }
-        return result.build();
+    /* package */ Collection getHandlers(EventClass eventClass) {
+        final Collection result = handlerRegistry.getSubscribers(eventClass);
+        return result;
     }
 
     @VisibleForTesting
@@ -191,15 +179,9 @@ public void register(EventDispatcher dispatcher) {
      * @param object the object whose methods should be unregistered
      * @throws IllegalArgumentException if the object was not previously registered
      */
-    public void unsubscribe(Object object) {
+    public void unsubscribe(EventHandler object) {
         checkNotNull(object);
-
-        final Map handlers = EventHandlerMethod.scan(object);
-        final boolean handlersEmpty = handlers.isEmpty();
-        checkHandlersNotEmpty(object, handlersEmpty);
-        if (!handlersEmpty) {
-            unsubscribeMap(handlers);
-        }
+        handlerRegistry.usubscribe(object);
     }
 
     /**
@@ -209,16 +191,7 @@ public void unregister(EventDispatcher dispatcher) {
         dispatcherRegistry.unregister(dispatcher);
     }
 
-    /**
-     * Removes passed event handlers from the bus.
-     *
-     * @param handlers a map of the event handlers to remove
-     */
-    private void unsubscribeMap(Map handlers) {
-        handlerRegistry.unsubscribe(handlers);
-    }
-
-    private Collection getSubscribers(EventClass c) {
+    private Collection getSubscribers(EventClass c) {
         return handlerRegistry.getSubscribers(c);
     }
 
@@ -248,7 +221,7 @@ public void post(Event event) {
     }
 
     private void callDispatchers(Event event) {
-        final EventClass eventClass = Events.getEventClass(event);
+        final EventClass eventClass = getEventClass(event);
         final Collection dispatchers = dispatcherRegistry.getDispatchers(eventClass);
         for (EventDispatcher dispatcher : dispatchers) {
             dispatcher.dispatch(event);
@@ -256,14 +229,14 @@ private void callDispatchers(Event event) {
     }
 
     private void invokeHandlers(Message event, EventContext context) {
-        final Collection handlers = getSubscribers(EventClass.of(event));
+        final Collection handlers = getSubscribers(EventClass.of(event));
 
         if (handlers.isEmpty()) {
             handleDeadEvent(event);
             return;
         }
 
-        for (EventHandlerMethod handler : handlers) {
+        for (EventHandler handler : handlers) {
             invokeHandler(handler, event, context);
         }
     }
@@ -272,14 +245,14 @@ private void store(Event event) {
         eventStore.append(event);
     }
 
-    private void invokeHandler(final EventHandlerMethod handler, final Message event, final EventContext context) {
+    private void invokeHandler(final EventHandler target, final Message event, final EventContext context) {
         executor.execute(new Runnable() {
             @Override
             public void run() {
                 try {
-                    handler.invoke(event, context);
+                    target.handle(event, context);
                 } catch (InvocationTargetException e) {
-                    processHandlerException(handler, e);
+                    processHandlerException(e, event, context);
                 }
             }
         });
@@ -289,8 +262,11 @@ private static void handleDeadEvent(Message event) {
         log().warn("No handler defined for event class: " + event.getClass().getName());
     }
 
-    private static void processHandlerException(EventHandlerMethod handler, InvocationTargetException e) {
-        log().error("Exception invoking method: " + handler.getFullName(), e);
+    private static void processHandlerException(InvocationTargetException e,
+                                                Message eventMessage,
+                                                EventContext eventContext) {
+        log().error("Exception handling event. Event message: {}, context: {}, cause: {}",
+                                                              eventMessage, eventContext, e.getCause());
     }
 
     @Override
diff --git a/server/src/main/java/org/spine3/server/EventDispatcher.java b/server/src/main/java/org/spine3/server/event/EventDispatcher.java
similarity index 95%
rename from server/src/main/java/org/spine3/server/EventDispatcher.java
rename to server/src/main/java/org/spine3/server/event/EventDispatcher.java
index f7e6d3b29b0..ec0cff17ac8 100644
--- a/server/src/main/java/org/spine3/server/EventDispatcher.java
+++ b/server/src/main/java/org/spine3/server/event/EventDispatcher.java
@@ -18,10 +18,10 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package org.spine3.server;
+package org.spine3.server.event;
 
 import org.spine3.base.Event;
-import org.spine3.type.EventClass;
+import org.spine3.server.type.EventClass;
 
 import java.util.Set;
 
diff --git a/server/src/main/java/org/spine3/server/event/EventHandler.java b/server/src/main/java/org/spine3/server/event/EventHandler.java
new file mode 100644
index 00000000000..eae65f9ec65
--- /dev/null
+++ b/server/src/main/java/org/spine3/server/event/EventHandler.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright 2016, TeamDev Ltd. All rights reserved.
+ *
+ * Redistribution and use in source and/or binary forms, with or without
+ * modification, must retain the above copyright notice and the following
+ * disclaimer.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.spine3.server.event;
+
+import com.google.protobuf.Message;
+import org.spine3.base.EventContext;
+import org.spine3.server.reflect.EventHandlerMethod;
+import org.spine3.server.reflect.MethodRegistry;
+
+import java.lang.reflect.InvocationTargetException;
+
+/**
+ * The abstract base for objects that can be subscribed to receive events from {@link EventBus}.
+ *
+ * 
Objects may also receive events via {@link EventDispatcher}s that can be registered with {@code EventBus}.
+ *
+ * @author Alexander Yevsyukov
+ * @see EventBus#subscribe(EventHandler)
+ * @see EventBus#register(EventDispatcher)
+ */
+public abstract class EventHandler {
+
+    public void handle(Message eventMessage, EventContext commandContext) throws InvocationTargetException {
+        final EventHandlerMethod method = getHandlerMethod(eventMessage.getClass());
+
+        method.invoke(this, eventMessage, commandContext);
+    }
+
+    private EventHandlerMethod getHandlerMethod(Class eventClass) {
+        return MethodRegistry.getInstance().get(getClass(), eventClass, EventHandlerMethod.factory());
+    }
+}
diff --git a/server/src/main/java/org/spine3/server/event/HandlerRegistry.java b/server/src/main/java/org/spine3/server/event/HandlerRegistry.java
index 5e9ea8dfc54..d35b9f1e1cb 100644
--- a/server/src/main/java/org/spine3/server/event/HandlerRegistry.java
+++ b/server/src/main/java/org/spine3/server/event/HandlerRegistry.java
@@ -23,12 +23,17 @@
 import com.google.common.collect.HashMultimap;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Multimap;
-import org.spine3.server.internal.EventHandlerMethod;
-import org.spine3.type.EventClass;
+import com.google.protobuf.Message;
+import org.spine3.server.reflect.EventHandlerMethod;
+import org.spine3.server.reflect.MethodMap;
+import org.spine3.server.type.EventClass;
 
 import java.util.Collection;
 import java.util.Map;
 
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+
 /**
  * The registry of event handling methods by event class.
  *
@@ -38,48 +43,44 @@
  */
 /* package */ class HandlerRegistry {
 
-    private final Multimap handlersByClass = HashMultimap.create();
-
-    /* package */ void subscribe(Map handlers) {
-        for (Map.Entry entry : handlers.entrySet()) {
-            handlersByClass.put(entry.getKey(), entry.getValue());
-        }
-    }
-
-    /* package */ void unsubscribe(Map handlers) {
-        for (Map.Entry entry : handlers.entrySet()) {
+    private final Multimap handlersByEventClass = HashMultimap.create();
 
-            final EventClass eventClass = entry.getKey();
-            final EventHandlerMethod handler = entry.getValue();
-
-            unsubscribe(eventClass, handler);
+    /* package */ void subscribe(EventHandler object) {
+        checkNotNull(object);
+        final MethodMap handlers = EventHandlerMethod.scan(object);
+        final boolean handlersEmpty = handlers.isEmpty();
+        checkHandlersNotEmpty(object, handlersEmpty);
+        for (Map.Entry, EventHandlerMethod> entry : handlers.entrySet()) {
+            handlersByEventClass.put(EventClass.of(entry.getKey()), object);
         }
     }
 
-    private void unsubscribe(EventClass c, EventHandlerMethod handler) {
-        final Collection currentSubscribers = handlersByClass.get(c);
-        if (!currentSubscribers.contains(handler)) {
-            throw handlerMethodWasNotRegistered(handler);
+    /* package */ void usubscribe(EventHandler object) {
+        final MethodMap handlers = EventHandlerMethod.scan(object);
+        final boolean handlersEmpty = handlers.isEmpty();
+        checkHandlersNotEmpty(object, handlersEmpty);
+        if (!handlersEmpty) {
+            for (Class eventClass : handlers.keySet()) {
+                handlersByEventClass.remove(EventClass.of(eventClass), object);
+            }
         }
-        currentSubscribers.remove(handler);
     }
 
     /* package */ void unsubscribeAll() {
-        handlersByClass.clear();
+        handlersByEventClass.clear();
         EventBus.log().info("All subscribers cleared.");
     }
 
-    private static IllegalArgumentException handlerMethodWasNotRegistered(EventHandlerMethod handler) {
-        return new IllegalArgumentException(
-                "Cannot un-subscribe the event handler, which was not subscribed before:" + handler.getFullName());
-    }
-
-    /* package */ Collection getSubscribers(EventClass c) {
-        return ImmutableList.copyOf(handlersByClass.get(c));
+    /* package */ Collection getSubscribers(EventClass c) {
+        return ImmutableList.copyOf(handlersByEventClass.get(c));
     }
 
     /* package */ boolean hasSubscribers(EventClass eventClass) {
-        final Collection handlers = getSubscribers(eventClass);
+        final Collection handlers = getSubscribers(eventClass);
         return !handlers.isEmpty();
     }
+
+    private static void checkHandlersNotEmpty(Object object, boolean handlersEmpty) {
+        checkArgument(!handlersEmpty, "No event subscriber methods found in %s", object);
+    }
 }
diff --git a/server/src/main/java/org/spine3/server/Subscribe.java b/server/src/main/java/org/spine3/server/event/Subscribe.java
similarity index 96%
rename from server/src/main/java/org/spine3/server/Subscribe.java
rename to server/src/main/java/org/spine3/server/event/Subscribe.java
index 179f6364732..7b8e2cb1b2b 100644
--- a/server/src/main/java/org/spine3/server/Subscribe.java
+++ b/server/src/main/java/org/spine3/server/event/Subscribe.java
@@ -18,9 +18,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package org.spine3.server;
-
-import org.spine3.server.event.EventBus;
+package org.spine3.server.event;
 
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
diff --git a/server/src/main/java/org/spine3/server/FailureThrowable.java b/server/src/main/java/org/spine3/server/failure/FailureThrowable.java
similarity index 96%
rename from server/src/main/java/org/spine3/server/FailureThrowable.java
rename to server/src/main/java/org/spine3/server/failure/FailureThrowable.java
index db10756efe6..f0ef6f92d92 100644
--- a/server/src/main/java/org/spine3/server/FailureThrowable.java
+++ b/server/src/main/java/org/spine3/server/failure/FailureThrowable.java
@@ -18,7 +18,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package org.spine3.server;
+package org.spine3.server.failure;
 
 import com.google.common.base.Throwables;
 import com.google.protobuf.Any;
@@ -32,7 +32,6 @@
  *
  * @author Alexander Yevsyukov
  */
-@SuppressWarnings("AbstractClassWithoutAbstractMethods")
 public abstract class FailureThrowable extends Throwable {
 
     private static final long serialVersionUID = 0L;
diff --git a/server/src/main/java/org/spine3/server/EventHandler.java b/server/src/main/java/org/spine3/server/failure/package-info.java
similarity index 70%
rename from server/src/main/java/org/spine3/server/EventHandler.java
rename to server/src/main/java/org/spine3/server/failure/package-info.java
index 3fd044c56d8..5784673ca97 100644
--- a/server/src/main/java/org/spine3/server/EventHandler.java
+++ b/server/src/main/java/org/spine3/server/failure/package-info.java
@@ -18,18 +18,11 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package org.spine3.server;
-
-import org.spine3.server.event.EventBus;
-
 /**
- * The marker interface for objects that can be subscribed to receive events from {@link EventBus}.
- *
- * 
Objects may also receive events via {@link EventDispatcher}s that can be registered with {@code EventBus}.
- *
- * @author Alexander Yevsyukov
- * @see EventBus#subscribe(EventHandler)
- * @see EventBus#register(EventDispatcher)
+ * This package provides classes for working with business failures.
  */
-public interface EventHandler {
-}
+
+@ParametersAreNonnullByDefault
+package org.spine3.server.failure;
+
+import javax.annotation.ParametersAreNonnullByDefault;
diff --git a/server/src/main/java/org/spine3/server/procman/ProcessManager.java b/server/src/main/java/org/spine3/server/procman/ProcessManager.java
index 1ef1b2c47af..76e5c8c6ae9 100644
--- a/server/src/main/java/org/spine3/server/procman/ProcessManager.java
+++ b/server/src/main/java/org/spine3/server/procman/ProcessManager.java
@@ -35,26 +35,23 @@
 import org.spine3.base.Events;
 import org.spine3.base.Identifiers;
 import org.spine3.base.UserId;
-import org.spine3.server.CommandHandler;
 import org.spine3.server.command.CommandBus;
 import org.spine3.server.entity.Entity;
-import org.spine3.server.internal.CommandHandlerMethod;
-import org.spine3.server.internal.EventHandlerMethod;
 import org.spine3.server.reflect.Classes;
-import org.spine3.server.reflect.MethodMap;
+import org.spine3.server.reflect.CommandHandlerMethod;
+import org.spine3.server.reflect.EventHandlerMethod;
+import org.spine3.server.reflect.MethodRegistry;
 import org.spine3.time.ZoneOffset;
 
 import javax.annotation.CheckReturnValue;
 import javax.annotation.Nullable;
 import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
 import java.util.List;
 import java.util.Set;
 
 import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.base.Preconditions.checkState;
-import static org.spine3.server.internal.EventHandlerMethod.PREDICATE;
-import static org.spine3.server.internal.EventHandlerMethod.checkModifiers;
+import static org.spine3.server.reflect.EventHandlerMethod.PREDICATE;
 
 /**
  * An independent component that reacts to domain events in a cross-aggregate, eventually consistent manner.
@@ -80,32 +77,13 @@
  * @param  the type of the process manager state
  * @author Alexander Litus
  */
-public abstract class ProcessManager extends Entity implements CommandHandler {
-
-    /**
-     * Keeps initialization state of the process manager.
-     */
-    private volatile boolean initialized = false;
+public abstract class ProcessManager extends Entity {
 
     /**
      * The Command Bus to post routed commands.
      */
     private volatile CommandBus commandBus;
 
-    /**
-     * The map of command handler methods of this process manager.
-     *
-     * @see Registry
-     */
-    private MethodMap commandHandlers;
-
-    /**
-     * The map of event handler methods of this process manager.
-     *
-     * @see Registry
-     */
-    private MethodMap eventHandlers;
-
     /**
      * Creates a new instance.
      *
@@ -117,23 +95,6 @@ public ProcessManager(I id) {
         super(id);
     }
 
-    /**
-     * Performs initialization of the instance and registers this class of process managers
-     * in the {@link Registry} if it is not registered yet.
-     */
-    private void init() {
-        if (!this.initialized) {
-            final Registry registry = Registry.getInstance();
-            final Class pmClass = getClass();
-            if (!registry.contains(pmClass)) {
-                registry.register(pmClass);
-            }
-            commandHandlers = registry.getCommandHandlers(pmClass);
-            eventHandlers = registry.getEventHandlers(pmClass);
-            this.initialized = true;
-        }
-    }
-
     /**
      * The method to inject {@code CommandBus} instance from the repository.
      */
@@ -161,14 +122,16 @@ protected List dispatchCommand(Message command, CommandContext context)
         checkNotNull(command);
         checkNotNull(context);
 
-        init();
         final Class commandClass = command.getClass();
-        final Method method = commandHandlers.get(commandClass);
+        final CommandHandlerMethod method = MethodRegistry.getInstance()
+                                                          .get(getClass(),
+                                                               commandClass,
+                                                               CommandHandlerMethod.factory());
         if (method == null) {
             throw missingCommandHandler(commandClass);
         }
-        final CommandHandlerMethod commandHandler = new CommandHandlerMethod(this, method);
-        final List events = commandHandler.invoke(command, context);
+
+        final List events = method.invoke(this, command, context);
         final List eventRecords = toEvents(events, context.getCommandId());
         return eventRecords;
     }
@@ -199,14 +162,14 @@ protected void dispatchEvent(Message event, EventContext context) throws Invocat
         checkNotNull(context);
         checkNotNull(event);
 
-        init();
         final Class eventClass = event.getClass();
-        final Method method = eventHandlers.get(eventClass);
+        final EventHandlerMethod method = MethodRegistry.getInstance()
+                                                        .get(getClass(), eventClass, EventHandlerMethod.factory());
         if (method == null) {
             throw missingEventHandler(eventClass);
         }
-        final EventHandlerMethod handler = new EventHandlerMethod(this, method);
-        handler.invoke(event, context);
+
+        method.invoke(this, event, context);
     }
 
     /**
@@ -386,52 +349,4 @@ private IllegalStateException missingEventHandler(Class event
                 eventClass, this.getClass()));
     }
 
-    /**
-     * The registry of method maps for all process manager classes.
-     *
-     * 
This registry is used for caching command/event handlers.
-     * Process managers register their classes in {@link ProcessManager#init()} method.
-     */
-    private static class Registry {
-
-        private final MethodMap.Registry commandHandlers = new MethodMap.Registry<>();
-        private final MethodMap.Registry eventHandlers = new MethodMap.Registry<>();
-
-        /* package */ void register(Class clazz) {
-            commandHandlers.register(clazz, CommandHandlerMethod.PREDICATE);
-            CommandHandlerMethod.checkModifiers(commandHandlers.get(clazz).values());
-
-            eventHandlers.register(clazz, PREDICATE);
-            checkModifiers(eventHandlers.get(clazz).values());
-        }
-
-        @CheckReturnValue
-        /* package */ boolean contains(Class clazz) {
-            final boolean result = commandHandlers.contains(clazz) && eventHandlers.contains(clazz);
-            return result;
-        }
-
-        @CheckReturnValue
-        /* package */ MethodMap getCommandHandlers(Class clazz) {
-            final MethodMap result = commandHandlers.get(clazz);
-            return result;
-        }
-
-        @CheckReturnValue
-        /* package */ MethodMap getEventHandlers(Class clazz) {
-            final MethodMap result = eventHandlers.get(clazz);
-            return result;
-        }
-
-        @CheckReturnValue
-        /* package */ static Registry getInstance() {
-            return Singleton.INSTANCE.value;
-        }
-
-        private enum Singleton {
-            INSTANCE;
-            @SuppressWarnings("NonSerializableFieldInSerializableClass")
-            private final Registry value = new Registry();
-        }
-    }
 }
diff --git a/server/src/main/java/org/spine3/server/procman/ProcessManagerRepository.java b/server/src/main/java/org/spine3/server/procman/ProcessManagerRepository.java
index 3a22cf1e479..0e9d1de544c 100644
--- a/server/src/main/java/org/spine3/server/procman/ProcessManagerRepository.java
+++ b/server/src/main/java/org/spine3/server/procman/ProcessManagerRepository.java
@@ -30,14 +30,15 @@
 import org.spine3.base.EventContext;
 import org.spine3.base.Events;
 import org.spine3.server.BoundedContext;
-import org.spine3.server.CommandDispatcher;
 import org.spine3.server.command.CommandBus;
+import org.spine3.server.command.CommandDispatcher;
 import org.spine3.server.entity.EntityEventDispatcher;
 import org.spine3.server.entity.EntityRepository;
-import org.spine3.server.command.GetTargetIdFromCommand;
+import org.spine3.server.entity.GetTargetIdFromCommand;
 import org.spine3.server.entity.IdFunction;
-import org.spine3.type.CommandClass;
-import org.spine3.type.EventClass;
+import org.spine3.server.event.EventBus;
+import org.spine3.server.type.CommandClass;
+import org.spine3.server.type.EventClass;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -112,7 +113,7 @@ public Set getEventClasses() {
      * @throws IllegalArgumentException if commands of this type are not handled by the process manager
      */
     @Override
-    public List dispatch(Command command)
+    public void dispatch(Command command)
             throws InvocationTargetException, IllegalStateException, IllegalArgumentException {
         final Message commandMessage = getMessage(checkNotNull(command));
         final CommandContext context = command.getContext();
@@ -122,7 +123,17 @@ public List dispatch(Command command)
         final PM manager = load(id);
         final List events = manager.dispatchCommand(commandMessage, context);
         store(manager);
-        return events;
+        postEvents(events);
+    }
+
+    /**
+     * Posts passed events to {@link EventBus}.
+     */
+    private void postEvents(Iterable events) {
+        final EventBus eventBus = getBoundedContext().getEventBus();
+        for (Event event : events) {
+            eventBus.post(event);
+        }
     }
 
     /**
diff --git a/server/src/main/java/org/spine3/server/projection/Projection.java b/server/src/main/java/org/spine3/server/projection/Projection.java
index 15bf01c5ab5..e134d022946 100644
--- a/server/src/main/java/org/spine3/server/projection/Projection.java
+++ b/server/src/main/java/org/spine3/server/projection/Projection.java
@@ -24,15 +24,14 @@
 import com.google.protobuf.Message;
 import org.spine3.base.EventContext;
 import org.spine3.server.entity.Entity;
-import org.spine3.server.internal.EventHandlerMethod;
 import org.spine3.server.reflect.Classes;
-import org.spine3.server.reflect.MethodMap;
+import org.spine3.server.reflect.EventHandlerMethod;
+import org.spine3.server.reflect.MethodRegistry;
 
 import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
 
 import static com.google.common.base.Throwables.propagate;
-import static org.spine3.server.internal.EventHandlerMethod.PREDICATE;
+import static org.spine3.server.reflect.EventHandlerMethod.PREDICATE;
 
 /**
  * {@link Projection} holds a structural representation of data extracted from a stream of events.
@@ -49,8 +48,6 @@
  */
 public abstract class Projection extends Entity {
 
-    private MethodMap handlers;
-
     /**
      * Creates a new instance.
      *
@@ -63,44 +60,23 @@ public Projection(I id) {
     }
 
     protected void handle(Message event, EventContext ctx) {
-        init();
         dispatch(event, ctx);
     }
 
     private void dispatch(Message event, EventContext ctx) {
         final Class eventClass = event.getClass();
-        final Method method = handlers.get(eventClass);
+        final EventHandlerMethod method = MethodRegistry.getInstance()
+                                                        .get(getClass(), eventClass, EventHandlerMethod.factory());
         if (method == null) {
             throw missingEventHandler(eventClass);
         }
-        final EventHandlerMethod handler = new EventHandlerMethod(this, method);
         try {
-            handler.invoke(event, ctx);
+            method.invoke(this, event, ctx);
         } catch (InvocationTargetException e) {
             propagate(e);
         }
     }
 
-    protected boolean isInitialized() {
-        return handlers != null;
-    }
-
-    /**
-     * Performs initialization of the instance.
-     */
-    protected void init() {
-        if (!isInitialized()) {
-            final Registry registry = Registry.getInstance();
-            final Class thisClass = getClass();
-
-            if (!registry.contains(thisClass)) {
-                registry.register(thisClass);
-            }
-
-            handlers = registry.getEventHandlers(thisClass);
-        }
-    }
-
     /**
      * Returns the set of event classes handled by the passed {@link Projection} class.
      *
@@ -116,31 +92,4 @@ private IllegalStateException missingEventHandler(Class event
                 eventClass, this.getClass()));
     }
 
-    private static class Registry {
-        private final MethodMap.Registry eventHandlers = new MethodMap.Registry<>();
-
-        boolean contains(Class clazz) {
-            return eventHandlers.contains(clazz);
-        }
-
-        void register(Class clazz) {
-            eventHandlers.register(clazz, PREDICATE);
-        }
-
-        MethodMap getEventHandlers(Class clazz) {
-            final MethodMap result = eventHandlers.get(clazz);
-            return result;
-        }
-
-        static Registry getInstance() {
-            return RegistrySingleton.INSTANCE.value;
-        }
-
-        private enum RegistrySingleton {
-            INSTANCE;
-
-            @SuppressWarnings("NonSerializableFieldInSerializableClass")
-            private final Registry value = new Registry();
-        }
-    }
 }
\ No newline at end of file
diff --git a/server/src/main/java/org/spine3/server/projection/ProjectionRepository.java b/server/src/main/java/org/spine3/server/projection/ProjectionRepository.java
index 378dc8c657c..f0083ca0c3e 100644
--- a/server/src/main/java/org/spine3/server/projection/ProjectionRepository.java
+++ b/server/src/main/java/org/spine3/server/projection/ProjectionRepository.java
@@ -26,12 +26,12 @@
 import org.spine3.base.EventContext;
 import org.spine3.base.Events;
 import org.spine3.server.BoundedContext;
-import org.spine3.server.EventDispatcher;
 import org.spine3.server.entity.EntityRepository;
+import org.spine3.server.event.EventDispatcher;
 import org.spine3.server.storage.EntityStorage;
 import org.spine3.server.storage.ProjectionStorage;
 import org.spine3.server.storage.StorageFactory;
-import org.spine3.type.EventClass;
+import org.spine3.server.type.EventClass;
 
 import javax.annotation.Nonnull;
 import java.util.Set;
diff --git a/server/src/main/java/org/spine3/server/reflect/Classes.java b/server/src/main/java/org/spine3/server/reflect/Classes.java
index 18fad13a09f..d6b59f9dbfd 100644
--- a/server/src/main/java/org/spine3/server/reflect/Classes.java
+++ b/server/src/main/java/org/spine3/server/reflect/Classes.java
@@ -75,7 +75,7 @@ public static ImmutableSet> getHandledMessageClasses(Cl
         for (Method method : clazz.getDeclaredMethods()) {
             final boolean methodMatches = predicate.apply(method);
             if (methodMatches) {
-                final Class firstParamType = Methods.getFirstParamType(method);
+                final Class firstParamType = HandlerMethod.getFirstParamType(method);
                 builder.add(firstParamType);
             }
         }
diff --git a/server/src/main/java/org/spine3/server/internal/CommandHandlerMethod.java b/server/src/main/java/org/spine3/server/reflect/CommandHandlerMethod.java
similarity index 74%
rename from server/src/main/java/org/spine3/server/internal/CommandHandlerMethod.java
rename to server/src/main/java/org/spine3/server/reflect/CommandHandlerMethod.java
index a4eb6f18911..71e2ac48d31 100644
--- a/server/src/main/java/org/spine3/server/internal/CommandHandlerMethod.java
+++ b/server/src/main/java/org/spine3/server/reflect/CommandHandlerMethod.java
@@ -18,16 +18,13 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package org.spine3.server.internal;
+package org.spine3.server.reflect;
 
 import com.google.common.base.Predicate;
-import com.google.common.collect.ImmutableMap;
 import com.google.protobuf.Message;
 import org.spine3.base.CommandContext;
-import org.spine3.server.Assign;
-import org.spine3.server.CommandHandler;
-import org.spine3.server.reflect.MethodMap;
-import org.spine3.type.CommandClass;
+import org.spine3.server.command.Assign;
+import org.spine3.server.command.CommandHandler;
 
 import javax.annotation.CheckReturnValue;
 import javax.annotation.Nullable;
@@ -35,7 +32,6 @@
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.util.List;
-import java.util.Map;
 
 import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
@@ -45,7 +41,7 @@
  *
  * @author Alexander Yevsyukov
  */
-public class CommandHandlerMethod extends MessageHandlerMethod {
+public class CommandHandlerMethod extends HandlerMethod {
 
     /**
      * The instance of the predicate to filter command handler methods of a class.
@@ -55,23 +51,22 @@ public class CommandHandlerMethod extends MessageHandlerMethod R invoke(Message message, CommandContext context) throws InvocationTargetException {
-        final R handlingResult = super.invoke(message, context);
+    public  R invoke(Object target, Message message, CommandContext context) throws InvocationTargetException {
+        final R handlingResult = super.invoke(target, message, context);
 
-        final List events = commandHandlingResultToEvents(handlingResult);
+        final List events = toList(handlingResult);
         // The list of event messages/records is the return type expected.
         @SuppressWarnings("unchecked")
         final R result = (R) events;
@@ -85,7 +80,7 @@ public  R invoke(Message message, CommandContext context) throws InvocationTa
      *                       or {@code null}.
      * @return the list of event messages or an empty list if {@code null} is passed
      */
-    protected  List commandHandlingResultToEvents(@Nullable R handlingResult) {
+    private static  List toList(@Nullable R handlingResult) {
         if (handlingResult == null) {
             return emptyList();
         }
@@ -110,29 +105,9 @@ protected  List commandHandlingResultToEvents(@Nullable R
      * @return immutable map
      */
     @CheckReturnValue
-    public static Map scan(CommandHandler object) {
-        final ImmutableMap.Builder result = ImmutableMap.builder();
-
-        final Map handlers = getHandlers(object);
-        result.putAll(handlers);
-
-        return result.build();
-    }
-
-    private static Map getHandlers(CommandHandler object) {
-        final ImmutableMap.Builder result = ImmutableMap.builder();
-
-        final Predicate methodPredicate = PREDICATE;
-        final MethodMap handlers = new MethodMap(object.getClass(), methodPredicate);
-
-        checkModifiers(handlers.values());
-
-        for (Map.Entry, Method> entry : handlers.entrySet()) {
-            final CommandClass commandClass = CommandClass.of(entry.getKey());
-            final CommandHandlerMethod handler = new CommandHandlerMethod(object, entry.getValue());
-            result.put(commandClass, handler);
-        }
-        return result.build();
+    public static MethodMap scan(CommandHandler object) {
+        final MethodMap handlers = MethodMap.create(object.getClass(), factory());
+        return handlers;
     }
 
     /**
@@ -141,7 +116,7 @@ private static Map getHandlers(CommandHandle
      * 
Logs warning for the methods with a non-public modifier.
      *
      * @param methods the methods to check
-     * @see MessageHandlerMethod#log()
+     * @see HandlerMethod#log()
      */
     public static void checkModifiers(Iterable methods) {
         for (Method method : methods) {
@@ -152,6 +127,41 @@ public static void checkModifiers(Iterable methods) {
         }
     }
 
+    public static HandlerMethod.Factory factory() {
+        return Factory.instance();
+    }
+
+    /**
+     * The factory for filtering methods that match {@code CommandHandlerMethod} specification.
+     */
+    private static class Factory implements HandlerMethod.Factory {
+
+        @Override
+        public Class getMethodClass() {
+            return CommandHandlerMethod.class;
+        }
+
+        @Override
+        public CommandHandlerMethod create(Method method) {
+            return new CommandHandlerMethod(method);
+        }
+
+        @Override
+        public Predicate getPredicate() {
+            return PREDICATE;
+        }
+
+        private enum Singleton {
+            INSTANCE;
+            @SuppressWarnings("NonSerializableFieldInSerializableClass")
+            private final Factory value = new Factory();
+        }
+
+        private static Factory instance() {
+            return Singleton.INSTANCE.value;
+        }
+    }
+
     /**
      * The predicate class that allows to filter command handling methods.
      */
diff --git a/server/src/main/java/org/spine3/server/internal/EventHandlerMethod.java b/server/src/main/java/org/spine3/server/reflect/EventHandlerMethod.java
similarity index 73%
rename from server/src/main/java/org/spine3/server/internal/EventHandlerMethod.java
rename to server/src/main/java/org/spine3/server/reflect/EventHandlerMethod.java
index 5737bd48e10..80935ca14be 100644
--- a/server/src/main/java/org/spine3/server/internal/EventHandlerMethod.java
+++ b/server/src/main/java/org/spine3/server/reflect/EventHandlerMethod.java
@@ -18,22 +18,18 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package org.spine3.server.internal;
+package org.spine3.server.reflect;
 
 import com.google.common.base.Predicate;
-import com.google.common.collect.ImmutableMap;
 import com.google.protobuf.Message;
 import org.spine3.base.EventContext;
-import org.spine3.server.Subscribe;
-import org.spine3.server.reflect.MethodMap;
-import org.spine3.type.EventClass;
+import org.spine3.server.event.Subscribe;
 
 import javax.annotation.CheckReturnValue;
 import javax.annotation.Nullable;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
-import java.util.Map;
 
 import static com.google.common.base.Preconditions.checkNotNull;
 
@@ -42,7 +38,7 @@
  *
  * @author Alexander Yevsyukov
  */
-public class EventHandlerMethod extends MessageHandlerMethod {
+public class EventHandlerMethod extends HandlerMethod {
 
     /**
      * The instance of the predicate to filter event handler methods of a class.
@@ -52,11 +48,10 @@ public class EventHandlerMethod extends MessageHandlerMethod scan(Object target) {
-        final ImmutableMap.Builder result = ImmutableMap.builder();
-
-        // Scan for declared event handler methods.
-        final MethodMap handlers = new MethodMap(target.getClass(), PREDICATE);
-        checkModifiers(handlers.values());
-
-        for (ImmutableMap.Entry, Method> entry : handlers.entrySet()) {
-            final EventClass eventClass = EventClass.of(entry.getKey());
-            final EventHandlerMethod handler = new EventHandlerMethod(target, entry.getValue());
-            result.put(eventClass, handler);
-        }
-        return result.build();
+    public static MethodMap scan(Object target) {
+        final MethodMap result = MethodMap.create(target.getClass(), factory());
+        return result;
     }
 
     @Override
-    public  R invoke(Message message, EventContext context) throws InvocationTargetException {
-        return super.invoke(message, context);
+    public  R invoke(Object target, Message message, EventContext context) throws InvocationTargetException {
+        return super.invoke(target, message, context);
     }
 
     /**
@@ -92,7 +77,7 @@ public  R invoke(Message message, EventContext context) throws InvocationTarg
      * 
Logs warning for the methods with a non-public modifier.
      *
      * @param methods the map of methods to check
-     * @see MessageHandlerMethod#log()
+     * @see HandlerMethod#log()
      */
     public static void checkModifiers(Iterable methods) {
         for (Method method : methods) {
@@ -104,13 +89,42 @@ public static void checkModifiers(Iterable methods) {
     }
 
     /**
-     * {@inheritDoc}
+     * @return the factory for filtering and creating event handler methods
      */
-    @Override // Promote to public to make it visible to routines inspecting EventBus.
-    public Object getTarget() {
-        return super.getTarget();
+    public static HandlerMethod.Factory factory() {
+        return Factory.instance();
     }
 
+    /**
+     * The factory for filtering methods that match {@code EventHandlerMethod} specification.
+     */
+    private static class Factory implements HandlerMethod.Factory {
+
+        @Override
+        public Class getMethodClass() {
+            return EventHandlerMethod.class;
+        }
+
+        @Override
+        public EventHandlerMethod create(Method method) {
+            return new EventHandlerMethod(method);
+        }
+
+        @Override
+        public Predicate getPredicate() {
+            return PREDICATE;
+        }
+
+        private enum Singleton {
+            INSTANCE;
+            @SuppressWarnings("NonSerializableFieldInSerializableClass")
+            private final Factory value = new Factory();
+        }
+
+        private static Factory instance() {
+            return Singleton.INSTANCE.value;
+        }
+    }
     /**
      * The predicate class allowing to filter event handling methods.
      *
diff --git a/server/src/main/java/org/spine3/server/internal/MessageHandlerMethod.java b/server/src/main/java/org/spine3/server/reflect/HandlerMethod.java
similarity index 64%
rename from server/src/main/java/org/spine3/server/internal/MessageHandlerMethod.java
rename to server/src/main/java/org/spine3/server/reflect/HandlerMethod.java
index 9edd4caecc3..ebc50cc9cce 100644
--- a/server/src/main/java/org/spine3/server/internal/MessageHandlerMethod.java
+++ b/server/src/main/java/org/spine3/server/reflect/HandlerMethod.java
@@ -17,12 +17,12 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
-package org.spine3.server.internal;
+package org.spine3.server.reflect;
 
+import com.google.common.base.Predicate;
 import com.google.protobuf.Message;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-import org.spine3.server.reflect.Methods;
 
 import javax.annotation.Nullable;
 import java.lang.reflect.InvocationTargetException;
@@ -41,44 +41,43 @@
  *
  * @author Mikhail Melnik
  * @author Alexander Yevsyukov
-
- * @param  the type of the target object
  * @param  the type of the message context or {@code Void} if context is not used
  */
-@SuppressWarnings("AbstractClassWithoutAbstractMethods")
-public abstract class MessageHandlerMethod {
+public abstract class HandlerMethod {
 
     /**
-     * Object sporting the handler method.
+     * The method to be called.
      */
-    private final T target;
+    private final Method method;
 
     /**
-     * Handler method.
+     * The number of parameters the method has.
      */
-    private final Method method;
+    private final int paramCount;
 
     /**
      * Creates a new instance to wrap {@code method} on {@code target}.
      *
-     * @param target object to which the method applies
      * @param method subscriber method
      */
-    protected MessageHandlerMethod(T target, Method method) {
-        this.target = checkNotNull(target);
+    protected HandlerMethod(Method method) {
         this.method = checkNotNull(method);
+        this.paramCount = method.getParameterTypes().length;
         method.setAccessible(true);
     }
 
     protected static void warnOnWrongModifier(String messageFormat, Method method) {
-        log().warn(messageFormat, Methods.getFullMethodName(method));
+        log().warn(messageFormat, getFullMethodName(method));
     }
 
     /**
-     * @return the target object on which the method call is made
+     * Returns a full method name without parameters.
+     *
+     * @param method a method to get name for
+     * @return full method name
      */
-    protected T getTarget() {
-        return target;
+    private static String getFullMethodName(Method method) {
+        return method.getDeclaringClass().getName() + '.' + method.getName() + "()";
     }
 
     /**
@@ -104,17 +103,25 @@ protected boolean isPrivate() {
         return result;
     }
 
+    //TODO:2016-04-19:alexander.yevsyukov: Check the value returned by this method in the invoke() methods below.
+    // See if we can have a common internal method that accepts null as the context parameter and ignores it
+    // if the underlying method accepts only one parameter.
+
+    protected int getParamCount() {
+        return paramCount;
+    }
+
     /**
      * Invokes the wrapped subscriber method to handle {@code message} with the {@code context}.
      *
      * @param      the type of the expected handler invocation result
-     * @param message the message to handle
+     * @param target  the target object on which call the method
+     * @param message the message to handle   @return the result of message handling
      * @param context the context of the message
-     * @return the result of message handling
      * @throws InvocationTargetException if the wrapped method throws any {@link Throwable} that is not an {@link Error}.
      *                                   {@code Error} instances are propagated as-is.
      */
-    protected  R invoke(Message message, C context) throws InvocationTargetException {
+    protected  R invoke(Object target, Message message, C context) throws InvocationTargetException {
         checkNotNull(message);
         checkNotNull(context);
         try {
@@ -136,12 +143,13 @@ protected  R invoke(Message message, C context) throws InvocationTargetExcept
      * Invokes the wrapped subscriber method to handle {@code message}.
      *
      * @param      the type of the expected handler invocation result
-     * @param message a message to handle
+     * @param target  the target object on which call the method
+     * @param message  a message to handle
      * @return the result of message handling
-     * @throws InvocationTargetException if the wrapped method throws any {@link Throwable} that is not an {@link Error}.
-     *                                   {@code Error} instances are propagated as-is.
+     * @throws InvocationTargetException if the wrapped method throws any {@link Throwable} that is not
+     *                                   an {@link Error}. {@code Error} instances are propagated as-is.
      */
-    protected  R invoke(Message message) throws InvocationTargetException {
+    protected  R invoke(Object target, Message message) throws InvocationTargetException {
         checkNotNull(message);
         try {
             @SuppressWarnings("unchecked")
@@ -167,7 +175,7 @@ protected  R invoke(Message message) throws InvocationTargetException {
      * @return full name of the subscriber
      */
     public String getFullName() {
-        return Methods.getFullMethodName(method);
+        return getFullMethodName(method);
     }
 
     /**
@@ -182,8 +190,7 @@ public String toString() {
     @Override
     public int hashCode() {
         final int prime = 31;
-        return (prime + method.hashCode()) * prime
-                + System.identityHashCode(target);
+        return (prime + method.hashCode());
     }
 
     @Override
@@ -194,19 +201,48 @@ public boolean equals(@Nullable Object obj) {
         if (obj == null || getClass() != obj.getClass()) {
             return false;
         }
-        final MessageHandlerMethod other = (MessageHandlerMethod) obj;
+        final HandlerMethod other = (HandlerMethod) obj;
+
+        return Objects.equals(this.method, other.method);
+    }
+
+    /**
+     * Returns the class of the first parameter of the passed handler method object.
+     *
+     * 
It is expected that the first parameter of the passed method is always of
+     * a class implementing {@link Message}.
+     *
+     * @param handler the method object to take first parameter type from
+     * @return the class of the first method parameter
+     * @throws ClassCastException if the first parameter isn't a class implementing {@link Message}
+     */
+    /* package */ static Class getFirstParamType(Method handler) {
+        @SuppressWarnings("unchecked") /* we always expect first param as {@link Message} */
+        final Class result = (Class) handler.getParameterTypes()[0];
+        return result;
+    }
+
+    /**
+     * The interface for factory objects that can filter {@link Method} objects
+     * that represent handler methods and create corresponding {@code HandlerMethod} instances
+     * that wrap those methods.
+     *
+     * @param  the type of the handler method objects to create
+     */
+    public interface Factory {
+
+        Class getMethodClass();
+
+        H create(Method method);
 
-        // Use == to verify that the instances of the target objects are the same.
-        // This way we'd allow having handlers for target objects that are otherwise equal.
-        return (this.target == other.target)
-                && Objects.equals(this.method, other.method);
+        Predicate getPredicate();
     }
 
     private enum LogSingleton {
         INSTANCE;
 
         @SuppressWarnings("NonSerializableFieldInSerializableClass")
-        private final Logger value = LoggerFactory.getLogger(MessageHandlerMethod.class);
+        private final Logger value = LoggerFactory.getLogger(HandlerMethod.class);
     }
 
     /**
diff --git a/server/src/main/java/org/spine3/server/reflect/MethodMap.java b/server/src/main/java/org/spine3/server/reflect/MethodMap.java
index 2032b8c3fca..4d8b7932690 100644
--- a/server/src/main/java/org/spine3/server/reflect/MethodMap.java
+++ b/server/src/main/java/org/spine3/server/reflect/MethodMap.java
@@ -26,6 +26,7 @@
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Maps;
 import com.google.protobuf.Message;
+import org.spine3.error.DuplicateHandlerMethodException;
 
 import javax.annotation.CheckReturnValue;
 import javax.annotation.Nullable;
@@ -37,20 +38,64 @@
 /**
  * A map for storing methods handling messages.
  *
+ * @param  the type of the handler method instances stored in the map
  * @author Alexander Yevsyukov
  */
-public class MethodMap {
+public class MethodMap {
 
-    private final ImmutableMap, Method> map;
+    private final ImmutableMap, H> map;
 
-    public MethodMap(Class clazz, Predicate filter) {
-        this(Methods.scan(clazz, filter));
+    private MethodMap(Class clazz, HandlerMethod.Factory factory) {
+        final Map, Method> rawMethods = scan(clazz, factory.getPredicate());
+
+        final ImmutableMap.Builder, H> builder = ImmutableMap.builder();
+        for (Map.Entry, Method> entry : rawMethods.entrySet()) {
+            final H value = factory.create(entry.getValue());
+            builder.put(entry.getKey(), value);
+        }
+
+        this.map = builder.build();
     }
 
-    private MethodMap(Map, Method> map) {
-        this.map = ImmutableMap., Method>builder()
-                .putAll(map)
-                .build();
+    /**
+     * Creates a new method map for the passed class using the passed factory.
+     *
+     * @param clazz the class to inspect
+     * @param factory the factory for handler methods
+     * @param  the type of the handler methods
+     * @return new method map
+     */
+    public static  MethodMap create(Class clazz, HandlerMethod.Factory factory) {
+        return new MethodMap<>(clazz, factory);
+    }
+
+    /**
+     * Returns a map of the {@link HandlerMethod} objects to the corresponding message class.
+     *
+     * @param declaringClass   the class that declares methods to scan
+     * @param filter the predicate that defines rules for subscriber scanning
+     * @return the map of message subscribers
+     * @throws DuplicateHandlerMethodException if there are more than one handler for the same message class are encountered
+     */
+    private static Map, Method> scan(Class declaringClass, Predicate filter) {
+        final Map, Method> tempMap = Maps.newHashMap();
+        for (Method method : declaringClass.getDeclaredMethods()) {
+            if (filter.apply(method)) {
+                final Class messageClass = HandlerMethod.getFirstParamType(method);
+                if (tempMap.containsKey(messageClass)) {
+                    final Method alreadyPresent = tempMap.get(messageClass);
+                    throw new DuplicateHandlerMethodException(
+                            declaringClass,
+                            messageClass,
+                            alreadyPresent.getName(),
+                            method.getName());
+                }
+                tempMap.put(messageClass, method);
+            }
+        }
+        final ImmutableMap.Builder, Method> builder = ImmutableMap.builder();
+        builder.putAll(tempMap);
+        return builder.build();
     }
 
     /**
@@ -67,66 +112,18 @@ public ImmutableSet> keySet() {
     }
 
     @CheckReturnValue
-    public ImmutableSet, Method>> entrySet() {
+    public ImmutableSet, H>> entrySet() {
         return map.entrySet();
     }
 
     @CheckReturnValue
-    public ImmutableCollection values() {
+    public ImmutableCollection values() {
         return map.values();
     }
 
     @CheckReturnValue
     @Nullable
-    public Method get(Class messageClass) {
+    public H get(Class messageClass) {
         return map.get(checkNotNull(messageClass));
     }
-
-    /**
-     * The registry of message maps by class.
-     *
-     * @param  the type of objects tracked by the registry
-     */
-    public static class Registry {
-
-        private final Map, MethodMap> entries = Maps.newConcurrentMap();
-
-        /**
-         * Verifies if the class is already registered.
-         *
-         * @param clazz the class to check
-         * @return {@code true} if there is a message map for the passed class, {@code false} otherwise
-         */
-        @CheckReturnValue
-        public boolean contains(Class clazz) {
-            final boolean result = entries.containsKey(clazz);
-            return result;
-        }
-
-        /**
-         * Registers methods of the class in the registry.
-         *
-         * @param clazz the class to register
-         * @param filter a filter for selecting methods to register
-         * @throws IllegalArgumentException if the class was already registered
-         * @see #contains(Class)
-         */
-        public void register(Class clazz, Predicate filter) {
-            if (contains(clazz)) {
-                throw new IllegalArgumentException("The class is already registered: " + clazz.getName());
-            }
-
-            final MethodMap entry = new MethodMap(clazz, filter);
-            entries.put(clazz, entry);
-        }
-
-        /**
-         * Obtains method map for the passed class.
-         */
-        @CheckReturnValue
-        public MethodMap get(Class clazz) {
-            final MethodMap result = entries.get(clazz);
-            return result;
-        }
-    }
 }
diff --git a/server/src/main/java/org/spine3/server/reflect/MethodRegistry.java b/server/src/main/java/org/spine3/server/reflect/MethodRegistry.java
new file mode 100644
index 00000000000..4bd525e73da
--- /dev/null
+++ b/server/src/main/java/org/spine3/server/reflect/MethodRegistry.java
@@ -0,0 +1,114 @@
+/*
+ * Copyright 2016, TeamDev Ltd. All rights reserved.
+ *
+ * Redistribution and use in source and/or binary forms, with or without
+ * modification, must retain the above copyright notice and the following
+ * disclaimer.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.spine3.server.reflect;
+
+import com.google.common.collect.Maps;
+import com.google.protobuf.Message;
+
+import javax.annotation.CheckReturnValue;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * The {@code MethodRegistry} stores handler methods per class exposing those methods.
+ *
+ * @author Alexander Yevsyukov
+ */
+public class MethodRegistry {
+
+    private final Map, MethodMap> items = Maps.newConcurrentMap();
+
+    /**
+     * Obtains a handler method, which handles the passed message class.
+     *
+     * 
If the registry does not have the data structures ready for the target class,
+     * they are created using the passed {@code factory} of the handler methods.
+     * Then the method is obtained.
+     *
+     * @param targetClass the class of the target object
+     * @param messageClass the class of the message to handle
+     * @param factory the handler method factory for getting methods from the target class
+     * @param  the type of the target object class
+     * @param  the type of the message handler method
+     * @return a handler method
+     */
+    public  H get(Class targetClass,
+                                              Class messageClass,
+                                              HandlerMethod.Factory factory) {
+
+        final Key key = new Key<>(targetClass, factory.getMethodClass());
+        @SuppressWarnings("unchecked") /* We can cast as the map type is the same as one of the passed factory,
+                                          which is used in creating the entry in the `if` block below. */
+        MethodMap methods = items.get(key);
+        if (methods == null) {
+            methods = MethodMap.create(targetClass, factory);
+            items.put(key, methods);
+        }
+
+        final H handlerMethod = methods.get(messageClass);
+        return handlerMethod;
+    }
+
+    /**
+     * The map entry key which consists of target object class and method class.
+     *
+     * @param  the type of the target class
+     * @param  the type of the method handler class
+     */
+    private static class Key {
+        private final Class targetClass;
+        private final Class methodClass;
+
+        private Key(Class targetClass, Class methodClass) {
+            this.targetClass = targetClass;
+            this.methodClass = methodClass;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (!(o instanceof Key)) {
+                return false;
+            }
+            final Key key = (Key) o;
+            return Objects.equals(targetClass, key.targetClass) &&
+                    Objects.equals(methodClass, key.methodClass);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(targetClass, methodClass);
+        }
+    }
+
+    @CheckReturnValue
+    public static MethodRegistry getInstance() {
+        return Singleton.INSTANCE.value;
+    }
+
+    private enum Singleton {
+        INSTANCE;
+        @SuppressWarnings("NonSerializableFieldInSerializableClass")
+        private final MethodRegistry value = new MethodRegistry();
+    }
+}
diff --git a/server/src/main/java/org/spine3/server/reflect/Methods.java b/server/src/main/java/org/spine3/server/reflect/Methods.java
deleted file mode 100644
index 58e62ad6f4e..00000000000
--- a/server/src/main/java/org/spine3/server/reflect/Methods.java
+++ /dev/null
@@ -1,96 +0,0 @@
-/*
- * Copyright 2016, TeamDev Ltd. All rights reserved.
- *
- * Redistribution and use in source and/or binary forms, with or without
- * modification, must retain the above copyright notice and the following
- * disclaimer.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-package org.spine3.server.reflect;
-
-import com.google.common.base.Predicate;
-import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.Maps;
-import com.google.protobuf.Message;
-import org.spine3.error.DuplicateHandlerMethodException;
-import org.spine3.server.internal.MessageHandlerMethod;
-
-import java.lang.reflect.Method;
-import java.util.Map;
-
-/**
- * Utilities for client-side methods.
- *
- * @author Alexander Yevsyukov
- */
-public class Methods {
-
-    private Methods() {}
-
-    /**
-     * Returns a full method name without parameters.
-     *
-     * @param method a method to get name for
-     * @return full method name
-     */
-        public static String getFullMethodName(Method method) {
-        return method.getDeclaringClass().getName() + '.' + method.getName() + "()";
-    }
-
-    /**
-     * Returns the class of the first parameter of the passed handler method object.
-     *
-     * 
It is expected that the first parameter of the passed method is always of
-     * a class implementing {@link Message}.
-     *
-     * @param handler the method object to take first parameter type from
-     * @return the class of the first method parameter
-     * @throws ClassCastException if the first parameter isn't a class implementing {@link Message}
-     */
-    public static Class getFirstParamType(Method handler) {
-        @SuppressWarnings("unchecked") /* we always expect first param as {@link Message} */
-        final Class result = (Class) handler.getParameterTypes()[0];
-        return result;
-    }
-
-    /**
-     * Returns a map of the {@link MessageHandlerMethod} objects to the corresponding message class.
-     *
-     * @param declaringClass   the class that declares methods to scan
-     * @param filter the predicate that defines rules for subscriber scanning
-     * @return the map of message subscribers
-     * @throws DuplicateHandlerMethodException if there are more than one handler for the same message class are encountered
-     */
-    public static Map, Method> scan(Class declaringClass, Predicate filter) {
-        final Map, Method> tempMap = Maps.newHashMap();
-        for (Method method : declaringClass.getDeclaredMethods()) {
-            if (filter.apply(method)) {
-                final Class messageClass = getFirstParamType(method);
-                if (tempMap.containsKey(messageClass)) {
-                    final Method alreadyPresent = tempMap.get(messageClass);
-                    throw new DuplicateHandlerMethodException(
-                            declaringClass,
-                            messageClass,
-                            alreadyPresent.getName(),
-                            method.getName());
-                }
-                tempMap.put(messageClass, method);
-            }
-        }
-        final ImmutableMap.Builder, Method> builder = ImmutableMap.builder();
-        builder.putAll(tempMap);
-        return builder.build();
-    }
-}
diff --git a/server/src/main/java/org/spine3/server/storage/CommandStorage.java b/server/src/main/java/org/spine3/server/storage/CommandStorage.java
index 48d9727ba8a..5b5897b4a65 100644
--- a/server/src/main/java/org/spine3/server/storage/CommandStorage.java
+++ b/server/src/main/java/org/spine3/server/storage/CommandStorage.java
@@ -32,7 +32,7 @@
 import org.spine3.base.Error;
 import org.spine3.base.Failure;
 import org.spine3.server.command.CommandStore;
-import org.spine3.server.command.GetTargetIdFromCommand;
+import org.spine3.server.entity.GetTargetIdFromCommand;
 import org.spine3.server.error.MissingEntityIdException;
 import org.spine3.type.TypeName;
 
@@ -52,7 +52,6 @@ public abstract class CommandStorage extends AbstractStorage ID_FUNCTION = GetTargetIdFromCommand.newInstance();
 
-    //TODO:2016-02-18:alexander.yevsyukov: Define constraints the command declaration and use our validation to check the passed parameter.
     /**
      * Stores a command by a command ID from a command context.
      *
diff --git a/client/src/main/java/org/spine3/type/CommandClass.java b/server/src/main/java/org/spine3/server/type/CommandClass.java
similarity index 97%
rename from client/src/main/java/org/spine3/type/CommandClass.java
rename to server/src/main/java/org/spine3/server/type/CommandClass.java
index 4fdde819a32..bf296d13e3d 100644
--- a/client/src/main/java/org/spine3/type/CommandClass.java
+++ b/server/src/main/java/org/spine3/server/type/CommandClass.java
@@ -18,7 +18,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package org.spine3.type;
+package org.spine3.server.type;
 
 import com.google.common.collect.ImmutableSet;
 import com.google.protobuf.Message;
@@ -34,7 +34,7 @@
  *
  * @author Alexander Yevsyukov
  */
-public final class CommandClass extends ClassTypeValue {
+public final class CommandClass extends MessageClass {
 
     private CommandClass(Class value) {
         super(value);
diff --git a/client/src/main/java/org/spine3/type/EventClass.java b/server/src/main/java/org/spine3/server/type/EventClass.java
similarity index 96%
rename from client/src/main/java/org/spine3/type/EventClass.java
rename to server/src/main/java/org/spine3/server/type/EventClass.java
index 7b3379bf74b..190290f7b49 100644
--- a/client/src/main/java/org/spine3/type/EventClass.java
+++ b/server/src/main/java/org/spine3/server/type/EventClass.java
@@ -18,7 +18,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package org.spine3.type;
+package org.spine3.server.type;
 
 import com.google.common.collect.ImmutableSet;
 import com.google.protobuf.Message;
@@ -32,7 +32,7 @@
  *
  * @author Alexander Yevsyukov
  */
-public final class EventClass extends ClassTypeValue {
+public final class EventClass extends MessageClass {
 
     private EventClass(Class value) {
         super(value);
diff --git a/client/src/main/java/org/spine3/type/ClassTypeValue.java b/server/src/main/java/org/spine3/server/type/MessageClass.java
similarity index 84%
rename from client/src/main/java/org/spine3/type/ClassTypeValue.java
rename to server/src/main/java/org/spine3/server/type/MessageClass.java
index ae794d5dc7a..8c7de4109f2 100644
--- a/client/src/main/java/org/spine3/type/ClassTypeValue.java
+++ b/server/src/main/java/org/spine3/server/type/MessageClass.java
@@ -18,7 +18,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package org.spine3.type;
+package org.spine3.server.type;
 
 import com.google.protobuf.Message;
 
@@ -30,13 +30,11 @@
  *
  * @author Alexander Yevsyukov
  */
-@SuppressWarnings("AbstractClassWithoutAbstractMethods") // is OK for value object base.
-// NOTE: this class is named using 'Type' infix to prevent the name clash with java.lang.ClassValue.
-abstract class ClassTypeValue {
+public abstract class MessageClass {
 
     private final Class value;
 
-    protected ClassTypeValue(Class value) {
+    protected MessageClass(Class value) {
         this.value = value;
     }
 
@@ -72,7 +70,7 @@ public boolean equals(@Nullable Object obj) {
         if (obj == null || getClass() != obj.getClass()) {
             return false;
         }
-        final ClassTypeValue other = (ClassTypeValue) obj;
+        final MessageClass other = (MessageClass) obj;
         return Objects.equals(this.value, other.value);
     }
 
diff --git a/server/src/main/java/org/spine3/server/type/package-info.java b/server/src/main/java/org/spine3/server/type/package-info.java
new file mode 100644
index 00000000000..29b6db4ea3b
--- /dev/null
+++ b/server/src/main/java/org/spine3/server/type/package-info.java
@@ -0,0 +1,28 @@
+/*
+ * Copyright 2016, TeamDev Ltd. All rights reserved.
+ *
+ * Redistribution and use in source and/or binary forms, with or without
+ * modification, must retain the above copyright notice and the following
+ * disclaimer.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/**
+ * This package contains commonly used server-side data classes.
+ */
+
+@ParametersAreNonnullByDefault
+package org.spine3.server.type;
+
+import javax.annotation.ParametersAreNonnullByDefault;
diff --git a/server/src/main/java/org/spine3/server/validate/ByteStringFieldValidator.java b/server/src/main/java/org/spine3/server/validate/ByteStringFieldValidator.java
index 97a40953899..a174442fd54 100644
--- a/server/src/main/java/org/spine3/server/validate/ByteStringFieldValidator.java
+++ b/server/src/main/java/org/spine3/server/validate/ByteStringFieldValidator.java
@@ -24,7 +24,7 @@
 import com.google.protobuf.ByteString;
 import com.google.protobuf.Descriptors.FieldDescriptor;
 import org.spine3.base.FieldPath;
-import org.spine3.validation.options.ConstraintViolation;
+import org.spine3.validate.options.ConstraintViolation;
 
 import java.util.List;
 
diff --git a/server/src/main/java/org/spine3/server/validate/FieldValidator.java b/server/src/main/java/org/spine3/server/validate/FieldValidator.java
index 15aba8e65a7..389268604b5 100644
--- a/server/src/main/java/org/spine3/server/validate/FieldValidator.java
+++ b/server/src/main/java/org/spine3/server/validate/FieldValidator.java
@@ -28,9 +28,9 @@
 import com.google.protobuf.GeneratedMessage.GeneratedExtension;
 import com.google.protobuf.Message;
 import org.spine3.base.FieldPath;
-import org.spine3.validation.options.ConstraintViolation;
-import org.spine3.validation.options.RequiredOption;
-import org.spine3.validation.options.ValidationProto;
+import org.spine3.validate.options.ConstraintViolation;
+import org.spine3.validate.options.RequiredOption;
+import org.spine3.validate.options.ValidationProto;
 
 import java.util.List;
 
@@ -167,7 +167,7 @@ protected void addViolation(ConstraintViolation violation) {
     }
 
     private ConstraintViolation newViolation(RequiredOption option) {
-        final String msg = getErrorMsgFormat(option, option.getMsg());
+        final String msg = getErrorMsgFormat(option, option.getMsgFormat());
         final ConstraintViolation violation = ConstraintViolation.newBuilder()
                 .setMsgFormat(msg)
                 .setFieldPath(getFieldPath())
diff --git a/server/src/main/java/org/spine3/server/validate/FloatFieldValidatorBase.java b/server/src/main/java/org/spine3/server/validate/FloatFieldValidatorBase.java
index e7bbb6ac2bf..b4e5a7a9d93 100644
--- a/server/src/main/java/org/spine3/server/validate/FloatFieldValidatorBase.java
+++ b/server/src/main/java/org/spine3/server/validate/FloatFieldValidatorBase.java
@@ -23,7 +23,7 @@
 import com.google.common.collect.ImmutableList;
 import com.google.protobuf.Descriptors.FieldDescriptor;
 import org.spine3.base.FieldPath;
-import org.spine3.validation.options.ConstraintViolation;
+import org.spine3.validate.options.ConstraintViolation;
 
 /**
  * A base for floating point number field validators.
diff --git a/server/src/main/java/org/spine3/server/validate/MessageFieldValidator.java b/server/src/main/java/org/spine3/server/validate/MessageFieldValidator.java
index 50c72d488a0..204590a700e 100644
--- a/server/src/main/java/org/spine3/server/validate/MessageFieldValidator.java
+++ b/server/src/main/java/org/spine3/server/validate/MessageFieldValidator.java
@@ -25,11 +25,11 @@
 import com.google.protobuf.Message;
 import com.google.protobuf.Timestamp;
 import org.spine3.base.FieldPath;
-import org.spine3.validation.options.ConstraintViolation;
-import org.spine3.validation.options.Time;
-import org.spine3.validation.options.TimeOption;
-import org.spine3.validation.options.ValidOption;
-import org.spine3.validation.options.ValidationProto;
+import org.spine3.validate.options.ConstraintViolation;
+import org.spine3.validate.options.Time;
+import org.spine3.validate.options.TimeOption;
+import org.spine3.validate.options.ValidOption;
+import org.spine3.validate.options.ValidationProto;
 
 import java.util.List;
 
@@ -37,8 +37,8 @@
 import static org.spine3.protobuf.Messages.toAny;
 import static org.spine3.protobuf.Timestamps.isAfter;
 import static org.spine3.validate.Validate.isDefault;
-import static org.spine3.validation.options.Time.FUTURE;
-import static org.spine3.validation.options.Time.UNDEFINED;
+import static org.spine3.validate.options.Time.FUTURE;
+import static org.spine3.validate.options.Time.UNDEFINED;
 
 /**
  * Validates fields of type {@link Message}.
@@ -128,7 +128,7 @@ private static boolean isTimeInvalid(Timestamp time, Time when, Timestamp now) {
     }
 
     private ConstraintViolation newTimeViolation(Timestamp fieldValue) {
-        final String msg = getErrorMsgFormat(timeOption, timeOption.getMsg());
+        final String msg = getErrorMsgFormat(timeOption, timeOption.getMsgFormat());
         final String when = timeOption.getIn().toString().toLowerCase();
         final ConstraintViolation violation = ConstraintViolation.newBuilder()
                 .setMsgFormat(msg)
@@ -140,7 +140,7 @@ private ConstraintViolation newTimeViolation(Timestamp fieldValue) {
     }
 
     private ConstraintViolation newValidViolation(Message fieldValue, Iterable violations) {
-        final String msg = getErrorMsgFormat(validOption, validOption.getMsg());
+        final String msg = getErrorMsgFormat(validOption, validOption.getMsgFormat());
         final ConstraintViolation violation = ConstraintViolation.newBuilder()
                 .setMsgFormat(msg)
                 .setFieldPath(getFieldPath())
diff --git a/server/src/main/java/org/spine3/server/validate/MessageValidator.java b/server/src/main/java/org/spine3/server/validate/MessageValidator.java
index 7f801bbc618..64dbb23ca8a 100644
--- a/server/src/main/java/org/spine3/server/validate/MessageValidator.java
+++ b/server/src/main/java/org/spine3/server/validate/MessageValidator.java
@@ -25,7 +25,7 @@
 import com.google.protobuf.Message;
 import org.spine3.Internal;
 import org.spine3.base.FieldPath;
-import org.spine3.validation.options.ConstraintViolation;
+import org.spine3.validate.options.ConstraintViolation;
 
 import java.util.List;
 
diff --git a/server/src/main/java/org/spine3/server/validate/NumberFieldValidator.java b/server/src/main/java/org/spine3/server/validate/NumberFieldValidator.java
index 6af1582d221..2ac60a59baf 100644
--- a/server/src/main/java/org/spine3/server/validate/NumberFieldValidator.java
+++ b/server/src/main/java/org/spine3/server/validate/NumberFieldValidator.java
@@ -27,13 +27,13 @@
 import com.google.protobuf.Int32Value;
 import com.google.protobuf.Message;
 import org.spine3.base.FieldPath;
-import org.spine3.validation.options.ConstraintViolation;
-import org.spine3.validation.options.DecimalMaxOption;
-import org.spine3.validation.options.DecimalMinOption;
-import org.spine3.validation.options.DigitsOption;
-import org.spine3.validation.options.MaxOption;
-import org.spine3.validation.options.MinOption;
-import org.spine3.validation.options.ValidationProto;
+import org.spine3.validate.options.ConstraintViolation;
+import org.spine3.validate.options.DecimalMaxOption;
+import org.spine3.validate.options.DecimalMinOption;
+import org.spine3.validate.options.DigitsOption;
+import org.spine3.validate.options.MaxOption;
+import org.spine3.validate.options.MinOption;
+import org.spine3.validate.options.ValidationProto;
 
 import java.util.List;
 import java.util.regex.Pattern;
@@ -112,19 +112,19 @@ protected boolean isValueNotSet(V value) {
     private void validateRangeOptions(V value) {
         if (notFitToDecimalMin(value)) {
             addViolation(
-                    newDecimalViolation(value, minDecimalOpt, minDecimalOpt.getMsg(),
+                    newDecimalViolation(value, minDecimalOpt, minDecimalOpt.getMsgFormat(),
                             minDecimalOpt.getInclusive(), minDecimalOpt.getValue()));
         }
         if (notFitToDecimalMax(value)) {
             addViolation(
-                    newDecimalViolation(value, maxDecimalOpt, maxDecimalOpt.getMsg(),
+                    newDecimalViolation(value, maxDecimalOpt, maxDecimalOpt.getMsgFormat(),
                             maxDecimalOpt.getInclusive(), maxDecimalOpt.getValue()));
         }
         if (notFitToMin(value)) {
-            addViolation(newMinOrMaxViolation(value, minOption, minOption.getMsg(), minOption.getValue()));
+            addViolation(newMinOrMaxViolation(value, minOption, minOption.getMsgFormat(), minOption.getValue()));
         }
         if (notFitToMax(value)) {
-            addViolation(newMinOrMaxViolation(value, maxOption, maxOption.getMsg(), maxOption.getValue()));
+            addViolation(newMinOrMaxViolation(value, maxOption, maxOption.getMsgFormat(), maxOption.getValue()));
         }
     }
 
@@ -219,7 +219,7 @@ private ConstraintViolation newMinOrMaxViolation(V value, Message option, String
     }
 
     private ConstraintViolation newDigitsViolation(V value) {
-        final String msg = getErrorMsgFormat(digitsOption, digitsOption.getMsg());
+        final String msg = getErrorMsgFormat(digitsOption, digitsOption.getMsgFormat());
         final String intMax = String.valueOf(digitsOption.getIntegerMax());
         final String fractionMax = String.valueOf(digitsOption.getFractionMax());
         final ConstraintViolation.Builder violation = ConstraintViolation.newBuilder()
diff --git a/server/src/main/java/org/spine3/server/validate/StringFieldValidator.java b/server/src/main/java/org/spine3/server/validate/StringFieldValidator.java
index 80742348dec..3d72cbe69e9 100644
--- a/server/src/main/java/org/spine3/server/validate/StringFieldValidator.java
+++ b/server/src/main/java/org/spine3/server/validate/StringFieldValidator.java
@@ -23,9 +23,9 @@
 import com.google.common.collect.ImmutableList;
 import com.google.protobuf.Descriptors.FieldDescriptor;
 import org.spine3.base.FieldPath;
-import org.spine3.validation.options.ConstraintViolation;
-import org.spine3.validation.options.PatternOption;
-import org.spine3.validation.options.ValidationProto;
+import org.spine3.validate.options.ConstraintViolation;
+import org.spine3.validate.options.PatternOption;
+import org.spine3.validate.options.ValidationProto;
 
 import java.util.List;
 
@@ -75,7 +75,7 @@ private void checkIfMatchesToRegexp() {
     }
 
     private ConstraintViolation newViolation(String fieldValue) {
-        final String msg = getErrorMsgFormat(patternOption, patternOption.getMsg());
+        final String msg = getErrorMsgFormat(patternOption, patternOption.getMsgFormat());
         final ConstraintViolation violation = ConstraintViolation.newBuilder()
                 .setMsgFormat(msg)
                 .addParam(regex)
diff --git a/server/src/test/java/org/spine3/server/BoundedContextShould.java b/server/src/test/java/org/spine3/server/BoundedContextShould.java
index 390458b1fea..1a07e74c237 100644
--- a/server/src/test/java/org/spine3/server/BoundedContextShould.java
+++ b/server/src/test/java/org/spine3/server/BoundedContextShould.java
@@ -22,11 +22,9 @@
 
 import com.google.common.util.concurrent.MoreExecutors;
 import com.google.protobuf.Any;
-import com.google.protobuf.Duration;
 import com.google.protobuf.Empty;
 import com.google.protobuf.Message;
 import com.google.protobuf.StringValue;
-import com.google.protobuf.Timestamp;
 import io.grpc.stub.StreamObserver;
 import org.junit.After;
 import org.junit.Before;
@@ -34,18 +32,20 @@
 import org.spine3.base.Command;
 import org.spine3.base.CommandContext;
 import org.spine3.base.CommandValidationError;
-import org.spine3.base.Event;
 import org.spine3.base.EventContext;
 import org.spine3.base.Response;
+import org.spine3.base.Responses;
 import org.spine3.base.UserId;
 import org.spine3.server.aggregate.Aggregate;
 import org.spine3.server.aggregate.AggregateRepository;
 import org.spine3.server.aggregate.Apply;
+import org.spine3.server.command.Assign;
 import org.spine3.server.entity.IdFunction;
-import org.spine3.server.error.UnsupportedCommandException;
 import org.spine3.server.event.EventBus;
+import org.spine3.server.event.EventHandler;
 import org.spine3.server.event.EventStore;
 import org.spine3.server.event.GetProducerIdFromEvent;
+import org.spine3.server.event.Subscribe;
 import org.spine3.server.procman.CommandRouted;
 import org.spine3.server.procman.ProcessManager;
 import org.spine3.server.procman.ProcessManagerRepository;
@@ -53,6 +53,7 @@
 import org.spine3.server.projection.ProjectionRepository;
 import org.spine3.server.storage.StorageFactory;
 import org.spine3.server.storage.memory.InMemoryStorageFactory;
+import org.spine3.server.type.EventClass;
 import org.spine3.test.project.Project;
 import org.spine3.test.project.ProjectId;
 import org.spine3.test.project.command.AddTask;
@@ -62,21 +63,16 @@
 import org.spine3.test.project.event.ProjectStarted;
 import org.spine3.test.project.event.TaskAdded;
 import org.spine3.testdata.TestAggregateIdFactory;
-import org.spine3.type.EventClass;
 
 import java.util.List;
 
 import static com.google.common.collect.Lists.newArrayList;
-import static com.google.common.collect.Lists.newLinkedList;
-import static com.google.protobuf.util.TimeUtil.add;
 import static com.google.protobuf.util.TimeUtil.getCurrentTime;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.*;
 import static org.spine3.base.Identifiers.newUuid;
 import static org.spine3.client.UserUtil.newUserId;
-import static org.spine3.protobuf.Durations.seconds;
-import static org.spine3.protobuf.Messages.fromAny;
-import static org.spine3.testdata.TestCommands.*;
+import static org.spine3.testdata.TestCommands.createProject;
+import static org.spine3.testdata.TestCommands.newCommandBus;
 import static org.spine3.testdata.TestEventMessageFactory.*;
 
 /**
@@ -93,6 +89,20 @@ public class BoundedContextShould {
     private BoundedContext boundedContext;
     private boolean handlersRegistered = false;
 
+    private final StreamObserver responseObserver = new StreamObserver() {
+        @Override
+        public void onNext(Response response) {
+        }
+
+        @Override
+        public void onError(Throwable throwable) {
+        }
+
+        @Override
+        public void onCompleted() {
+        }
+    };
+
     @Before
     public void setUp() {
         storageFactory = InMemoryStorageFactory.getInstance();
@@ -125,32 +135,6 @@ private void registerAll() {
         handlersRegistered = true;
     }
 
-    //TODO:2016-01-25:alexander.yevsyukov: Move the command result verification tests into AggregateRepositoryShould.
-
-    private List processRequests(Iterable requests) {
-
-        final List results = newLinkedList();
-        for (Command request : requests) {
-            final CommandResult result = boundedContext.process(request);
-            results.add(result);
-        }
-        return results;
-    }
-
-    private List generateRequests() {
-
-        final Duration delta = seconds(10);
-        final Timestamp time1 = getCurrentTime();
-        final Timestamp time2 = add(time1, delta);
-        final Timestamp time3 = add(time2, delta);
-
-        final Command createProject = createProject(userId, projectId, time1);
-        final Command addTask = addTask(userId, projectId, time2);
-        final Command startProject = startProject(userId, projectId, time3);
-
-        return newArrayList(createProject, addTask, startProject);
-    }
-
     @Test
     public void return_EventBus() {
         assertNotNull(boundedContext.getEventBus());
@@ -161,15 +145,20 @@ public void return_CommandDispatcher() {
         assertNotNull(boundedContext.getCommandBus());
     }
 
-    @SuppressWarnings("ConstantConditions") // Passing null is the purpose of this method.
-    @Test(expected = NullPointerException.class)
-    public void throw_NPE_on_null_Command() {
-        boundedContext.process(null);
-    }
-
-    @Test(expected = UnsupportedCommandException.class)
-    public void throw_exception_if_not_register_any_repositories_and_try_to_process_command() {
-        boundedContext.post(createProject());
+    @Test
+    public void return_unsupported_command_response_if_no_handlers_or_dispatchers() {
+        boundedContext.post(createProject(), new StreamObserver() {
+            @Override
+            public void onNext(Response response) {
+                assertTrue(Responses.isUnsupportedCommand(response));
+            }
+
+            @Override
+            public void onError(Throwable throwable) {}
+
+            @Override
+            public void onCompleted() {}
+        });
     }
 
     @Test
@@ -198,31 +187,18 @@ public void post_Command() {
         registerAll();
         final Command request = createProject(userId, projectId, getCurrentTime());
 
-        boundedContext.post(request);
-    }
+        boundedContext.post(request, new StreamObserver() {
+            @Override
+            public void onNext(Response response) {}
 
-    private void assertCommandResultsAreValid(List requests, List results) {
-        assertEquals(requests.size(), results.size());
+            @Override
+            public void onError(Throwable throwable) {}
 
-        for (int i = 0; i < requests.size(); i++) {
-            assertRequestAndResultMatch(requests.get(i), results.get(i));
-        }
+            @Override
+            public void onCompleted() {}
+        });
     }
 
-    private void assertRequestAndResultMatch(Command request, CommandResult result) {
-        final Timestamp expectedTime = request.getContext().getTimestamp();
-
-        final List events = result.getEventList();
-        assertEquals(1, events.size());
-        final Event actualRecord = events.get(0);
-        final ProjectId actualProjectId = fromAny(actualRecord.getContext().getProducerId());
-
-        assertEquals(projectId, actualProjectId);
-        assertEquals(userId, actualRecord.getContext().getCommandContext().getActor());
-        assertEquals(expectedTime, actualRecord.getContext().getCommandContext().getTimestamp());
-    }
-
-
     private static class ResponseObserver implements StreamObserver {
 
         private Response response;
@@ -344,7 +320,7 @@ private ProjectAggregateRepository(BoundedContext boundedContext) {
     }
 
     @SuppressWarnings("UnusedParameters") // It is intended in this empty handler class.
-    private static class EmptyHandler implements EventHandler {
+    private static class EmptyHandler extends EventHandler {
 
         @Subscribe
         public void on(ProjectCreated event, EventContext context) {
diff --git a/server/src/test/java/org/spine3/server/BoundedContextTestStubs.java b/server/src/test/java/org/spine3/server/BoundedContextTestStubs.java
index 37a4ed47157..30ac415fc1f 100644
--- a/server/src/test/java/org/spine3/server/BoundedContextTestStubs.java
+++ b/server/src/test/java/org/spine3/server/BoundedContextTestStubs.java
@@ -27,6 +27,8 @@
 import org.spine3.server.storage.StorageFactory;
 import org.spine3.server.storage.memory.InMemoryStorageFactory;
 
+import static org.mockito.Mockito.spy;
+
 import static org.spine3.testdata.TestCommands.newCommandBus;
 
 /**
@@ -44,13 +46,13 @@ public static BoundedContext create() {
     public static BoundedContext create(StorageFactory storageFactory) {
         final CommandBus commandBus = newCommandBus(storageFactory);
         final EventBus eventBus = EventBus.newInstance(EventStore.newBuilder()
-                .setStreamExecutor(MoreExecutors.directExecutor())
-                .setStorage(storageFactory.createEventStorage())
-                .build());
+                                                                 .setStreamExecutor(MoreExecutors.directExecutor())
+                                                                 .setStorage(storageFactory.createEventStorage())
+                                                                 .build());
         final BoundedContext.Builder builder = BoundedContext.newBuilder()
                 .setStorageFactory(storageFactory)
                 .setCommandBus(commandBus)
-                .setEventBus(eventBus);
+                .setEventBus(spy(eventBus));
         return builder.build();
     }
 
diff --git a/server/src/test/java/org/spine3/server/aggregate/AggregateRepositoryShould.java b/server/src/test/java/org/spine3/server/aggregate/AggregateRepositoryShould.java
index 473c380f92a..29f707dbaee 100644
--- a/server/src/test/java/org/spine3/server/aggregate/AggregateRepositoryShould.java
+++ b/server/src/test/java/org/spine3/server/aggregate/AggregateRepositoryShould.java
@@ -22,20 +22,13 @@
 
 import org.junit.Before;
 import org.junit.Test;
-import org.spine3.base.CommandContext;
-import org.spine3.server.Assign;
 import org.spine3.server.BoundedContext;
 import org.spine3.server.BoundedContextTestStubs;
 import org.spine3.server.storage.StorageFactory;
 import org.spine3.server.storage.memory.InMemoryStorageFactory;
-import org.spine3.test.project.Project;
+import org.spine3.server.type.CommandClass;
 import org.spine3.test.project.ProjectId;
-import org.spine3.test.project.command.AddTask;
-import org.spine3.test.project.command.CreateProject;
-import org.spine3.test.project.event.ProjectCreated;
-import org.spine3.test.project.event.TaskAdded;
 import org.spine3.testdata.ProjectAggregate;
-import org.spine3.type.CommandClass;
 import org.spine3.validate.Validate;
 
 import java.util.Set;
@@ -43,8 +36,6 @@
 import static com.google.common.base.Preconditions.checkNotNull;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
-import static org.spine3.testdata.TestEventMessageFactory.projectCreatedEvent;
-import static org.spine3.testdata.TestEventMessageFactory.taskAddedEvent;
 
 @SuppressWarnings("InstanceMethodNamingConvention")
 public class AggregateRepositoryShould {
diff --git a/server/src/test/java/org/spine3/server/aggregate/AggregateShould.java b/server/src/test/java/org/spine3/server/aggregate/AggregateShould.java
index a1e5b485cb9..54218c5f365 100644
--- a/server/src/test/java/org/spine3/server/aggregate/AggregateShould.java
+++ b/server/src/test/java/org/spine3/server/aggregate/AggregateShould.java
@@ -35,7 +35,7 @@
 import org.spine3.base.UserId;
 import org.spine3.client.UserUtil;
 import org.spine3.protobuf.Timestamps;
-import org.spine3.server.Assign;
+import org.spine3.server.command.Assign;
 import org.spine3.test.project.Project;
 import org.spine3.test.project.ProjectId;
 import org.spine3.test.project.command.AddTask;
diff --git a/server/src/test/java/org/spine3/server/command/CommandBusShould.java b/server/src/test/java/org/spine3/server/command/CommandBusShould.java
index b2d3368039c..2298911bd04 100644
--- a/server/src/test/java/org/spine3/server/command/CommandBusShould.java
+++ b/server/src/test/java/org/spine3/server/command/CommandBusShould.java
@@ -29,32 +29,28 @@
 import org.spine3.base.CommandId;
 import org.spine3.base.Commands;
 import org.spine3.base.Errors;
-import org.spine3.base.Event;
 import org.spine3.base.Responses;
 import org.spine3.client.CommandFactory;
 import org.spine3.client.test.TestCommandFactory;
-import org.spine3.server.Assign;
-import org.spine3.server.CommandDispatcher;
-import org.spine3.server.CommandHandler;
-import org.spine3.server.FailureThrowable;
 import org.spine3.server.error.UnsupportedCommandException;
+import org.spine3.server.event.EventBus;
+import org.spine3.server.failure.FailureThrowable;
+import org.spine3.server.type.CommandClass;
 import org.spine3.test.failures.Failures;
 import org.spine3.test.project.command.AddTask;
 import org.spine3.test.project.command.CreateProject;
 import org.spine3.test.project.command.StartProject;
 import org.spine3.test.project.event.ProjectCreated;
-import org.spine3.type.CommandClass;
 
 import java.io.IOException;
 import java.util.Collections;
-import java.util.List;
 import java.util.Set;
 
 import static org.junit.Assert.*;
 import static org.mockito.Mockito.*;
 import static org.spine3.base.Identifiers.newUuid;
+import static org.spine3.base.Responses.isUnsupportedCommand;
 import static org.spine3.protobuf.Durations.minutes;
-import static org.spine3.server.command.CommandValidation.isUnsupportedCommand;
 import static org.spine3.testdata.TestCommands.*;
 import static org.spine3.testdata.TestContextFactory.createCommandContext;
 
@@ -64,8 +60,9 @@ public class CommandBusShould {
     private CommandBus commandBus;
     private CommandStore commandStore;
     private CommandFactory commandFactory;
-    private ExecutorCommandScheduler scheduler;
     private CommandBus.ProblemLog log;
+    private EventBus eventBus;
+    private ExecutorCommandScheduler scheduler;
 
     @Before
     public void setUp() {
@@ -77,6 +74,7 @@ public void setUp() {
                                .build();
         log = spy(CommandBus.ProblemLog.class);
         commandBus.setProblemLog(log);
+        eventBus = mock(EventBus.class);
         commandFactory = TestCommandFactory.newInstance(CommandBusShould.class);
     }
 
@@ -99,9 +97,7 @@ public Set getCommandClasses() {
         }
 
         @Override
-        public List dispatch(Command request) throws Exception {
-            //noinspection ReturnOfNull
-            return null;
+        public void dispatch(Command request) throws Exception {
         }
     }
 
@@ -112,11 +108,14 @@ public void do_not_accept_empty_dispatchers() {
 
     @Test(expected = IllegalArgumentException.class)
     public void do_not_accept_command_handlers_without_methods() {
-        commandBus.register(new EmptyCommandHandler());
+        commandBus.register(new EmptyCommandHandler(eventBus));
     }
 
     @SuppressWarnings("EmptyClass")
-    private static class EmptyCommandHandler implements CommandHandler {
+    private static class EmptyCommandHandler extends CommandHandler {
+        private EmptyCommandHandler(EventBus eventBus) {
+            super(newUuid(), eventBus);
+        }
     }
 
     //
@@ -131,9 +130,7 @@ public Set getCommandClasses() {
         }
 
         @Override
-        public List dispatch(Command request) throws Exception {
-            //noinspection ReturnOfNull
-            return null;
+        public void dispatch(Command request) throws Exception {
         }
     }
 
@@ -155,9 +152,7 @@ public Set getCommandClasses() {
             }
 
             @Override
-            public List dispatch(Command request) throws Exception {
-                //noinspection ReturnOfNull
-                return null;
+            public void dispatch(Command request) throws Exception {
             }
         });
 
@@ -179,9 +174,7 @@ public Set getCommandClasses() {
             }
 
             @Override
-            public List dispatch(Command request) throws Exception {
-                //noinspection ReturnOfNull
-                return null;
+            public void dispatch(Command request) throws Exception {
             }
         };
 
@@ -201,27 +194,33 @@ public List dispatch(Command request) throws Exception {
     @Test(expected = IllegalArgumentException.class)
     public void do_not_allow_to_register_dispatcher_for_the_command_with_registered_handler() {
 
-        final CommandHandler createProjectHandler = new CreateProjectHandler();
+        final CommandHandler createProjectHandler = new CreateProjectHandler(eventBus);
         final CommandDispatcher createProjectDispatcher = new CreateProjectDispatcher();
 
         commandBus.register(createProjectHandler);
+
         commandBus.register(createProjectDispatcher);
     }
 
     @Test(expected = IllegalArgumentException.class)
     public void do_not_allow_to_register_handler_for_the_command_with_registered_dispatcher() {
 
-        final CommandHandler createProjectHandler = new CreateProjectHandler();
+        final CommandHandler createProjectHandler = new CreateProjectHandler(eventBus);
         final CommandDispatcher createProjectDispatcher = new CreateProjectDispatcher();
 
         commandBus.register(createProjectDispatcher);
+
         commandBus.register(createProjectHandler);
     }
 
-    private static class CreateProjectHandler implements CommandHandler {
+    private static class CreateProjectHandler extends CommandHandler {
 
         private boolean handlerInvoked = false;
 
+        private CreateProjectHandler(EventBus eventBus) {
+            super(newUuid(), eventBus);
+        }
+
         @Assign
         public ProjectCreated handle(CreateProject command, CommandContext ctx) throws TestFailure, TestThrowable {
             handlerInvoked = true;
@@ -240,15 +239,13 @@ public Set getCommandClasses() {
         }
 
         @Override
-        public List dispatch(Command request) throws Exception {
-            //noinspection ReturnOfNull
-            return null;
+        public void dispatch(Command request) throws Exception {
         }
     }
 
     @Test
     public void unregister_handler() {
-        final CommandHandler handler = new CreateProjectHandler();
+        final CommandHandler handler = new CreateProjectHandler(eventBus);
         commandBus.register(handler);
         commandBus.unregister(handler);
         final String projectId = newUuid();
@@ -257,7 +254,7 @@ public void unregister_handler() {
 
     @Test
     public void validate_commands_both_dispatched_and_handled() {
-        final CommandHandler handler = new CreateProjectHandler();
+        final CommandHandler handler = new CreateProjectHandler(eventBus);
         final CommandDispatcher dispatcher = new AddTaskDispatcher();
         commandBus.register(handler);
         commandBus.register(dispatcher);
@@ -277,10 +274,8 @@ public Set getCommandClasses() {
         }
 
         @Override
-        public List dispatch(Command request) throws Exception {
+        public void dispatch(Command request) throws Exception {
             dispatcherInvoked = true;
-            //noinspection ReturnOfNull
-            return null;
         }
 
         public boolean wasDispatcherInvoked() {
@@ -309,7 +304,7 @@ public void shutdown_CommandScheduler_when_closed() throws Exception {
 
     @Test
     public void remove_all_handlers_on_close() throws Exception {
-        final CommandHandler handler = new CreateProjectHandler();
+        final CommandHandler handler = new CreateProjectHandler(eventBus);
         commandBus.register(handler);
 
         commandBus.close();
@@ -318,7 +313,7 @@ public void remove_all_handlers_on_close() throws Exception {
 
     @Test
     public void invoke_handler_when_command_posted() {
-        final CreateProjectHandler handler = new CreateProjectHandler();
+        final CreateProjectHandler handler = new CreateProjectHandler(eventBus);
         commandBus.register(handler);
 
         final Command command = commandFactory.create(createProject(newUuid()));
@@ -348,15 +343,14 @@ public void throw_exception_when_there_is_no_neither_handler_nor_dispatcher() {
 
     @Test
     public void set_command_status_to_OK_when_handler_returns() {
-        final CreateProjectHandler handler = new CreateProjectHandler();
+        final CreateProjectHandler handler = new CreateProjectHandler(eventBus);
         commandBus.register(handler);
         final Command command = commandFactory.create(createProject(newUuid()));
 
         commandBus.post(command);
 
         // See that we called CommandStore only once with the right command ID.
-        verify(commandStore, times(1)).setCommandStatusOk(command.getContext()
-                                                                 .getCommandId());
+        verify(commandStore, times(1)).setCommandStatusOk(command.getContext().getCommandId());
     }
 
     @Test
@@ -384,16 +378,19 @@ public void set_command_status_to_failure_when_handler_throws_failure() throws T
         commandBus.post(command);
 
         // Verify we updated the status.
-
-        verify(commandStore, times(1)).updateStatus(eq(commandId), eq(failure.toMessage()));
+        verify(commandStore, atMost(1)).updateStatus(eq(commandId), eq(failure.toMessage()));
         // Verify we logged the failure.
-        verify(log, times(1)).failureHandling(eq(failure), eq(commandMessage), eq(commandId));
+        verify(log, atMost(1)).failureHandling(eq(failure), eq(commandMessage), eq(commandId));
     }
 
     @Test
     public void set_command_status_to_failure_when_handler_throws_exception() throws TestFailure, TestThrowable {
+        final CreateProjectHandler handler = mock(CreateProjectHandler.class);
         final RuntimeException exception = new IllegalStateException("handler throws");
-        givenThrowingHandler(exception);
+        doThrow(exception).when(handler)
+                          .handle(any(CreateProject.class), any(CommandContext.class));
+
+        commandBus.register(handler);
         final Command command = commandFactory.create(createProject(newUuid()));
         final CommandId commandId = command.getContext().getCommandId();
         final Message commandMessage = Commands.getMessage(command);
@@ -401,15 +398,19 @@ public void set_command_status_to_failure_when_handler_throws_exception() throws
         commandBus.post(command);
 
         // Verify we updated the status.
-        verify(commandStore, times(1)).updateStatus(eq(commandId), eq(exception));
+        verify(commandStore, atMost(1)).updateStatus(eq(commandId), eq(exception));
         // Verify we logged the failure.
-        verify(log, times(1)).errorHandling(eq(exception), eq(commandMessage), eq(commandId));
+        verify(log, atMost(1)).errorHandling(eq(exception), eq(commandMessage), eq(commandId));
     }
 
     @Test
     public void set_command_status_to_failure_when_handler_throws_unknown_Throwable() throws TestFailure, TestThrowable {
+        final CreateProjectHandler handler = mock(CreateProjectHandler.class);
         final Throwable throwable = new TestThrowable();
-        givenThrowingHandler(throwable);
+        doThrow(throwable).when(handler)
+                          .handle(any(CreateProject.class), any(CommandContext.class));
+
+        commandBus.register(handler);
         final Command command = commandFactory.create(createProject(newUuid()));
         final CommandId commandId = command.getContext().getCommandId();
         final Message commandMessage = Commands.getMessage(command);
@@ -417,11 +418,12 @@ public void set_command_status_to_failure_when_handler_throws_unknown_Throwable(
         commandBus.post(command);
 
         // Verify we updated the status.
-        verify(commandStore, times(1)).updateStatus(eq(commandId), eq(Errors.fromThrowable(throwable)));
+        verify(commandStore, atMost(1)).updateStatus(eq(commandId), eq(Errors.fromThrowable(throwable)));
         // Verify we logged the failure.
-        verify(log, times(1)).errorHandlingUnknown(eq(throwable), eq(commandMessage), eq(commandId));
+        verify(log, atMost(1)).errorHandlingUnknown(eq(throwable), eq(commandMessage), eq(commandId));
     }
 
+
     private  void givenThrowingHandler(E throwable) throws TestThrowable, TestFailure {
         final CreateProjectHandler handler = mock(CreateProjectHandler.class);
         doThrow(throwable)
@@ -454,7 +456,7 @@ public void schedule_command_if_delay_is_set() {
 
     @Test
     public void do_not_schedule_command_if_no_scheduling_options_are_set() {
-        commandBus.register(new CreateProjectHandler());
+        commandBus.register(new CreateProjectHandler(eventBus));
         final Command cmd = commandFactory.create(createProject(newUuid()));
 
         commandBus.post(cmd);
diff --git a/server/src/test/java/org/spine3/server/event/EventBusShould.java b/server/src/test/java/org/spine3/server/event/EventBusShould.java
index dcab9aba90c..00111cd1336 100644
--- a/server/src/test/java/org/spine3/server/event/EventBusShould.java
+++ b/server/src/test/java/org/spine3/server/event/EventBusShould.java
@@ -26,14 +26,12 @@
 import org.junit.Test;
 import org.spine3.base.Event;
 import org.spine3.base.EventContext;
-import org.spine3.server.EventDispatcher;
-import org.spine3.server.EventHandler;
-import org.spine3.server.Subscribe;
 import org.spine3.server.storage.StorageFactory;
 import org.spine3.server.storage.memory.InMemoryStorageFactory;
+import org.spine3.server.type.EventClass;
 import org.spine3.test.project.event.ProjectCreated;
-import org.spine3.type.EventClass;
 
+import java.util.Collection;
 import java.util.Set;
 import java.util.concurrent.Executors;
 
@@ -83,7 +81,7 @@ public void reject_object_with_no_subscriber_methods() {
     /**
      * A simple one subscriber method handler class used in tests below.
      */
-    private static class ProjectCreatedHandler implements EventHandler {
+    private static class ProjectCreatedHandler extends EventHandler {
 
         private boolean methodCalled = false;
 
@@ -109,7 +107,7 @@ public void register_event_handler() {
         final EventClass eventClass = EventClass.of(ProjectCreated.class);
         assertTrue(eventBus.hasSubscribers(eventClass));
 
-        final Set subscribers = eventBus.getHandlers(eventClass);
+        final Collection subscribers = eventBus.getHandlers(eventClass);
         assertTrue(subscribers.contains(handlerOne));
         assertTrue(subscribers.contains(handlerTwo));
     }
@@ -126,7 +124,7 @@ public void unregister_handlers() {
 
         // Check that the 2nd subscriber with the same event handling method remains
         // after the 1st subscriber unregisters.
-        final Set subscribers = eventBus.getHandlers(eventClass);
+        final Collection subscribers = eventBus.getHandlers(eventClass);
         assertFalse(subscribers.contains(handlerOne));
         assertTrue(subscribers.contains(handlerTwo));
 
@@ -221,7 +219,7 @@ public void catches_exceptions_caused_by_handlers() {
     /**
      * The handler which throws exception from the subscriber method.
      */
-    private static class FaultyHandler implements EventHandler {
+    private static class FaultyHandler extends EventHandler {
 
         private boolean methodCalled = false;
 
diff --git a/server/src/test/java/org/spine3/server/procman/ProcessManagerRepositoryShould.java b/server/src/test/java/org/spine3/server/procman/ProcessManagerRepositoryShould.java
index e19e64ee0b6..e0b93dfb8a3 100644
--- a/server/src/test/java/org/spine3/server/procman/ProcessManagerRepositoryShould.java
+++ b/server/src/test/java/org/spine3/server/procman/ProcessManagerRepositoryShould.java
@@ -25,21 +25,24 @@
 import com.google.protobuf.StringValue;
 import org.junit.Before;
 import org.junit.Test;
+import org.mockito.ArgumentCaptor;
 import org.spine3.base.Command;
 import org.spine3.base.CommandContext;
 import org.spine3.base.Commands;
 import org.spine3.base.Event;
 import org.spine3.base.EventContext;
 import org.spine3.base.Events;
-import org.spine3.server.Assign;
 import org.spine3.server.BoundedContext;
 import org.spine3.server.BoundedContextTestStubs;
-import org.spine3.server.CommandDispatcher;
-import org.spine3.server.FailureThrowable;
-import org.spine3.server.Subscribe;
+import org.spine3.server.command.Assign;
+import org.spine3.server.command.CommandDispatcher;
 import org.spine3.server.entity.IdFunction;
 import org.spine3.server.event.GetProducerIdFromEvent;
+import org.spine3.server.event.Subscribe;
+import org.spine3.server.failure.FailureThrowable;
 import org.spine3.server.storage.memory.InMemoryStorageFactory;
+import org.spine3.server.type.CommandClass;
+import org.spine3.server.type.EventClass;
 import org.spine3.test.project.Project;
 import org.spine3.test.project.ProjectId;
 import org.spine3.test.project.command.AddTask;
@@ -50,15 +53,13 @@
 import org.spine3.test.project.event.TaskAdded;
 import org.spine3.testdata.TestAggregateIdFactory;
 import org.spine3.testdata.TestCommands;
-import org.spine3.type.CommandClass;
-import org.spine3.type.EventClass;
 
 import java.lang.reflect.InvocationTargetException;
-import java.util.Collections;
-import java.util.List;
 import java.util.Set;
 
 import static org.junit.Assert.*;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
 import static org.spine3.protobuf.Messages.fromAny;
 import static org.spine3.testdata.TestCommands.*;
 import static org.spine3.testdata.TestEventMessageFactory.*;
@@ -66,16 +67,17 @@
 /**
  * @author Alexander Litus
  */
-@SuppressWarnings({"InstanceMethodNamingConvention"})
+@SuppressWarnings({"InstanceMethodNamingConvention", "OverlyCoupledClass"})
 public class ProcessManagerRepositoryShould {
 
     private static final ProjectId ID = TestAggregateIdFactory.newProjectId();
 
+    private BoundedContext boundedContext;
     private TestProcessManagerRepository repository;
 
     @Before
     public void setUp() {
-        final BoundedContext boundedContext = BoundedContextTestStubs.create();
+        boundedContext = BoundedContextTestStubs.create();
 
         boundedContext.getCommandBus().register(new CommandDispatcher() {
             @Override
@@ -84,10 +86,9 @@ public Set getCommandClasses() {
             }
 
             @Override
-            public List dispatch(Command request) throws Exception {
+            public void dispatch(Command request) throws Exception {
                 // Simply swallow the command. We need this dispatcher for allowing Process Manager
                 // under test to route the AddTask command.
-                return Collections.emptyList();
             }
         });
 
@@ -132,20 +133,23 @@ public void dispatch_several_commands() throws InvocationTargetException, Failur
         testDispatchCommand(startProject(ID));
     }
 
-    private List testDispatchCommand(Message command) throws InvocationTargetException, FailureThrowable {
+    private void testDispatchCommand(Message command) throws InvocationTargetException, FailureThrowable {
         final Command request = Commands.create(command, CommandContext.getDefaultInstance());
-        final List events = repository.dispatch(request);
+        repository.dispatch(request);
         final TestProcessManager manager = repository.load(ID);
         assertEquals(toState(command), manager.getState());
-        return events;
     }
 
     @Test
     public void dispatch_command_and_return_events() throws InvocationTargetException, FailureThrowable {
-        final List events = testDispatchCommand(addTask(ID));
+        testDispatchCommand(addTask(ID));
+
+        final ArgumentCaptor argumentCaptor = ArgumentCaptor.forClass(Event.class);
+
+        verify(boundedContext.getEventBus(), times(1)).post(argumentCaptor.capture());
+
+        final Event event = argumentCaptor.getValue();
 
-        assertEquals(1, events.size());
-        final Event event = events.get(0);
         assertNotNull(event);
         final TaskAdded message = fromAny(event.getMessage());
         assertEquals(ID, message.getProjectId());
diff --git a/server/src/test/java/org/spine3/server/procman/ProcessManagerShould.java b/server/src/test/java/org/spine3/server/procman/ProcessManagerShould.java
index 3aa069178c6..d7f88454790 100644
--- a/server/src/test/java/org/spine3/server/procman/ProcessManagerShould.java
+++ b/server/src/test/java/org/spine3/server/procman/ProcessManagerShould.java
@@ -33,9 +33,9 @@
 import org.spine3.base.EventContext;
 import org.spine3.base.Events;
 import org.spine3.protobuf.Messages;
-import org.spine3.server.Assign;
-import org.spine3.server.Subscribe;
+import org.spine3.server.command.Assign;
 import org.spine3.server.command.CommandBus;
+import org.spine3.server.event.Subscribe;
 import org.spine3.test.project.ProjectId;
 import org.spine3.test.project.command.AddTask;
 import org.spine3.test.project.command.CreateProject;
diff --git a/server/src/test/java/org/spine3/server/projection/ProjectionRepositoryShould.java b/server/src/test/java/org/spine3/server/projection/ProjectionRepositoryShould.java
index ac606c3bb1c..d74005a2457 100644
--- a/server/src/test/java/org/spine3/server/projection/ProjectionRepositoryShould.java
+++ b/server/src/test/java/org/spine3/server/projection/ProjectionRepositoryShould.java
@@ -29,16 +29,16 @@
 import org.spine3.base.Events;
 import org.spine3.server.BoundedContext;
 import org.spine3.server.BoundedContextTestStubs;
-import org.spine3.server.Subscribe;
+import org.spine3.server.event.Subscribe;
 import org.spine3.server.storage.EntityStorage;
 import org.spine3.server.storage.StorageFactory;
 import org.spine3.server.storage.memory.InMemoryStorageFactory;
+import org.spine3.server.type.EventClass;
 import org.spine3.test.project.Project;
 import org.spine3.test.project.ProjectId;
 import org.spine3.test.project.event.ProjectCreated;
 import org.spine3.test.project.event.ProjectStarted;
 import org.spine3.test.project.event.TaskAdded;
-import org.spine3.type.EventClass;
 
 import java.lang.reflect.InvocationTargetException;
 import java.util.Set;
diff --git a/server/src/test/java/org/spine3/server/projection/ProjectionShould.java b/server/src/test/java/org/spine3/server/projection/ProjectionShould.java
index 0e05e2c3fb6..2e5e9e8e075 100644
--- a/server/src/test/java/org/spine3/server/projection/ProjectionShould.java
+++ b/server/src/test/java/org/spine3/server/projection/ProjectionShould.java
@@ -26,7 +26,7 @@
 import org.junit.Before;
 import org.junit.Test;
 import org.spine3.base.EventContext;
-import org.spine3.server.Subscribe;
+import org.spine3.server.event.Subscribe;
 
 import static org.junit.Assert.assertTrue;
 import static org.spine3.protobuf.Values.newStringValue;
diff --git a/server/src/test/java/org/spine3/server/internal/MessageHandlerMethodShould.java b/server/src/test/java/org/spine3/server/reflect/MessageHandlerMethodShould.java
similarity index 76%
rename from server/src/test/java/org/spine3/server/internal/MessageHandlerMethodShould.java
rename to server/src/test/java/org/spine3/server/reflect/MessageHandlerMethodShould.java
index ab1666172a7..7e902d57d85 100644
--- a/server/src/test/java/org/spine3/server/internal/MessageHandlerMethodShould.java
+++ b/server/src/test/java/org/spine3/server/reflect/MessageHandlerMethodShould.java
@@ -18,7 +18,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package org.spine3.server.internal;
+package org.spine3.server.reflect;
 
 import com.google.protobuf.BoolValue;
 import com.google.protobuf.StringValue;
@@ -35,30 +35,30 @@
 @SuppressWarnings("InstanceMethodNamingConvention")
 public class MessageHandlerMethodShould {
 
-    private static class TwoParamMethod extends MessageHandlerMethod {
+    private static class TwoParamMethod extends HandlerMethod {
 
-        protected TwoParamMethod(Object target, Method method) {
-            super(target, method);
+        protected TwoParamMethod(Method method) {
+            super(method);
         }
     }
 
-    private static class OneParamMethod extends MessageHandlerMethod {
+    private static class OneParamMethod extends HandlerMethod {
 
-        protected OneParamMethod(Object target, Method method) {
-            super(target, method);
+        protected OneParamMethod(Method method) {
+            super(method);
         }
     }
 
-    private MessageHandlerMethod twoParamMethod;
-    private MessageHandlerMethod oneParamMethod;
+    private HandlerMethod twoParamMethod;
+    private HandlerMethod oneParamMethod;
 
     private Object target;
 
     @Before
     public void setUp() {
         target = new StubHandler();
-        twoParamMethod = new TwoParamMethod(target, StubHandler.getTwoParameterMethod());
-        oneParamMethod = new OneParamMethod(target, StubHandler.getOneParameterMethod());
+        twoParamMethod = new TwoParamMethod(StubHandler.getTwoParameterMethod());
+        oneParamMethod = new OneParamMethod(StubHandler.getOneParameterMethod());
     }
 
     @SuppressWarnings("UnusedParameters") // OK for test methods.
@@ -107,21 +107,10 @@ private void handle(BoolValue message) {
         }
     }
 
-    @Test(expected = NullPointerException.class)
-    public void do_not_accept_null_target() {
-        //noinspection ConstantConditions,ResultOfObjectAllocationIgnored
-        new TwoParamMethod(null, StubHandler.getTwoParameterMethod());
-    }
-
     @Test(expected = NullPointerException.class)
     public void do_not_accept_null_method() {
         //noinspection ConstantConditions,ResultOfObjectAllocationIgnored
-        new TwoParamMethod(new StubHandler(), null);
-    }
-
-    @Test
-    public void return_target() {
-        assertEquals(target, twoParamMethod.getTarget());
+        new TwoParamMethod(null);
     }
 
     @Test
@@ -141,14 +130,14 @@ public void check_if_private() {
 
     @Test
     public void invoke_the_method_with_two_parameters() throws InvocationTargetException {
-        twoParamMethod.invoke(StringValue.getDefaultInstance(), EventContext.getDefaultInstance());
+        twoParamMethod.invoke(target, StringValue.getDefaultInstance(), EventContext.getDefaultInstance());
 
         assertTrue(((StubHandler)target).wasOnInvoked());
     }
 
     @Test
     public void invoke_the_method_with_one_parameter() throws InvocationTargetException {
-        oneParamMethod.invoke(BoolValue.getDefaultInstance());
+        oneParamMethod.invoke(target, BoolValue.getDefaultInstance());
 
         assertTrue(((StubHandler)target).wasHandleInvoked());
     }
@@ -178,8 +167,8 @@ public void be_not_equal_to_another_class_instance() {
 
     @Test
     public void compare_fields_in_equals() {
-        final MessageHandlerMethod anotherMethod =
-                new TwoParamMethod(target, StubHandler.getTwoParameterMethod());
+        final HandlerMethod anotherMethod =
+                new TwoParamMethod(StubHandler.getTwoParameterMethod());
 
         assertTrue(twoParamMethod.equals(anotherMethod));
     }
diff --git a/server/src/test/java/org/spine3/server/reflect/MethodMapShould.java b/server/src/test/java/org/spine3/server/reflect/MethodMapShould.java
index 139f9667315..ce0d017b6d5 100644
--- a/server/src/test/java/org/spine3/server/reflect/MethodMapShould.java
+++ b/server/src/test/java/org/spine3/server/reflect/MethodMapShould.java
@@ -22,9 +22,8 @@
 
 import org.junit.Test;
 import org.spine3.base.CommandContext;
-import org.spine3.server.Assign;
 import org.spine3.server.aggregate.Aggregate;
-import org.spine3.server.internal.CommandHandlerMethod;
+import org.spine3.server.command.Assign;
 import org.spine3.test.project.Project;
 import org.spine3.test.project.command.CreateProject;
 import org.spine3.test.project.event.ProjectCreated;
@@ -51,7 +50,7 @@ public ProjectCreated handle(CreateProject command, CommandContext context) {
 
     @Test
     public void expose_key_set() {
-        final MethodMap methodMap = new MethodMap(TestAggregate.class, CommandHandlerMethod.PREDICATE);
+        final MethodMap methodMap = MethodMap.create(TestAggregate.class, CommandHandlerMethod.factory());
         assertFalse(methodMap.keySet().isEmpty());
     }
 }
diff --git a/server/src/test/java/org/spine3/server/reflect/UtilitiesShould.java b/server/src/test/java/org/spine3/server/reflect/UtilitiesShould.java
index 0ea0e480062..d174d8befa4 100644
--- a/server/src/test/java/org/spine3/server/reflect/UtilitiesShould.java
+++ b/server/src/test/java/org/spine3/server/reflect/UtilitiesShould.java
@@ -61,7 +61,6 @@ public void have_private_constructors() {
         checkPrivateConstructor(Identifiers.class);
         checkPrivateConstructor(IoUtil.class);
         checkPrivateConstructor(Math.class);
-        checkPrivateConstructor(Methods.class);
         checkPrivateConstructor(Tests.class);
 
         // testutil package
diff --git a/client/src/test/java/org/spine3/type/EventClassShould.java b/server/src/test/java/org/spine3/server/type/EventClassShould.java
similarity index 97%
rename from client/src/test/java/org/spine3/type/EventClassShould.java
rename to server/src/test/java/org/spine3/server/type/EventClassShould.java
index 779a7862254..402756df65a 100644
--- a/client/src/test/java/org/spine3/type/EventClassShould.java
+++ b/server/src/test/java/org/spine3/server/type/EventClassShould.java
@@ -18,7 +18,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package org.spine3.type;
+package org.spine3.server.type;
 
 import com.google.protobuf.BoolValue;
 import com.google.protobuf.Int32Value;
diff --git a/client/src/test/java/org/spine3/type/ClassTypeValueShould.java b/server/src/test/java/org/spine3/server/type/MessageClassShould.java
similarity index 77%
rename from client/src/test/java/org/spine3/type/ClassTypeValueShould.java
rename to server/src/test/java/org/spine3/server/type/MessageClassShould.java
index b1567f3c7f4..080f4aa2d50 100644
--- a/client/src/test/java/org/spine3/type/ClassTypeValueShould.java
+++ b/server/src/test/java/org/spine3/server/type/MessageClassShould.java
@@ -18,39 +18,41 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package org.spine3.type;
+package org.spine3.server.type;
 
 import com.google.protobuf.Message;
 import com.google.protobuf.StringValue;
 import com.google.protobuf.UInt32Value;
+import org.junit.Assert;
 import org.junit.Test;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
 
-public class ClassTypeValueShould {
+public class MessageClassShould {
 
     @Test
     public void return_enclosed_value() {
         final Class expected = StringValue.class;
-        assertEquals(expected, new  ClassTypeValue(expected) {}.value());
+        Assert.assertEquals(expected, new  MessageClass(expected) {}.value());
     }
 
     @Test
     public void be_not_equal_to_null() {
         //noinspection ObjectEqualsNull
-        assertFalse(new ClassTypeValue(UInt32Value.class){}.equals(null));
+        assertFalse(new MessageClass(UInt32Value.class){}.equals(null));
     }
 
     @Test
     public void be_not_equal_to_object_of_another_class() {
         // Notice that we're creating new inner classes here with the same value passed.
         //noinspection EqualsBetweenInconvertibleTypes
-        assertFalse(new ClassTypeValue(StringValue.class){}.equals(new ClassTypeValue(StringValue.class){}));
+        assertFalse(new MessageClass(StringValue.class){}.equals(new MessageClass(StringValue.class){}));
     }
 
     @Test
     public void be_equal_to_self() {
-        final ClassTypeValue test = new ClassTypeValue(UInt32Value.class){};
+        final MessageClass test = new MessageClass(UInt32Value.class){};
         //noinspection EqualsWithItself
         assertTrue(test.equals(test));
     }
diff --git a/server/src/test/java/org/spine3/server/validate/FieldValidatorFactoryShould.java b/server/src/test/java/org/spine3/server/validate/FieldValidatorFactoryShould.java
index 86f37ca7334..0d0fba1444d 100644
--- a/server/src/test/java/org/spine3/server/validate/FieldValidatorFactoryShould.java
+++ b/server/src/test/java/org/spine3/server/validate/FieldValidatorFactoryShould.java
@@ -28,9 +28,9 @@
 import com.google.protobuf.StringValue;
 import org.junit.Test;
 import org.spine3.base.FieldPath;
-import org.spine3.test.validation.msg.AnnotatedEnumFieldValue;
-import org.spine3.test.validation.msg.RequiredByteStringFieldValue;
-import org.spine3.test.validation.msg.RequiredMsgFieldValue;
+import org.spine3.test.validate.msg.AnnotatedEnumFieldValue;
+import org.spine3.test.validate.msg.RequiredByteStringFieldValue;
+import org.spine3.test.validate.msg.RequiredMsgFieldValue;
 
 import static com.google.protobuf.Descriptors.FieldDescriptor;
 import static org.junit.Assert.assertTrue;
diff --git a/server/src/test/java/org/spine3/server/validate/MessageValidatorShould.java b/server/src/test/java/org/spine3/server/validate/MessageValidatorShould.java
index 85670df1fd1..2db28876a83 100644
--- a/server/src/test/java/org/spine3/server/validate/MessageValidatorShould.java
+++ b/server/src/test/java/org/spine3/server/validate/MessageValidatorShould.java
@@ -30,33 +30,33 @@
 import org.spine3.base.FieldPath;
 import org.spine3.protobuf.Durations;
 import org.spine3.protobuf.Values;
-import org.spine3.test.validation.msg.AnnotatedBooleanFieldValue;
-import org.spine3.test.validation.msg.AnnotatedEnumFieldValue;
-import org.spine3.test.validation.msg.DecimalMaxIncNumberFieldValue;
-import org.spine3.test.validation.msg.DecimalMaxNotIncNumberFieldValue;
-import org.spine3.test.validation.msg.DecimalMinIncNumberFieldValue;
-import org.spine3.test.validation.msg.DecimalMinNotIncNumberFieldValue;
-import org.spine3.test.validation.msg.DigitsCountNumberFieldValue;
-import org.spine3.test.validation.msg.EnclosedMessageFieldValue;
-import org.spine3.test.validation.msg.EnclosedMessageWithoutAnnotationFieldValue;
-import org.spine3.test.validation.msg.EntityIdByteStringFieldValue;
-import org.spine3.test.validation.msg.EntityIdDoubleFieldValue;
-import org.spine3.test.validation.msg.EntityIdIntFieldValue;
-import org.spine3.test.validation.msg.EntityIdLongFieldValue;
-import org.spine3.test.validation.msg.EntityIdMsgFieldValue;
-import org.spine3.test.validation.msg.EntityIdRepeatedFieldValue;
-import org.spine3.test.validation.msg.EntityIdStringFieldValue;
-import org.spine3.test.validation.msg.MaxNumberFieldValue;
-import org.spine3.test.validation.msg.MinNumberFieldValue;
-import org.spine3.test.validation.msg.PatternStringFieldValue;
-import org.spine3.test.validation.msg.RepeatedRequiredMsgFieldValue;
-import org.spine3.test.validation.msg.RequiredByteStringFieldValue;
-import org.spine3.test.validation.msg.RequiredMsgFieldValue;
-import org.spine3.test.validation.msg.RequiredStringFieldValue;
-import org.spine3.test.validation.msg.TimeInFutureFieldValue;
-import org.spine3.test.validation.msg.TimeInPastFieldValue;
-import org.spine3.test.validation.msg.TimeWithoutOptsFieldValue;
-import org.spine3.validation.options.ConstraintViolation;
+import org.spine3.test.validate.msg.AnnotatedBooleanFieldValue;
+import org.spine3.test.validate.msg.AnnotatedEnumFieldValue;
+import org.spine3.test.validate.msg.DecimalMaxIncNumberFieldValue;
+import org.spine3.test.validate.msg.DecimalMaxNotIncNumberFieldValue;
+import org.spine3.test.validate.msg.DecimalMinIncNumberFieldValue;
+import org.spine3.test.validate.msg.DecimalMinNotIncNumberFieldValue;
+import org.spine3.test.validate.msg.DigitsCountNumberFieldValue;
+import org.spine3.test.validate.msg.EnclosedMessageFieldValue;
+import org.spine3.test.validate.msg.EnclosedMessageWithoutAnnotationFieldValue;
+import org.spine3.test.validate.msg.EntityIdByteStringFieldValue;
+import org.spine3.test.validate.msg.EntityIdDoubleFieldValue;
+import org.spine3.test.validate.msg.EntityIdIntFieldValue;
+import org.spine3.test.validate.msg.EntityIdLongFieldValue;
+import org.spine3.test.validate.msg.EntityIdMsgFieldValue;
+import org.spine3.test.validate.msg.EntityIdRepeatedFieldValue;
+import org.spine3.test.validate.msg.EntityIdStringFieldValue;
+import org.spine3.test.validate.msg.MaxNumberFieldValue;
+import org.spine3.test.validate.msg.MinNumberFieldValue;
+import org.spine3.test.validate.msg.PatternStringFieldValue;
+import org.spine3.test.validate.msg.RepeatedRequiredMsgFieldValue;
+import org.spine3.test.validate.msg.RequiredByteStringFieldValue;
+import org.spine3.test.validate.msg.RequiredMsgFieldValue;
+import org.spine3.test.validate.msg.RequiredStringFieldValue;
+import org.spine3.test.validate.msg.TimeInFutureFieldValue;
+import org.spine3.test.validate.msg.TimeInPastFieldValue;
+import org.spine3.test.validate.msg.TimeWithoutOptsFieldValue;
+import org.spine3.validate.options.ConstraintViolation;
 
 import java.util.List;
 
diff --git a/server/src/test/java/org/spine3/testdata/ProjectAggregate.java b/server/src/test/java/org/spine3/testdata/ProjectAggregate.java
index 0219abb0083..ced19aba786 100644
--- a/server/src/test/java/org/spine3/testdata/ProjectAggregate.java
+++ b/server/src/test/java/org/spine3/testdata/ProjectAggregate.java
@@ -21,8 +21,8 @@
 package org.spine3.testdata;
 
 import org.spine3.base.CommandContext;
-import org.spine3.server.Assign;
 import org.spine3.server.aggregate.Aggregate;
+import org.spine3.server.command.Assign;
 import org.spine3.test.project.Project;
 import org.spine3.test.project.ProjectId;
 import org.spine3.test.project.command.AddTask;
diff --git a/server/src/test/proto/spine/test/validation/msg/commands.proto b/server/src/test/proto/spine/test/validate/msg/commands.proto
similarity index 95%
rename from server/src/test/proto/spine/test/validation/msg/commands.proto
rename to server/src/test/proto/spine/test/validate/msg/commands.proto
index 5962a8e0d1b..fe2e791d434 100644
--- a/server/src/test/proto/spine/test/validation/msg/commands.proto
+++ b/server/src/test/proto/spine/test/validate/msg/commands.proto
@@ -19,12 +19,12 @@
 //
 syntax = "proto3";
 
-package spine.test.validation.msg;
+package spine.test.validate.msg;
 
 option java_generate_equals_and_hash = true;
 option java_multiple_files = true;
 option java_outer_classname = "ValidationTestCommandsProto";
-option java_package = "org.spine3.test.validation.msg";
+option java_package = "org.spine3.test.validate.msg";
 
 import "google/protobuf/wrappers.proto";
 import "spine/validation.proto";
diff --git a/server/src/test/proto/spine/test/validation/msg/messages.proto b/server/src/test/proto/spine/test/validate/msg/messages.proto
similarity index 97%
rename from server/src/test/proto/spine/test/validation/msg/messages.proto
rename to server/src/test/proto/spine/test/validate/msg/messages.proto
index d8bb6e9c16b..c42c476e065 100644
--- a/server/src/test/proto/spine/test/validation/msg/messages.proto
+++ b/server/src/test/proto/spine/test/validate/msg/messages.proto
@@ -19,12 +19,12 @@
 //
 syntax = "proto3";
 
-package spine.test.validation.msg;
+package spine.test.validate.msg;
 
 option java_generate_equals_and_hash = true;
 option java_multiple_files = true;
 option java_outer_classname = "ValidationTestMessagesProto";
-option java_package = "org.spine3.test.validation.msg";
+option java_package = "org.spine3.test.validate.msg";
 
 import "google/protobuf/timestamp.proto";
 import "google/protobuf/wrappers.proto";
diff --git a/server/src/test/proto/spine/test/validation/msg/stub_aggregate.proto b/server/src/test/proto/spine/test/validate/msg/stub_aggregate.proto
similarity index 93%
rename from server/src/test/proto/spine/test/validation/msg/stub_aggregate.proto
rename to server/src/test/proto/spine/test/validate/msg/stub_aggregate.proto
index bb8db3bea14..9d9c4c8f865 100644
--- a/server/src/test/proto/spine/test/validation/msg/stub_aggregate.proto
+++ b/server/src/test/proto/spine/test/validate/msg/stub_aggregate.proto
@@ -19,11 +19,11 @@
 //
 syntax = "proto3";
 
-package spine.test.validation.msg;
+package spine.test.validate.msg;
 
 option java_generate_equals_and_hash = true;
 option java_multiple_files = true;
-option java_package = "org.spine3.test.validation.msg";
+option java_package = "org.spine3.test.validate.msg";
 
 import "spine/entity.proto";
 
diff --git a/values/build.gradle b/values/build.gradle
index 205c7bd4370..504f638579f 100644
--- a/values/build.gradle
+++ b/values/build.gradle
@@ -4,7 +4,7 @@ buildscript {
         resolutionStrategy.cacheChangingModulesFor 0, 'seconds'
     }
     dependencies {
-        classpath group: 'org.spine3.tools', name: 'protobuf-plugin', version: '1.2', changing: true
+        classpath group: 'org.spine3.tools', name: 'protobuf-plugin', version: '1.3.1', changing: true
     }
 }
 
@@ -36,9 +36,10 @@ protobuf {
     generateProtoTasks {
         all().each { final task ->
             task.plugins {
-                grpc {
-//                    option 'nano=true'
-                }
+                grpc {}
+                task.generateDescriptorSet = true
+                task.descriptorSetOptions.path = "${projectDir}/build/descriptors/${task.sourceSet.name}.desc"
+                task.descriptorSetOptions.includeImports = true
             }
         }
     }

From a2567acce16990bdee34ef1f2f18887f07945a63 Mon Sep 17 00:00:00 2001
From: Alexander Litus 
Date: Tue, 19 Apr 2016 17:32:29 +0300
Subject: [PATCH 19/26] Merge branch 'master' into this one.

---
 server/src/main/java/org/spine3/server/command/CommandBus.java | 1 -
 1 file changed, 1 deletion(-)

diff --git a/server/src/main/java/org/spine3/server/command/CommandBus.java b/server/src/main/java/org/spine3/server/command/CommandBus.java
index 7cb22537b6e..646a2c1e96c 100644
--- a/server/src/main/java/org/spine3/server/command/CommandBus.java
+++ b/server/src/main/java/org/spine3/server/command/CommandBus.java
@@ -35,7 +35,6 @@
 import org.spine3.server.type.CommandClass;
 import org.spine3.server.validate.MessageValidator;
 import org.spine3.validate.options.ConstraintViolation;
-import org.spine3.type.CommandClass;
 
 import javax.annotation.Nullable;
 import java.lang.reflect.InvocationTargetException;

From 5be63438f17d662556292d161ffb9deac30697ee Mon Sep 17 00:00:00 2001
From: Alexander Litus 
Date: Tue, 19 Apr 2016 18:05:53 +0300
Subject: [PATCH 20/26] 0.3 version.

---
 build.gradle | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/build.gradle b/build.gradle
index 4855b483023..ee199c9c158 100644
--- a/build.gradle
+++ b/build.gradle
@@ -15,7 +15,7 @@ allprojects {
     apply plugin: 'jacoco'
 
     group = 'org.spine3'
-    version = '0.2'
+    version = '0.3'
 }
 
 project.ext {

From 203390e2145c9869c73a2a1c35116a8799083121 Mon Sep 17 00:00:00 2001
From: Alexander Litus 
Date: Tue, 19 Apr 2016 18:24:40 +0300
Subject: [PATCH 21/26] Update protobuf-plugin dep-cy.

---
 client/build.gradle | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/client/build.gradle b/client/build.gradle
index 7491242a5e7..c775db48eb0 100644
--- a/client/build.gradle
+++ b/client/build.gradle
@@ -4,7 +4,7 @@ buildscript {
         resolutionStrategy.cacheChangingModulesFor 0, 'seconds'
     }
     dependencies {
-        classpath group: 'org.spine3.tools', name: 'protobuf-plugin', version: '1.2', changing: true
+        classpath group: 'org.spine3.tools', name: 'protobuf-plugin', version: '1.3.1', changing: true
     }
 }
 

From 5384729d0b0aa8d7b8836b17cd4cea42ae51a42e Mon Sep 17 00:00:00 2001
From: Alexander Litus 
Date: Tue, 19 Apr 2016 18:27:35 +0300
Subject: [PATCH 22/26] Remove redundant tag in docs.

---
 client/src/main/java/org/spine3/protobuf/Durations.java | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/client/src/main/java/org/spine3/protobuf/Durations.java b/client/src/main/java/org/spine3/protobuf/Durations.java
index 6556e08e8d1..c14ea52ef16 100644
--- a/client/src/main/java/org/spine3/protobuf/Durations.java
+++ b/client/src/main/java/org/spine3/protobuf/Durations.java
@@ -19,7 +19,7 @@
 
 /**
  * Utility class for working with durations in addition to those available from {@link TimeUtil}.
- * 

+ *
  * 
Use {@code import static org.spine3.protobuf.Durations.*} for compact initialization like this:
  * 
  *      Duration d = add(hours(2), minutes(30));
@@ -87,6 +87,7 @@ public static Duration ofHours(long hours) {
 
     // Methods for brief computations with Durations like
     //       add(hours(2), minutes(30));
+    /////////////////////////////////////////////////////
 
     /**
      * Obtains an instance of {@code Duration} representing the passed number of nanoseconds.

From 9193013a9e0e91d6b549eff59537788466a12815 Mon Sep 17 00:00:00 2001
From: Alexander Litus 
Date: Tue, 19 Apr 2016 18:33:17 +0300
Subject: [PATCH 23/26] Minor changes.

---
 .../src/main/java/org/spine3/server/reflect/MethodMap.java   | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/server/src/main/java/org/spine3/server/reflect/MethodMap.java b/server/src/main/java/org/spine3/server/reflect/MethodMap.java
index 4d8b7932690..e097bb4065d 100644
--- a/server/src/main/java/org/spine3/server/reflect/MethodMap.java
+++ b/server/src/main/java/org/spine3/server/reflect/MethodMap.java
@@ -93,9 +93,8 @@ private static Map, Method> scan(Class declaringClas
                 tempMap.put(messageClass, method);
             }
         }
-        final ImmutableMap.Builder, Method> builder = ImmutableMap.builder();
-        builder.putAll(tempMap);
-        return builder.build();
+        final ImmutableMap, Method> result = ImmutableMap.copyOf(tempMap);
+        return result;
     }
 
     /**

From e225e12d6bc92130d076505d73812acdccb6999f Mon Sep 17 00:00:00 2001
From: Alexander Litus 
Date: Tue, 19 Apr 2016 18:36:07 +0300
Subject: [PATCH 24/26] Remove redundant code.

---
 values/build.gradle | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/values/build.gradle b/values/build.gradle
index 504f638579f..310100b1162 100644
--- a/values/build.gradle
+++ b/values/build.gradle
@@ -28,15 +28,9 @@ sourceSets {
 }
 
 protobuf {
-    plugins {
-        grpc {
-            artifact = 'io.grpc:protoc-gen-grpc-java:0.13.1'
-        }
-    }
     generateProtoTasks {
         all().each { final task ->
             task.plugins {
-                grpc {}
                 task.generateDescriptorSet = true
                 task.descriptorSetOptions.path = "${projectDir}/build/descriptors/${task.sourceSet.name}.desc"
                 task.descriptorSetOptions.includeImports = true

From cdb9a1eebb639cf20f3886ba3c377d593c2eb03a Mon Sep 17 00:00:00 2001
From: Alexander Litus 
Date: Wed, 20 Apr 2016 11:49:24 +0300
Subject: [PATCH 25/26] Add a method to Responses.

---
 .../main/java/org/spine3/base/Responses.java  | 21 +++++++++++++
 .../java/org/spine3/base/ResponsesShould.java | 30 +++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/client/src/main/java/org/spine3/base/Responses.java b/client/src/main/java/org/spine3/base/Responses.java
index 0a8a5e602ec..d1eaf4ebac6 100644
--- a/client/src/main/java/org/spine3/base/Responses.java
+++ b/client/src/main/java/org/spine3/base/Responses.java
@@ -22,6 +22,8 @@
 
 import com.google.protobuf.Empty;
 
+import static org.spine3.protobuf.Messages.fromAny;
+
 /**
  * Utilities for working with {@link org.spine3.base.Response} objects.
  *
@@ -47,6 +49,8 @@ public static Response ok() {
     }
 
     /**
+     * Checks if the response is OK.
+     *
      * @return {@code true} if the passed response represents `ok` status,
      *         {@code false} otherwise
      */
@@ -56,6 +60,8 @@ public static boolean isOk(Response response) {
     }
 
     /**
+     * Checks if the response is `unsupported command`.
+     *
      * @return {@code true} if the passed response represents `unsupported command` error,
      *         {@code false} otherwise
      */
@@ -67,4 +73,19 @@ public static boolean isUnsupportedCommand(Response response) {
         }
         return false;
     }
+
+    /**
+     * Checks if the response is `invalid command`.
+     *
+     * @return {@code true} if the passed response represents `invalid command` error,
+     *         {@code false} otherwise
+     */
+    public static boolean isInvalidCommand(Response response) {
+        if (response.getStatusCase() == Response.StatusCase.FAILURE) {
+            final ValidationFailure failure = fromAny(response.getFailure().getInstance());
+            final boolean isInvalid = !failure.getConstraintViolationList().isEmpty();
+            return isInvalid;
+        }
+        return false;
+    }
 }
diff --git a/client/src/test/java/org/spine3/base/ResponsesShould.java b/client/src/test/java/org/spine3/base/ResponsesShould.java
index 427fe545c4e..b99833fbed7 100644
--- a/client/src/test/java/org/spine3/base/ResponsesShould.java
+++ b/client/src/test/java/org/spine3/base/ResponsesShould.java
@@ -21,10 +21,15 @@
 package org.spine3.base;
 
 import org.junit.Test;
+import org.spine3.validate.options.ConstraintViolation;
+
+import java.util.List;
 
 import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.collect.Lists.newArrayList;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
+import static org.spine3.protobuf.Messages.toAny;
 import static org.spine3.test.Tests.hasPrivateUtilityConstructor;
 
 @SuppressWarnings("InstanceMethodNamingConvention")
@@ -35,6 +40,8 @@ public class ResponsesShould {
                            .setCode(CommandValidationError.UNSUPPORTED_COMMAND.getNumber()))
             .build();
 
+    private static final Response RESPONSE_INVALID_COMMAND = newInvalidCommandResponse();
+
     @Test
     public void have_private_constructor() {
         assertTrue(hasPrivateUtilityConstructor(Responses.class));
@@ -64,4 +71,27 @@ public void recognize_UNSUPPORTED_COMMAND_response() {
     public void return_false_if_not_UNSUPPORTED_COMMAND_response() {
         assertFalse(Responses.isUnsupportedCommand(Responses.ok()));
     }
+
+    @Test
+    public void recognize_INVALID_COMMAND_response() {
+        assertTrue(Responses.isInvalidCommand(RESPONSE_INVALID_COMMAND));
+    }
+
+    @Test
+    public void return_false_if_not_INVALID_COMMAND_response() {
+        assertFalse(Responses.isInvalidCommand(Responses.ok()));
+    }
+
+    private static Response newInvalidCommandResponse() {
+        final List violations = newArrayList(ConstraintViolation.getDefaultInstance());
+        final ValidationFailure failureInstance = ValidationFailure.newBuilder()
+                                                                   .addAllConstraintViolation(violations)
+                                                                   .build();
+        final Failure.Builder failure = Failure.newBuilder()
+                                               .setInstance(toAny(failureInstance));
+        final Response response = Response.newBuilder()
+                                          .setFailure(failure)
+                                          .build();
+        return response;
+    }
 }

From e0e8215c1a713a722e17dbdfafeca2eb7bbfd1fc Mon Sep 17 00:00:00 2001
From: Alexander Litus 
Date: Wed, 20 Apr 2016 11:54:29 +0300
Subject: [PATCH 26/26] Fix and add command bus tests.

---
 .../org/spine3/server/command/CommandBus.java |  14 +-
 .../server/BoundedContextBuilderShould.java   |  10 +-
 .../spine3/server/BoundedContextShould.java   |  15 +-
 .../server/BoundedContextTestStubs.java       |  11 +-
 .../server/command/CommandBusShould.java      | 146 +++++++++++-------
 .../org/spine3/testdata/TestCommands.java     |  14 +-
 .../org/spine3/testdata/TestEventFactory.java |  16 ++
 7 files changed, 130 insertions(+), 96 deletions(-)

diff --git a/server/src/main/java/org/spine3/server/command/CommandBus.java b/server/src/main/java/org/spine3/server/command/CommandBus.java
index 646a2c1e96c..b54da078e83 100644
--- a/server/src/main/java/org/spine3/server/command/CommandBus.java
+++ b/server/src/main/java/org/spine3/server/command/CommandBus.java
@@ -65,6 +65,7 @@ public class CommandBus implements AutoCloseable {
     
     private ProblemLog problemLog = new ProblemLog();
     private final CommandStatusService commandStatusService;
+    private MessageValidator messageValidator;
 
     private CommandBus(Builder builder) {
         commandStore = builder.getCommandStore();
@@ -73,6 +74,7 @@ private CommandBus(Builder builder) {
             scheduler.setPostFunction(newPostFunction());
         }
         commandStatusService = new CommandStatusService(commandStore);
+        messageValidator = new MessageValidator();
     }
 
     /**
@@ -145,8 +147,7 @@ public Response validate(Message command) {
         if (isUnsupportedCommand(commandClass)) {
             return unsupportedCommand(command);
         }
-        final MessageValidator validator = new MessageValidator();
-        final List violations = validator.validate(command);
+        final List violations = messageValidator.validate(command);
         if (!violations.isEmpty()) {
             return invalidCommand(command, violations);
         }
@@ -277,6 +278,11 @@ private void schedule(Command command) {
         this.problemLog = problemLog;
     }
 
+    @VisibleForTesting
+    /* package */ void setMessageValidator(MessageValidator messageValidator) {
+        this.messageValidator = messageValidator;
+    }
+
     private void store(Command request) {
         commandStore.store(request);
     }
@@ -300,9 +306,7 @@ private Function newPostFunction() {
             @Nullable
             @Override
             public Command apply(@Nullable Command command) {
-                if (command == null) {
-                    return null;
-                }
+                //noinspection ConstantConditions
                 post(command);
                 return command;
             }
diff --git a/server/src/test/java/org/spine3/server/BoundedContextBuilderShould.java b/server/src/test/java/org/spine3/server/BoundedContextBuilderShould.java
index 173412cbd5e..92a6ebbed5b 100644
--- a/server/src/test/java/org/spine3/server/BoundedContextBuilderShould.java
+++ b/server/src/test/java/org/spine3/server/BoundedContextBuilderShould.java
@@ -20,18 +20,17 @@
 
 package org.spine3.server;
 
-import com.google.common.util.concurrent.MoreExecutors;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.spine3.server.command.CommandBus;
 import org.spine3.server.event.EventBus;
-import org.spine3.server.event.EventStore;
 import org.spine3.server.storage.StorageFactory;
 import org.spine3.server.storage.memory.InMemoryStorageFactory;
 
 import static org.junit.Assert.*;
 import static org.spine3.testdata.TestCommands.newCommandBus;
+import static org.spine3.testdata.TestEventFactory.newEventBus;
 
 @SuppressWarnings("InstanceMethodNamingConvention")
 public class BoundedContextBuilderShould {
@@ -99,11 +98,4 @@ public void do_not_accept_null_EventBus() {
         //noinspection ConstantConditions
         BoundedContext.newBuilder().setEventBus(null);
     }
-
-    private static EventBus newEventBus(StorageFactory storageFactory) {
-        return EventBus.newInstance(EventStore.newBuilder()
-                                              .setStreamExecutor(MoreExecutors.directExecutor())
-                                              .setStorage(storageFactory.createEventStorage())
-                                              .build());
-    }
 }
diff --git a/server/src/test/java/org/spine3/server/BoundedContextShould.java b/server/src/test/java/org/spine3/server/BoundedContextShould.java
index 4463b4a2122..56b9d0dfb24 100644
--- a/server/src/test/java/org/spine3/server/BoundedContextShould.java
+++ b/server/src/test/java/org/spine3/server/BoundedContextShould.java
@@ -20,7 +20,6 @@
 
 package org.spine3.server;
 
-import com.google.common.util.concurrent.MoreExecutors;
 import com.google.protobuf.Any;
 import com.google.protobuf.Empty;
 import com.google.protobuf.Message;
@@ -40,13 +39,8 @@
 import org.spine3.server.aggregate.AggregateRepository;
 import org.spine3.server.aggregate.Apply;
 import org.spine3.server.command.Assign;
-import org.spine3.server.command.Assign;
-import org.spine3.server.command.CommandBus;
-import org.spine3.server.command.CommandStore;
 import org.spine3.server.entity.IdFunction;
-import org.spine3.server.event.EventBus;
 import org.spine3.server.event.EventHandler;
-import org.spine3.server.event.EventStore;
 import org.spine3.server.event.GetProducerIdFromEvent;
 import org.spine3.server.event.Subscribe;
 import org.spine3.server.procman.CommandRouted;
@@ -75,8 +69,8 @@
 import static org.spine3.base.Identifiers.newUuid;
 import static org.spine3.client.UserUtil.newUserId;
 import static org.spine3.testdata.TestCommands.createProject;
-import static org.spine3.testdata.TestCommands.createProject;
 import static org.spine3.testdata.TestCommands.newCommandBus;
+import static org.spine3.testdata.TestEventFactory.newEventBus;
 import static org.spine3.testdata.TestEventMessageFactory.*;
 
 /**
@@ -113,13 +107,6 @@ public void setUp() {
         boundedContext = BoundedContextTestStubs.create(storageFactory);
     }
 
-    private static EventBus newEventBus(StorageFactory storageFactory) {
-        return EventBus.newInstance(EventStore.newBuilder()
-                                              .setStreamExecutor(MoreExecutors.directExecutor())
-                                              .setStorage(storageFactory.createEventStorage())
-                                              .build());
-    }
-
     @After
     public void tearDown() throws Exception {
         if (handlersRegistered) {
diff --git a/server/src/test/java/org/spine3/server/BoundedContextTestStubs.java b/server/src/test/java/org/spine3/server/BoundedContextTestStubs.java
index dc155c69a1f..98da6e59f80 100644
--- a/server/src/test/java/org/spine3/server/BoundedContextTestStubs.java
+++ b/server/src/test/java/org/spine3/server/BoundedContextTestStubs.java
@@ -20,18 +20,14 @@
 
 package org.spine3.server;
 
-import com.google.common.util.concurrent.MoreExecutors;
 import org.spine3.server.command.CommandBus;
 import org.spine3.server.event.EventBus;
-import org.spine3.server.event.EventStore;
 import org.spine3.server.storage.StorageFactory;
 import org.spine3.server.storage.memory.InMemoryStorageFactory;
 
 import static org.mockito.Mockito.spy;
-
 import static org.spine3.testdata.TestCommands.newCommandBus;
-
-import static org.mockito.Mockito.spy;
+import static org.spine3.testdata.TestEventFactory.newEventBus;
 
 /**
  * Creates stubs with instances of {@link BoundedContext} for testing purposes.
@@ -47,10 +43,7 @@ public static BoundedContext create() {
 
     public static BoundedContext create(StorageFactory storageFactory) {
         final CommandBus commandBus = newCommandBus(storageFactory);
-        final EventBus eventBus = EventBus.newInstance(EventStore.newBuilder()
-                                                                 .setStreamExecutor(MoreExecutors.directExecutor())
-                                                                 .setStorage(storageFactory.createEventStorage())
-                                                                 .build());
+        final EventBus eventBus = newEventBus(storageFactory);
         final BoundedContext.Builder builder = BoundedContext.newBuilder()
                 .setStorageFactory(storageFactory)
                 .setCommandBus(commandBus)
diff --git a/server/src/test/java/org/spine3/server/command/CommandBusShould.java b/server/src/test/java/org/spine3/server/command/CommandBusShould.java
index 2298911bd04..4f70704a8da 100644
--- a/server/src/test/java/org/spine3/server/command/CommandBusShould.java
+++ b/server/src/test/java/org/spine3/server/command/CommandBusShould.java
@@ -29,32 +29,41 @@
 import org.spine3.base.CommandId;
 import org.spine3.base.Commands;
 import org.spine3.base.Errors;
+import org.spine3.base.Response;
 import org.spine3.base.Responses;
 import org.spine3.client.CommandFactory;
 import org.spine3.client.test.TestCommandFactory;
 import org.spine3.server.error.UnsupportedCommandException;
 import org.spine3.server.event.EventBus;
 import org.spine3.server.failure.FailureThrowable;
+import org.spine3.server.storage.memory.InMemoryStorageFactory;
 import org.spine3.server.type.CommandClass;
+import org.spine3.server.validate.MessageValidator;
 import org.spine3.test.failures.Failures;
 import org.spine3.test.project.command.AddTask;
 import org.spine3.test.project.command.CreateProject;
 import org.spine3.test.project.command.StartProject;
 import org.spine3.test.project.event.ProjectCreated;
+import org.spine3.testdata.TestEventFactory;
+import org.spine3.validate.options.ConstraintViolation;
 
 import java.io.IOException;
 import java.util.Collections;
 import java.util.Set;
 
+import static com.google.common.collect.Lists.newArrayList;
 import static org.junit.Assert.*;
+import static org.mockito.Matchers.eq;
 import static org.mockito.Mockito.*;
 import static org.spine3.base.Identifiers.newUuid;
+import static org.spine3.base.Responses.isInvalidCommand;
 import static org.spine3.base.Responses.isUnsupportedCommand;
+import static org.spine3.protobuf.Durations.milliseconds;
 import static org.spine3.protobuf.Durations.minutes;
 import static org.spine3.testdata.TestCommands.*;
 import static org.spine3.testdata.TestContextFactory.createCommandContext;
 
-@SuppressWarnings({"InstanceMethodNamingConvention", "ClassWithTooManyMethods"})
+@SuppressWarnings({"InstanceMethodNamingConvention", "ClassWithTooManyMethods", "OverlyCoupledClass"})
 public class CommandBusShould {
 
     private CommandBus commandBus;
@@ -63,19 +72,19 @@ public class CommandBusShould {
     private CommandBus.ProblemLog log;
     private EventBus eventBus;
     private ExecutorCommandScheduler scheduler;
+    private CreateProjectHandler handler;
 
     @Before
     public void setUp() {
-        commandStore = mock(CommandStore.class);
-        scheduler = mock(ExecutorCommandScheduler.class);
-        commandBus = CommandBus.newBuilder()
-                               .setCommandStore(commandStore)
-                               .setScheduler(scheduler)
-                               .build();
-        log = spy(CommandBus.ProblemLog.class);
+        final InMemoryStorageFactory storageFactory = InMemoryStorageFactory.getInstance();
+        commandStore = spy(new CommandStore(storageFactory.createCommandStorage()));
+        scheduler = spy(new ExecutorCommandScheduler());
+        commandBus = newCommandBus(commandStore, scheduler);
+        log = spy(new CommandBus.ProblemLog());
         commandBus.setProblemLog(log);
-        eventBus = mock(EventBus.class);
+        eventBus = spy(TestEventFactory.newEventBus(storageFactory));
         commandFactory = TestCommandFactory.newInstance(CommandBusShould.class);
+        handler = new CreateProjectHandler(newUuid(), eventBus);
     }
 
     @Test(expected = NullPointerException.class)
@@ -108,13 +117,13 @@ public void do_not_accept_empty_dispatchers() {
 
     @Test(expected = IllegalArgumentException.class)
     public void do_not_accept_command_handlers_without_methods() {
-        commandBus.register(new EmptyCommandHandler(eventBus));
+        commandBus.register(new EmptyCommandHandler(newUuid(), eventBus));
     }
 
     @SuppressWarnings("EmptyClass")
     private static class EmptyCommandHandler extends CommandHandler {
-        private EmptyCommandHandler(EventBus eventBus) {
-            super(newUuid(), eventBus);
+        protected EmptyCommandHandler(String id, EventBus eventBus) {
+            super(id, eventBus);
         }
     }
 
@@ -187,38 +196,43 @@ public void dispatch(Command request) throws Exception {
         assertTrue(isUnsupportedCommand(commandBus.validate(addTask(projectId))));
     }
 
+    @Test
+    public void return_invalid_command_response_if_command_is_invalid() {
+        commandBus.register(handler);
+        final MessageValidator validator = mock(MessageValidator.class);
+        doReturn(newArrayList(ConstraintViolation.getDefaultInstance()))
+                .when(validator)
+                .validate(any(Message.class));
+        commandBus.setMessageValidator(validator);
+
+        final Response response = commandBus.validate(createProject(newUuid()));
+        assertTrue(isInvalidCommand(response));
+    }
+
     //
     // Tests for not overriding handlers by dispatchers and vice versa
     //-------------------------------------------------------------------
 
     @Test(expected = IllegalArgumentException.class)
     public void do_not_allow_to_register_dispatcher_for_the_command_with_registered_handler() {
-
-        final CommandHandler createProjectHandler = new CreateProjectHandler(eventBus);
         final CommandDispatcher createProjectDispatcher = new CreateProjectDispatcher();
-
-        commandBus.register(createProjectHandler);
-
+        commandBus.register(handler);
         commandBus.register(createProjectDispatcher);
     }
 
     @Test(expected = IllegalArgumentException.class)
     public void do_not_allow_to_register_handler_for_the_command_with_registered_dispatcher() {
-
-        final CommandHandler createProjectHandler = new CreateProjectHandler(eventBus);
         final CommandDispatcher createProjectDispatcher = new CreateProjectDispatcher();
-
         commandBus.register(createProjectDispatcher);
-
-        commandBus.register(createProjectHandler);
+        commandBus.register(handler);
     }
 
     private static class CreateProjectHandler extends CommandHandler {
 
         private boolean handlerInvoked = false;
 
-        private CreateProjectHandler(EventBus eventBus) {
-            super(newUuid(), eventBus);
+        protected CreateProjectHandler(String id, EventBus eventBus) {
+            super(id, eventBus);
         }
 
         @Assign
@@ -245,7 +259,6 @@ public void dispatch(Command request) throws Exception {
 
     @Test
     public void unregister_handler() {
-        final CommandHandler handler = new CreateProjectHandler(eventBus);
         commandBus.register(handler);
         commandBus.unregister(handler);
         final String projectId = newUuid();
@@ -254,7 +267,6 @@ public void unregister_handler() {
 
     @Test
     public void validate_commands_both_dispatched_and_handled() {
-        final CommandHandler handler = new CreateProjectHandler(eventBus);
         final CommandDispatcher dispatcher = new AddTaskDispatcher();
         commandBus.register(handler);
         commandBus.register(dispatcher);
@@ -288,6 +300,11 @@ public void have_log() {
         assertNotNull(CommandBus.log());
     }
 
+    @Test // To improve coverage stats.
+    public void have_command_status_service() {
+        assertNotNull(commandBus.getCommandStatusService());
+    }
+
     @Test
     public void close_CommandStore_when_closed() throws Exception {
         commandBus.close();
@@ -304,7 +321,6 @@ public void shutdown_CommandScheduler_when_closed() throws Exception {
 
     @Test
     public void remove_all_handlers_on_close() throws Exception {
-        final CommandHandler handler = new CreateProjectHandler(eventBus);
         commandBus.register(handler);
 
         commandBus.close();
@@ -313,7 +329,6 @@ public void remove_all_handlers_on_close() throws Exception {
 
     @Test
     public void invoke_handler_when_command_posted() {
-        final CreateProjectHandler handler = new CreateProjectHandler(eventBus);
         commandBus.register(handler);
 
         final Command command = commandFactory.create(createProject(newUuid()));
@@ -343,14 +358,14 @@ public void throw_exception_when_there_is_no_neither_handler_nor_dispatcher() {
 
     @Test
     public void set_command_status_to_OK_when_handler_returns() {
-        final CreateProjectHandler handler = new CreateProjectHandler(eventBus);
         commandBus.register(handler);
         final Command command = commandFactory.create(createProject(newUuid()));
 
         commandBus.post(command);
 
         // See that we called CommandStore only once with the right command ID.
-        verify(commandStore, times(1)).setCommandStatusOk(command.getContext().getCommandId());
+        verify(commandStore, times(1)).setCommandStatusOk(command.getContext()
+                                                                 .getCommandId());
     }
 
     @Test
@@ -370,66 +385,55 @@ public void set_command_status_to_error_when_dispatcher_throws() throws Exceptio
     @Test
     public void set_command_status_to_failure_when_handler_throws_failure() throws TestFailure, TestThrowable {
         final TestFailure failure = new TestFailure();
-        givenThrowingHandler(failure);
-        final Command command = commandFactory.create(createProject(newUuid()));
+        final Command command = givenThrowingHandler(failure);
         final CommandId commandId = command.getContext().getCommandId();
         final Message commandMessage = Commands.getMessage(command);
 
         commandBus.post(command);
 
         // Verify we updated the status.
-        verify(commandStore, atMost(1)).updateStatus(eq(commandId), eq(failure.toMessage()));
+
+        verify(commandStore, times(1)).updateStatus(eq(commandId), eq(failure.toMessage()));
         // Verify we logged the failure.
-        verify(log, atMost(1)).failureHandling(eq(failure), eq(commandMessage), eq(commandId));
+        verify(log, times(1)).failureHandling(eq(failure), eq(commandMessage), eq(commandId));
     }
 
     @Test
     public void set_command_status_to_failure_when_handler_throws_exception() throws TestFailure, TestThrowable {
-        final CreateProjectHandler handler = mock(CreateProjectHandler.class);
         final RuntimeException exception = new IllegalStateException("handler throws");
-        doThrow(exception).when(handler)
-                          .handle(any(CreateProject.class), any(CommandContext.class));
-
-        commandBus.register(handler);
-        final Command command = commandFactory.create(createProject(newUuid()));
+        final Command command = givenThrowingHandler(exception);
         final CommandId commandId = command.getContext().getCommandId();
         final Message commandMessage = Commands.getMessage(command);
 
         commandBus.post(command);
 
         // Verify we updated the status.
-        verify(commandStore, atMost(1)).updateStatus(eq(commandId), eq(exception));
+        verify(commandStore, times(1)).updateStatus(eq(commandId), eq(exception));
         // Verify we logged the failure.
-        verify(log, atMost(1)).errorHandling(eq(exception), eq(commandMessage), eq(commandId));
+        verify(log, times(1)).errorHandling(eq(exception), eq(commandMessage), eq(commandId));
     }
 
     @Test
     public void set_command_status_to_failure_when_handler_throws_unknown_Throwable() throws TestFailure, TestThrowable {
-        final CreateProjectHandler handler = mock(CreateProjectHandler.class);
         final Throwable throwable = new TestThrowable();
-        doThrow(throwable).when(handler)
-                          .handle(any(CreateProject.class), any(CommandContext.class));
-
-        commandBus.register(handler);
-        final Command command = commandFactory.create(createProject(newUuid()));
+        final Command command = givenThrowingHandler(throwable);
         final CommandId commandId = command.getContext().getCommandId();
         final Message commandMessage = Commands.getMessage(command);
 
         commandBus.post(command);
 
         // Verify we updated the status.
-        verify(commandStore, atMost(1)).updateStatus(eq(commandId), eq(Errors.fromThrowable(throwable)));
+        verify(commandStore, times(1)).updateStatus(eq(commandId), eq(Errors.fromThrowable(throwable)));
         // Verify we logged the failure.
-        verify(log, atMost(1)).errorHandlingUnknown(eq(throwable), eq(commandMessage), eq(commandId));
+        verify(log, times(1)).errorHandlingUnknown(eq(throwable), eq(commandMessage), eq(commandId));
     }
 
-
-    private  void givenThrowingHandler(E throwable) throws TestThrowable, TestFailure {
-        final CreateProjectHandler handler = mock(CreateProjectHandler.class);
-        doThrow(throwable)
-                .when(handler)
-                .handle(any(CreateProject.class), any(CommandContext.class));
+    private  Command givenThrowingHandler(E throwable) throws TestThrowable, TestFailure {
+        final CommandHandler handler = new ThrowingCreateProjectHandler(eventBus, throwable);
         commandBus.register(handler);
+        final CreateProject msg = createProject(newUuid());
+        final Command command = commandFactory.create(msg);
+        return command;
     }
 
     private  E givenThrowingDispatcher() throws Exception {
@@ -447,16 +451,19 @@ private  E givenThrowingDispatcher() throws Exception {
 
     @Test
     public void schedule_command_if_delay_is_set() {
-        final Command cmd = newCommand(/*delay=*/minutes(1));
+        final int delayMsec = 1100;
+        final Command cmd = newCommand(/*delay=*/milliseconds(delayMsec));
 
         commandBus.post(cmd);
 
         verify(scheduler, times(1)).schedule(cmd);
+        verify(scheduler, never()).post(cmd);
+        verify(scheduler, after(delayMsec).times(1)).post(cmd);
     }
 
     @Test
     public void do_not_schedule_command_if_no_scheduling_options_are_set() {
-        commandBus.register(new CreateProjectHandler(eventBus));
+        commandBus.register(new CreateProjectHandler(newUuid(), eventBus));
         final Command cmd = commandFactory.create(createProject(newUuid()));
 
         commandBus.post(cmd);
@@ -501,4 +508,27 @@ private TestFailure() {
     @SuppressWarnings("serial")
     private static class TestThrowable extends Throwable {
     }
+
+    /**
+     * A stub handler that throws passed `Throwable` in the command handler method.
+     *
+     * @see #set_command_status_to_failure_when_handler_throws_failure
+     * @see #set_command_status_to_failure_when_handler_throws_exception
+     * @see #set_command_status_to_failure_when_handler_throws_unknown_Throwable
+     */
+    private static class ThrowingCreateProjectHandler extends CommandHandler {
+
+        private final Throwable throwable;
+
+        protected ThrowingCreateProjectHandler(EventBus eventBus, Throwable throwable) {
+            super(newUuid(), eventBus);
+            this.throwable = throwable;
+        }
+
+        @Assign
+        public ProjectCreated handle(CreateProject msg, CommandContext context) throws Throwable {
+            //noinspection ProhibitedExceptionThrown
+            throw throwable;
+        }
+    }
 }
diff --git a/server/src/test/java/org/spine3/testdata/TestCommands.java b/server/src/test/java/org/spine3/testdata/TestCommands.java
index dcfaba22832..9172fbec74e 100644
--- a/server/src/test/java/org/spine3/testdata/TestCommands.java
+++ b/server/src/test/java/org/spine3/testdata/TestCommands.java
@@ -29,6 +29,7 @@
 import org.spine3.base.Commands;
 import org.spine3.base.UserId;
 import org.spine3.server.command.CommandBus;
+import org.spine3.server.command.CommandScheduler;
 import org.spine3.server.command.CommandStore;
 import org.spine3.server.storage.StorageFactory;
 import org.spine3.test.project.ProjectId;
@@ -157,7 +158,7 @@ public static StartProject startProject(String projectId) {
     }
 
     /**
-     * Creates a new command bus.
+     * Creates a new command bus with the given storage factory.
      */
     public static CommandBus newCommandBus(StorageFactory storageFactory) {
         final CommandStore store = new CommandStore(storageFactory.createCommandStorage());
@@ -166,4 +167,15 @@ public static CommandBus newCommandBus(StorageFactory storageFactory) {
                 .build();
         return commandBus;
     }
+
+    /**
+     * Creates a new command bus with the given command store and scheduler.
+     */
+    public static CommandBus newCommandBus(CommandStore store, CommandScheduler scheduler) {
+        final CommandBus commandBus = CommandBus.newBuilder()
+                                                .setCommandStore(store)
+                                                .setScheduler(scheduler)
+                                                .build();
+        return commandBus;
+    }
 }
diff --git a/server/src/test/java/org/spine3/testdata/TestEventFactory.java b/server/src/test/java/org/spine3/testdata/TestEventFactory.java
index b613514b543..36ac3dcf3a7 100644
--- a/server/src/test/java/org/spine3/testdata/TestEventFactory.java
+++ b/server/src/test/java/org/spine3/testdata/TestEventFactory.java
@@ -20,8 +20,12 @@
 
 package org.spine3.testdata;
 
+import com.google.common.util.concurrent.MoreExecutors;
 import org.spine3.base.Event;
 import org.spine3.base.EventContext;
+import org.spine3.server.event.EventBus;
+import org.spine3.server.event.EventStore;
+import org.spine3.server.storage.StorageFactory;
 import org.spine3.test.project.ProjectId;
 import org.spine3.test.project.event.ProjectCreated;
 import org.spine3.test.project.event.ProjectStarted;
@@ -117,4 +121,16 @@ public static Event projectStarted(ProjectId projectId, EventContext eventContex
         final Event.Builder builder = Event.newBuilder().setContext(eventContext).setMessage(toAny(event));
         return builder.build();
     }
+
+    /**
+     * Creates a new event bus with the given storage factory.
+     */
+    public static EventBus newEventBus(StorageFactory storageFactory) {
+        final EventStore store = EventStore.newBuilder()
+                                           .setStreamExecutor(MoreExecutors.directExecutor())
+                                           .setStorage(storageFactory.createEventStorage())
+                                           .build();
+        final EventBus eventBus = EventBus.newInstance(store);
+        return eventBus;
+    }
 }