Fix empty dispatching delivery

server/src/main/java/io/spine/server/aggregate/AggregateEndpoint.java

@@ -90,7 +90,7 @@ public final void dispatchTo(I aggregateId) {
 
     private void storeAndPost(A aggregate, DispatchOutcome outcome) {
         Success success = outcome.getSuccess();
-        if (success.hasProducedEvents()) {
+        if (success.hasEvents()) {
             store(aggregate);
             List<Event> events = success.getProducedEvents()
                                         .getEventList();
@@ -126,7 +126,7 @@ private A loadOrCreate(I aggregateId) {
     final DispatchOutcome handleAndApplyEvents(A aggregate) {
         DispatchOutcome outcome = invokeDispatcher(aggregate);
         Success successfulOutcome = outcome.getSuccess();
-        return successfulOutcome.hasProducedEvents()
+        return successfulOutcome.hasEvents()
                ? applyProducedEvents(aggregate, outcome)
                : outcome;
     }

server/src/main/java/io/spine/server/dispatch/SuccessMixin.java

@@ -49,4 +49,24 @@ default Object readValue(FieldDescriptor field) {
                 return getField(field);
         }
     }
+
+    /**
+     * Determines if the outcome has any produced events.
+     *
+     * @implNote Prefer using this method over the generated {@code hasProducedEvents}
+     *         while the latter only checks if the message is set.
+     */
+    default boolean hasEvents() {
+        return hasProducedEvents() && getProducedEvents().getEventCount() > 0;
+    }
+
+    /**
+     * Determines if the outcome has any produced commands.
+     *
+     * @implNote Prefer using this method over the generated {@code hasProducedCommands}
+     *         while the latter only checks if the message is set.
+     */
+    default boolean hasCommands() {
+        return hasProducedCommands() && getProducedCommands().getCommandCount() > 0;
+    }
 }

server/src/test/java/io/spine/server/aggregate/AggregateTest.java

@@ -37,6 +37,7 @@
 import io.spine.core.Ack;
 import io.spine.core.Command;
 import io.spine.core.Event;
+import io.spine.core.EventContext;
 import io.spine.core.MessageId;
 import io.spine.core.TenantId;
 import io.spine.server.BoundedContext;
@@ -50,6 +51,11 @@
 import io.spine.server.aggregate.given.aggregate.TaskAggregateRepository;
 import io.spine.server.aggregate.given.aggregate.TestAggregate;
 import io.spine.server.aggregate.given.aggregate.TestAggregateRepository;
+import io.spine.server.aggregate.given.thermometer.SafeThermometer;
+import io.spine.server.aggregate.given.thermometer.SafeThermometerRepo;
+import io.spine.server.aggregate.given.thermometer.Thermometer;
+import io.spine.server.aggregate.given.thermometer.ThermometerId;
+import io.spine.server.aggregate.given.thermometer.event.TemperatureChanged;
 import io.spine.server.commandbus.CommandBus;
 import io.spine.server.delivery.MessageEndpoint;
 import io.spine.server.dispatch.BatchDispatchOutcome;
@@ -81,7 +87,7 @@
 import io.spine.test.aggregate.rejection.Rejections.AggCannotReassignUnassignedTask;
 import io.spine.testing.logging.MuteLogging;
 import io.spine.testing.server.EventSubject;
-import io.spine.testing.server.blackbox.BlackBoxContext;
+import io.spine.testing.server.blackbox.ContextAwareTest;
 import io.spine.testing.server.model.ModelTests;
 import io.spine.time.testing.TimeTests;
 import org.junit.jupiter.api.AfterEach;
@@ -317,12 +323,13 @@ void writeVersionIntoEventContext() {
         dispatchCommand(aggregate, command(createProject));
 
         // Get the first event since the command handler produces only one event message.
-        Aggregate<?, ?, ?> agg = this.aggregate;
-        List<Event> uncommittedEvents = agg.getUncommittedEvents().list();
+        Aggregate<?, ?, ?> agg = aggregate;
+        List<Event> uncommittedEvents = agg.getUncommittedEvents()
+                                           .list();
         Event event = uncommittedEvents.get(0);
-
-        assertEquals(this.aggregate.version(), event.context()
-                                                    .getVersion());
+        EventContext context = event.context();
+        assertThat(aggregate.version())
+                .isEqualTo(context.getVersion());
     }
 
     @Test
@@ -719,7 +726,8 @@ void throughNewestEventsFirst() {
 
         private ProtoSubject assertNextCommandId() {
             Event event = history.next();
-            return assertThat(event.rootMessage().asCommandId());
+            return assertThat(event.rootMessage()
+                                   .asCommandId());
         }
 
         @Test
@@ -818,27 +826,20 @@ void checkEventsUponHistory() {
     private static void dispatch(TenantId tenant,
                                  Supplier<MessageEndpoint<ProjectId, ?>> endpoint) {
         with(tenant).run(
-                () -> endpoint.get().dispatchTo(ID)
+                () -> endpoint.get()
+                              .dispatchTo(ID)
         );
     }
 
     @Nested
     @DisplayName("create a single event when emitting a pair without second value")
-    class CreateSingleEventForPair {
-
-        private BlackBoxContext context;
-
-        @BeforeEach
-        void prepareContext() {
-            context = BlackBoxContext.from(
-                    BoundedContextBuilder.assumingTests()
-                                         .add(new TaskAggregateRepository())
-            );
-        }
+    class CreateSingleEventForPair extends ContextAwareTest {
 
-        @AfterEach
-        void closeContext() {
-            context.close();
+        @Override
+        protected BoundedContextBuilder contextBuilder() {
+            return BoundedContextBuilder
+                    .assumingTests()
+                    .add(new TaskAggregateRepository());
         }
 
         /**
@@ -852,10 +853,10 @@ void closeContext() {
         @Test
         @DisplayName("when dispatching a command")
         void fromCommandDispatch() {
-            context.receivesCommand(createTask())
-                   .assertEvents()
-                   .withType(AggTaskCreated.class)
-                   .isNotEmpty();
+            context().receivesCommand(createTask())
+                     .assertEvents()
+                     .withType(AggTaskCreated.class)
+                     .isNotEmpty();
         }
 
         /**
@@ -870,8 +871,8 @@ void fromCommandDispatch() {
         @Test
         @DisplayName("when reacting on an event")
         void fromEventReact() {
-            EventSubject assertEvents = context.receivesCommand(assignTask())
-                                               .assertEvents();
+            EventSubject assertEvents = context().receivesCommand(assignTask())
+                                                 .assertEvents();
             assertEvents.hasSize(2);
             assertEvents.withType(AggTaskAssigned.class)
                         .hasSize(1);
@@ -891,13 +892,55 @@ void fromEventReact() {
         @Test
         @DisplayName("when reacting on a rejection")
         void fromRejectionReact() {
-            EventSubject assertEvents = context.receivesCommand(reassignTask())
-                                               .assertEvents();
+            EventSubject assertEvents = context().receivesCommand(reassignTask())
+                                                 .assertEvents();
             assertEvents.hasSize(2);
             assertEvents.withType(AggCannotReassignUnassignedTask.class)
                         .hasSize(1);
             assertEvents.withType(AggUserNotified.class)
                         .hasSize(1);
         }
     }
+
+    @Nested
+    @DisplayName("allow having validation on the aggregate state and")
+    class AllowValidatedAggregates extends ContextAwareTest {
+
+        private final ThermometerId thermometer = ThermometerId.generate();
+
+        @Override
+        protected BoundedContextBuilder contextBuilder() {
+            return BoundedContextBuilder
+                    .assumingTests()
+                    .add(new SafeThermometerRepo(thermometer));
+        }
+
+        @Test
+        @DisplayName("not change the Aggregate state when there is no reaction on the event")
+        void notChangeStateIfNoReaction() {
+            TemperatureChanged booksOnFire =
+                    TemperatureChanged.newBuilder()
+                                      .setFahrenheit(451)
+                                      .vBuild();
+            context().receivesExternalEvent(booksOnFire)
+                     .assertEntity(thermometer, SafeThermometer.class)
+                     .doesNotExist();
+        }
+
+        @Test
+        @DisplayName("save valid aggregate state on change")
+        void safelySaveValidState() {
+            TemperatureChanged gettingWarmer =
+                    TemperatureChanged.newBuilder()
+                                      .setFahrenheit(72)
+                                      .vBuild();
+            context().receivesExternalEvent(gettingWarmer);
+            Thermometer expected = Thermometer
+                    .newBuilder()
+                    .setId(thermometer)
+                    .setFahrenheit(72)
+                    .vBuild();
+            context().assertState(thermometer, expected);
+        }
+    }
 }

server/src/test/java/io/spine/server/aggregate/given/thermometer/SafeThermometer.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2021, TeamDev. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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 io.spine.server.aggregate.given.thermometer;
+
+import io.spine.core.External;
+import io.spine.server.aggregate.Aggregate;
+import io.spine.server.aggregate.Apply;
+import io.spine.server.aggregate.given.thermometer.event.TemperatureChanged;
+import io.spine.server.aggregate.given.thermometer.event.TermTemperatureChanged;
+import io.spine.server.event.React;
+
+import java.util.Optional;
+
+/**
+ * Ignores temperature changes outside its own range.
+ */
+public final class SafeThermometer extends Aggregate<ThermometerId, Thermometer, Thermometer.Builder> {
+
+    private static final double MIN = 0;
+    private static final double MAX = 120;
+
+    @React
+    Optional<TermTemperatureChanged> on(@External TemperatureChanged e) {
+        double temperature = e.getFahrenheit();
+        if (!withinBounds(temperature)) {
+            return Optional.empty();
+        }
+        return Optional.of(
+                TermTemperatureChanged
+                        .newBuilder()
+                        .setThermometer(id())
+                        .setChange(
+                                TemperatureChange
+                                        .newBuilder()
+                                        .setNewValue(temperature)
+                                        .setPreviousValue(state().getFahrenheit())
+                        )
+                        .vBuild()
+        );
+    }
+
+    private static boolean withinBounds(double temperature) {
+        return temperature > MIN && temperature < MAX;
+    }
+
+    @Apply
+    private void on(TermTemperatureChanged e) {
+        builder().setFahrenheit(e.getChange()
+                                 .getNewValue());
+    }
+}

server/src/test/java/io/spine/server/aggregate/given/thermometer/SafeThermometerRepo.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2021, TeamDev. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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 io.spine.server.aggregate.given.thermometer;
+
+import io.spine.server.aggregate.AggregateRepository;
+import io.spine.server.aggregate.given.thermometer.event.TemperatureChanged;
+import io.spine.server.route.EventRouting;
+
+import static io.spine.util.Preconditions2.checkNotDefaultArg;
+
+/**
+ * A {@link SafeThermometer thermometer} repository.
+ */
+public final class SafeThermometerRepo extends AggregateRepository<ThermometerId, SafeThermometer> {
+
+    private final ThermometerId thermometer;
+
+    /**
+     * Creates a new repository for the {@code thermometer}.
+     */
+    public SafeThermometerRepo(ThermometerId thermometer) {
+        this.thermometer = checkNotDefaultArg(thermometer);
+    }
+
+    @Override
+    protected void setupEventRouting(EventRouting<ThermometerId> routing) {
+        routing.unicast(TemperatureChanged.class, (e) -> thermometer);
+    }
+}