Improve support of rejections thrown from the CommandBus filters

client/src/main/java/io/spine/grpc/CompositeObserver.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2020, TeamDev. 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 io.spine.grpc;
+
+import com.google.common.collect.ImmutableList;
+import io.grpc.stub.StreamObserver;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * A stream observer which delegates calls to multiple other observers with the same target type.
+ *
+ * <p>The observers are called in the exact same order in which they are specified on the object
+ * construction.
+ *
+ * @param <T>
+ *         the observed type
+ */
+public final class CompositeObserver<T> implements StreamObserver<T> {
+
+    private final ImmutableList<StreamObserver<? super T>> observers;
+
+    public CompositeObserver(Iterable<StreamObserver<? super T>> observers) {
+        checkNotNull(observers);
+        this.observers = ImmutableList.copyOf(observers);
+    }
+
+    @Override
+    public void onNext(T value) {
+        observers.forEach(o -> o.onNext(value));
+    }
+
+    @Override
+    public void onError(Throwable t) {
+        observers.forEach(o -> o.onError(t));
+    }
+
+    @Override
+    public void onCompleted() {
+        observers.forEach(StreamObserver::onCompleted);
+    }
+}

client/src/test/java/io/spine/grpc/CompositeObserverTest.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright 2020, TeamDev. 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 io.spine.grpc;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.testing.NullPointerTester;
+import io.grpc.stub.StreamObserver;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import static com.google.common.truth.Truth.assertThat;
+
+@DisplayName("`CompositeObserver` should")
+class CompositeObserverTest {
+
+    @Test
+    @DisplayName("not accept `null` observer list on construction")
+    void passNullToleranceCheck() {
+        new NullPointerTester()
+                .testAllPublicConstructors(CompositeObserver.class);
+    }
+
+    @Test
+    @DisplayName("delegate `onNext` calls to wrapped observers")
+    void delegateOnNext() {
+        MemoizingObserver<String> observer1 = StreamObservers.memoizingObserver();
+        MemoizingObserver<String> observer2 = StreamObservers.memoizingObserver();
+        StreamObserver<String> observer =
+                new CompositeObserver<>(ImmutableList.of(observer1, observer2));
+
+        String value = "String value.";
+        observer.onNext(value);
+
+        assertThat(observer1.firstResponse()).isEqualTo(value);
+        assertThat(observer2.firstResponse()).isEqualTo(value);
+    }
+
+    @Test
+    @DisplayName("delegate `onError` calls to wrapped observers")
+    void delegateOnError() {
+        MemoizingObserver<String> observer1 = StreamObservers.memoizingObserver();
+        MemoizingObserver<String> observer2 = StreamObservers.memoizingObserver();
+        StreamObserver<String> observer =
+                new CompositeObserver<>(ImmutableList.of(observer1, observer2));
+
+        RuntimeException error = new RuntimeException("An error.");
+        observer.onError(error);
+
+        assertThat(observer1.getError()).isEqualTo(error);
+        assertThat(observer2.getError()).isEqualTo(error);
+    }
+
+    @Test
+    @DisplayName("delegate `onCompleted` calls to wrapped observers")
+    void delegateOnCompleted() {
+        MemoizingObserver<String> observer1 = StreamObservers.memoizingObserver();
+        MemoizingObserver<String> observer2 = StreamObservers.memoizingObserver();
+        StreamObserver<String> observer =
+                new CompositeObserver<>(ImmutableList.of(observer1, observer2));
+
+        observer.onCompleted();
+
+        assertThat(observer1.isCompleted()).isTrue();
+        assertThat(observer2.isCompleted()).isTrue();
+    }
+}

license-report.md

@@ -1,6 +1,6 @@
 
 
-# Dependencies of `io.spine:spine-client:1.5.25`
+# Dependencies of `io.spine:spine-client:1.5.27`
 
 ## Runtime
 1. **Group:** com.google.android **Name:** annotations **Version:** 4.1.1.4
@@ -406,12 +406,12 @@
  The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
 
-This report was generated on **Tue Aug 18 15:45:58 EEST 2020** using [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
+This report was generated on **Mon Aug 31 12:45:57 EEST 2020** using [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-core:1.5.25`
+# Dependencies of `io.spine:spine-core:1.5.27`
 
 ## Runtime
 1. **Group:** com.google.code.findbugs **Name:** jsr305 **Version:** 3.0.2
@@ -777,12 +777,12 @@ This report was generated on **Tue Aug 18 15:45:58 EEST 2020** using [Gradle-Lic
  The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
 
-This report was generated on **Tue Aug 18 15:45:59 EEST 2020** using [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
+This report was generated on **Mon Aug 31 12:45:57 EEST 2020** using [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine.tools:spine-model-assembler:1.5.25`
+# Dependencies of `io.spine.tools:spine-model-assembler:1.5.27`
 
 ## Runtime
 1. **Group:** com.google.android **Name:** annotations **Version:** 4.1.1.4
@@ -1183,12 +1183,12 @@ This report was generated on **Tue Aug 18 15:45:59 EEST 2020** using [Gradle-Lic
  The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
 
-This report was generated on **Tue Aug 18 15:46:00 EEST 2020** using [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
+This report was generated on **Mon Aug 31 12:45:58 EEST 2020** using [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine.tools:spine-model-verifier:1.5.25`
+# Dependencies of `io.spine.tools:spine-model-verifier:1.5.27`
 
 ## Runtime
 1. **Group:** com.google.android **Name:** annotations **Version:** 4.1.1.4
@@ -1659,12 +1659,12 @@ This report was generated on **Tue Aug 18 15:46:00 EEST 2020** using [Gradle-Lic
  The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
 
-This report was generated on **Tue Aug 18 15:46:00 EEST 2020** using [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
+This report was generated on **Mon Aug 31 12:45:59 EEST 2020** using [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-server:1.5.25`
+# Dependencies of `io.spine:spine-server:1.5.27`
 
 ## Runtime
 1. **Group:** com.google.android **Name:** annotations **Version:** 4.1.1.4
@@ -2082,12 +2082,12 @@ This report was generated on **Tue Aug 18 15:46:00 EEST 2020** using [Gradle-Lic
  The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
 
-This report was generated on **Tue Aug 18 15:46:01 EEST 2020** using [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
+This report was generated on **Mon Aug 31 12:45:59 EEST 2020** using [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-testutil-client:1.5.25`
+# Dependencies of `io.spine:spine-testutil-client:1.5.27`
 
 ## Runtime
 1. **Group:** com.google.android **Name:** annotations **Version:** 4.1.1.4
@@ -2542,12 +2542,12 @@ This report was generated on **Tue Aug 18 15:46:01 EEST 2020** using [Gradle-Lic
  The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
 
-This report was generated on **Tue Aug 18 15:46:04 EEST 2020** using [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
+This report was generated on **Mon Aug 31 12:46:01 EEST 2020** using [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-testutil-core:1.5.25`
+# Dependencies of `io.spine:spine-testutil-core:1.5.27`
 
 ## Runtime
 1. **Group:** com.google.android **Name:** annotations **Version:** 4.1.1.4
@@ -3010,12 +3010,12 @@ This report was generated on **Tue Aug 18 15:46:04 EEST 2020** using [Gradle-Lic
  The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
 
-This report was generated on **Tue Aug 18 15:46:05 EEST 2020** using [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
+This report was generated on **Mon Aug 31 12:46:02 EEST 2020** using [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-testutil-server:1.5.25`
+# Dependencies of `io.spine:spine-testutil-server:1.5.27`
 
 ## Runtime
 1. **Group:** com.google.android **Name:** annotations **Version:** 4.1.1.4
@@ -3514,4 +3514,4 @@ This report was generated on **Tue Aug 18 15:46:05 EEST 2020** using [Gradle-Lic
  The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
 
-This report was generated on **Tue Aug 18 15:46:08 EEST 2020** using [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
+This report was generated on **Mon Aug 31 12:46:05 EEST 2020** using [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).

pom.xml

@@ -12,7 +12,7 @@ all modules and does not describe the project structure per-subproject.
 
 <groupId>io.spine</groupId>
 <artifactId>spine-core-java</artifactId>
-<version>1.5.25</version>
+<version>1.5.27</version>
 
 <inceptionYear>2015</inceptionYear>
 
@@ -70,25 +70,25 @@ all modules and does not describe the project structure per-subproject.
   <dependency>
     <groupId>io.spine</groupId>
     <artifactId>spine-base</artifactId>
-    <version>1.5.23</version>
+    <version>1.5.29</version>
     <scope>compile</scope>
   </dependency>
   <dependency>
     <groupId>io.spine</groupId>
     <artifactId>spine-time</artifactId>
-    <version>1.5.21</version>
+    <version>1.5.24</version>
     <scope>compile</scope>
   </dependency>
   <dependency>
     <groupId>io.spine.tools</groupId>
     <artifactId>spine-model-compiler</artifactId>
-    <version>1.5.23</version>
+    <version>1.5.29</version>
     <scope>compile</scope>
   </dependency>
   <dependency>
     <groupId>io.spine.tools</groupId>
     <artifactId>spine-plugin-base</artifactId>
-    <version>1.5.23</version>
+    <version>1.5.29</version>
     <scope>compile</scope>
   </dependency>
   <dependency>
@@ -130,25 +130,25 @@ all modules and does not describe the project structure per-subproject.
   <dependency>
     <groupId>io.spine</groupId>
     <artifactId>spine-testlib</artifactId>
-    <version>1.5.23</version>
+    <version>1.5.29</version>
     <scope>test</scope>
   </dependency>
   <dependency>
     <groupId>io.spine</groupId>
     <artifactId>spine-testutil-time</artifactId>
-    <version>1.5.21</version>
+    <version>1.5.24</version>
     <scope>test</scope>
   </dependency>
   <dependency>
     <groupId>io.spine.tools</groupId>
     <artifactId>spine-mute-logging</artifactId>
-    <version>1.5.23</version>
+    <version>1.5.29</version>
     <scope>test</scope>
   </dependency>
   <dependency>
     <groupId>io.spine.tools</groupId>
     <artifactId>spine-plugin-testlib</artifactId>
-    <version>1.5.23</version>
+    <version>1.5.29</version>
     <scope>test</scope>
   </dependency>
   <dependency>
@@ -204,12 +204,12 @@ all modules and does not describe the project structure per-subproject.
   <dependency>
     <groupId>io.spine.tools</groupId>
     <artifactId>spine-javadoc-filter</artifactId>
-    <version>1.5.23</version>
+    <version>1.5.29</version>
   </dependency>
   <dependency>
     <groupId>io.spine.tools</groupId>
     <artifactId>spine-protoc-plugin</artifactId>
-    <version>1.5.23</version>
+    <version>1.5.29</version>
   </dependency>
   <dependency>
     <groupId>net.sourceforge.pmd</groupId>

server/src/main/java/io/spine/server/BoundedContext.java

@@ -147,6 +147,7 @@ protected final void init() {
         eventBus.registerWith(this);
         tenantIndex.registerWith(this);
         broker.registerWith(this);
+        commandBus.initObservers(eventBus);
     }
 
     /**

server/src/main/java/io/spine/server/BoundedContextBuilder.java

@@ -283,6 +283,7 @@ public BoundedContextBuilder addCommandDispatcher(CommandDispatcher commandDispa
      * <p>The order of appending the filters to the builder is the order of the filters in
      * the {@code CommandBus}.
      */
+    @CanIgnoreReturnValue
     public BoundedContextBuilder addCommandFilter(BusFilter<CommandEnvelope> filter) {
         checkNotNull(filter);
         commandBus.appendFilter(filter);
@@ -321,6 +322,7 @@ public BoundedContextBuilder addEventDispatcher(EventDispatcher eventDispatcher)
      * @param filter
      *         the filter to add
      */
+    @CanIgnoreReturnValue
     public BoundedContextBuilder addEventFilter(BusFilter<EventEnvelope> filter) {
         checkNotNull(filter);
         eventBus.appendFilter(filter);
@@ -656,7 +658,9 @@ public BoundedContextBuilder testingCopy() {
         copy.enrichEventsUsing(enricher);
         repositories().forEach(copy::add);
         commandDispatchers().forEach(copy::addCommandDispatcher);
+        commandBus.filters().forEach(copy::addCommandFilter);
         eventDispatchers().forEach(copy::addEventDispatcher);
+        eventBus.filters().forEach(copy::addEventFilter);
         return copy;
     }
 }

server/src/main/java/io/spine/server/CommandService.java

@@ -36,7 +36,7 @@
 import java.util.Map;
 import java.util.Set;
 
-import static io.spine.server.bus.Buses.reject;
+import static io.spine.server.bus.Acks.reject;
 
 /**
  * The {@code CommandService} allows client applications to post commands and