Clarify how custom event types can be used

Actually you need them to be in a subpackage of
RemoteApplicationEvent.

Fixes gh-33

docs/src/main/asciidoc/spring-cloud-bus.adoc

@@ -103,5 +103,9 @@ queries on the data. Or forward it to a specialized tracing service.
 
 The Bus can carry any event of type `RemoteApplicationEvent`, but the
 default transport is JSON and the deserializer needs to know which
-types are going to be used ahead of time. To register a new type you
-can use `@JsonTypeName` on your custom class.
+types are going to be used ahead of time. To register a new type it
+needs to be in a subpackage of `org.springframework.cloud.bus.event`.
+You can use `@JsonTypeName` on your custom class or rely on the
+default strategy which is to use the simple name of the class. Note
+that both the producer and the consumer will need access to the class
+definition.

spring-cloud-bus/src/main/java/org/springframework/cloud/bus/jackson/BusJacksonAutoConfiguration.java

@@ -22,6 +22,7 @@ import org.springframework.core.type.classreading.CachingMetadataReaderFactory;
 import org.springframework.core.type.classreading.MetadataReader;
 import org.springframework.core.type.classreading.MetadataReaderFactory;
 import org.springframework.messaging.Message;
+import org.springframework.messaging.converter.MessageConverter;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.MimeTypeUtils;
 
@@ -39,7 +40,7 @@ import com.fasterxml.jackson.databind.SerializationFeature;
 public class BusJacksonAutoConfiguration {
 
 	@Bean
-	public BusJacksonMessageConverter busJsonConverter() {
+	public MessageConverter busJsonConverter() {
 		return new BusJacksonMessageConverter();
 	}
 
@@ -68,8 +69,8 @@ class BusJacksonMessageConverter extends AbstractFromMessageConverter {
 
 	public BusJacksonMessageConverter() {
 		super(MimeTypeUtils.APPLICATION_JSON, MessageConverterUtils.X_JAVA_OBJECT);
-		mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
-		mapper.registerModule(new SubtypeModule(findSubTypes()));
+		this.mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
+		this.mapper.registerModule(new SubtypeModule(findSubTypes()));
 	}
 
 	private Class<?>[] findSubTypes() {
@@ -125,14 +126,14 @@ class BusJacksonMessageConverter extends AbstractFromMessageConverter {
 			Object payload = message.getPayload();
 
 			if (payload instanceof byte[]) {
-				result = mapper.readValue((byte[]) payload, targetClass);
+				result = this.mapper.readValue((byte[]) payload, targetClass);
 			}
 			else if (payload instanceof String) {
-				result = mapper.readValue((String) payload, targetClass);
+				result = this.mapper.readValue((String) payload, targetClass);
 			}
 		}
 		catch (Exception e) {
-			logger.error(e.getMessage(), e);
+			this.logger.error(e.getMessage(), e);
 			return null;
 		}
 		return result;

spring-cloud-bus/src/test/java/org/springframework/cloud/bus/event/test/TestRemoteApplicationEvent.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2015 the original author or authors.
+ *
+ * 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
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.bus.event.test;
+
+import org.springframework.cloud.bus.event.RemoteApplicationEvent;
+
+@SuppressWarnings("serial")
+public class TestRemoteApplicationEvent extends RemoteApplicationEvent {
+	@SuppressWarnings("unused")
+	private TestRemoteApplicationEvent() {
+	}
+
+	protected TestRemoteApplicationEvent(Object source, String originService,
+			String destinationService) {
+		super(source, originService, destinationService);
+	}
+
+	protected TestRemoteApplicationEvent(Object source, String originService) {
+		super(source, originService);
+	}
+}

spring-cloud-bus/src/test/java/org/springframework/cloud/bus/event/test/TypedRemoteApplicationEvent.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2015 the original author or authors.
+ *
+ * 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
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.bus.event.test;
+
+import org.springframework.cloud.bus.event.RemoteApplicationEvent;
+
+import com.fasterxml.jackson.annotation.JsonTypeName;
+
+@SuppressWarnings("serial")
+@JsonTypeName("typed")
+public class TypedRemoteApplicationEvent extends RemoteApplicationEvent {
+	@SuppressWarnings("unused")
+	private TypedRemoteApplicationEvent() {
+	}
+
+	protected TypedRemoteApplicationEvent(Object source, String originService,
+			String destinationService) {
+		super(source, originService, destinationService);
+	}
+
+	protected TypedRemoteApplicationEvent(Object source, String originService) {
+		super(source, originService);
+	}
+}

spring-cloud-bus/src/test/java/org/springframework/cloud/bus/jackson/SubtypeModuleTests.java

@@ -5,6 +5,10 @@ import static org.junit.Assert.assertTrue;
 
 import org.junit.Test;
 import org.springframework.cloud.bus.event.RemoteApplicationEvent;
+import org.springframework.cloud.bus.event.test.TestRemoteApplicationEvent;
+import org.springframework.cloud.bus.event.test.TypedRemoteApplicationEvent;
+import org.springframework.messaging.converter.MessageConverter;
+import org.springframework.messaging.support.MessageBuilder;
 
 import com.fasterxml.jackson.annotation.JsonTypeName;
 import com.fasterxml.jackson.databind.ObjectMapper;
@@ -15,7 +19,7 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 public class SubtypeModuleTests {
 
 	@Test
-	public void testSubclass() throws Exception {
+	public void testDeserializeSubclass() throws Exception {
 		ObjectMapper mapper = new ObjectMapper();
 		mapper.registerModule(new SubtypeModule(MyRemoteApplicationEvent.class));
 
@@ -27,12 +31,35 @@ public class SubtypeModuleTests {
 		assertEquals("originService was wrong", "myorigin", myEvent.getOriginService());
 		assertEquals("destinationService was wrong", "myservice",
 				myEvent.getDestinationService());
+	}
 
-		event = mapper.readValue("{\"type\":\"another\"}",
+	@Test
+	public void testDeserializeWhenTypeIsKnown() throws Exception {
+		ObjectMapper mapper = new ObjectMapper();
+
+		RemoteApplicationEvent event = mapper.readValue("{\"type\":\"another\"}",
 				AnotherRemoteApplicationEvent.class);
 		assertTrue("event is wrong type", event instanceof AnotherRemoteApplicationEvent);
 	}
 
+	@Test
+	public void testDeserializeWithMessageConverter() throws Exception {
+		MessageConverter converter = new BusJacksonAutoConfiguration().busJsonConverter();
+		Object event = converter.fromMessage(
+				MessageBuilder.withPayload("{\"type\":\"TestRemoteApplicationEvent\"}").build(),
+				RemoteApplicationEvent.class);
+		assertTrue("event is wrong type", event instanceof TestRemoteApplicationEvent);
+	}
+
+	@Test
+	public void testDeserializeJsonTypeWithMessageConverter() throws Exception {
+		MessageConverter converter = new BusJacksonAutoConfiguration().busJsonConverter();
+		Object event = converter.fromMessage(
+				MessageBuilder.withPayload("{\"type\":\"typed\"}").build(),
+				RemoteApplicationEvent.class);
+		assertTrue("event is wrong type", event instanceof TypedRemoteApplicationEvent);
+	}
+
 	@SuppressWarnings("serial")
 	@JsonTypeName("my")
 	public static class MyRemoteApplicationEvent extends RemoteApplicationEvent {