Add SimpleMessageConverter

spring-messaging/src/main/java/org/springframework/messaging/core/AbstractMessageSendingTemplate.java

@@ -15,8 +15,6 @@
  */
 package org.springframework.messaging.core;
 
-import java.util.ArrayList;
-import java.util.Collection;
 import java.util.Map;
 
 import org.apache.commons.logging.Log;
@@ -24,10 +22,8 @@ import org.apache.commons.logging.LogFactory;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageHeaders;
 import org.springframework.messaging.MessagingException;
-import org.springframework.messaging.support.converter.ByteArrayMessageConverter;
-import org.springframework.messaging.support.converter.CompositeMessageConverter;
 import org.springframework.messaging.support.converter.MessageConverter;
-import org.springframework.messaging.support.converter.StringMessageConverter;
+import org.springframework.messaging.support.converter.SimpleMessageConverter;
 import org.springframework.util.Assert;
 
 
@@ -44,16 +40,9 @@ public abstract class AbstractMessageSendingTemplate<D> implements MessageSendin
 
 	private volatile D defaultDestination;
 
-	private volatile MessageConverter converter;
+	private volatile MessageConverter converter = new SimpleMessageConverter();
 
 
-	public AbstractMessageSendingTemplate() {
-		Collection<MessageConverter> converters = new ArrayList<MessageConverter>();
-		converters.add(new StringMessageConverter());
-		converters.add(new ByteArrayMessageConverter());
-		this.converter = new CompositeMessageConverter(converters);
-	}
-
 	public void setDefaultDestination(D defaultDestination) {
 		this.defaultDestination = defaultDestination;
 	}

spring-messaging/src/main/java/org/springframework/messaging/simp/config/WebSocketMessageBrokerConfigurationSupport.java

@@ -209,14 +209,17 @@ public abstract class WebSocketMessageBrokerConfigurationSupport {
 
 	@Bean
 	public CompositeMessageConverter simpMessageConverter() {
+
 		DefaultContentTypeResolver contentTypeResolver = new DefaultContentTypeResolver();
+
 		List<MessageConverter> converters = new ArrayList<MessageConverter>();
-		converters.add(new StringMessageConverter());
-		converters.add(new ByteArrayMessageConverter());
 		if (jackson2Present) {
 			converters.add(new MappingJackson2MessageConverter());
 			contentTypeResolver.setDefaultMimeType(MimeTypeUtils.APPLICATION_JSON);
 		}
+		converters.add(new StringMessageConverter());
+		converters.add(new ByteArrayMessageConverter());
+
 		return new CompositeMessageConverter(converters, contentTypeResolver);
 	}
 

spring-messaging/src/main/java/org/springframework/messaging/support/MessageHeaderAccessor.java

@@ -183,10 +183,12 @@ public class MessageHeaderAccessor {
 	 * values.
 	 */
 	public void copyHeaders(Map<String, ?> headersToCopy) {
-		Set<String> keys = headersToCopy.keySet();
-		for (String key : keys) {
-			if (!isReadOnly(key)) {
-				setHeader(key, headersToCopy.get(key));
+		if (headersToCopy != null) {
+			Set<String> keys = headersToCopy.keySet();
+			for (String key : keys) {
+				if (!isReadOnly(key)) {
+					setHeader(key, headersToCopy.get(key));
+				}
 			}
 		}
 	}
@@ -196,10 +198,12 @@ public class MessageHeaderAccessor {
 	 * overwrite any existing values.
 	 */
 	public void copyHeadersIfAbsent(Map<String, ?> headersToCopy) {
-		Set<String> keys = headersToCopy.keySet();
-		for (String key : keys) {
-			if (!this.isReadOnly(key)) {
-				setHeaderIfAbsent(key, headersToCopy.get(key));
+		if (headersToCopy != null) {
+			Set<String> keys = headersToCopy.keySet();
+			for (String key : keys) {
+				if (!this.isReadOnly(key)) {
+					setHeaderIfAbsent(key, headersToCopy.get(key));
+				}
 			}
 		}
 	}

spring-messaging/src/main/java/org/springframework/messaging/support/converter/SimpleMessageConverter.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2002-2013 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.messaging.support.converter;
+
+import org.springframework.messaging.Message;
+import org.springframework.messaging.MessageHeaders;
+import org.springframework.messaging.support.MessageBuilder;
+import org.springframework.util.ClassUtils;
+
+/**
+ * A simple converter that simply unwraps the message payload as long as it matches the
+ * expected target class. Or reversely, simply wraps the payload in a message.
+ * <p>
+ * Note that this converter ignores any content type information that may be present in
+ * message headers and should not be used if payload conversion is actually required.
+ *
+ * @author Rossen Stoyanchev
+ * @since 4.0
+ */
+public class SimpleMessageConverter implements MessageConverter {
+
+	@Override
+	public Object fromMessage(Message<?> message, Class<?> targetClass) {
+		Object payload = message.getPayload();
+		if (targetClass == null) {
+			return payload;
+		}
+		return ClassUtils.isAssignableValue(targetClass, payload) ? payload : null;
+	}
+
+	@Override
+	public Message<?> toMessage(Object payload, MessageHeaders headers) {
+		return (payload != null) ? MessageBuilder.withPayload(payload).copyHeaders(headers).build() : null;
+	}
+
+}

spring-messaging/src/test/java/org/springframework/messaging/support/MessageHeaderAccessorTests.java

@@ -75,4 +75,13 @@ public class MessageHeaderAccessorTests {
 		assertEquals("baz", actual.get("bar"));
 	}
 
+	@Test
+	public void copyHeadersNullMap() {
+		MessageHeaderAccessor headers = new MessageHeaderAccessor();
+		headers.copyHeaders(null);
+		headers.copyHeadersIfAbsent(null);
+
+		assertEquals(0, headers.toMap().size());
+	}
+
 }