DefaultMessageEndpoint now provides a ReplyHandler callback for ConcurrentHandlers.

spring-integration-core/src/main/java/org/springframework/integration/channel/SimpleChannel.java

@@ -23,6 +23,7 @@ import java.util.concurrent.TimeUnit;
 import org.springframework.beans.factory.BeanNameAware;
 import org.springframework.integration.dispatcher.DispatcherPolicy;
 import org.springframework.integration.message.Message;
+import org.springframework.util.Assert;
 
 /**
  * Simple implementation of a message channel. Each {@link Message} is
@@ -33,7 +34,7 @@ import org.springframework.integration.message.Message;
  */
 public class SimpleChannel implements MessageChannel, BeanNameAware {
 
-	private static final int DEFAULT_CAPACITY = 25;
+	private static final int DEFAULT_CAPACITY = 100;
 
 	private String name;
 
@@ -110,6 +111,7 @@ public class SimpleChannel implements MessageChannel, BeanNameAware {
 	 * <code>false</code> if the sending thread is interrupted.
 	 */
 	public boolean send(Message message) {
+		Assert.notNull(message, "'message' must not be null");
 		try {
 			queue.put(message);
 			return true;
@@ -134,6 +136,7 @@ public class SimpleChannel implements MessageChannel, BeanNameAware {
 	 * time or the sending thread is interrupted.
 	 */
 	public boolean send(Message message, long timeout) {
+		Assert.notNull(message, "'message' must not be null");
 		try {
 			if (timeout > 0) {
 				return this.queue.offer(message, timeout, TimeUnit.MILLISECONDS);

spring-integration-core/src/main/java/org/springframework/integration/dispatcher/DispatcherTask.java

@@ -29,7 +29,9 @@ import org.springframework.integration.MessageDeliveryException;
 import org.springframework.integration.MessageHandlingException;
 import org.springframework.integration.channel.MessageChannel;
 import org.springframework.integration.handler.MessageHandler;
+import org.springframework.integration.handler.MessageHandlerNotRunningException;
 import org.springframework.integration.message.Message;
+import org.springframework.integration.message.selector.MessageSelectorRejectedException;
 import org.springframework.integration.scheduling.MessagingTask;
 import org.springframework.integration.scheduling.Schedule;
 import org.springframework.util.Assert;

spring-integration-core/src/main/java/org/springframework/integration/endpoint/DefaultMessageEndpoint.java

@@ -28,15 +28,18 @@ import org.springframework.integration.bus.Subscription;
 import org.springframework.integration.channel.ChannelRegistry;
 import org.springframework.integration.channel.ChannelRegistryAware;
 import org.springframework.integration.channel.MessageChannel;
-import org.springframework.integration.dispatcher.MessageHandlerNotRunningException;
-import org.springframework.integration.dispatcher.MessageHandlerRejectedExecutionException;
-import org.springframework.integration.dispatcher.MessageSelectorRejectedException;
 import org.springframework.integration.handler.ConcurrentHandler;
 import org.springframework.integration.handler.MessageHandler;
+import org.springframework.integration.handler.MessageHandlerNotRunningException;
+import org.springframework.integration.handler.MessageHandlerRejectedExecutionException;
+import org.springframework.integration.handler.ReplyHandler;
 import org.springframework.integration.message.Message;
+import org.springframework.integration.message.MessageHeader;
 import org.springframework.integration.message.selector.MessageSelector;
+import org.springframework.integration.message.selector.MessageSelectorRejectedException;
 import org.springframework.integration.util.ErrorHandler;
 import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
 
 /**
  * Default implementation of the {@link MessageEndpoint} interface.
@@ -57,6 +60,8 @@ public class DefaultMessageEndpoint implements MessageEndpoint, ChannelRegistryA
 
 	private ErrorHandler errorHandler;
 
+	private ReplyHandler replyHandler = new EndpointReplyHandler();
+
 	private String defaultOutputChannelName;
 
 	private ChannelRegistry channelRegistry;
@@ -145,7 +150,7 @@ public class DefaultMessageEndpoint implements MessageEndpoint, ChannelRegistryA
 	}
 
 	public void afterPropertiesSet() {
-		if (this.concurrencyPolicy != null) {
+		if (this.concurrencyPolicy != null || this.handler instanceof ConcurrentHandler) {
 			if (!(this.handler instanceof ConcurrentHandler)) {
 				this.handler = new ConcurrentHandler(this.handler, this.concurrencyPolicy);
 			}
@@ -153,6 +158,7 @@ public class DefaultMessageEndpoint implements MessageEndpoint, ChannelRegistryA
 			if (this.errorHandler != null) {
 				concurrentHandler.setErrorHandler(this.errorHandler);
 			}
+			concurrentHandler.setReplyHandler(this.replyHandler);
 			concurrentHandler.afterPropertiesSet();
 		}
 		this.initialized = true;
@@ -206,13 +212,7 @@ public class DefaultMessageEndpoint implements MessageEndpoint, ChannelRegistryA
 		try {
 			Message<?> replyMessage = handler.handle(message);
 			if (replyMessage != null) {
-				MessageChannel replyChannel = this.resolveReplyChannel(message);
-				if (replyChannel == null) {
-					throw new MessageHandlingException("Unable to determine reply channel for message. "
-							+ "Provide a 'replyChannelName' in the message header or a 'defaultOutputChannelName' "
-							+ "on the message endpoint.");
-				}
-				replyChannel.send(replyMessage);
+				this.replyHandler.handle(replyMessage, message.getHeader());
 			}
 		}
 		catch (MessageHandlerRejectedExecutionException e) {
@@ -228,12 +228,11 @@ public class DefaultMessageEndpoint implements MessageEndpoint, ChannelRegistryA
 		return null;
 	}
 
-	private MessageChannel resolveReplyChannel(Message<?> message) {
+	private MessageChannel resolveReplyChannel(String replyChannelName) {
 		if (this.channelRegistry == null) {
 			return null;
 		}
-		String replyChannelName = message.getHeader().getReplyChannelName();
-		if (replyChannelName != null && replyChannelName.trim().length() > 0) {
+		if (StringUtils.hasText(replyChannelName)) {
 			return this.channelRegistry.lookupChannel(replyChannelName);
 		}
 		if (this.defaultOutputChannelName != null) {
@@ -242,4 +241,22 @@ public class DefaultMessageEndpoint implements MessageEndpoint, ChannelRegistryA
 		return null;
 	}
 
+
+	private class EndpointReplyHandler implements ReplyHandler {
+
+		public void handle(Message<?> replyMessage, MessageHeader originalMessageHeader) {
+			if (replyMessage == null) {
+				return;
+			}
+			String replyChannelName = originalMessageHeader.getReplyChannelName();
+			MessageChannel replyChannel = resolveReplyChannel(replyChannelName);
+			if (replyChannel == null) {
+				throw new MessageHandlingException("Unable to determine reply channel for message. "
+						+ "Provide a 'replyChannelName' in the message header or a 'defaultOutputChannelName' "
+						+ "on the message endpoint.");
+			}
+			replyChannel.send(replyMessage);
+		}
+	}
+
 }

spring-integration-core/src/main/java/org/springframework/integration/handler/ConcurrentHandler.java

@@ -21,8 +21,6 @@ import org.apache.commons.logging.LogFactory;
 
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.context.Lifecycle;
-import org.springframework.integration.dispatcher.MessageHandlerNotRunningException;
-import org.springframework.integration.dispatcher.MessageHandlerRejectedExecutionException;
 import org.springframework.integration.endpoint.ConcurrencyPolicy;
 import org.springframework.integration.message.Message;
 import org.springframework.integration.util.ErrorHandler;
@@ -51,6 +49,8 @@ public class ConcurrentHandler implements MessageHandler, Lifecycle, Initializin
 
 	private ErrorHandler errorHandler;
 
+	private ReplyHandler replyHandler;
+
 	private volatile boolean running;
 
 	private Object lifecycleMonitor = new Object();
@@ -83,6 +83,10 @@ public class ConcurrentHandler implements MessageHandler, Lifecycle, Initializin
 		this.errorHandler = errorHandler;
 	}
 
+	public void setReplyHandler(ReplyHandler replyHandler) {
+		this.replyHandler = replyHandler;
+	}
+
 	public void afterPropertiesSet() {
 		refreshExecutor();
 	}
@@ -173,7 +177,10 @@ public class ConcurrentHandler implements MessageHandler, Lifecycle, Initializin
 
 		public void run() {
 			try {
-				handler.handle(this.message);
+				Message<?> reply = handler.handle(this.message);
+				if (replyHandler != null) {
+					replyHandler.handle(reply, this.message.getHeader());
+				}
 			}
 			catch (Throwable t) {
 				if (errorHandler != null) {

spring-integration-core/src/main/java/org/springframework/integration/handler/MessageHandlerNotRunningException.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.integration.dispatcher;
+package org.springframework.integration.handler;
 
 import org.springframework.integration.MessageHandlingException;
 

spring-integration-core/src/main/java/org/springframework/integration/handler/MessageHandlerRejectedExecutionException.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.integration.dispatcher;
+package org.springframework.integration.handler;
 
 import org.springframework.integration.MessageHandlingException;
 

spring-integration-core/src/main/java/org/springframework/integration/handler/ReplyHandler.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2002-2007 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.integration.handler;
+
+import org.springframework.integration.message.Message;
+import org.springframework.integration.message.MessageHeader;
+
+/**
+ * Strategy interface for handling reply messages.
+ * 
+ * @author Mark Fisher
+ */
+public interface ReplyHandler {
+
+	void handle(Message<?> replyMessage, MessageHeader originalMessageHeader);
+
+}

spring-integration-core/src/main/java/org/springframework/integration/message/selector/MessageSelectorRejectedException.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.integration.dispatcher;
+package org.springframework.integration.message.selector;
 
 import org.springframework.integration.MessageHandlingException;