MessageFilter is now an endpoint.

org.springframework.integration/src/main/java/org/springframework/integration/aggregator/AbstractMessageBarrierEndpoint.java

@@ -29,7 +29,6 @@ import java.util.concurrent.TimeUnit;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
-import org.springframework.beans.factory.InitializingBean;
 import org.springframework.integration.channel.BlockingChannel;
 import org.springframework.integration.channel.MessageChannel;
 import org.springframework.integration.endpoint.AbstractInOutEndpoint;
@@ -61,7 +60,7 @@ import org.springframework.util.ObjectUtils;
  * @author Mark Fisher
  * @author Marius Bogoevici
  */
-public abstract class AbstractMessageBarrierEndpoint extends AbstractInOutEndpoint implements InitializingBean {
+public abstract class AbstractMessageBarrierEndpoint extends AbstractInOutEndpoint {
 
 	public final static long DEFAULT_SEND_TIMEOUT = 1000;
 
@@ -151,7 +150,8 @@ public abstract class AbstractMessageBarrierEndpoint extends AbstractInOutEndpoi
 	/**
 	 * Initialize this endpoint.
 	 */
-	public void afterPropertiesSet() {
+	@Override
+	protected void initialize() {
 		this.trackedCorrelationIds = new ArrayBlockingQueue<Object>(this.trackedCorrelationIdCapacity);
 		this.executor.scheduleWithFixedDelay(new ReaperTask(),
 				this.reaperInterval, this.reaperInterval, TimeUnit.MILLISECONDS);

org.springframework.integration/src/main/java/org/springframework/integration/endpoint/AbstractEndpoint.java

@@ -20,6 +20,8 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
 import org.springframework.beans.factory.BeanNameAware;
+import org.springframework.beans.factory.InitializingBean;
+import org.springframework.integration.ConfigurationException;
 import org.springframework.integration.channel.ChannelRegistry;
 import org.springframework.integration.channel.ChannelRegistryAware;
 import org.springframework.integration.message.Message;
@@ -27,6 +29,7 @@ import org.springframework.integration.message.MessageExchangeTemplate;
 import org.springframework.integration.message.MessageHandlingException;
 import org.springframework.integration.message.MessageSource;
 import org.springframework.integration.message.MessagingException;
+import org.springframework.integration.message.SubscribableSource;
 import org.springframework.integration.util.ErrorHandler;
 
 /**
@@ -34,7 +37,7 @@ import org.springframework.integration.util.ErrorHandler;
  * 
  * @author Mark Fisher
  */
-public abstract class AbstractEndpoint implements MessageEndpoint, ChannelRegistryAware, BeanNameAware {
+public abstract class AbstractEndpoint implements MessageEndpoint, ChannelRegistryAware, BeanNameAware, InitializingBean {
 
 	protected final Log logger = LogFactory.getLog(this.getClass());
 
@@ -90,6 +93,27 @@ public abstract class AbstractEndpoint implements MessageEndpoint, ChannelRegist
 		this.errorHandler = errorHandler;
 	}
 
+	public final void afterPropertiesSet() {
+		if (this.source != null && (this.source instanceof SubscribableSource)) {
+			((SubscribableSource) this.source).subscribe(this);
+		}
+		try {
+			this.initialize();
+		}
+		catch (Exception e) {
+			if (e instanceof RuntimeException) {
+				throw (RuntimeException) e;
+			}
+			throw new ConfigurationException("failed to initialize endpoint '" + this.getName() + "'", e);
+		}
+	}
+
+	/**
+	 * Subclasses may override this method for custom initialization requirements.
+	 */
+	protected void initialize()  throws Exception {
+	}
+
 	public final boolean send(Message<?> message) {
 		if (message == null || message.getPayload() == null) {
 			throw new IllegalArgumentException("Message and its payload must not be null");

org.springframework.integration/src/main/java/org/springframework/integration/endpoint/AbstractInOutEndpoint.java

@@ -91,7 +91,14 @@ public abstract class AbstractInOutEndpoint extends AbstractEndpoint {
 			}
 			return true;
 		}
-		Message<?> reply = buildReplyMessage(result, message.getHeaders());
+		Message<?> reply = null;
+		if (result instanceof Message && result.equals(message)) {
+			// we simply pass along an unaltered request Message
+			reply = (Message<?>) result;
+		}
+		else {
+			reply = buildReplyMessage(result, message.getHeaders());
+		}
 		MessageChannel replyChannel = this.resolveReplyChannel(message);
 		if (reply instanceof CompositeMessage && this.shouldSplitComposite()) {
 			boolean sentAtLeastOne = false;

org.springframework.integration/src/main/java/org/springframework/integration/endpoint/ServiceActivatorEndpoint.java

@@ -26,7 +26,7 @@ import org.springframework.util.Assert;
 /**
  * @author Mark Fisher
  */
-public class ServiceActivatorEndpoint extends AbstractInOutEndpoint implements InitializingBean {
+public class ServiceActivatorEndpoint extends AbstractInOutEndpoint {
 
 	public static final String DEFAULT_LISTENER_METHOD = "handle";
 
@@ -48,7 +48,8 @@ public class ServiceActivatorEndpoint extends AbstractInOutEndpoint implements I
 	}
 
 
-	public void afterPropertiesSet() throws Exception {
+	@Override
+	protected void initialize() throws Exception {
 		if (this.invoker instanceof InitializingBean) {
 			((InitializingBean) this.invoker).afterPropertiesSet();
 		}

org.springframework.integration/src/main/java/org/springframework/integration/gateway/SimpleMessagingGateway.java

@@ -206,6 +206,7 @@ public class SimpleMessagingGateway extends MessagingGatewaySupport implements M
 			ReplyMessageCorrelator correlator = new ReplyMessageCorrelator(this.replyMapCapacity);
 			correlator.setBeanName("internal.correlator." + this);
 			correlator.setSource(this.replyChannel);
+			correlator.afterPropertiesSet();
 			this.endpointRegistry.registerEndpoint(correlator);
 			this.replyMessageCorrelator = correlator;
 		}

org.springframework.integration/src/main/java/org/springframework/integration/handler/MessageFilter.java

@@ -16,25 +16,30 @@
 
 package org.springframework.integration.handler;
 
+import org.springframework.integration.endpoint.AbstractInOutEndpoint;
 import org.springframework.integration.message.Message;
 import org.springframework.integration.message.selector.MessageSelector;
+import org.springframework.util.Assert;
 
 /**
- * Handler for deciding whether to pass a message. Implements
- * {@link MessageHandler} and simply delegates to a {@link MessageSelector}.
+ * Message Endpoint that decides whether to pass a message along to its
+ * output channel. Delegates to a {@link MessageSelector}.
  * 
  * @author Mark Fisher
  */
-public class MessageFilter implements MessageHandler {
+public class MessageFilter extends AbstractInOutEndpoint {
 
 	private MessageSelector selector;
 
 
 	public MessageFilter(MessageSelector selector) {
+		Assert.notNull(selector, "selector must not be null");
 		this.selector = selector;
 	}
 
-	public Message<?> handle(Message<?> message) {
+
+	@Override
+	protected Message<?> handle(Message<?> message) {
 		if (this.selector.accept(message)) {
 			return message;
 		}