INT-775 Added SpEL-based Message Router and parser support for the "expression" attribute on the <router/> element.

org.springframework.integration/src/main/java/org/springframework/integration/config/RouterFactoryBean.java

@@ -21,6 +21,7 @@ import org.springframework.integration.core.MessageChannel;
 import org.springframework.integration.message.MessageHandler;
 import org.springframework.integration.router.AbstractChannelNameResolvingMessageRouter;
 import org.springframework.integration.router.AbstractMessageRouter;
+import org.springframework.integration.router.ExpressionEvaluatingRouter;
 import org.springframework.integration.router.MethodInvokingRouter;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
@@ -86,6 +87,11 @@ public class RouterFactoryBean extends AbstractMessageHandlerFactoryBean {
 		return router;
 	}
 
+	@Override
+	MessageHandler createExpressionEvaluatingHandler(String expression) {
+		return new ExpressionEvaluatingRouter(expression);
+	}
+
 	private AbstractMessageRouter createRouter(Object targetObject, String targetMethodName) {
 		if (targetObject instanceof AbstractMessageRouter) {
 			Assert.isTrue(!StringUtils.hasText(targetMethodName),

org.springframework.integration/src/main/java/org/springframework/integration/router/AbstractMessageProcessingRouter.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2002-2009 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.router;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.integration.core.Message;
+import org.springframework.integration.handler.MessageProcessor;
+import org.springframework.util.Assert;
+
+/**
+ * A base class for Router implementations that delegate to a
+ * {@link MessageProcessor} instance.
+ * 
+ * @author Mark Fisher
+ * @since 2.0
+ */
+class AbstractMessageProcessingRouter extends AbstractChannelNameResolvingMessageRouter {
+
+	private final MessageProcessor messageProcessor;
+
+
+	AbstractMessageProcessingRouter(MessageProcessor messageProcessor) {
+		Assert.notNull(messageProcessor, "messageProcessor must not be null");
+		this.messageProcessor = messageProcessor;
+	}
+
+	@Override
+	protected List<Object> getChannelIndicatorList(Message<?> message) {
+		Object result = this.messageProcessor.processMessage(message);
+		List<Object> asList = new ArrayList<Object>();
+		asList.add(result);
+		return asList;
+	}
+
+}

org.springframework.integration/src/main/java/org/springframework/integration/router/ExpressionEvaluatingRouter.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2002-2009 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.router;
+
+import org.springframework.integration.handler.ExpressionEvaluatingMessageProcessor;
+
+/**
+ * A Message Router implementation that evaluates the specified SpEL
+ * expression. The result of evaluation will typically be a String to be
+ * resolved to a channel name or a Collection (or Array) of strings.
+ * 
+ * @author Mark Fisher
+ * @since 2.0
+ */
+public class ExpressionEvaluatingRouter extends AbstractMessageProcessingRouter {
+
+	public ExpressionEvaluatingRouter(String expression) {
+		super(new ExpressionEvaluatingMessageProcessor(expression));
+	}
+
+}

org.springframework.integration/src/main/java/org/springframework/integration/router/MethodInvokingRouter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2008 the original author or authors.
+ * Copyright 2002-2009 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.
@@ -17,12 +17,9 @@
 package org.springframework.integration.router;
 
 import java.lang.reflect.Method;
-import java.util.ArrayList;
-import java.util.List;
 
 import org.springframework.integration.annotation.Router;
 import org.springframework.integration.channel.ChannelResolver;
-import org.springframework.integration.core.Message;
 import org.springframework.integration.handler.MessageMappingMethodInvoker;
 
 /**
@@ -34,30 +31,18 @@ import org.springframework.integration.handler.MessageMappingMethodInvoker;
  * 
  * @author Mark Fisher
  */
-public class MethodInvokingRouter extends AbstractChannelNameResolvingMessageRouter {
-
-	private final MessageMappingMethodInvoker invoker;
-
-	
+public class MethodInvokingRouter extends AbstractMessageProcessingRouter {
 
 	public MethodInvokingRouter(Object object, Method method) {
-		this.invoker = new MessageMappingMethodInvoker(object, method);
+		super(new MessageMappingMethodInvoker(object, method));
 	}
 
 	public MethodInvokingRouter(Object object, String methodName) {
-		this.invoker = new MessageMappingMethodInvoker(object, methodName);
+		super(new MessageMappingMethodInvoker(object, methodName));
 	}
 
 	public MethodInvokingRouter(Object object) {
-		this.invoker = new MessageMappingMethodInvoker(object, Router.class);
-	}
-
-	@Override
-	protected List<Object> getChannelIndicatorList(Message<?> message) {
-		Object result = this.invoker.processMessage(message);
-		List<Object> asList = new ArrayList<Object>();
-		asList.add(result);
-		return asList;
+		super(new MessageMappingMethodInvoker(object, Router.class));
 	}
 
 }

org.springframework.integration/src/main/resources/org/springframework/integration/config/xml/spring-integration-2.0.xsd

@@ -1136,9 +1136,8 @@
 			<xsd:complexContent>
 				<xsd:extension base="channelResolvingRouterType">
 					<xsd:all>   
-					  <xsd:element name="poller" type="innerPollerType"
-							minOccurs="0" maxOccurs="1" />          
-	                    <xsd:element ref="beans:bean" minOccurs="0" maxOccurs="1" />                
+						<xsd:element name="poller" type="innerPollerType" minOccurs="0" maxOccurs="1" />
+	                	<xsd:element ref="beans:bean" minOccurs="0" maxOccurs="1" />                
 	                </xsd:all>
 					<xsd:attribute name="ref" type="xsd:string">
 						<xsd:annotation>
@@ -1150,6 +1149,7 @@
 						</xsd:annotation>
 					</xsd:attribute>
 					<xsd:attribute name="method" type="xsd:string" />
+					<xsd:attribute name="expression" type="xsd:string"/>
 					<xsd:attribute name="channel-resolver" type="xsd:string">
 						<xsd:annotation>
 							<xsd:documentation><![CDATA[