<message-bus/> will automatically add a MessageBusAwareBeanPostProcessor to the context.

spring-integration-core/src/main/java/org/springframework/integration/config/MessageBusParser.java

@@ -16,30 +16,36 @@
 
 package org.springframework.integration.config;
 
-import org.w3c.dom.Element;
-import org.w3c.dom.Node;
-import org.w3c.dom.NodeList;
-
 import org.springframework.beans.factory.BeanDefinitionStoreException;
+import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.beans.factory.config.RuntimeBeanReference;
 import org.springframework.beans.factory.support.AbstractBeanDefinition;
 import org.springframework.beans.factory.support.BeanDefinitionBuilder;
+import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.beans.factory.xml.AbstractSimpleBeanDefinitionParser;
 import org.springframework.beans.factory.xml.ParserContext;
 import org.springframework.core.Conventions;
 import org.springframework.integration.ConfigurationException;
 import org.springframework.integration.bus.MessageBus;
+import org.springframework.integration.bus.MessageBusAwareBeanPostProcessor;
 import org.springframework.integration.endpoint.ConcurrencyPolicy;
 import org.springframework.util.StringUtils;
+import org.w3c.dom.Element;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
 
 /**
  * Parser for the <em>message-bus</em> element of the integration namespace.
  * 
  * @author Mark Fisher
+ * @author Marius Bogoevici
  */
 public class MessageBusParser extends AbstractSimpleBeanDefinitionParser {
 
 	public static final String MESSAGE_BUS_BEAN_NAME = "internal.MessageBus";
 
+	public static final String MESSAGE_BUS_AWARE_POST_PROCESSOR_BEAN_NAME = "internal.MessageBusAwareBeanPostProcessor";
+
 	private static final Class<?> MESSAGE_BUS_CLASS = MessageBus.class;
 
 	private static final String ERROR_CHANNEL_ATTRIBUTE = "error-channel";
@@ -48,7 +54,6 @@ public class MessageBusParser extends AbstractSimpleBeanDefinitionParser {
 
 	private static final String DEFAULT_CONCURRENCY_PROPERTY = "defaultConcurrencyPolicy";
 
-
 	@Override
 	protected String resolveId(Element element, AbstractBeanDefinition definition, ParserContext parserContext)
 			throws BeanDefinitionStoreException {
@@ -93,4 +98,21 @@ public class MessageBusParser extends AbstractSimpleBeanDefinitionParser {
 		}
 	}
 
+	@Override
+	protected void doParse(Element element, ParserContext parserContext, BeanDefinitionBuilder builder) {
+		super.doParse(element, parserContext, builder);
+		addPostProcessors(parserContext);
+	}
+
+	/**
+	 * Adds extra post-processors to the context, to inject the objects configured by the MessageBus
+	 */
+	private void addPostProcessors(ParserContext parserContext) {
+		BeanDefinition postProcessorDefinition = new RootBeanDefinition(MessageBusAwareBeanPostProcessor.class);
+		postProcessorDefinition.getConstructorArgumentValues().addGenericArgumentValue(
+				new RuntimeBeanReference(MessageBusParser.MESSAGE_BUS_BEAN_NAME));
+		parserContext.getRegistry().registerBeanDefinition(MESSAGE_BUS_AWARE_POST_PROCESSOR_BEAN_NAME,
+				postProcessorDefinition);
+	}
+
 }

spring-integration-core/src/test/java/org/springframework/integration/config/MessageBusParserTests.java

@@ -28,12 +28,14 @@ import org.springframework.context.ApplicationContext;
 import org.springframework.context.support.ClassPathXmlApplicationContext;
 import org.springframework.integration.ConfigurationException;
 import org.springframework.integration.bus.MessageBus;
+import org.springframework.integration.bus.TestMessageBusAwareImpl;
 import org.springframework.integration.endpoint.TargetEndpoint;
 import org.springframework.integration.handler.TestHandlers;
 import org.springframework.integration.scheduling.Subscription;
 
 /**
  * @author Mark Fisher
+ * @author Marius Bogoevici
  */
 public class MessageBusParserTests {
 
@@ -97,7 +99,12 @@ public class MessageBusParserTests {
 		}
 		catch (BeanCreationException e) {
 			exceptionThrown = true;
-			assertEquals(ConfigurationException.class, e.getCause().getClass());
+			// an exception is thrown when creating the post-processor, which
+			// tries to get a reference to the message bus
+			assertEquals(BeanCreationException.class, e.getCause().getClass());
+			assertEquals(e.getBeanName(), MessageBusParser.MESSAGE_BUS_AWARE_POST_PROCESSOR_BEAN_NAME);
+			assertEquals(ConfigurationException.class, ((BeanCreationException) e.getCause()).getCause().getClass());
+			assertEquals(((BeanCreationException) e.getCause()).getBeanName(), MessageBusParser.MESSAGE_BUS_BEAN_NAME);
 		}
 		assertTrue(exceptionThrown);
 	}
@@ -128,5 +135,13 @@ public class MessageBusParserTests {
 		assertEquals(14, endpoint2.getConcurrencyPolicy().getCoreSize());
 		assertEquals(17, endpoint2.getConcurrencyPolicy().getMaxSize());	
 	}
+	
+	@Test
+	public void testMessageBusAwareAutomaticallyAddedByNamespace() {
+		ApplicationContext context = new ClassPathXmlApplicationContext("messageBusWithMessageBusAware.xml", 
+				this.getClass());
+		TestMessageBusAwareImpl messageBusAware = (TestMessageBusAwareImpl) context.getBean("messageBusAwareBean");
+		assertTrue(messageBusAware.getMessageBus() == context.getBean(MessageBusParser.MESSAGE_BUS_BEAN_NAME));
+	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/config/messageBusWithMessageBusAware.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans:beans xmlns="http://www.springframework.org/schema/integration"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xmlns:beans="http://www.springframework.org/schema/beans"
+	xsi:schemaLocation="http://www.springframework.org/schema/beans
+			http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
+			http://www.springframework.org/schema/integration
+			http://www.springframework.org/schema/integration/spring-integration-core-1.0.xsd">
+
+	<message-bus/>
+
+	<beans:bean id="messageBusAwareBean" class="org.springframework.integration.bus.TestMessageBusAwareImpl"/>
+
+</beans:beans>