From 727a554ccf86b27add0c0b3183c6df26a6c4f730 Mon Sep 17 00:00:00 2001
From: Gary Russell <grussell@gopivotal.com>
Date: Tue, 4 Mar 2014 18:28:57 -0500
Subject: [PATCH] INT-3294 Support Implicit Input Channel with Ann.

JIRA: https://jira.springsource.org/browse/INT-3294

Previously, implicit input channel creation was not
supported for annotated endpoints.

Register a `DirectChannel` if the input channel does
not exist in the context.
---
 ...AbstractMethodAnnotationPostProcessor.java | 16 ++++++++++++-
 .../AnnotatedEndpointActivationTests.java     | 23 +++++++++++++++++--
 2 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/spring-integration-core/src/main/java/org/springframework/integration/config/annotation/AbstractMethodAnnotationPostProcessor.java b/spring-integration-core/src/main/java/org/springframework/integration/config/annotation/AbstractMethodAnnotationPostProcessor.java
index cd559a0b05..048a26b084 100644
--- a/spring-integration-core/src/main/java/org/springframework/integration/config/annotation/AbstractMethodAnnotationPostProcessor.java
+++ b/spring-integration-core/src/main/java/org/springframework/integration/config/annotation/AbstractMethodAnnotationPostProcessor.java
@@ -29,6 +29,7 @@ import org.springframework.beans.factory.ListableBeanFactory;
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.core.annotation.Order;
+import org.springframework.integration.channel.DirectChannel;
 import org.springframework.integration.config.IntegrationConfigUtils;
 import org.springframework.integration.context.Orderable;
 import org.springframework.integration.endpoint.AbstractEndpoint;
@@ -38,6 +39,7 @@ import org.springframework.integration.support.channel.BeanFactoryChannelResolve
 import org.springframework.messaging.MessageChannel;
 import org.springframework.messaging.MessageHandler;
 import org.springframework.messaging.SubscribableChannel;
+import org.springframework.messaging.core.DestinationResolutionException;
 import org.springframework.messaging.core.DestinationResolver;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
@@ -47,6 +49,7 @@ import org.springframework.util.StringUtils;
  * Base class for Method-level annotation post-processors.
  *
  * @author Mark Fisher
+ * @author Artem Bilan
  * @author Gary Russell
  */
 public abstract class AbstractMethodAnnotationPostProcessor<T extends Annotation> implements MethodAnnotationPostProcessor<T> {
@@ -133,7 +136,18 @@ public abstract class AbstractMethodAnnotationPostProcessor<T extends Annotation
 		AbstractEndpoint endpoint = null;
 		String inputChannelName = (String) AnnotationUtils.getValue(annotation, INPUT_CHANNEL_ATTRIBUTE);
 		if (StringUtils.hasText(inputChannelName)) {
-			MessageChannel inputChannel = this.channelResolver.resolveDestination(inputChannelName);
+			MessageChannel inputChannel;
+			try {
+				inputChannel = this.channelResolver.resolveDestination(inputChannelName);
+			}
+			catch (DestinationResolutionException e) {
+				inputChannel = new DirectChannel();
+				if (this.beanFactory instanceof ConfigurableListableBeanFactory) {
+					ConfigurableListableBeanFactory listableBeanFactory = (ConfigurableListableBeanFactory) this.beanFactory;
+					listableBeanFactory.registerSingleton(inputChannelName, inputChannel);
+					inputChannel = (MessageChannel) listableBeanFactory.initializeBean(inputChannel, inputChannelName);
+				}
+			}
 			Assert.notNull(inputChannel, "failed to resolve inputChannel '" + inputChannelName + "'");
 			Assert.isInstanceOf(SubscribableChannel.class, inputChannel,
 					"The input channel for an Annotation-based endpoint must be a SubscribableChannel.");
diff --git a/spring-integration-core/src/test/java/org/springframework/integration/config/annotation/AnnotatedEndpointActivationTests.java b/spring-integration-core/src/test/java/org/springframework/integration/config/annotation/AnnotatedEndpointActivationTests.java
index 4891fa74c4..44b73eff3f 100644
--- a/spring-integration-core/src/test/java/org/springframework/integration/config/annotation/AnnotatedEndpointActivationTests.java
+++ b/spring-integration-core/src/test/java/org/springframework/integration/config/annotation/AnnotatedEndpointActivationTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2008 the original author or authors.
+ * Copyright 2002-2014 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.
@@ -23,22 +23,24 @@ import static org.junit.Assert.assertTrue;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.context.support.AbstractApplicationContext;
 import org.springframework.integration.annotation.MessageEndpoint;
 import org.springframework.integration.annotation.ServiceActivator;
-import org.springframework.messaging.support.GenericMessage;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageChannel;
 import org.springframework.messaging.MessageDeliveryException;
 import org.springframework.messaging.PollableChannel;
+import org.springframework.messaging.support.GenericMessage;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 
 /**
  * @author Dave Syer
  * @author Mark Fisher
+ * @author Gary Russell
  */
 @ContextConfiguration
 @RunWith(SpringJUnit4ClassRunner.class)
@@ -69,6 +71,13 @@ public class AnnotatedEndpointActivationTests {
 		return result;
 	}
 
+	@ServiceActivator(inputChannel = "inputImplicit", outputChannel = "output")
+	public String processImplicit(String message) {
+		count++;
+		String result = message + ": " + count;
+		return result;
+	}
+
 	@Before
 	public void resetCount() {
 		count = 0;
@@ -88,6 +97,16 @@ public class AnnotatedEndpointActivationTests {
 		assertEquals(1, count);
 	}
 
+	@Test
+	public void sendAndReceiveImplicitInputChannel() {
+		MessageChannel input = this.applicationContext.getBean("inputImplicit", MessageChannel.class);
+		input.send(new GenericMessage<String>("foo"));
+		Message<?> message = this.output.receive(100);
+		assertNotNull(message);
+		assertEquals("foo: 1", message.getPayload());
+		assertEquals(1, count);
+	}
+
 	@Test(expected = MessageDeliveryException.class)
 	public void stopContext() {
 		applicationContext.stop();