INT-1688 added fallback to resolution of framework methods in service-activator: MessageHandler or RequestReplyExchanger as created by Gateway proxies.

spring-integration-core/src/main/java/org/springframework/integration/util/MessagingMethodInvokerHelper.java

@@ -33,6 +33,7 @@ import java.util.concurrent.atomic.AtomicReference;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+
 import org.springframework.aop.support.AopUtils;
 import org.springframework.core.LocalVariableTableParameterNameDiscoverer;
 import org.springframework.core.MethodParameter;
@@ -51,6 +52,7 @@ import org.springframework.integration.annotation.Header;
 import org.springframework.integration.annotation.Headers;
 import org.springframework.integration.annotation.Payload;
 import org.springframework.integration.annotation.Payloads;
+import org.springframework.integration.annotation.ServiceActivator;
 import org.springframework.util.Assert;
 import org.springframework.util.ReflectionUtils;
 import org.springframework.util.ReflectionUtils.MethodCallback;
@@ -317,6 +319,28 @@ public class MessagingMethodInvokerHelper<T> extends AbstractExpressionEvaluator
 		if (!candidateMethods.isEmpty()) {
 			return candidateMethods;
 		}
+		if ((fallbackMethods.isEmpty() || ambiguousFallbackType.get() != null) && ServiceActivator.class.equals(annotationType)) {
+			// a Service Activator can fallback to either MessageHandler.handleMessage(m) or RequestReplyExchanger.exchange(m)
+			List<Method> frameworkMethods = new ArrayList<Method>();
+			Class<?>[] allInterfaces = org.springframework.util.ClassUtils.getAllInterfacesForClass(targetClass);
+			for (Class<?> iface : allInterfaces) {
+				try {
+					if ("org.springframework.integration.gateway.RequestReplyExchanger".equals(iface.getName())) {
+						frameworkMethods.add(targetClass.getMethod("exchange", Message.class));
+					}
+					else if ("org.springframework.integration.core.MessageHandler".equals(iface.getName()) && !requiresReply) {
+						frameworkMethods.add(targetClass.getMethod("handleMessage", Message.class));
+					}
+				}
+				catch (Exception e) {
+					// should never happen (but would fall through to errors below)
+				}
+			}
+			if (frameworkMethods.size() == 1) {
+				HandlerMethod handlerMethod = new HandlerMethod(frameworkMethods.get(0), canProcessMessageList);
+				return Collections.<Class<?>, HandlerMethod>singletonMap(Object.class, handlerMethod);
+			}
+		}
 		Assert.notEmpty(fallbackMethods, "Target object of type [" + this.targetObject.getClass()
 				+ "] has no eligible methods for handling Messages.");
 		Assert.isNull(ambiguousFallbackType.get(), "Found ambiguous parameter type [" + ambiguousFallbackType
@@ -370,6 +394,7 @@ public class MessagingMethodInvokerHelper<T> extends AbstractExpressionEvaluator
 		return (method.getName().equals("clone") && method.getParameterTypes().length == 0);
 	}
 
+
 	/**
 	 * Helper class for generating and exposing metadata for a candidate handler method. The metadata includes the SpEL
 	 * expression and the expected payload type.
@@ -380,30 +405,33 @@ public class MessagingMethodInvokerHelper<T> extends AbstractExpressionEvaluator
 
 		private static final ParameterNameDiscoverer PARAMETER_NAME_DISCOVERER = new LocalVariableTableParameterNameDiscoverer();
 
-		private final Method method;
-
-		private final Expression expression;
-
-		private volatile TypeDescriptor targetParameterType;
-
 		private static final TypeDescriptor messageTypeDescriptor = TypeDescriptor.valueOf(Message.class);
 
-		private static final TypeDescriptor messageListTypeDescriptor = new TypeDescriptor(ReflectionUtils.findField(
-				HandlerMethod.class, "dummyMessages"));
+		private static final TypeDescriptor messageListTypeDescriptor = new TypeDescriptor(
+				ReflectionUtils.findField(HandlerMethod.class, "dummyMessages"));
 
 		private static final TypeDescriptor messageArrayTypeDescriptor = TypeDescriptor.valueOf(Message[].class);
 
 		@SuppressWarnings("unused")
 		private static final List<Message<?>> dummyMessages = Collections.emptyList();
 
+
+		private final Method method;
+
+		private final Expression expression;
+
+		private volatile TypeDescriptor targetParameterType;
+
 		private final boolean canProcessMessageList;
 
+
 		HandlerMethod(Method method, boolean canProcessMessageList) {
 			this.method = method;
 			this.canProcessMessageList = canProcessMessageList;
 			this.expression = this.generateExpression(method);
 		}
 
+
 		Expression getExpression() {
 			return this.expression;
 		}

spring-integration-core/src/test/java/org/springframework/integration/handler/ServiceActivatorDefaultFrameworkMethodTests-context.xml

@@ -0,0 +1,28 @@
+<?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.xsd
+			http://www.springframework.org/schema/integration
+			http://www.springframework.org/schema/integration/spring-integration.xsd">
+
+	<message-history/>
+
+	<service-activator id="gatewayTestService" input-channel="gatewayTestInputChannel" ref="gateway"/>
+
+	<service-activator id="handlerTestService" input-channel="handlerTestInputChannel" ref="testMessageHandler"/>
+
+	<gateway id="gateway" default-request-channel="requestChannel" default-reply-channel="replyChannel"/>
+
+	<channel id="requestChannel"/>
+
+	<bridge id="bridge" input-channel="requestChannel" output-channel="replyChannel"/>
+
+	<channel id="replyChannel">
+		<queue/>
+	</channel>
+
+	<beans:bean id="testMessageHandler" class="org.springframework.integration.handler.ServiceActivatorDefaultFrameworkMethodTests$TestMessageHandler"/>
+
+</beans:beans>

spring-integration-core/src/test/java/org/springframework/integration/handler/ServiceActivatorDefaultFrameworkMethodTests.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright 2002-2010 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 static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.integration.Message;
+import org.springframework.integration.MessageChannel;
+import org.springframework.integration.channel.QueueChannel;
+import org.springframework.integration.handler.AbstractReplyProducingMessageHandler;
+import org.springframework.integration.support.MessageBuilder;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+/**
+ * See INT-1688 for background.
+ * 
+ * @author Mark Fisher
+ * @since 2.0.1
+ */
+@ContextConfiguration
+@RunWith(SpringJUnit4ClassRunner.class)
+public class ServiceActivatorDefaultFrameworkMethodTests {
+
+	@Autowired
+	private MessageChannel gatewayTestInputChannel;
+
+	@Autowired
+	private MessageChannel handlerTestInputChannel;
+
+	@Test
+	public void testGateway() {
+		QueueChannel replyChannel = new QueueChannel();
+		Message<?> message = MessageBuilder.withPayload("test").setReplyChannel(replyChannel).build();
+		this.gatewayTestInputChannel.send(message);
+		Message<?> reply = replyChannel.receive(0);
+		assertEquals("gatewayTestInputChannel,gatewayTestService,gateway,requestChannel,bridge,replyChannel", reply.getHeaders().get("history").toString());
+	}
+
+	@Test
+	public void testMessageHandler() {
+		QueueChannel replyChannel = new QueueChannel();
+		Message<?> message = MessageBuilder.withPayload("test").setReplyChannel(replyChannel).build();
+		this.handlerTestInputChannel.send(message);
+		Message<?> reply = replyChannel.receive(0);
+		assertEquals("TEST", reply.getPayload());
+		assertEquals("handlerTestInputChannel,handlerTestService,testMessageHandler", reply.getHeaders().get("history").toString());
+	}
+
+
+	@SuppressWarnings("unused")
+	private static class TestMessageHandler extends AbstractReplyProducingMessageHandler {
+
+		@Override
+		protected Object handleRequestMessage(Message<?> requestMessage) {
+			return requestMessage.getPayload().toString().toUpperCase();
+		}
+	}
+
+}