ChannelInterceptor which allows transformation on send or receive from a channel

org.springframework.integration/src/test/java/org/springframework/integration/transformer/MessageTransformingChannelInterceptorTests.java

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+/*
+ * Copyright 2002-2008 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.transformer;
+
+import static org.junit.Assert.*;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.integration.channel.AbstractMessageChannel;
+import org.springframework.integration.channel.QueueChannel;
+import org.springframework.integration.message.Message;
+import org.springframework.integration.message.StringMessage;
+
+/**
+ * 
+ * @author Jonas Partner
+ * 
+ */
+public class MessageTransformingChannelInterceptorTests {
+	
+	AbstractMessageChannel channel; 
+	
+	StringMessage message;
+	
+	TestTransformer transfomer;
+	
+	MessageTransformingChannelInterceptor channelInterceptor;
+	
+	@Before
+	public void setUp(){
+		channel = new QueueChannel();
+		message = new StringMessage("test");
+		transfomer = new TestTransformer();
+		channelInterceptor = new MessageTransformingChannelInterceptor(transfomer);
+		channel.addInterceptor(channelInterceptor);
+	}
+	
+	@Test
+	public void testTransformOnReceive(){
+		channelInterceptor.setConvertOnSend(false);
+		channel.send(message);
+		assertFalse("Transfomrer on incorrectly invoked on send", transfomer.invoked);
+		Message msg = channel.receive(1);
+		assertEquals("Wrong message",message, msg);
+		assertTrue("Transfomer not invoked on receive", transfomer.invoked);
+	}
+	
+	@Test
+	public void testTransformOnSend(){
+		channelInterceptor.setConvertOnSend(true);
+		channel.send(message);
+		assertTrue("Transfomrer not invoked on send", transfomer.invoked);
+		Message msg = channel.receive(1);
+		assertEquals("Wrong message",message, msg);
+		assertEquals("Transfomer invoked on receive", 1, transfomer.invokedCount);
+	}
+	
+	
+	private static class TestTransformer implements MessageTransformer{
+
+		boolean invoked = false;
+		
+		int invokedCount = 0;
+		
+		public void transform(Message<?> message) {
+			invoked = true;
+			invokedCount++;
+		}
+		
+	}
+
+}