Added PayloadTransformer strategy interface, MethodInvokingPayloadTransformer, and PayloadTransformingMessageHandler.

org.springframework.integration/src/main/java/org/springframework/integration/transformer/MethodInvokingPayloadTransformer.java

@@ -16,24 +16,15 @@
 
 package org.springframework.integration.transformer;
 
-import org.springframework.integration.handler.MessageHandler;
-import org.springframework.integration.message.Message;
+import org.springframework.integration.util.AbstractMethodInvokingAdapter;
 
 /**
  * @author Mark Fisher
  */
-public class TransformerMessageHandlerAdapter implements MessageHandler {
+public class MethodInvokingPayloadTransformer extends AbstractMethodInvokingAdapter implements PayloadTransformer<Object, Object> {
 
-	private final MessageTransformer transformer;
-
-
-	public TransformerMessageHandlerAdapter(MessageTransformer transformer) {
-		this.transformer = transformer;
-	}
-
-
-	public Message<?> handle(Message<?> message) {
-		return this.transformer.transform(message);
+	public Object transform(Object payload) throws Exception {
+		return this.invokeMethod(payload); 
 	}
 
 }

org.springframework.integration/src/main/java/org/springframework/integration/transformer/PayloadTransformer.java

@@ -0,0 +1,26 @@
+/*
+ * 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;
+
+/**
+ * @author Mark Fisher
+ */
+public interface PayloadTransformer<T, U> {
+
+	U transform(T payload) throws Exception;
+
+}

org.springframework.integration/src/main/java/org/springframework/integration/transformer/PayloadTransformingMessageHandler.java

@@ -16,20 +16,30 @@
 
 package org.springframework.integration.transformer;
 
+import org.springframework.integration.handler.MessageHandler;
 import org.springframework.integration.message.Message;
 import org.springframework.integration.message.MessageBuilder;
 import org.springframework.integration.message.MessagingException;
-import org.springframework.integration.util.AbstractMethodInvokingAdapter;
+import org.springframework.util.Assert;
 
 /**
  * @author Mark Fisher
  */
-public class PayloadTransformerAdapter extends AbstractMethodInvokingAdapter implements MessageTransformer {
+@SuppressWarnings("unchecked")
+public class PayloadTransformingMessageHandler implements MessageHandler {
 
-	@SuppressWarnings("unchecked")
-	public Message<?> transform(Message<?> message) {
+	private final PayloadTransformer transformer;
+
+
+	public PayloadTransformingMessageHandler(PayloadTransformer transformer) {
+		Assert.notNull(transformer, "transformer must not be null");
+		this.transformer = transformer;
+	}
+
+
+	public Message<?> handle(Message<?> message) {
 		try {
-	        Object result = this.invokeMethod(message.getPayload());
+	        Object result = this.transformer.transform(message.getPayload());
 	        return MessageBuilder.fromPayload(result).copyHeaders(message.getHeaders()).build();
         } catch (Exception e) {
         	throw new MessagingException(message, "failed to transform message payload", e);