INT-1627 moved command message processor to 'handler' package

spring-integration-core/src/main/java/org/springframework/integration/handler/ExpressionPayloadMessageProcessor.java

@@ -0,0 +1,44 @@
+/*
+ * 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 org.springframework.expression.Expression;
+import org.springframework.integration.Message;
+
+/**
+ * A MessageProcessor implementation that expects an Expression or expressionString
+ * as the Message payload. When processing, it simply evaluates that expression.
+ * 
+ * @author Dave Syer
+ * @author Mark Fisher
+ * @since 2.0
+ */
+public class ExpressionPayloadMessageProcessor extends AbstractMessageProcessor<Object> {
+
+	/**
+	 * Evaluates the Message payload expression.
+	 * @throws IllegalArgumentException if the payload is not an Exception or String
+	 */
+	public Object processMessage(Message<?> message) {
+		Object expression = message.getPayload();
+		if (expression instanceof Expression) {
+			return evaluateExpression((Expression) expression, message);
+		}
+		if (expression instanceof String) {
+			return evaluateExpression((String) expression, message);
+		}
+		throw new IllegalArgumentException("Message payload must be an Expression instance or an expression String.");
+	}
+
+}