001/** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.camel.processor; 018 019import org.apache.camel.AsyncCallback; 020import org.apache.camel.AsyncProcessor; 021import org.apache.camel.Exchange; 022import org.apache.camel.Expression; 023import org.apache.camel.Message; 024import org.apache.camel.Traceable; 025import org.apache.camel.impl.DefaultMessage; 026import org.apache.camel.spi.IdAware; 027import org.apache.camel.support.ServiceSupport; 028import org.apache.camel.util.AsyncProcessorHelper; 029import org.apache.camel.util.ExchangeHelper; 030import org.apache.camel.util.ObjectHelper; 031 032/** 033 * A processor which sets the body on the OUT message with an {@link Expression}. 034 */ 035public class TransformProcessor extends ServiceSupport implements AsyncProcessor, Traceable, IdAware { 036 private String id; 037 private final Expression expression; 038 039 public TransformProcessor(Expression expression) { 040 ObjectHelper.notNull(expression, "expression", this); 041 this.expression = expression; 042 } 043 044 public void process(Exchange exchange) throws Exception { 045 AsyncProcessorHelper.process(this, exchange); 046 } 047 048 public boolean process(Exchange exchange, AsyncCallback callback) { 049 try { 050 Object newBody = expression.evaluate(exchange, Object.class); 051 052 if (exchange.getException() != null) { 053 // the expression threw an exception so we should break-out 054 callback.done(true); 055 return true; 056 } 057 058 boolean out = exchange.hasOut(); 059 Message old = out ? exchange.getOut() : exchange.getIn(); 060 061 // create a new message container so we do not drag specialized message objects along 062 // but that is only needed if the old message is a specialized message 063 boolean copyNeeded = !(old.getClass().equals(DefaultMessage.class)); 064 065 if (copyNeeded) { 066 Message msg = new DefaultMessage(); 067 msg.copyFrom(old); 068 msg.setBody(newBody); 069 070 // replace message on exchange (must set as OUT) 071 ExchangeHelper.replaceMessage(exchange, msg, true); 072 } else { 073 // no copy needed so set replace value directly 074 old.setBody(newBody); 075 076 // but the message must be on OUT 077 if (!exchange.hasOut()) { 078 exchange.setOut(exchange.getIn()); 079 } 080 } 081 082 } catch (Throwable e) { 083 exchange.setException(e); 084 } 085 086 callback.done(true); 087 return true; 088 } 089 090 @Override 091 public String toString() { 092 return "Transform(" + expression + ")"; 093 } 094 095 public String getTraceLabel() { 096 return "transform[" + expression + "]"; 097 } 098 099 public String getId() { 100 return id; 101 } 102 103 public void setId(String id) { 104 this.id = id; 105 } 106 107 public Expression getExpression() { 108 return expression; 109 } 110 111 @Override 112 protected void doStart() throws Exception { 113 // noop 114 } 115 116 @Override 117 protected void doStop() throws Exception { 118 // noop 119 } 120}