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     */
017    package org.apache.camel.processor;
018    
019    import org.apache.camel.Exchange;
020    import org.apache.camel.Expression;
021    import org.apache.camel.Message;
022    import org.apache.camel.Processor;
023    import org.apache.camel.Traceable;
024    import org.apache.camel.impl.DefaultMessage;
025    import org.apache.camel.support.ServiceSupport;
026    import org.apache.camel.util.ObjectHelper;
027    
028    /**
029     * A processor which sets the body on the OUT message with an {@link Expression}
030     */
031    public class TransformProcessor extends ServiceSupport implements Processor, Traceable {
032        private final Expression expression;
033    
034        public TransformProcessor(Expression expression) {
035            ObjectHelper.notNull(expression, "expression", this);
036            this.expression = expression;
037        }
038    
039        public void process(Exchange exchange) throws Exception {
040            Object newBody = expression.evaluate(exchange, Object.class);
041    
042            Message old = exchange.getIn();
043    
044            // create a new message container so we do not drag specialized message objects along
045            Message msg = new DefaultMessage();
046            msg.copyFrom(old);
047            msg.setBody(newBody);
048            exchange.setOut(msg);
049        }
050    
051        @Override
052        public String toString() {
053            return "Transform(" + expression + ")";
054        }
055    
056        public String getTraceLabel() {
057            return "transform[" + expression + "]";
058        }
059    
060        @Override
061        protected void doStart() throws Exception {
062            // noop
063        }
064    
065        @Override
066        protected void doStop() throws Exception {
067            // noop
068        }
069    }