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.AsyncCallback;
020    import org.apache.camel.AsyncProcessor;
021    import org.apache.camel.Exchange;
022    import org.apache.camel.Expression;
023    import org.apache.camel.Message;
024    import org.apache.camel.Traceable;
025    import org.apache.camel.impl.DefaultMessage;
026    import org.apache.camel.support.ServiceSupport;
027    import org.apache.camel.util.AsyncProcessorHelper;
028    import org.apache.camel.util.ObjectHelper;
029    
030    /**
031     * A processor which sets the body on the OUT message with an {@link Expression}
032     */
033    public class TransformProcessor extends ServiceSupport implements AsyncProcessor, Traceable {
034        private final Expression expression;
035    
036        public TransformProcessor(Expression expression) {
037            ObjectHelper.notNull(expression, "expression", this);
038            this.expression = expression;
039        }
040    
041        public void process(Exchange exchange) throws Exception {
042            AsyncProcessorHelper.process(this, exchange);
043        }
044    
045        public boolean process(Exchange exchange, AsyncCallback callback) {
046            try {
047                Object newBody = expression.evaluate(exchange, Object.class);
048    
049                Message old = exchange.getIn();
050    
051                // create a new message container so we do not drag specialized message objects along
052                Message msg = new DefaultMessage();
053                msg.copyFrom(old);
054                msg.setBody(newBody);
055                exchange.setOut(msg);
056            } catch (Exception e) {
057                exchange.setException(e);
058            }
059    
060            callback.done(true);
061            return true;
062        }
063    
064        @Override
065        public String toString() {
066            return "Transform(" + expression + ")";
067        }
068    
069        public String getTraceLabel() {
070            return "transform[" + expression + "]";
071        }
072    
073        @Override
074        protected void doStart() throws Exception {
075            // noop
076        }
077    
078        @Override
079        protected void doStop() throws Exception {
080            // noop
081        }
082    }