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.support.ServiceSupport;
027import org.apache.camel.util.AsyncProcessorHelper;
028import org.apache.camel.util.ExchangeHelper;
029
030/**
031 * A processor which sets the body on the IN or OUT message with an {@link Expression}
032 */
033public class SetBodyProcessor extends ServiceSupport implements AsyncProcessor, Traceable {
034    private final Expression expression;
035
036    public SetBodyProcessor(Expression expression) {
037        this.expression = expression;
038    }
039
040    public void process(Exchange exchange) throws Exception {
041        AsyncProcessorHelper.process(this, exchange);
042    }
043
044    @Override
045    public boolean process(Exchange exchange, AsyncCallback callback) {
046        try {
047            Object newBody = expression.evaluate(exchange, Object.class);
048
049            if (exchange.getException() != null) {
050                // the expression threw an exception so we should break-out
051                callback.done(true);
052                return true;
053            }
054
055            boolean out = exchange.hasOut();
056            Message old = out ? exchange.getOut() : exchange.getIn();
057
058            // create a new message container so we do not drag specialized message objects along
059            // but that is only needed if the old message is a specialized message
060            boolean copyNeeded = !(old.getClass().equals(DefaultMessage.class));
061
062            if (copyNeeded) {
063                Message msg = new DefaultMessage();
064                msg.copyFrom(old);
065                msg.setBody(newBody);
066
067                // replace message on exchange
068                ExchangeHelper.replaceMessage(exchange, msg, false);
069            } else {
070                // no copy needed so set replace value directly
071                old.setBody(newBody);
072            }
073
074        } catch (Throwable e) {
075            exchange.setException(e);
076        }
077
078        callback.done(true);
079        return true;
080    }
081
082    @Override
083    public String toString() {
084        return "SetBody(" + expression + ")";
085    }
086
087    public String getTraceLabel() {
088        return "setBody[" + expression + "]";
089    }
090
091    @Override
092    protected void doStart() throws Exception {
093        // noop
094    }
095
096    @Override
097    protected void doStop() throws Exception {
098        // noop
099    }
100}