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.spi.IdAware;
026import org.apache.camel.support.ServiceSupport;
027import org.apache.camel.util.AsyncProcessorHelper;
028
029/**
030 * A processor which sets the header on the IN or OUT message with an {@link org.apache.camel.Expression}
031 */
032public class SetHeaderProcessor extends ServiceSupport implements AsyncProcessor, Traceable, IdAware {
033    private String id;
034    private final String headerName;
035    private final Expression expression;
036
037    public SetHeaderProcessor(String headerName, Expression expression) {
038        this.headerName = headerName;
039        this.expression = expression;
040    }
041
042    public void process(Exchange exchange) throws Exception {
043        AsyncProcessorHelper.process(this, exchange);
044    }
045
046    @Override
047    public boolean process(Exchange exchange, AsyncCallback callback) {
048        try {
049            Object newHeader = expression.evaluate(exchange, Object.class);
050
051            if (exchange.getException() != null) {
052                // the expression threw an exception so we should break-out
053                callback.done(true);
054                return true;
055            }
056
057            boolean out = exchange.hasOut();
058            Message old = out ? exchange.getOut() : exchange.getIn();
059
060            old.setHeader(headerName, newHeader);
061
062        } catch (Throwable e) {
063            exchange.setException(e);
064        }
065
066        callback.done(true);
067        return true;
068    }
069
070    @Override
071    public String toString() {
072        return "SetHeader(" + headerName + ", " + expression + ")";
073    }
074
075    public String getTraceLabel() {
076        return "setHeader[" + headerName + ", " + expression + "]";
077    }
078
079    public String getId() {
080        return id;
081    }
082
083    public void setId(String id) {
084        this.id = id;
085    }
086
087    public String getHeaderName() {
088        return headerName;
089    }
090
091    public Expression getExpression() {
092        return expression;
093    }
094
095    @Override
096    protected void doStart() throws Exception {
097        // noop
098    }
099
100    @Override
101    protected void doStop() throws Exception {
102        // noop
103    }
104}