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;
028import org.apache.camel.util.ObjectHelper;
029
030/**
031 * A processor which sets the header on the IN or OUT message with an {@link org.apache.camel.Expression}
032 */
033public class SetHeaderProcessor extends ServiceSupport implements AsyncProcessor, Traceable, IdAware {
034    private String id;
035    private final Expression headerName;
036    private final Expression expression;
037
038    public SetHeaderProcessor(Expression headerName, Expression expression) {
039        this.headerName = headerName;
040        this.expression = expression;
041        ObjectHelper.notNull(headerName, "headerName");
042        ObjectHelper.notNull(expression, "expression");
043    }
044
045    public void process(Exchange exchange) throws Exception {
046        AsyncProcessorHelper.process(this, exchange);
047    }
048
049    @Override
050    public boolean process(Exchange exchange, AsyncCallback callback) {
051        try {
052            Object newHeader = expression.evaluate(exchange, Object.class);
053
054            if (exchange.getException() != null) {
055                // the expression threw an exception so we should break-out
056                callback.done(true);
057                return true;
058            }
059
060            boolean out = exchange.hasOut();
061            Message old = out ? exchange.getOut() : exchange.getIn();
062
063            String key = headerName.evaluate(exchange, String.class);
064            old.setHeader(key, newHeader);
065
066        } catch (Throwable e) {
067            exchange.setException(e);
068        }
069
070        callback.done(true);
071        return true;
072    }
073
074    @Override
075    public String toString() {
076        return "SetHeader(" + headerName + ", " + expression + ")";
077    }
078
079    public String getTraceLabel() {
080        return "setHeader[" + headerName + ", " + expression + "]";
081    }
082
083    public String getId() {
084        return id;
085    }
086
087    public void setId(String id) {
088        this.id = id;
089    }
090
091    public String getHeaderName() {
092        return headerName.toString();
093    }
094
095    public Expression getExpression() {
096        return expression;
097    }
098
099    @Override
100    protected void doStart() throws Exception {
101        //noop
102    }
103
104    @Override
105    protected void doStop() throws Exception {
106        // noop
107    }
108}