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.support.ServiceSupport; 026import org.apache.camel.util.AsyncProcessorHelper; 027 028/** 029 * A processor which sets the header on the IN or OUT message with an {@link org.apache.camel.Expression} 030 */ 031public class SetHeaderProcessor extends ServiceSupport implements AsyncProcessor, Traceable { 032 private final String headerName; 033 private final Expression expression; 034 035 public SetHeaderProcessor(String headerName, Expression expression) { 036 this.headerName = headerName; 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 newHeader = 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 old.setHeader(headerName, newHeader); 059 060 } catch (Throwable e) { 061 exchange.setException(e); 062 } 063 064 callback.done(true); 065 return true; 066 } 067 068 @Override 069 public String toString() { 070 return "SetHeader(" + headerName + ", " + expression + ")"; 071 } 072 073 public String getTraceLabel() { 074 return "setHeader[" + headerName + ", " + expression + "]"; 075 } 076 077 @Override 078 protected void doStart() throws Exception { 079 // noop 080 } 081 082 @Override 083 protected void doStop() throws Exception { 084 // noop 085 } 086}