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.Exchange;
020    import org.apache.camel.Processor;
021    import org.apache.camel.impl.ServiceSupport;
022    import org.apache.camel.spi.Policy;
023    import org.apache.camel.util.ServiceHelper;
024    
025    /**
026     * A Delegate pattern which delegates processing to a nested processor which can
027     * be useful for implementation inheritance when writing an {@link Policy}
028     * 
029     * @version $Revision: 41713 $
030     */
031    public class DelegateProcessor extends ServiceSupport implements Processor {
032        protected Processor processor;
033    
034        public DelegateProcessor() {
035        }
036    
037        public DelegateProcessor(Processor processor) {
038            if (processor == this) {
039                throw new IllegalArgumentException("Recursive DelegateProcessor!");
040            }
041            this.processor = processor;
042        }
043    
044        public void process(Exchange exchange) throws Exception {
045            processNext(exchange);
046        }
047    
048        protected void processNext(Exchange exchange) throws Exception {
049            if (processor != null) {
050                processor.process(exchange);
051            }
052        }
053    
054        @Override
055        public String toString() {
056            return "Delegate(" + processor + ")";
057        }
058    
059        public Processor getProcessor() {
060            return processor;
061        }
062    
063        public void setProcessor(Processor processor) {
064            this.processor = processor;
065        }
066    
067        protected void doStart() throws Exception {
068            ServiceHelper.startServices(processor);
069        }
070    
071        protected void doStop() throws Exception {
072            ServiceHelper.stopServices(processor);
073        }
074    
075        /**
076         * Proceed with the underlying delegated processor
077         */
078        public void proceed(Exchange exchange) throws Exception {
079            processNext(exchange);
080        }
081    }