001    /**
002     *
003     * Licensed to the Apache Software Foundation (ASF) under one or more
004     * contributor license agreements.  See the NOTICE file distributed with
005     * this work for additional information regarding copyright ownership.
006     * The ASF licenses this file to You under the Apache License, Version 2.0
007     * (the "License"); you may not use this file except in compliance with
008     * the License.  You may obtain a copy of the License at
009     *
010     * http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    package org.apache.camel.processor;
019    
020    import org.apache.camel.Processor;
021    import org.apache.camel.Exchange;
022    import org.apache.camel.spi.Policy;
023    import org.apache.camel.impl.ServiceSupport;
024    import org.apache.camel.util.ServiceHelper;
025    
026    /**
027     * A Delegate pattern which delegates processing to a nested processor which can be useful for implementation inheritence
028     * when writing an {@link Policy}
029     *
030     * @version $Revision: 519941 $
031     */
032    public class DelegateProcessor extends ServiceSupport implements Processor {
033        protected Processor next;
034    
035        public DelegateProcessor() {
036        }
037    
038        public DelegateProcessor(Processor next) {
039            this.next = next;
040        }
041    
042        public void process(Exchange exchange) throws Exception {
043            processNext(exchange);
044        }
045    
046        protected void processNext(Exchange exchange) throws Exception {
047            if (next != null) {
048                next.process(exchange);
049            }
050        }
051    
052        @Override
053        public String toString() {
054            return "delegate(" + next + ")";
055        }
056    
057        public Processor getNext() {
058            return next;
059        }
060    
061        public void setNext(Processor next) {
062            this.next = next;
063        }
064    
065        protected void doStart() throws Exception {
066            ServiceHelper.startServices(next);
067        }
068    
069        protected void doStop() throws Exception {
070            ServiceHelper.stopServices(next);
071        }
072    }