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: 658240 $
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 }