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.util.ServiceHelper;
023
024 /**
025 * A Delegate pattern which delegates processing to a nested processor which can
026 * be useful for implementation inheritance when writing an {@link org.apache.camel.spi.Policy}
027 *
028 * @version $Revision: 751221 $
029 */
030 public class DelegateProcessor extends ServiceSupport implements Processor {
031 protected Processor processor;
032
033 public DelegateProcessor() {
034 }
035
036 public DelegateProcessor(Processor processor) {
037 if (processor == this) {
038 throw new IllegalArgumentException("Recursive DelegateProcessor!");
039 }
040 this.processor = processor;
041 }
042
043 public void process(Exchange exchange) throws Exception {
044 processNext(exchange);
045 }
046
047 protected void processNext(Exchange exchange) throws Exception {
048 if (processor != null) {
049 processor.process(exchange);
050 }
051 }
052
053 @Override
054 public String toString() {
055 return "Delegate(" + processor + ")";
056 }
057
058 public Processor getProcessor() {
059 return processor;
060 }
061
062 public void setProcessor(Processor processor) {
063 this.processor = processor;
064 }
065
066 protected void doStart() throws Exception {
067 ServiceHelper.startServices(processor);
068 }
069
070 protected void doStop() throws Exception {
071 ServiceHelper.stopServices(processor);
072 }
073
074 /**
075 * Proceed with the underlying delegated processor
076 */
077 public void proceed(Exchange exchange) throws Exception {
078 processNext(exchange);
079 }
080 }