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: 551 $ 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 }