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 java.util.ArrayList; 020 import java.util.List; 021 022 import org.apache.camel.Exchange; 023 import org.apache.camel.Navigate; 024 import org.apache.camel.Predicate; 025 import org.apache.camel.Processor; 026 import org.apache.camel.impl.ServiceSupport; 027 import org.apache.camel.util.ServiceHelper; 028 029 /** 030 * Implements a Choice structure where one or more predicates are used which if 031 * they are true their processors are used, with a default otherwise clause used 032 * if none match. 033 * 034 * @version $Revision: 769303 $ 035 */ 036 public class ChoiceProcessor extends ServiceSupport implements Processor, Navigate<Processor> { 037 private final List<FilterProcessor> filters; 038 private final Processor otherwise; 039 040 public ChoiceProcessor(List<FilterProcessor> filters, Processor otherwise) { 041 this.filters = filters; 042 this.otherwise = otherwise; 043 } 044 045 public void process(Exchange exchange) throws Exception { 046 for (FilterProcessor filterProcessor : filters) { 047 Predicate predicate = filterProcessor.getPredicate(); 048 if (predicate != null && predicate.matches(exchange)) { 049 // process next will also take care (has not null test) if next was a stop(). 050 // stop() has no processor to execute, and thus we will end in a NPE 051 filterProcessor.processNext(exchange); 052 return; 053 } 054 } 055 if (otherwise != null) { 056 otherwise.process(exchange); 057 } 058 } 059 060 @Override 061 public String toString() { 062 StringBuilder builder = new StringBuilder("choice{"); 063 boolean first = true; 064 for (FilterProcessor processor : filters) { 065 if (first) { 066 first = false; 067 } else { 068 builder.append(", "); 069 } 070 builder.append("when "); 071 builder.append(processor.getPredicate().toString()); 072 builder.append(": "); 073 builder.append(processor.getProcessor()); 074 } 075 if (otherwise != null) { 076 builder.append(", otherwise: "); 077 builder.append(otherwise); 078 } 079 builder.append("}"); 080 return builder.toString(); 081 } 082 083 public List<FilterProcessor> getFilters() { 084 return filters; 085 } 086 087 public Processor getOtherwise() { 088 return otherwise; 089 } 090 091 public List<Processor> next() { 092 if (!hasNext()) { 093 return null; 094 } 095 List<Processor> answer = new ArrayList<Processor>(); 096 if (filters != null) { 097 answer.addAll(filters); 098 } 099 if (otherwise != null) { 100 answer.add(otherwise); 101 } 102 return answer; 103 } 104 105 public boolean hasNext() { 106 return otherwise != null || (filters != null && !filters.isEmpty()); 107 } 108 109 protected void doStart() throws Exception { 110 ServiceHelper.startServices(filters, otherwise); 111 } 112 113 protected void doStop() throws Exception { 114 ServiceHelper.stopServices(otherwise, filters); 115 } 116 }