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.Predicate;
024 import org.apache.camel.Processor;
025 import org.apache.camel.impl.ServiceSupport;
026 import org.apache.camel.util.ServiceHelper;
027
028 /**
029 * Implements a Choice structure where one or more predicates are used which if
030 * they are true their processors are used, with a default otherwise clause used
031 * if none match.
032 *
033 * @version $Revision: 709613 $
034 */
035 public class ChoiceProcessor extends ServiceSupport implements Processor {
036 private List<FilterProcessor> filters = new ArrayList<FilterProcessor>();
037 private Processor otherwise;
038
039 public ChoiceProcessor(List<FilterProcessor> filters, Processor otherwise) {
040 this.filters = filters;
041 this.otherwise = otherwise;
042 }
043
044 public void process(Exchange exchange) throws Exception {
045 for (FilterProcessor filterProcessor : filters) {
046 Predicate predicate = filterProcessor.getPredicate();
047 if (predicate != null && predicate.matches(exchange)) {
048 // process next will also take care (has not null test) if next was a stop().
049 // stop() has no processor to execute, and thus we will end in a NPE
050 filterProcessor.processNext(exchange);
051 return;
052 }
053 }
054 if (otherwise != null) {
055 otherwise.process(exchange);
056 }
057 }
058
059 @Override
060 public String toString() {
061 StringBuilder builder = new StringBuilder("choice{");
062 boolean first = true;
063 for (FilterProcessor processor : filters) {
064 if (first) {
065 first = false;
066 } else {
067 builder.append(", ");
068 }
069 builder.append("when ");
070 builder.append(processor.getPredicate().toString());
071 builder.append(": ");
072 builder.append(processor.getProcessor());
073 }
074 if (otherwise != null) {
075 builder.append(", otherwise: ");
076 builder.append(otherwise);
077 }
078 builder.append("}");
079 return builder.toString();
080 }
081
082 public List<FilterProcessor> getFilters() {
083 return filters;
084 }
085
086 public Processor getOtherwise() {
087 return otherwise;
088 }
089
090 protected void doStart() throws Exception {
091 ServiceHelper.startServices(filters);
092 ServiceHelper.startServices(otherwise);
093 }
094
095 protected void doStop() throws Exception {
096 ServiceHelper.stopServices(otherwise);
097 ServiceHelper.stopServices(filters);
098 }
099 }