001    /**
002     *
003     * Licensed to the Apache Software Foundation (ASF) under one or more
004     * contributor license agreements.  See the NOTICE file distributed with
005     * this work for additional information regarding copyright ownership.
006     * The ASF licenses this file to You under the Apache License, Version 2.0
007     * (the "License"); you may not use this file except in compliance with
008     * the License.  You may obtain a copy of the License at
009     *
010     * http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    package org.apache.camel.processor;
019    
020    import org.apache.camel.Predicate;
021    import org.apache.camel.Processor;
022    import org.apache.camel.Exchange;
023    import org.apache.camel.util.ServiceHelper;
024    import org.apache.camel.impl.ServiceSupport;
025    
026    import java.util.ArrayList;
027    import java.util.List;
028    
029    /**
030     * Implements a Choice structure where one or more predicates are used which if they are true their processors
031     * are used, with a default otherwise clause used if none match.
032     *
033     * @version $Revision: 534145 $
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<Exchange> predicate = filterProcessor.getPredicate();
047                if (predicate != null && predicate.matches(exchange)) {
048                    filterProcessor.getProcessor().process(exchange);
049                    return;
050                }
051            }
052            if (otherwise != null) {
053                otherwise.process(exchange);
054            }
055        }
056    
057        @Override
058        public String toString() {
059            StringBuilder builder = new StringBuilder("choice{");
060            boolean first = true;
061            for (FilterProcessor processor : filters) {
062                if (first) {
063                    first = false;
064                }
065                else {
066                    builder.append(", ");
067                }
068                builder.append("when ");
069                builder.append(processor.getPredicate().toString());
070                builder.append(": ");
071                builder.append(processor.getProcessor());
072            }
073            if (otherwise != null) {
074                builder.append(", otherwise: ");
075                builder.append(otherwise);
076            }
077            builder.append("}");
078            return builder.toString();
079        }
080    
081        public List<FilterProcessor> getFilters() {
082            return filters;
083        }
084    
085        public Processor getOtherwise() {
086            return otherwise;
087        }
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    }