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.Iterator;
020    
021    import org.apache.camel.Endpoint;
022    import org.apache.camel.Exchange;
023    import org.apache.camel.Expression;
024    import org.apache.camel.Processor;
025    import org.apache.camel.converter.ObjectConverter;
026    import org.apache.camel.impl.ServiceSupport;
027    import org.apache.camel.util.ExchangeHelper;
028    import org.apache.camel.util.ProducerCache;
029    
030    import static org.apache.camel.util.ObjectHelper.notNull;
031    
032    /**
033     * Implements a dynamic <a
034     * href="http://activemq.apache.org/camel/recipient-list.html">Recipient List</a>
035     * pattern where the list of actual endpoints to send a message exchange to are
036     * dependent on some dynamic expression.
037     * 
038     * @version $Revision: 563607 $
039     */
040    public class RecipientList extends ServiceSupport implements Processor {
041        private final Expression<Exchange> expression;
042        private ProducerCache<Exchange> producerCache = new ProducerCache<Exchange>();
043    
044        public RecipientList(Expression<Exchange> expression) {
045            notNull(expression, "expression");
046            this.expression = expression;
047        }
048    
049        @Override
050        public String toString() {
051            return "RecipientList[" + expression + "]";
052        }
053    
054        public void process(Exchange exchange) throws Exception {
055            Object receipientList = expression.evaluate(exchange);
056            Iterator iter = ObjectConverter.iterator(receipientList);
057            while (iter.hasNext()) {
058                Object recipient = iter.next();
059                Endpoint<Exchange> endpoint = resolveEndpoint(exchange, recipient);
060                producerCache.getProducer(endpoint).process(exchange);
061            }
062        }
063    
064        protected Endpoint<Exchange> resolveEndpoint(Exchange exchange, Object recipient) {
065            return ExchangeHelper.resolveEndpoint(exchange, recipient);
066        }
067    
068        protected void doStop() throws Exception {
069            producerCache.stop();
070        }
071    
072        protected void doStart() throws Exception {
073        }
074    }