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.Endpoint;
021    import org.apache.camel.Exchange;
022    import org.apache.camel.Expression;
023    import org.apache.camel.Processor;
024    import org.apache.camel.converter.ObjectConverter;
025    import org.apache.camel.impl.ServiceSupport;
026    import org.apache.camel.util.ExchangeHelper;
027    import static org.apache.camel.util.ObjectHelper.notNull;
028    import org.apache.camel.util.ProducerCache;
029    
030    import java.util.Iterator;
031    
032    /**
033     * Implements a dynamic <a href="http://activemq.apache.org/camel/recipient-list.html">Recipient List</a> pattern
034     * where the list of actual endpoints to send a message exchange to are dependent on some dynamic expression.
035     *
036     * @version $Revision: 534145 $
037     */
038    public class RecipientList extends ServiceSupport implements Processor {
039        private final Expression<Exchange> expression;
040        private ProducerCache<Exchange> producerCache = new ProducerCache<Exchange>();
041    
042        public RecipientList(Expression<Exchange> expression) {
043            notNull(expression, "expression");
044            this.expression = expression;
045        }
046    
047        @Override
048        public String toString() {
049            return "RecipientList[" + expression + "]";
050        }
051    
052        public void process(Exchange exchange) throws Exception {
053            Object receipientList = expression.evaluate(exchange);
054            Iterator iter = ObjectConverter.iterator(receipientList);
055            while (iter.hasNext()) {
056                Object recipient = iter.next();
057                Endpoint<Exchange> endpoint = resolveEndpoint(exchange, recipient);
058                producerCache.getProducer(endpoint).process(exchange);
059            }
060        }
061    
062        protected Endpoint<Exchange> resolveEndpoint(Exchange exchange, Object recipient) {
063            return ExchangeHelper.resolveEndpoint(exchange, recipient);
064        }
065    
066        protected void doStop() throws Exception {
067            producerCache.stop();
068        }
069    
070        protected void doStart() throws Exception {
071        }
072    }