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.component.queue;
019    
020    import org.apache.camel.AlreadyStoppedException;
021    import org.apache.camel.Consumer;
022    import org.apache.camel.Exchange;
023    import org.apache.camel.Processor;
024    import org.apache.camel.impl.ServiceSupport;
025    import org.apache.commons.logging.Log;
026    import org.apache.commons.logging.LogFactory;
027    
028    import java.util.concurrent.TimeUnit;
029    
030    /**
031     * @version $Revision: 553312 $
032     */
033    public class QueueEndpointConsumer<E extends Exchange> extends ServiceSupport implements Consumer<E>, Runnable {
034        private static final Log log = LogFactory.getLog(QueueEndpointConsumer.class);
035        private static int counter;
036    
037        private QueueEndpoint<E> endpoint;
038        private Processor processor;
039        private Thread thread;
040    
041        public QueueEndpointConsumer(QueueEndpoint<E> endpoint, Processor processor) {
042            this.endpoint = endpoint;
043            this.processor = processor;
044        }
045    
046        @Override
047        public String toString() {
048            return "QueueEndpointConsumer: " + endpoint.getEndpointUri();
049        }
050    
051        public void run() {
052            while (!isStopping()) {
053                E exchange;
054                try {
055                    exchange = endpoint.getQueue().poll(1000, TimeUnit.MILLISECONDS);
056                }
057                catch (InterruptedException e) {
058                    break;
059                }
060                if (exchange != null && !isStopping()) {
061                    try {
062                        processor.process(exchange);
063                    }
064                    catch (AlreadyStoppedException e) {
065                        log.debug("Ignoring failed message due to shutdown: " + e, e);
066                        break;
067                    }
068                    catch (Throwable e) {
069                        log.error(e);
070                    }
071                }
072            }
073        }
074    
075        protected void doStart() throws Exception {
076            thread = new Thread(this, endpoint.getEndpointUri() + " thread:" + nextCounter());
077            thread.setDaemon(true);
078            thread.start();
079        }
080    
081        protected void doStop() throws Exception {
082            thread.join();
083        }
084    
085        protected static synchronized int nextCounter() {
086            return ++counter;
087        }
088    }