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: 553477 $
032     */
033    public class QueueConsumer<E extends Exchange> extends ServiceSupport implements Consumer<E>, Runnable {
034        private static final Log log = LogFactory.getLog(QueueConsumer.class);
035    
036        private QueueEndpoint<E> endpoint;
037        private Processor processor;
038        private Thread thread;
039    
040        public QueueConsumer(QueueEndpoint<E> endpoint, Processor processor) {
041            this.endpoint = endpoint;
042            this.processor = processor;
043        }
044    
045        @Override
046        public String toString() {
047            return "QueueConsumer: " + endpoint.getEndpointUri();
048        }
049    
050        public void run() {
051            while (!isStopping()) {
052                E exchange;
053                try {
054                    exchange = endpoint.getQueue().poll(1000, TimeUnit.MILLISECONDS);
055                }
056                catch (InterruptedException e) {
057                    break;
058                }
059                if (exchange != null && !isStopping()) {
060                    try {
061                        processor.process(exchange);
062                    }
063                    catch (AlreadyStoppedException e) {
064                        log.debug("Ignoring failed message due to shutdown: " + e, e);
065                        break;
066                    }
067                    catch (Throwable e) {
068                        log.error(e);
069                    }
070                }
071            }
072        }
073    
074        protected void doStart() throws Exception {
075            thread = new Thread(this, getThreadName(endpoint.getEndpointUri()));
076            thread.setDaemon(true);
077            thread.start();
078        }
079    
080        protected void doStop() throws Exception {
081            thread.join();
082        }
083    
084    }