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.impl;
018    
019    import org.apache.camel.AsyncProcessor;
020    import org.apache.camel.Consumer;
021    import org.apache.camel.Endpoint;
022    import org.apache.camel.Processor;
023    import org.apache.camel.impl.converter.AsyncProcessorTypeConverter;
024    import org.apache.camel.spi.ExceptionHandler;
025    import org.apache.camel.util.ServiceHelper;
026    
027    /**
028     * A default consumer useful for implementation inheritance.
029     *
030     * @version $Revision: 751221 $
031     */
032    public class DefaultConsumer extends ServiceSupport implements Consumer {
033        private final Endpoint endpoint;
034        private final Processor processor;
035        private AsyncProcessor asyncProcessor;
036        private ExceptionHandler exceptionHandler;
037    
038        public DefaultConsumer(Endpoint endpoint, Processor processor) {
039            this.endpoint = endpoint;
040            this.processor = processor;
041        }
042    
043        @Override
044        public String toString() {
045            return "Consumer on " + endpoint;
046        }
047    
048        public Endpoint getEndpoint() {
049            return endpoint;
050        }
051    
052        public Processor getProcessor() {
053            return processor;
054        }
055    
056        /**
057         * Provides an {@link AsyncProcessor} interface to the configured
058         * processor on the consumer.  If the processor does not implement
059         * the interface, it will be adapted so that it does.  
060         */
061        public AsyncProcessor getAsyncProcessor() {
062            if (asyncProcessor == null) {
063                asyncProcessor = AsyncProcessorTypeConverter.convert(processor);
064            }
065            return asyncProcessor;
066        }
067    
068        public ExceptionHandler getExceptionHandler() {
069            if (exceptionHandler == null) {
070                exceptionHandler = new LoggingExceptionHandler(getClass());
071            }
072            return exceptionHandler;
073        }
074    
075        public void setExceptionHandler(ExceptionHandler exceptionHandler) {
076            this.exceptionHandler = exceptionHandler;
077        }
078    
079        protected void doStop() throws Exception {
080            ServiceHelper.stopServices(processor);
081        }
082    
083        protected void doStart() throws Exception {
084            ServiceHelper.startServices(processor);
085        }
086    
087        /**
088         * Handles the given exception using the {@link #getExceptionHandler()}
089         * 
090         * @param t the exception to handle
091         */
092        protected void handleException(Throwable t) {
093            Throwable newt = (t == null) ? new Throwable("Handling [null] exception") : t;
094            getExceptionHandler().handleException(newt);
095        }
096    }