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.Exchange;
023    import org.apache.camel.Processor;
024    import org.apache.camel.impl.converter.AsyncProcessorTypeConverter;
025    import org.apache.camel.spi.ExceptionHandler;
026    import org.apache.camel.util.ServiceHelper;
027    
028    /**
029     * A default consumer useful for implementation inheritance.
030     *
031     * @version $Revision: 46133 $
032     */
033    public class DefaultConsumer<E extends Exchange> extends ServiceSupport implements Consumer<E> {
034        private Endpoint<E> endpoint;
035        private Processor processor;
036        private AsyncProcessor asyncProcessor;
037        private ExceptionHandler exceptionHandler;
038    
039        public DefaultConsumer(Endpoint<E> endpoint, Processor processor) {
040            this.endpoint = endpoint;
041            this.processor = processor;
042        }
043    
044        @Override
045        public String toString() {
046            return "Consumer on " + endpoint;
047        }
048    
049        public Endpoint<E> getEndpoint() {
050            return endpoint;
051        }
052    
053        public Processor getProcessor() {
054            return processor;
055        }
056    
057        /**
058         * Provides an {@link AsyncProcessor} interface to the configured
059         * processor on the consumer.  If the processor does not implement
060         * the interface, it will be adapted so that it does.  
061         */
062        public AsyncProcessor getAsyncProcessor() {
063            if (asyncProcessor == null) {
064                asyncProcessor = AsyncProcessorTypeConverter.convert(processor);
065            }
066            return asyncProcessor;
067        }
068    
069        public ExceptionHandler getExceptionHandler() {
070            if (exceptionHandler == null) {
071                exceptionHandler = new LoggingExceptionHandler(getClass());
072            }
073            return exceptionHandler;
074        }
075    
076        public void setExceptionHandler(ExceptionHandler exceptionHandler) {
077            this.exceptionHandler = exceptionHandler;
078        }
079    
080        protected void doStop() throws Exception {
081            ServiceHelper.stopServices(processor);
082        }
083    
084        protected void doStart() throws Exception {
085            ServiceHelper.startServices(processor);
086        }
087    
088        /**
089         * Handles the given exception using the {@link #getExceptionHandler()}
090         * 
091         * @param t the exception to handle
092         */
093        protected void handleException(Throwable t) {
094            Throwable newt = (t == null) ? new Throwable("Handling [null] exception") : t;
095            getExceptionHandler().handleException(newt);
096        }
097    }