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.processor;
018    
019    import org.apache.camel.Exchange;
020    import org.apache.camel.Processor;
021    import org.apache.camel.impl.DefaultUnitOfWork;
022    import static org.apache.camel.util.ObjectHelper.wrapRuntimeCamelException;
023    
024    /** 
025     * Handles calling the UnitOfWork.done() method when processing of an exchange
026     * is complete.
027     */
028    public final class UnitOfWorkProcessor extends DelegateProcessor {
029    
030        public UnitOfWorkProcessor(Processor processor) {
031            super(processor);
032        }
033        
034        @Override
035        public String toString() {
036            return "UnitOfWork(" + processor + ")";
037        }
038    
039        @Override
040        protected void processNext(Exchange exchange) throws Exception {
041            if (exchange.getUnitOfWork() == null) {
042                // If there is no existing UoW, then we should start one and
043                // terminate it once processing is completed for the exchange.
044                final DefaultUnitOfWork uow = new DefaultUnitOfWork(exchange);
045                exchange.setUnitOfWork(uow);
046                try {
047                    uow.start();
048                } catch (Exception e) {
049                    throw wrapRuntimeCamelException(e);
050                }
051    
052                // process the exchange
053                try {
054                    processor.process(exchange);
055                } catch (Exception e) {
056                    exchange.setException(e);
057                }
058    
059                // unit of work is done
060                exchange.getUnitOfWork().done(exchange);
061                try {
062                    uow.stop();
063                } catch (Exception e) {
064                    throw wrapRuntimeCamelException(e);
065                }
066                exchange.setUnitOfWork(null);
067            } else {
068                // There was an existing UoW, so we should just pass through..
069                // so that the guy the initiated the UoW can terminate it.
070                processor.process(exchange);
071            }
072        }
073    
074    }