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 */
017package org.apache.camel.processor.aggregate;
018
019import org.apache.camel.Exchange;
020import org.apache.camel.support.ServiceSupport;
021import org.apache.camel.util.ServiceHelper;
022
023import static org.apache.camel.util.ExchangeHelper.hasExceptionBeenHandledByErrorHandler;
024
025/**
026 * An {@link AggregationStrategy} which are used when the option <tt>shareUnitOfWork</tt> is enabled
027 * on EIPs such as multicast, splitter or recipientList.
028 * <p/>
029 * This strategy wraps the actual in use strategy to provide the logic needed for making shareUnitOfWork work.
030 * <p/>
031 * This strategy is <b>not</b> intended for end users to use.
032 */
033public final class ShareUnitOfWorkAggregationStrategy extends ServiceSupport implements AggregationStrategy, DelegateAggregationStrategy {
034
035    private final AggregationStrategy strategy;
036
037    public ShareUnitOfWorkAggregationStrategy(AggregationStrategy strategy) {
038        this.strategy = strategy;
039    }
040
041    public AggregationStrategy getDelegate() {
042        return strategy;
043    }
044
045    public Exchange aggregate(Exchange oldExchange, Exchange newExchange) {
046        // aggregate using the actual strategy first
047        Exchange answer = strategy.aggregate(oldExchange, newExchange);
048        // ensure any errors is propagated from the new exchange to the answer
049        propagateFailure(answer, newExchange);
050
051        return answer;
052    }
053
054    protected void propagateFailure(Exchange answer, Exchange newExchange) {
055        // if new exchange failed then propagate all the error related properties to the answer
056        boolean exceptionHandled = hasExceptionBeenHandledByErrorHandler(newExchange);
057        if (newExchange.isFailed() || newExchange.isRollbackOnly() || exceptionHandled) {
058            if (newExchange.getException() != null) {
059                answer.setException(newExchange.getException());
060            }
061            if (newExchange.getProperty(Exchange.EXCEPTION_CAUGHT) != null) {
062                answer.setProperty(Exchange.EXCEPTION_CAUGHT, newExchange.getProperty(Exchange.EXCEPTION_CAUGHT));
063            }
064            if (newExchange.getProperty(Exchange.FAILURE_ENDPOINT) != null) {
065                answer.setProperty(Exchange.FAILURE_ENDPOINT, newExchange.getProperty(Exchange.FAILURE_ENDPOINT));
066            }
067            if (newExchange.getProperty(Exchange.FAILURE_ROUTE_ID) != null) {
068                answer.setProperty(Exchange.FAILURE_ROUTE_ID, newExchange.getProperty(Exchange.FAILURE_ROUTE_ID));
069            }
070            if (newExchange.getProperty(Exchange.ERRORHANDLER_HANDLED) != null) {
071                answer.setProperty(Exchange.ERRORHANDLER_HANDLED, newExchange.getProperty(Exchange.ERRORHANDLER_HANDLED));
072            }
073            if (newExchange.getProperty(Exchange.FAILURE_HANDLED) != null) {
074                answer.setProperty(Exchange.FAILURE_HANDLED, newExchange.getProperty(Exchange.FAILURE_HANDLED));
075            }
076        }
077    }
078
079    @Override
080    public String toString() {
081        return "ShareUnitOfWorkAggregationStrategy";
082    }
083
084    @Override
085    protected void doStart() throws Exception {
086        ServiceHelper.startService(strategy);
087    }
088
089    @Override
090    protected void doStop() throws Exception {
091        ServiceHelper.stopAndShutdownServices(strategy);
092    }
093}