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 java.util.List;
020
021import org.apache.camel.Exchange;
022import org.apache.camel.impl.DefaultExchange;
023
024/**
025 * Aggregate all exchanges into a single combined Exchange holding all the aggregated exchanges
026 * in a {@link List} of {@link Exchange} as the message body.
027 * <p/>
028 * <b>Important:</b> This strategy is not to be used with the <a href="http://camel.apache.org/content-enricher.html">Content Enricher</a> EIP
029 * which is enrich or pollEnrich.
030 *
031 * @version 
032 */
033public class GroupedExchangeAggregationStrategy extends AbstractListAggregationStrategy<Exchange> {
034
035    @Override
036    public void onCompletion(Exchange exchange) {
037        if (isStoreAsBodyOnCompletion()) {
038            // lets be backwards compatible
039            // TODO: Remove this method in Camel 3.0
040            List<?> list = (List<?>) exchange.getProperty(Exchange.GROUPED_EXCHANGE);
041            if (list != null) {
042                exchange.getIn().setBody(list);
043            }
044        }
045    }
046
047    @Override
048    public Exchange aggregate(Exchange oldExchange, Exchange newExchange) {
049        if (oldExchange == null) {
050            // for the first time we must create a new empty exchange as the holder, as the outgoing exchange
051            // must not be one of the grouped exchanges, as that causes a endless circular reference
052            oldExchange = new DefaultExchange(newExchange);
053        }
054        return super.aggregate(oldExchange, newExchange);
055    }
056
057    @Override
058    public Exchange getValue(Exchange exchange) {
059        return exchange;
060    }
061
062}
063