/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.camel.processor.aggregate;

import java.util.ArrayList;
import java.util.List;

import org.apache.camel.Exchange;
import org.apache.camel.impl.DefaultExchange;

/**
 * Aggregate all exchanges into a single combined Exchange holding all the aggregated exchanges
 * in a {@link java.util.List} as a exchange property with the key
 * {@link org.apache.camel.Exchange#GROUPED_EXCHANGE}.
 *
 * @version $Revision$
 */
public class GroupedExchangeAggregationStrategy implements AggregationStrategy {

    @SuppressWarnings("unchecked")
    public Exchange aggregate(Exchange oldExchange, Exchange newExchange) {
        List<Exchange> list;
        Exchange answer = oldExchange;

        if (oldExchange == null) {
            answer = new DefaultExchange(newExchange);
            list = new ArrayList<Exchange>();
            answer.setProperty(Exchange.GROUPED_EXCHANGE, list);
        } else {
            list = oldExchange.getProperty(Exchange.GROUPED_EXCHANGE, List.class);
        }

        if (newExchange != null) {
            list.add(newExchange);
        }
        return answer;
    }

}

