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.aggregate;
018    
019    import org.apache.camel.Exchange;
020    
021    /**
022     * A strategy for aggregating two exchanges together into a single exchange.
023     * Possible implementations include performing some kind of combining or delta
024     * processing, such as adding line items together into an invoice or just using
025     * the newest exchange and removing old exchanges such as for state tracking or
026     * market data prices; where old values are of little use.
027     * 
028     * @version $Revision: 303 $
029     */
030    public interface AggregationStrategy {
031    
032        /**
033         * Aggregates an old and new exchange together to create a single combined
034         * exchange
035         *
036         * @param oldExchange the oldest exchange
037         * @param newExchange the newest exchange
038         * @return a combined composite of the two exchanges
039         */
040        Exchange aggregate(Exchange oldExchange, Exchange newExchange);
041    }