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 * An {@link AggregationStrategy} which just uses the latest exchange which is useful 023 * for status messages where old status messages have no real value. Another example is things 024 * like market data prices, where old stock prices are not that relevant, only the current price is. 025 * 026 * @version $Revision: 885364 $ 027 */ 028 public class UseLatestAggregationStrategy implements AggregationStrategy { 029 030 public Exchange aggregate(Exchange oldExchange, Exchange newExchange) { 031 if (newExchange == null) { 032 return oldExchange; 033 } 034 newExchange.setException(checkException(oldExchange, newExchange)); 035 return newExchange; 036 } 037 038 protected Exception checkException(Exchange oldExchange, Exchange newExchange) { 039 if (oldExchange == null) { 040 return newExchange.getException(); 041 } else { 042 return (newExchange != null && newExchange.getException() != null) 043 ? newExchange.getException() 044 : oldExchange.getException(); 045 } 046 } 047 048 @Override 049 public String toString() { 050 return "UseLatestAggregationStrategy"; 051 } 052 }