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 java.util.AbstractCollection; 020 import java.util.Collection; 021 import java.util.Iterator; 022 import java.util.LinkedHashMap; 023 import java.util.Map; 024 025 import org.apache.camel.Exchange; 026 import org.apache.camel.Expression; 027 import org.apache.commons.logging.Log; 028 import org.apache.commons.logging.LogFactory; 029 030 /** 031 * A {@link Collection} which aggregates exchanges together using a correlation 032 * expression so that there is only a single message exchange sent for a single 033 * correlation key. 034 * 035 * @version $Revision: 67174 $ 036 */ 037 public class DefaultAggregationCollection extends AbstractCollection<Exchange> implements AggregationCollection { 038 039 private static final transient Log LOG = LogFactory.getLog(DefaultAggregationCollection.class); 040 private Expression<Exchange> correlationExpression; 041 private AggregationStrategy aggregationStrategy; 042 private Map<Object, Exchange> map = new LinkedHashMap<Object, Exchange>(); 043 044 public DefaultAggregationCollection() { 045 } 046 047 public DefaultAggregationCollection(Expression<Exchange> correlationExpression, AggregationStrategy aggregationStrategy) { 048 this.correlationExpression = correlationExpression; 049 this.aggregationStrategy = aggregationStrategy; 050 } 051 052 protected Map<Object, Exchange> getMap() { 053 return map; 054 } 055 056 @Override 057 public boolean add(Exchange exchange) { 058 Object correlationKey = correlationExpression.evaluate(exchange); 059 if (LOG.isDebugEnabled()) { 060 LOG.debug("evaluated expression: " + correlationExpression + " as CorrelationKey: " + correlationKey); 061 } 062 Exchange oldExchange = map.get(correlationKey); 063 Exchange newExchange = exchange; 064 065 if (oldExchange != null) { 066 Integer count = oldExchange.getProperty(Exchange.AGGREGATED_COUNT, Integer.class); 067 if (count == null) { 068 count = 1; 069 } 070 count++; 071 newExchange = aggregationStrategy.aggregate(oldExchange, newExchange); 072 newExchange.setProperty(Exchange.AGGREGATED_COUNT, count); 073 } 074 075 // the strategy may just update the old exchange and return it 076 if (newExchange != oldExchange) { 077 if (LOG.isDebugEnabled()) { 078 LOG.debug("put exchange:" + newExchange + " for key:" + correlationKey); 079 } 080 if (oldExchange == null) { 081 newExchange.setProperty(Exchange.AGGREGATED_COUNT, Integer.valueOf(1)); 082 } 083 map.put(correlationKey, newExchange); 084 } 085 086 onAggregation(correlationKey, newExchange); 087 088 return true; 089 } 090 091 public Iterator<Exchange> iterator() { 092 return map.values().iterator(); 093 } 094 095 public int size() { 096 return map.size(); 097 } 098 099 @Override 100 public void clear() { 101 map.clear(); 102 } 103 104 public void onAggregation(Object correlationKey, Exchange newExchange) { 105 } 106 107 public Expression<Exchange> getCorrelationExpression() { 108 return correlationExpression; 109 } 110 111 public void setCorrelationExpression(Expression<Exchange> correlationExpression) { 112 this.correlationExpression = correlationExpression; 113 } 114 115 public AggregationStrategy getAggregationStrategy() { 116 return aggregationStrategy; 117 } 118 119 public void setAggregationStrategy(AggregationStrategy aggregationStrategy) { 120 this.aggregationStrategy = aggregationStrategy; 121 } 122 }