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.Iterator; 021 import java.util.LinkedHashMap; 022 import java.util.Map; 023 024 import org.apache.camel.Exchange; 025 import org.apache.camel.Expression; 026 import org.apache.commons.logging.Log; 027 import org.apache.commons.logging.LogFactory; 028 029 /** 030 * A {@link java.util.Collection} which aggregates exchanges together using a correlation 031 * expression so that there is only a single message exchange sent for a single 032 * correlation key. 033 * 034 * @version $Revision: 752464 $ 035 */ 036 public class DefaultAggregationCollection extends AbstractCollection<Exchange> implements AggregationCollection { 037 038 private static final transient Log LOG = LogFactory.getLog(DefaultAggregationCollection.class); 039 private Expression correlationExpression; 040 private AggregationStrategy aggregationStrategy; 041 private final Map<Object, Exchange> aggregated = new LinkedHashMap<Object, Exchange>(); 042 043 public DefaultAggregationCollection() { 044 } 045 046 public DefaultAggregationCollection(Expression correlationExpression, AggregationStrategy aggregationStrategy) { 047 this.correlationExpression = correlationExpression; 048 this.aggregationStrategy = aggregationStrategy; 049 } 050 051 protected Map<Object, Exchange> getAggregated() { 052 return aggregated; 053 } 054 055 @Override 056 public boolean add(Exchange exchange) { 057 Object correlationKey = correlationExpression.evaluate(exchange); 058 if (LOG.isDebugEnabled()) { 059 LOG.debug("Evaluated expression: " + correlationExpression + " as CorrelationKey: " + correlationKey); 060 } 061 Exchange oldExchange = aggregated.get(correlationKey); 062 Exchange newExchange = exchange; 063 064 if (oldExchange != null) { 065 Integer count = oldExchange.getProperty(Exchange.AGGREGATED_SIZE, Integer.class); 066 if (count == null) { 067 count = 1; 068 } 069 count++; 070 newExchange = aggregationStrategy.aggregate(oldExchange, newExchange); 071 newExchange.setProperty(Exchange.AGGREGATED_SIZE, count); 072 } 073 074 // the strategy may just update the old exchange and return it 075 if (!newExchange.equals(oldExchange)) { 076 if (LOG.isDebugEnabled()) { 077 LOG.debug("Put exchange:" + newExchange + " with coorelation key:" + correlationKey); 078 } 079 if (oldExchange == null) { 080 newExchange.setProperty(Exchange.AGGREGATED_SIZE, Integer.valueOf(1)); 081 } 082 aggregated.put(correlationKey, newExchange); 083 } 084 085 onAggregation(correlationKey, newExchange); 086 087 return true; 088 } 089 090 public Iterator<Exchange> iterator() { 091 return aggregated.values().iterator(); 092 } 093 094 public int size() { 095 return aggregated.size(); 096 } 097 098 @Override 099 public void clear() { 100 aggregated.clear(); 101 } 102 103 public void onAggregation(Object correlationKey, Exchange newExchange) { 104 } 105 106 public Expression getCorrelationExpression() { 107 return correlationExpression; 108 } 109 110 public void setCorrelationExpression(Expression correlationExpression) { 111 this.correlationExpression = correlationExpression; 112 } 113 114 public AggregationStrategy getAggregationStrategy() { 115 return aggregationStrategy; 116 } 117 118 public void setAggregationStrategy(AggregationStrategy aggregationStrategy) { 119 this.aggregationStrategy = aggregationStrategy; 120 } 121 }