00001 /* 00002 * ReducerAggregator.hpp 00003 * 00004 * Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved. 00005 * 00006 * Oracle is a registered trademarks of Oracle Corporation and/or its 00007 * affiliates. 00008 * 00009 * This software is the confidential and proprietary information of Oracle 00010 * Corporation. You shall not disclose such confidential and proprietary 00011 * information and shall use it only in accordance with the terms of the 00012 * license agreement you entered into with Oracle. 00013 * 00014 * This notice may not be removed or altered. 00015 */ 00016 #ifndef COH_REDUCER_AGGREGATOR_HPP 00017 #define COH_REDUCER_AGGREGATOR_HPP 00018 00019 #include "coherence/lang.ns" 00020 00021 #include "coherence/util/aggregator/AbstractAggregator.hpp" 00022 #include "coherence/util/ValueExtractor.hpp" 00023 00024 COH_OPEN_NAMESPACE3(coherence,util,aggregator) 00025 00026 00027 /** 00028 * The ReducerAggregator is used to implement functionality similar to 00029 * <tt>CacheMap::getAll(Collection)</tt> API. Instead of returning the complete 00030 * set of values, it will return a portion of value attributes based on the 00031 * provided <tt>ValueExtractor</tt>. 00032 * 00033 * This aggregator could be used in combination with 00034 * <tt>coherence.util.extractor.MultiExtractor</tt> allowing one to collect 00035 * tuples that are a subset of the attributes of each object stored in the cache. 00036 * 00037 * @author par 04.25.13 00038 */ 00039 class COH_EXPORT ReducerAggregator 00040 : public class_spec<ReducerAggregator, 00041 extends<AbstractAggregator> > 00042 { 00043 friend class factory<ReducerAggregator>; 00044 00045 00046 // ----- constructors --------------------------------------------------- 00047 00048 protected: 00049 /** 00050 * Default constructor. 00051 */ 00052 ReducerAggregator(); 00053 00054 /** 00055 * Construct a ReducerAggregator based on the specified extractor. 00056 * 00057 * @param vExtractor the extractor that is used to extract the portion 00058 * of the cached value 00059 */ 00060 ReducerAggregator(ValueExtractor::View vExtractor); 00061 00062 /** 00063 * Construct a ReducerAggregator based on the specified method name. 00064 * 00065 * @param vsMethod the name of the method that is used to extract the 00066 * portion of the cached value 00067 */ 00068 ReducerAggregator(String::View vsMethod); 00069 00070 private: 00071 /** 00072 * Blocked copy constructor. 00073 */ 00074 ReducerAggregator(const ReducerAggregator&); 00075 00076 00077 // ----- AbstractAggregator methods ------------------------------------- 00078 00079 protected: 00080 /** 00081 * {@inheritDoc} 00082 */ 00083 virtual void init(bool fFinal); 00084 00085 /** 00086 * {@inheritDoc} 00087 */ 00088 virtual void process(Object::View vO, bool fFinal); 00089 00090 /** 00091 * {@inheritDoc} 00092 */ 00093 virtual Object::Holder finalizeResult(bool fFinal); 00094 00095 00096 // ----- internal helpers ----------------------------------------------- 00097 00098 protected: 00099 /** 00100 * Return a map that can be used to store reduced values, creating it if 00101 * one has not already been created. 00102 * 00103 * @return a set that can be used to store distinct values 00104 */ 00105 virtual Map::Handle ensureMap(); 00106 00107 00108 // ----- data members --------------------------------------------------- 00109 00110 private: 00111 /** 00112 * The resulting map of reduced values. 00113 */ 00114 MemberHandle<Map> m_hMap; 00115 }; 00116 00117 COH_CLOSE_NAMESPACE3 00118 00119 #endif //COH_REDUCER_AGGREGATOR_HPP