00001 /* 00002 * QueryMapComparator.hpp 00003 * 00004 * Copyright (c) 2000, 2013, 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_QUERY_MAP_COMPARATOR_HPP 00017 #define COH_QUERY_MAP_COMPARATOR_HPP 00018 00019 #include "coherence/lang.ns" 00020 00021 #include "coherence/util/Comparator.hpp" 00022 #include "coherence/util/QueryMap.hpp" 00023 00024 COH_OPEN_NAMESPACE3(coherence,util,comparator) 00025 00026 00027 /** 00028 * This interface is used by Comparator implementations that can use value 00029 * extraction optimization exposed by the 00030 * QueryMap::Entry interface. 00031 * 00032 * @author djl 2008.03.03 00033 */ 00034 class COH_EXPORT QueryMapComparator 00035 : public interface_spec<QueryMapComparator, 00036 implements<Comparator> > 00037 { 00038 // ----- QueryMap interface --------------------------------------------- 00039 00040 public: 00041 /** 00042 * Compare two entries based on the rules specified by Comparator. 00043 * 00044 * If possible, use the coherence::util::QueryMap.Entry::extract() 00045 * method to optimize the value extraction process. 00046 * 00047 * This method is expected to be implemented by Comparator wrappers, 00048 * such as ChainedComparator and InverseComparator, which simply pass 00049 * on this invocation to the wrapped Comparator objects if they too 00050 * implement this interface, or to invoke their default compare method 00051 * passing the actual objects (not the extracted values) obtained from 00052 * the extractor using the passed entries. 00053 * 00054 * This interface is also expected to be implemented by ValueExtractor 00055 * implementations that implement the Comparator interface. It is expected 00056 * that in most cases, the Comparator wrappers will eventually terminate 00057 * at (i.e. delegate to) ValueExtractors that also implement this 00058 * interface. 00059 * 00060 * @param vEntry1 the first entry to compare values from; read-only 00061 * @param vEntry2 the second entry to compare values from; read-only 00062 * 00063 * @return a negative integer, zero, or a positive integer as the first 00064 * entry denotes a value that is is less than, equal to, or 00065 * greater than the value denoted by the second entry 00066 * 00067 * @throws ClassCastException if the arguments' types prevent them from 00068 * being compared by this Comparator. 00069 * @throws IllegalArgumentException if the extractor cannot handle 00070 * the passed objects for any other reason; an implementor should 00071 * include a descriptive message 00072 */ 00073 virtual int32_t compareEntries(QueryMap::Entry::View vEntry1, 00074 QueryMap::Entry::View vEntry2) const = 0; 00075 }; 00076 00077 COH_CLOSE_NAMESPACE3 00078 00079 #endif // COH_QUERY_MAP_COMPARATOR_HPP