00001 /* 00002 * Copyright (c) 2000, 2020, Oracle and/or its affiliates. 00003 * 00004 * Licensed under the Universal Permissive License v 1.0 as shown at 00005 * http://oss.oracle.com/licenses/upl. 00006 */ 00007 #ifndef COH_QUERY_MAP_COMPARATOR_HPP 00008 #define COH_QUERY_MAP_COMPARATOR_HPP 00009 00010 #include "coherence/lang.ns" 00011 00012 #include "coherence/util/Comparator.hpp" 00013 #include "coherence/util/QueryMap.hpp" 00014 00015 COH_OPEN_NAMESPACE3(coherence,util,comparator) 00016 00017 00018 /** 00019 * This interface is used by Comparator implementations that can use value 00020 * extraction optimization exposed by the 00021 * QueryMap::Entry interface. 00022 * 00023 * @author djl 2008.03.03 00024 */ 00025 class COH_EXPORT QueryMapComparator 00026 : public interface_spec<QueryMapComparator, 00027 implements<Comparator> > 00028 { 00029 // ----- QueryMap interface --------------------------------------------- 00030 00031 public: 00032 /** 00033 * Compare two entries based on the rules specified by Comparator. 00034 * 00035 * If possible, use the coherence::util::QueryMap.Entry::extract() 00036 * method to optimize the value extraction process. 00037 * 00038 * This method is expected to be implemented by Comparator wrappers, 00039 * such as ChainedComparator and InverseComparator, which simply pass 00040 * on this invocation to the wrapped Comparator objects if they too 00041 * implement this interface, or to invoke their default compare method 00042 * passing the actual objects (not the extracted values) obtained from 00043 * the extractor using the passed entries. 00044 * 00045 * This interface is also expected to be implemented by ValueExtractor 00046 * implementations that implement the Comparator interface. It is expected 00047 * that in most cases, the Comparator wrappers will eventually terminate 00048 * at (i.e. delegate to) ValueExtractors that also implement this 00049 * interface. 00050 * 00051 * @param vEntry1 the first entry to compare values from; read-only 00052 * @param vEntry2 the second entry to compare values from; read-only 00053 * 00054 * @return a negative integer, zero, or a positive integer as the first 00055 * entry denotes a value that is is less than, equal to, or 00056 * greater than the value denoted by the second entry 00057 * 00058 * @throws ClassCastException if the arguments' types prevent them from 00059 * being compared by this Comparator. 00060 * @throws IllegalArgumentException if the extractor cannot handle 00061 * the passed objects for any other reason; an implementor should 00062 * include a descriptive message 00063 */ 00064 virtual int32_t compareEntries(QueryMap::Entry::View vEntry1, 00065 QueryMap::Entry::View vEntry2) const = 0; 00066 }; 00067 00068 COH_CLOSE_NAMESPACE3 00069 00070 #endif // COH_QUERY_MAP_COMPARATOR_HPP