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_EXTRACTOR_EVENT_TRANSFORMER_HPP 00008 #define COH_EXTRACTOR_EVENT_TRANSFORMER_HPP 00009 00010 #include "coherence/lang.ns" 00011 00012 #include "coherence/io/pof/PofReader.hpp" 00013 #include "coherence/io/pof/PofWriter.hpp" 00014 #include "coherence/io/pof/PortableObject.hpp" 00015 #include "coherence/util/MapEvent.hpp" 00016 #include "coherence/util/MapEventTransformer.hpp" 00017 #include "coherence/util/ValueExtractor.hpp" 00018 00019 COH_OPEN_NAMESPACE3(coherence,util,transformer) 00020 00021 using coherence::io::pof::PofReader; 00022 using coherence::io::pof::PofWriter; 00023 using coherence::io::pof::PortableObject; 00024 00025 00026 /** 00027 * ExtractorEventTransformer is a special purpose MapEventTransformer 00028 * implementation that transforms emitted events, extracting one or more 00029 * properties from either the OldValue or the NewValue. This transformation 00030 * will generally result in the change of the values' data type. 00031 * <p/> 00032 * Example: the following code will register a listener to receive events only 00033 * if the value of the AccountBalance property changes. The transformed 00034 * event's NewValue will be a List containing the LastTransactionTime and 00035 * AccountBalance properties. The OldValue will always be null. 00036 * <pre> 00037 * Filter::View vFilter = 00038 * ValueChangeEventFilter::create("getAccountBalance"); 00039 * ValueExtractor::View vExtractor = 00040 * MultiExtractor::create(MultiExtractor::createExtractors( 00041 * "getLastTransactionTime,getAccountBalance")); 00042 * MapEventTransformer::Handle hTransformer = 00043 * ExtractorEventTransformer::create(NULL, vExtractor); 00044 * 00045 * cache->addMapListener(listener, 00046 * MapEventTransformerFilter::create(vFilter, hTransformer), false); 00047 * </pre> 00048 * 00049 * @author djl 2008.06.17 00050 */ 00051 class COH_EXPORT ExtractorEventTransformer 00052 : public class_spec<ExtractorEventTransformer, 00053 extends<Object>, 00054 implements<PortableObject, MapEventTransformer> > 00055 { 00056 friend class factory<ExtractorEventTransformer>; 00057 00058 // ----- constructors --------------------------------------------------- 00059 00060 protected: 00061 /** 00062 * Default constructor (necessary for the PortableObject interface). 00063 */ 00064 ExtractorEventTransformer(); 00065 00066 /** 00067 * Construct a ExtractorEventTransformer that transforms MapEvent 00068 * values based on the specified extractor. 00069 * 00070 * Note: The specified extractor will be applied to both old and new 00071 * values. 00072 * 00073 * @param vExtractor ValueExtractor to extract MapEvent values 00074 */ 00075 ExtractorEventTransformer(ValueExtractor::View vExtractor); 00076 00077 /** 00078 * Construct a ExtractorEventTransformer that transforms MapEvent 00079 * values based on the specified extractors. Passing null indicates 00080 * that the corresponding values should be skipped completely. 00081 * 00082 * @param vExtractorOld extractor to extract the OldValue property(s) 00083 * @param vExtractorNew extractor to extract the NewValue property(s) 00084 */ 00085 ExtractorEventTransformer(ValueExtractor::View vExtractorOld, 00086 ValueExtractor::View vExtractorNew); 00087 00088 00089 // ----- MapEventTransformer interface ---------------------------------- 00090 00091 public: 00092 /** 00093 * {@inheritDoc} 00094 */ 00095 virtual MapEvent::Handle transform(MapEvent::Handle hEvent) const; 00096 00097 00098 // ----- PortableObject interface --------------------------------------- 00099 00100 public: 00101 /** 00102 * {@inheritDoc} 00103 */ 00104 virtual void readExternal(PofReader::Handle hIn); 00105 00106 /** 00107 * {@inheritDoc} 00108 */ 00109 virtual void writeExternal(PofWriter::Handle hOut) const; 00110 00111 00112 // ----- Object interface ----------------------------------------------- 00113 00114 public: 00115 /** 00116 * {@inheritDoc} 00117 */ 00118 virtual bool equals(Object::View v) const; 00119 00120 /** 00121 * {@inheritDoc} 00122 */ 00123 virtual size32_t hashCode() const; 00124 00125 /** 00126 * {@inheritDoc} 00127 */ 00128 virtual TypedHandle<const String> toString() const; 00129 00130 00131 // ----- data member accessors ------------------------------------------ 00132 00133 public: 00134 /** 00135 * Return a ValueExtractor used to transfrom the event's OldValue. 00136 * 00137 * @return an extractor from the OldValue 00138 */ 00139 virtual ValueExtractor::View getOldValueExtractor() const; 00140 00141 /** 00142 * Return a ValueExtractor used to transfrom the event's NewValue. 00143 * 00144 * @return an extractor from the NewValue 00145 */ 00146 virtual ValueExtractor::View getNewValueExtractor() const; 00147 00148 00149 // ----- data members --------------------------------------------------- 00150 00151 private: 00152 /** 00153 * The OldValueExtractor. 00154 */ 00155 FinalView<ValueExtractor> f_vExtractorOld; 00156 00157 /** 00158 * The NewValueExtractor. 00159 */ 00160 FinalView<ValueExtractor> f_vExtractorNew; 00161 }; 00162 00163 COH_CLOSE_NAMESPACE3 00164 00165 #endif // COH_EXTRACTOR_EVENT_TRANSFORMER_HPP