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_ATOMIC_COUNTER_HPP 00008 #define COH_ATOMIC_COUNTER_HPP 00009 00010 #include "coherence/lang.ns" 00011 00012 #include "coherence/native/NativeAtomic64.hpp" 00013 00014 COH_OPEN_NAMESPACE2(coherence,util) 00015 00016 using coherence::native::NativeAtomic64; 00017 00018 00019 /** 00020 * AtomicCounter allows for atomic updates to a "int64_t" value where possible 00021 * without requiring synchronization. 00022 * 00023 * @author nsa 12.28.2007 00024 */ 00025 class COH_EXPORT AtomicCounter 00026 : public cloneable_spec<AtomicCounter> 00027 { 00028 friend class factory<AtomicCounter>; 00029 00030 // ----- constructor ---------------------------------------------------- 00031 00032 protected: 00033 /** 00034 * Create an AtomicCounter initialized with a specified value. 00035 * 00036 * @param cValue the initial value of the Atomic64 00037 */ 00038 AtomicCounter(int64_t cValue = 0); 00039 00040 /** 00041 * Copy constructor. 00042 */ 00043 AtomicCounter(const AtomicCounter& that); 00044 00045 00046 // ----- AtomicCounter interface ---------------------------------------- 00047 00048 public: 00049 /** 00050 * Incremenet the value by c, and return the new value. 00051 * 00052 * @param c the amount to increment the counter by 00053 * 00054 * @return the new value 00055 */ 00056 virtual int64_t increment(int64_t c = 1); 00057 00058 /** 00059 * Incremenet the value by c, and return the original value. 00060 * 00061 * @param c the amount to increment the counter by 00062 * 00063 * @return the original value 00064 */ 00065 virtual int64_t postIncrement(int64_t c = 1); 00066 00067 /** 00068 * Decrement the value by c, and return the new value. 00069 * 00070 * @param c the amount to decrement the counter by 00071 * 00072 * @return the new value 00073 */ 00074 virtual int64_t decrement(int64_t c = 1); 00075 00076 /** 00077 * Decrement the value by c, and return the original value. 00078 * 00079 * @param c the amount to decrement the counter by 00080 * 00081 * @return the original value 00082 */ 00083 virtual int64_t postDecrement(int64_t c = 1); 00084 00085 /** 00086 * Return the current value of the counter. 00087 * 00088 * @return the current value 00089 */ 00090 virtual int64_t getCount() const; 00091 00092 /** 00093 * Update the current value, only if it is equal to the assumed value. 00094 * 00095 * @param cAssume the assumed old value 00096 * @param cNew the new value 00097 * 00098 * @return the prior actual value, if the returned value does is not 00099 * equal to the supplied assumed value then update did not take 00100 * place 00101 */ 00102 virtual int64_t update(int64_t cAssume, int64_t cNew); 00103 00104 /** 00105 * Update the current value, and return the previous value. 00106 * 00107 * @param cNew the new value 00108 * 00109 * @return the previous value just before the update went through 00110 */ 00111 virtual int64_t setCount(int64_t cNew); 00112 00113 00114 // ----- Object interface ----------------------------------------------- 00115 00116 public: 00117 /** 00118 * {@inheritDoc} 00119 */ 00120 virtual TypedHandle<const String> toString() const; 00121 00122 00123 // ----- data members --------------------------------------------------- 00124 00125 protected: 00126 /** 00127 * The underlying native implementation. 00128 */ 00129 NativeAtomic64 m_atomic; 00130 }; 00131 00132 COH_CLOSE_NAMESPACE2 00133 00134 #endif // COH_ATOMIC_COUNTER_HPP