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_ABSTACT_STABLE_ITERATOR_HPP 00008 #define COH_ABSTACT_STABLE_ITERATOR_HPP 00009 00010 #include "coherence/lang.ns" 00011 00012 #include "coherence/util/Muterator.hpp" 00013 00014 COH_OPEN_NAMESPACE2(coherence,util) 00015 00016 00017 /** 00018 * An abstract Iterator implementation that is stable between the hasNext() and 00019 * next() methods. 00020 * 00021 * @author mf 2008.02.28 00022 */ 00023 class COH_EXPORT AbstractStableIterator 00024 : public abstract_spec<AbstractStableIterator, 00025 extends<Object>, 00026 implements<Muterator> > 00027 { 00028 // ----- constructors --------------------------------------------------- 00029 00030 protected: 00031 /** 00032 * @internal 00033 */ 00034 AbstractStableIterator(); 00035 00036 00037 // ----- Muterator interface -------------------------------------------- 00038 00039 public: 00040 /** 00041 * {@inheritDoc} 00042 */ 00043 virtual void remove(); 00044 00045 00046 // ----- Iterator interface --------------------------------------------- 00047 00048 public: 00049 /** 00050 * {@inheritDoc} 00051 */ 00052 virtual bool hasNext() const; 00053 00054 /** 00055 * {@inheritDoc} 00056 */ 00057 virtual Object::Holder next(); 00058 00059 00060 // ----- internal ------------------------------------------------------- 00061 00062 protected: 00063 /** 00064 * Obtain the previous object provided by the Iterator. 00065 * 00066 * @return the object previously returned from a call to #next() 00067 */ 00068 virtual Object::Holder getPrevious() const; 00069 00070 /** 00071 * Specify the next object to provide from the Iterator. 00072 * 00073 * @param ohNext the next object to provide from the Iterator 00074 */ 00075 virtual void setNext(Object::Holder ohNext); 00076 00077 /** 00078 * Advance to the next object. 00079 * 00080 * This method must be implemented by the concrete sub-class by calling 00081 * #setNext() if there is a next object. 00082 */ 00083 virtual void advance() = 0; 00084 00085 /** 00086 * Remove the specified item. 00087 * 00088 * This is an optional operation. If the Iterator supports element 00089 * removal, then it should implement this method, which is delegated to by 00090 * the #remove() method. 00091 * 00092 * @param ohPrev the previously iterated object that should be removed 00093 * 00094 * @throws coherence::lang::UnsupportedOperationException if removal 00095 * is not supported 00096 */ 00097 virtual void remove(Object::Holder ohPrev); 00098 00099 00100 // ----- Object interface ----------------------------------------------- 00101 00102 protected: 00103 /** 00104 * {@inheritDoc} 00105 */ 00106 virtual void onInit(); 00107 00108 00109 // ----- data members --------------------------------------------------- 00110 00111 private: 00112 /** 00113 * Set to true when <tt>m_oNext</tt> is the next object to return 00114 * from the iterator. If there is no next object, or if the next object 00115 * is not determined yet, then this will be false. Set up by 00116 * #setNext() and reset by #next(). 00117 */ 00118 bool m_fNextReady; 00119 00120 /** 00121 * The next object to return from this iterator. Set up by 00122 * #setNext() and reset by #next(). 00123 */ 00124 MemberHolder<Object> m_ohNext; 00125 00126 /** 00127 * The object that can be deleted, if any. Set up by #next. 00128 */ 00129 MemberHolder<Object> m_ohPrev; 00130 00131 /** 00132 * Set to true when an element has been returned but not yet 00133 * removed. Set up by #next() and reset by #remove(). 00134 */ 00135 bool m_fCanDelete; 00136 }; 00137 00138 COH_CLOSE_NAMESPACE2 00139 00140 #endif // COH_ABSTACT_STABLE_ITERATOR_HPP