1 | // |
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2 | // Observer.h |
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3 | // |
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4 | // $Id: //poco/1.3/Foundation/include/Poco/Observer.h#1 $ |
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5 | // |
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6 | // Library: Foundation |
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7 | // Package: Notifications |
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8 | // Module: NotificationCenter |
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9 | // |
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10 | // Definition of the Observer class template. |
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11 | // |
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12 | // Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH. |
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13 | // and Contributors. |
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14 | // |
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15 | // Permission is hereby granted, free of charge, to any person or organization |
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16 | // obtaining a copy of the software and accompanying documentation covered by |
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17 | // this license (the "Software") to use, reproduce, display, distribute, |
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18 | // execute, and transmit the Software, and to prepare derivative works of the |
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19 | // Software, and to permit third-parties to whom the Software is furnished to |
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20 | // do so, all subject to the following: |
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21 | // |
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22 | // The copyright notices in the Software and this entire statement, including |
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23 | // the above license grant, this restriction and the following disclaimer, |
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24 | // must be included in all copies of the Software, in whole or in part, and |
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25 | // all derivative works of the Software, unless such copies or derivative |
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26 | // works are solely in the form of machine-executable object code generated by |
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27 | // a source language processor. |
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28 | // |
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29 | // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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30 | // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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31 | // FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT |
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32 | // SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE |
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33 | // FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, |
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34 | // ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
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35 | // DEALINGS IN THE SOFTWARE. |
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36 | // |
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37 | |
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38 | |
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39 | #ifndef Foundation_Observer_INCLUDED |
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40 | #define Foundation_Observer_INCLUDED |
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41 | |
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42 | |
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43 | #include "Poco/Foundation.h" |
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44 | #include "Poco/AbstractObserver.h" |
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45 | |
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46 | |
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47 | namespace Poco { |
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48 | |
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49 | |
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50 | template <class C, class N> |
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51 | class Observer: public AbstractObserver |
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52 | /// This template class implements an adapter that sits between |
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53 | /// a NotificationCenter and an object receiving notifications |
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54 | /// from it. It is quite similar in concept to the |
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55 | /// RunnableAdapter, but provides some NotificationCenter |
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56 | /// specific additional methods. |
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57 | /// See the NotificationCenter class for information on how |
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58 | /// to use this template class. |
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59 | /// |
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60 | /// Instead of the Observer class template, you might want to |
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61 | /// use the NObserver class template, which uses an AutoPtr to |
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62 | /// pass the Notification to the callback function, thus freeing |
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63 | /// you from memory management issues. |
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64 | { |
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65 | public: |
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66 | typedef void (C::*Callback)(N*); |
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67 | |
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68 | Observer(C& object, Callback method): |
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69 | _pObject(&object), |
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70 | _method(method) |
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71 | { |
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72 | } |
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73 | |
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74 | Observer(const Observer& observer): |
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75 | AbstractObserver(observer), |
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76 | _pObject(observer._pObject), |
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77 | _method(observer._method) |
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78 | { |
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79 | } |
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80 | |
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81 | ~Observer() |
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82 | { |
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83 | } |
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84 | |
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85 | Observer& operator = (const Observer& observer) |
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86 | { |
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87 | if (&observer != this) |
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88 | { |
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89 | _pObject = observer._pObject; |
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90 | _method = observer._method; |
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91 | } |
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92 | return *this; |
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93 | } |
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94 | |
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95 | void notify(Notification* pNf) const |
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96 | { |
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97 | N* pCastNf = dynamic_cast<N*>(pNf); |
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98 | if (pCastNf) |
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99 | { |
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100 | pCastNf->duplicate(); |
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101 | (_pObject->*_method)(pCastNf); |
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102 | } |
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103 | } |
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104 | |
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105 | bool equals(const AbstractObserver& abstractObserver) const |
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106 | { |
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107 | const Observer* pObs = dynamic_cast<const Observer*>(&abstractObserver); |
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108 | return pObs && pObs->_pObject == _pObject && pObs->_method == _method; |
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109 | } |
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110 | |
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111 | bool accepts(Notification* pNf) const |
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112 | { |
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113 | return dynamic_cast<N*>(pNf) != 0; |
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114 | } |
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115 | |
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116 | AbstractObserver* clone() const |
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117 | { |
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118 | return new Observer(*this); |
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119 | } |
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120 | |
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121 | private: |
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122 | Observer(); |
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123 | |
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124 | C* _pObject; |
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125 | Callback _method; |
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126 | }; |
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127 | |
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128 | |
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129 | } // namespace Poco |
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130 | |
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131 | |
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132 | #endif // Foundation_Observer_INCLUDED |
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