Developer Documentation
SingletonT.hh
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47 \*===========================================================================*/
48 
49 
50 //=============================================================================
51 //
52 // Implements a simple singleton template
53 //
54 //=============================================================================
55 
56 
57 #ifndef __SINGLETON_HH__
58 #define __SINGLETON_HH__
59 
60 
61 //=== INCLUDES ================================================================
62 
63 // OpenMesh
65 
66 // STL
67 #include <stdexcept>
68 
69 
70 //== NAMESPACES ===============================================================
71 
72 
73 namespace OpenMesh {
74 
75 
76 //=== IMPLEMENTATION ==========================================================
77 
78 
83 template <typename T>
85 {
86 public:
87 
94  static T& Instance()
95  {
96  if (!pInstance__)
97  {
98  // check if singleton alive
99  if (destroyed__)
100  {
101  OnDeadReference();
102  }
103  // first time request -> initialize
104  else
105  {
106  Create();
107  }
108  }
109  return *pInstance__;
110  }
111 
112 
113 private:
114 
115  // Disable constructors/assignment to enforce uniqueness
116  SingletonT();
117  SingletonT(const SingletonT&);
118  SingletonT& operator=(const SingletonT&);
119 
120  // Create a new singleton and store its pointer
121  static void Create()
122  {
123  static T theInstance;
124  pInstance__ = &theInstance;
125  }
126 
127  // Will be called if instance is accessed after its lifetime has expired
128  static void OnDeadReference()
129  {
130  throw std::runtime_error("[Singelton error] - Dead reference detected!\n");
131  }
132 
133  virtual ~SingletonT()
134  {
135  pInstance__ = 0;
136  destroyed__ = true;
137  }
138 
139  static T* pInstance__;
140  static bool destroyed__;
141 };
142 
143 
144 
145 //=============================================================================
146 } // namespace OpenMesh
147 //=============================================================================
148 #if defined(OM_INCLUDE_TEMPLATES) && !defined(OPENMESH_SINGLETON_C)
149 # define OPENMESH_SINGLETON_TEMPLATES
150 # include "SingletonT.cc"
151 #endif
152 //=============================================================================
153 #endif // __SINGLETON_HH__
154 //=============================================================================
static T & Instance()
Definition: SingletonT.hh:94