Singleton< T > Class Template Reference

singleton design pattern implementation More...

#include <singleton.h>

Inherited by UniversalManager< Font, FontManager >, and UniversalManager< Texture, TextureManager >.

Inheritance diagram for Singleton< T >:

[legend]Collaboration diagram for Singleton< T >:

[legend]List of all members.

Public Member Functions
virtual	~Singleton (void)
Static Public Member Functions
static T *	getInstance (void)
	returns instance pointer
static T *	getPtr (void)
	returns instance pointer
static T &	getRef (void)
	returns instance reference
Protected Member Functions
	Singleton (void)
	protected ctor due to singleton DP
	Singleton (const Singleton &)
	protected ctor due to singleton DP
Singleton &	operator= (const Singleton &)
	protected operator= due to singleton DP
Static Private Member Functions
static void	createInstance (void)
	creates a new instance of singleton class T
static void	destroyInstance (void)
	destroys the instance of singleton class T
Static Private Attributes
static T *	m_InstancePtr = 0
	static pointer to the instance of the singleton class T
static Singleton< T >::InstanceDestruction	m_InstanceDestruction
	static class that destroys singleton instance at the program exit.
Classes
class	InstanceDestruction
	class that will destroy the singleton instance at the program exit. More...

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Detailed Description

template<class T>
class Singleton< T >

singleton design pattern implementation

        // Singleton<T> usage example:

        class OneClass: public ClassA, ClassB, Singleton<OneClass>
        {

        // I. Singleton stuffs
        // only the Singleton<OneClass> can call OneClass::OneClass()
        friend class Singleton<OneClass>;
        protected:
                OneClass();  // protected ctor (singleton)
                ~OneClass(); // protected dtor (singleton)

        // II. OneClass definition - methods, attributes
        public:
                some_OneClass_method()
        };
        
        ...

        // Equivalent usage of the OneClass singleton:
        OneClass::getInstance()->some_OneClass_method();
        OneClass::getPtr()->some_OneClass_method();
        OneClass::getRef().some_OneClass_method();

Remarks:

Singleton variables are created at the first instance request. But it is STRONGLY recommended DO NOT using any Singleton class at static-variables initialization time (before entering the main()).

Singleton classes are destroyed at the program exit (at static variables destruction). Therefore, using other classes and global or static variables (other singletons as well) inside the destructor-body of some singleton class could be unsafe (the variables that we are attempting to use might be already destroyed)!

Sometimes, it can be possible to destroy the singleton directly by using delete SomeSingleton::getPtr(). It isn't recommended, however it shouldn't cause any program's crash...

Definition at line 75 of file singleton.h.

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Constructor & Destructor Documentation

template<class T> virtual Singleton< T >::~Singleton (  void   )  [inline, virtual]

Note: sets internal instance pointer to NULL due to safety reasons. Definition at line 81 of file singleton.h.

template<class T> Singleton< T >::Singleton (  void   )  [inline, protected]

protected ctor due to singleton DP Definition at line 121 of file singleton.h.

template<class T> Singleton< T >::Singleton (  const Singleton< T > &   )  [inline, protected]

protected ctor due to singleton DP Definition at line 124 of file singleton.h.

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Member Function Documentation

template<class T> static void Singleton< T >::createInstance (  void   )  [inline, static, private]

creates a new instance of singleton class T Definition at line 133 of file singleton.h. Referenced by Singleton< T >::getInstance().

template<class T> static void Singleton< T >::destroyInstance (  void   )  [inline, static, private]

destroys the instance of singleton class T Definition at line 141 of file singleton.h. Referenced by Singleton< T >::InstanceDestruction::~InstanceDestruction().

template<class T> T * Singleton< T >::getInstance (  void   )  [inline, static]

returns instance pointer The instance of T is created at the first getInstance() call. Returns: pointer to instace of type T Note: getInstance, getPtr and getRef are equivalent Definition at line 165 of file singleton.h. References Singleton< T >::createInstance(), and Singleton< T >::m_InstancePtr. Referenced by SurfaceFactory::create(), Singleton< FontManager >::getPtr(), Singleton< FontManager >::getRef(), TerrainClient::loadGlobalTexture(), and TerrainClient::loadLightmap(). Here is the call graph for this function:

template<class T> static T* Singleton< T >::getPtr (  void   )  [inline, static]

returns instance pointer The instance of T is created at the first getInstance() call. Returns: pointer to instace of type T Note: getInstance, getPtr and getRef are equivalent Definition at line 105 of file singleton.h. Referenced by GFX::clean().

template<class T> static T& Singleton< T >::getRef (  void   )  [inline, static]

returns instance reference The instance of T is created at the first getInstance() call. Returns: reference to instace of type T Note: getInstance, getPtr and getRef are equivalent Definition at line 116 of file singleton.h. Referenced by Messages::init(), Console::init(), and ApplicationClient::init().

template<class T> Singleton& Singleton< T >::operator= (  const Singleton< T > &   )  [inline, protected]

protected operator= due to singleton DP Definition at line 127 of file singleton.h.

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Member Data Documentation

template<class T> Singleton< T >::InstanceDestruction Singleton< T >::m_InstanceDestruction [static, private]

static class that destroys singleton instance at the program exit. Note: it doesn't fail if the instance was destroyed before somehow and set to null Definition at line 161 of file singleton.h.

template<class T> T * Singleton< T >::m_InstancePtr = 0 [static, private]

static pointer to the instance of the singleton class T Definition at line 130 of file singleton.h. Referenced by Singleton< FontManager >::createInstance(), Singleton< FontManager >::destroyInstance(), Singleton< T >::getInstance(), and Singleton< FontManager >::~Singleton().

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The documentation for this class was generated from the following file:

• singleton.h

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