两种实现单件模式代码重用的方法

#ifndef _ZKit_Singleton_h_

#define _ZKit_Singleton_h_

#include "ZKit_Config.h"

BEGIN_ZKIT

template <class T>

class Singleton

{

public:

static T* instance()

{

if ( 0 == s_instance )

{

s_instance = new T;

}

return s_instance;

}

static void unInstance()

{

if ( 0 != s_instance )

{

delete s_instance;

s_instance = 0;

}

}

protected:

Singleton() {}

virtual ~Singleton() {}

private:

Singleton(const Singleton<T> &);

Singleton<T>& operator= (const Singleton<T> &);

static T* s_instance;

};

template <class T>

T* Singleton<T>::s_instance = 0;

//////////////////////////////////////////////////////////////////////////

//用宏实现单件模式的代码重用, 可作为上面模板类的替代品

#define DECLARE_SINGLETON(Singleton) \

public:\

static Singleton* Instance(){if (m_instance == 0)m_instance = new Singleton();return m_instance;}\

static void Release(){delete m_instance;m_instance = 0;}\

private:\

Singleton& operator=(const Singleton&);\

Singleton(const Singleton&);\

static Singleton* m_instance;

#define IMPLEMENT_SINGLETON(Singleton) Singleton* Singleton::m_instance = 0;

END_ZKIT

#endif // _ZKit_Singleton_h_

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