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_

类别：c++ 查看评论