单件模式是一种用于确保整个应用程序中只有一个类实例且这个实例所占资源在整个应用程序中是共享时的程序设计方法
c# 实现：
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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
//单件模式基础模型
//来源：Gmap.net源代码中
namespace Design.Singleton
{
/// <summary>
/// generic for singletons
/// 单件模式 泛型
/// </summary>
/// <typeparam name="T"></typeparam>
public class Singleton<T> where T : new()
{
// ctor
protected Singleton()
{
if (Instance != null)
{
throw (new Exception("You have tried to create a new singleton class where you should have instanced it. Replace your \"new class()\" with \"class.Instance\""));
}
}
public static T Instance
{
get
{
return SingletonCreator.instance;
}
}
class SingletonCreator
{
static SingletonCreator()
{
}
internal static readonly T instance = new T();
}
}
}
c++实现
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//来源 boost 1.48 boost\thread\detail\singleton.hpp
//此非线程安全，线程安全使用 boost\serialization\singleton.hpp
template <class T>
class singleton : private T
{
private:
singleton();
~singleton();
public:
static T &instance();
};
template <class T>
inline singleton<T>::singleton()
{
/* no-op */
}
template <class T>
inline singleton<T>::~singleton()
{
/* no-op */
}
template <class T>
/*static*/ T &singleton<T>::instance()
{
// function-local static to force this to work correctly at static
// initialization time.
static singleton<T> s_oT;
return(s_oT);
}