程序中有时候需要保存全局的数据,比如程序的配置文件,需要随时检索的.比如程序中有些变量需要全局保存全局用,这时候我们不想用一个全局变量来保存
这时候,可以使用单例模式,从名称可以看出,单例模式就是类的实例全局只创建一个.怎么样才能保存只创建一个实例呢?
我们可以设置标识位,创建过的就不再创建了.下面是单例的简单实现
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61 |
template<class
T> class
Singleton { public: static
T* GetInstance() { static
Mutex mutex; if(!ms_instance) { Locker locker(mutex); if
(!ms_instance) { ms_instance = new
T; } } return
ms_instance; } static
void SetInstance(T* pInst) { ms_instance = pInst; } static
void DeleteInstance() { if
(ms_instance) { delete
ms_instance; ms_instance = NULL; } } private: class
Garbo { public: ~Garbo() { if( Singleton::ms_instance ) { delete
ms_instance; ms_instance = NULL; } } }; static
Garbo garbo; protected: Singleton() {} ~Singleton() {} Singleton(const
Singleton&) {} Singleton& operator=(const
Singleton&) {} private: static
T* ms_instance; }; template<class
T> T* Singleton<T>::ms_instance = 0; |
用法:
class Test : public Singleton<Test>
{
//your code
}
Test::GetInstance()->your method
原文：http://www.cnblogs.com/start1225/p/3720151.html