C++ FastDelegate 扩大,实现与.net类似的事务处理惩罚功能
添加时间:2013-8-5 点击量:
熟悉.NET的人都知道,  .NET应用委托可以快速实现调查者模式,免除写很多错杂反复的代码。遗憾的是,C++并没有供给如许的模型,为了达到类似的目标,须要持续一个类并重写virtual办法,这种做法须要写很多代码,效力斗劲低下。然而,在强大的C++面前,没有什么是不成能的,已经有很多人针对这个题目进行过研究,并且实现了各类委托模型,此中最有名的就是FastDelegate。为了让应用FastDelegate更象.NET,我新添加几个模板,首要如下:
 
起首添加一个两个类用于模仿事务产生源及事务参数类:
1: // 定义事务发送源(类似于.net的sender)
2: class IEventSource
3: {
4: public:
5: virtual ~IEventSource (){}
6: };
7: 
8: using namespace fastdelegate;
9: 
10: // 定义标准的事务参数
11: class CEventArgs
12: {
13: public:
14: CEventArgs (void)
15: {
16: bHandled = FALSE;
17: }
18: 
19: BOOL bHandled;
20: };
然后是定义一个事务句柄经管类:
1: // 定义事务句柄,用于经管事务中参加的委托
2: template <class TBase>
3: class CEventHandlerBase
4: {
5: public:
6: virtual ~CEventHandlerBase ()
7: {
8: for (int i = _delegates.GetSize () - 1; i >= 0; i --)
9: {
10: (TBase) _delegates[i];
11: }
12: _delegates.Empty ();
13: }
14:&#160;
15: size_t GetCount (void) { return _delegates.GetSize (); }
16:&#160;
17: // 添加委托
18: void operator += (TBase& eventDelegate)
19: {
20: _delegates.Add (new TBase (eventDelegate));
21: }
22:&#160;
23: // 删除委托
24: void operator -= (TBase& eventDelegate)
25: {
26: for (int i = _delegates.GetSize () - 1; i >= 0; i --)
27: {
28: if (((TBase) _delegates[i]) == eventDelegate)
29: {
30: (TBase) _delegates[i];
31: _delegates.Remove (i);
32: }
33: }
34: }
35:&#160;
36: public:
37: CStdPtrArray _delegates;
38: };
最后定义一个宏用于快速创建事务句柄:
1: // 定义天务句柄的类 handleClass 为句柄类名称,eventClass 为参数类名称
2: #define DEFINE_EVENT_HANDLER(handleClass, eventClass) \
3: typedef FastDelegate2<IEventSource , eventClass > eventClass##Delegate;\
4: class UILIB_API handleClass : public CEventHandlerBase<eventClass##Delegate>\
5: {\
6: public:\
7: void Fire (IEventSource sender, eventClass e)\
8: {\
9: for (int i = _delegates.GetSize () - 1; i >= 0; i --)\
10: {\
11: ((eventClass##Delegate) _delegates[i]) (sender, e);\
12: }\
13: }\
14: }
15:&#160;
16: DEFINE_EVENT_HANDLER (CStdEventHandler, CEventArgs);
应用如有两种景象,一是只用CEventArgs参数类型就可以满足请求,二是需扩大本身的参数类型。若是须要扩大参数,代码如下:
1: class CMouseEventArgs : public CEventArgs
2: {
3: public:
4: CMouseEventArgs (MouseButtons button1, int clicks1, int x1, int y1, int delta1);
5:&#160;
6: MouseButtons button; int clicks; int x; int y; int delta;
7: };
8:&#160;
9: // void handler (IEventSource sender, CMouseEventArgs e);
10: DEFINE_EVENT_HANDLER (CMouseEventDelegate, CMouseEventArgs);
应用代码示例如下:
1: class CGlobalWindowMsgHook : public IEventSource
2: {
3: private:
4: CGlobalWindowMsgHook (void);
5: public:
6: ~CGlobalWindowMsgHook (void);
7:&#160;
8: static CGlobalWindowMsgHook instance (void);
9:&#160;
10: // 定义鼠标点击事务
11: CMouseEventDelegate MouseClick;
12:&#160;
13: ……
14: protected:
15: static LRESULT CALLBACK MouseProc(int nCode, WPARAM wParam, LPARAM lParam)
16: {
17: CGlobalWindowMsgHook This = instance();
18: PMSLLHOOKSTRUCT hookStruct = (PMSLLHOOKSTRUCT)lParam;
19:
20: int msg = wParam;
21: int x = hookStruct->pt.x;
22: int y = hookStruct->pt.y;
23: int delta = (short)((hookStruct->mouseData >> 16) & 0 xffff);
24:
25: if (msg == WM_LBUTTONUP)
26: {
27: // 触发鼠标点击事务
28: This->MouseDown.Fire (This, &CMouseEventArgs (Left, 0, x, y, delta));
29: }
30: ……
31: }
32: ……
33: };
34:&#160;
35: // 测试类
36: class CTest
37: {
38: public:
39: CTest ()
40: {
41: CGlobalWindowMsgHook::instance()->MouseClick += MakeDelegate (this, &CTest::MouseDownHandler);
42: }
43: ~CTest ()
44: {
45: CGlobalWindowMsgHook::instance()->MouseClick -= MakeDelegate (this, &CTest::MouseDownHandler);
46: }
47:&#160;
48: void MouseDownHandler (IEventSource sender, CMouseEventArgs e)
49: {
50: printf (_T("hello"));
51: }
52: }
熟悉.NET的人都知道,&#160; .NET应用委托可以快速实现调查者模式,免除写很多错杂反复的代码。遗憾的是,C++并没有供给如许的模型,为了达到类似的目标,须要持续一个类并重写virtual办法,这种做法须要写很多代码,效力斗劲低下。然而,在强大的C++面前,没有什么是不成能的,已经有很多人针对这个题目进行过研究,并且实现了各类委托模型,此中最有名的就是FastDelegate。为了让应用FastDelegate更象.NET,我新添加几个模板,首要如下:
&#160;
起首添加一个两个类用于模仿事务产生源及事务参数类:
1: // 定义事务发送源(类似于.net的sender)
2: class IEventSource
3: {
4: public:
5: virtual ~IEventSource (){}
6: };
7:&#160;
8: using namespace fastdelegate;
9:&#160;
10: // 定义标准的事务参数
11: class CEventArgs
12: {
13: public:
14: CEventArgs (void)
15: {
16: bHandled = FALSE;
17: }
18:&#160;
19: BOOL bHandled;
20: };
然后是定义一个事务句柄经管类:
1: // 定义事务句柄,用于经管事务中参加的委托
2: template <class TBase>
3: class CEventHandlerBase
4: {
5: public:
6: virtual ~CEventHandlerBase ()
7: {
8: for (int i = _delegates.GetSize () - 1; i >= 0; i --)
9: {
10: (TBase) _delegates[i];
11: }
12: _delegates.Empty ();
13: }
14:&#160;
15: size_t GetCount (void) { return _delegates.GetSize (); }
16:&#160;
17: // 添加委托
18: void operator += (TBase& eventDelegate)
19: {
20: _delegates.Add (new TBase (eventDelegate));
21: }
22:&#160;
23: // 删除委托
24: void operator -= (TBase& eventDelegate)
25: {
26: for (int i = _delegates.GetSize () - 1; i >= 0; i --)
27: {
28: if (((TBase) _delegates[i]) == eventDelegate)
29: {
30: (TBase) _delegates[i];
31: _delegates.Remove (i);
32: }
33: }
34: }
35:&#160;
36: public:
37: CStdPtrArray _delegates;
38: };
最后定义一个宏用于快速创建事务句柄:
1: // 定义天务句柄的类 handleClass 为句柄类名称,eventClass 为参数类名称
2: #define DEFINE_EVENT_HANDLER(handleClass, eventClass) \
3: typedef FastDelegate2<IEventSource , eventClass > eventClass##Delegate;\
4: class UILIB_API handleClass : public CEventHandlerBase<eventClass##Delegate>\
5: {\
6: public:\
7: void Fire (IEventSource sender, eventClass e)\
8: {\
9: for (int i = _delegates.GetSize () - 1; i >= 0; i --)\
10: {\
11: ((eventClass##Delegate) _delegates[i]) (sender, e);\
12: }\
13: }\
14: }
15:&#160;
16: DEFINE_EVENT_HANDLER (CStdEventHandler, CEventArgs);
应用如有两种景象,一是只用CEventArgs参数类型就可以满足请求,二是需扩大本身的参数类型。若是须要扩大参数,代码如下:
1: class CMouseEventArgs : public CEventArgs
2: {
3: public:
4: CMouseEventArgs (MouseButtons button1, int clicks1, int x1, int y1, int delta1);
5:&#160;
6: MouseButtons button; int clicks; int x; int y; int delta;
7: };
8:&#160;
9: // void handler (IEventSource sender, CMouseEventArgs e);
10: DEFINE_EVENT_HANDLER (CMouseEventDelegate, CMouseEventArgs);
应用代码示例如下:
1: class CGlobalWindowMsgHook : public IEventSource
2: {
3: private:
4: CGlobalWindowMsgHook (void);
5: public:
6: ~CGlobalWindowMsgHook (void);
7:&#160;
8: static CGlobalWindowMsgHook instance (void);
9:&#160;
10: // 定义鼠标点击事务
11: CMouseEventDelegate MouseClick;
12:&#160;
13: ……
14: protected:
15: static LRESULT CALLBACK MouseProc(int nCode, WPARAM wParam, LPARAM lParam)
16: {
17: CGlobalWindowMsgHook This = instance();
18: PMSLLHOOKSTRUCT hookStruct = (PMSLLHOOKSTRUCT)lParam;
19:
20: int msg = wParam;
21: int x = hookStruct->pt.x;
22: int y = hookStruct->pt.y;
23: int delta = (short)((hookStruct->mouseData >> 16) & 0 xffff);
24:
25: if (msg == WM_LBUTTONUP)
26: {
27: // 触发鼠标点击事务
28: This->MouseDown.Fire (This, &CMouseEventArgs (Left, 0, x, y, delta));
29: }
30: ……
31: }
32: ……
33: };
34:&#160;
35: // 测试类
36: class CTest
37: {
38: public:
39: CTest ()
40: {
41: CGlobalWindowMsgHook::instance()->MouseClick += MakeDelegate (this, &CTest::MouseDownHandler);
42: }
43: ~CTest ()
44: {
45: CGlobalWindowMsgHook::instance()->MouseClick -= MakeDelegate (this, &CTest::MouseDownHandler);
46: }
47:&#160;
48: void MouseDownHandler (IEventSource sender, CMouseEventArgs e)
49: {
50: printf (_T("hello"));
51: }
52: }