demo3.cpp

两个观察者模式的例子

// DEMO3.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"


//------------参与者：Handler---------------------
class CAlarmHandlerBase
{
public:
	CAlarmHandlerBase() : m_pNext(NULL) {}
	void SetNextHandler(CAlarmHandlerBase *pNext)
	{
		m_pNext = pNext;
	}
	virtual void RealProcess() = 0;
	virtual void Process();
private:
	CAlarmHandlerBase *m_pNext;
};

void CAlarmHandlerBase::Process()
{
	RealProcess();
	if (NULL != m_pNext)
	{
		m_pNext->Process();
	}
}

//-----------参与者：ConcreteHandler(响报警音)--------------------
class CRingHandler : public CAlarmHandlerBase
{
public:
	CRingHandler():CAlarmHandlerBase(){}
	void RealProcess()
	{
		printf("工作：响报警音\n");
	}
};

//-----------参与者：ConcreteHandler(弹出窗口)--------------------
class CPopWinHandler : public CAlarmHandlerBase
{
public:
	CPopWinHandler():CAlarmHandlerBase(){}
	void RealProcess()
	{
		printf("工作：弹出窗口\n");
	}
};

//-----------参与者：ConcreteHandler(发送短信)--------------------
class CSmsHandler : public CAlarmHandlerBase
{
public:
	CSmsHandler():CAlarmHandlerBase(){}
	void RealProcess()
	{
		printf("工作：发送短信\n");
	}
};

int _tmain(int argc, _TCHAR* argv[])
{
char cmd[2], p1[256];
	bool bLoop = true;
	int i;
	int nCount = 0;
	CAlarmHandlerBase *pHandler[5];
	while(bLoop)
	{
		printf("------------\n");
		scanf("%s", cmd);
		switch(cmd[0])
		{
		case 'S':
		case 's':
			if (nCount > 0) break;
			scanf("%s", p1);
			for (i = 0; i < strlen(p1); i++)
			{
				switch(p1[i])
				{
				case '1':
					pHandler[nCount] = new CRingHandler();
					if (nCount > 0) 
						pHandler[nCount - 1]->SetNextHandler(pHandler[nCount]);
					nCount++;
					break;
				case '2':
					pHandler[nCount] = new CPopWinHandler();
					if (nCount > 0) 
						pHandler[nCount - 1]->SetNextHandler(pHandler[nCount]);
					nCount++;
					break;
				case '3':
					pHandler[nCount] = new CSmsHandler();
					if (nCount > 0) 
						pHandler[nCount - 1]->SetNextHandler(pHandler[nCount]);
					nCount++;
					break;
				}
				
			}
			break;
		case 'R':
		case 'r':
			pHandler[0]->Process();
			break;
		case 'Q':
		case 'q':
			for (i = 0; i < nCount; i ++)
			{
				delete pHandler[i];
			}
			bLoop = false;
			break;
		}
	}
	return 0;
}