设计模式C++学习笔记之十九(State状态模式)
时间:2011-04-21 来源:wang_gary
19.1.解释
概念:允许一个对象在其内部状态改变时改变它的行为。对象看起来似乎修改了它的类。
main(),客户
CLiftState,电梯状态抽象类
CCloseingState,电梯门关闭
COpenningState,电梯门打开
CRunningState,电梯运行
CStoppingState,电梯停止
CContext,电梯的控制面板
说明:CContext保持电梯的状态,并提供操作的接口函数。当函数被调用时,CContext直接调用当前状态的相应函数。由状态的接口函数来确定是否可以执行这个动作,以及修改状态为执行这个动作后的状态。
看代码:第一块是不使用模式的做法,第二块是使用模式的做法,在main()函数里会有调用的方式。
//ILift.h
#pragma once
class ILift
{
public:
ILift(void)
{
}
virtual ~ILift(void)
{
}
static const int OPENING_STATE = 1;
static const int CLOSING_STATE = 2;
static const int RUNNING_STATE = 3;
static const int STOPPING_STATE = 4;
virtual void SetState(int state) = 0;
virtual void Open() = 0;
virtual void Close() = 0;
virtual void Run() = 0;
virtual void Stop() = 0;
};
//Lift.h
#pragma once
#include "ilift.h"
class CLift :
public ILift
{
public:
CLift(void);
~CLift(void);
void SetState(int state);
void Open();
void Close();
void Run();
void Stop();
private:
int m_state;
void OpenWithoutLogic();
void CloseWithoutLogic();
void RunWithoutLogic();
void StopWithoutLogic();
};
//Lift.cpp
#include "StdAfx.h"
#include "Lift.h"
#include <iostream>
using std::cout;
using std::endl;
CLift::CLift(void)
{
this->m_state = 0;
}
CLift::~CLift(void)
{
}
void CLift::SetState(int state)
{
this->m_state = state;
}
void CLift::Open()
{
switch(this->m_state)
{
case OPENING_STATE:
break;
case CLOSING_STATE:
this->OpenWithoutLogic();
this->SetState(OPENING_STATE);
break;
case RUNNING_STATE:
break;
case STOPPING_STATE:
this->OpenWithoutLogic();
this->SetState(OPENING_STATE);
break;
}
}
void CLift::Close()
{
switch(this->m_state)
{
case OPENING_STATE:
this->CloseWithoutLogic();
this->SetState(CLOSING_STATE);
break;
case CLOSING_STATE:
break;
case RUNNING_STATE:
break;
case STOPPING_STATE:
break;
}
}
void CLift::Run()
{
switch(this->m_state)
{
case OPENING_STATE:
break;
case CLOSING_STATE:
this->RunWithoutLogic();
this->SetState(RUNNING_STATE);
break;
case RUNNING_STATE:
break;
case STOPPING_STATE:
this->RunWithoutLogic();
this->SetState(RUNNING_STATE);
break;
}
}
void CLift::Stop()
{
switch(this->m_state)
{
case OPENING_STATE:
break;
case CLOSING_STATE:
this->StopWithoutLogic();
this->SetState(CLOSING_STATE);
break;
case RUNNING_STATE:
this->StopWithoutLogic();
this->SetState(CLOSING_STATE);
break;
case STOPPING_STATE:
break;
}
}
void CLift::OpenWithoutLogic()
{
cout << "电梯门开启..." << endl;
}
void CLift::CloseWithoutLogic()
{
cout << "电梯门关闭..." << endl;
}
void CLift::RunWithoutLogic()
{
cout << "电梯上下跑起来..." << endl;
}
void CLift::StopWithoutLogic()
{
cout << "电梯停止了..." << endl;
}
//LiftState.h
#pragma once
class CContext;
class CLiftState
{
public:
CLiftState(void);
virtual ~CLiftState(void);
void SetContext(CContext *pContext);
virtual void Open() = 0;
virtual void Close() = 0;
virtual void Run() = 0;
virtual void Stop() = 0;
protected:
CContext *m_pContext;
};
//LiftState.cpp
#include "StdAfx.h"
#include "LiftState.h"
CLiftState::CLiftState(void)
{
}
CLiftState::~CLiftState(void)
{
}
void CLiftState::SetContext( CContext *pContext )
{
m_pContext = pContext;
}
//CloseingState.h
#pragma once
#include "liftstate.h"
class CCloseingState :
public CLiftState
{
public:
CCloseingState(void);
~CCloseingState(void);
void Open();
void Close();
void Run();
void Stop();
};
//CloseingState.cpp
#include "StdAfx.h"
#include "CloseingState.h"
#include "Context.h"
#include <iostream>
using std::cout;
using std::endl;
CCloseingState::CCloseingState(void)
{
}
CCloseingState::~CCloseingState(void)
{
}
void CCloseingState::Open()
{
this->CLiftState::m_pContext->SetLiftState(CContext::pOpenningState);
this->CLiftState::m_pContext->GetLiftState()->Open();
}
void CCloseingState::Close()
{
cout << "电梯门关闭..." << endl;
}
void CCloseingState::Run()
{
this->CLiftState::m_pContext->SetLiftState(CContext::pRunningState);
this->CLiftState::m_pContext->GetLiftState()->Run();
}
void CCloseingState::Stop()
{
this->CLiftState::m_pContext->SetLiftState(CContext::pStoppingState);
this->CLiftState::m_pContext->GetLiftState()->Stop();
}
//OpenningState.h
#pragma once
#include "liftstate.h"
class COpenningState :
public CLiftState
{
public:
COpenningState(void);
~COpenningState(void);
void Open();
void Close();
void Run();
void Stop();
};
//OpenningState.cpp
#include "StdAfx.h"
#include "OpenningState.h"
#include "Context.h"
#include <iostream>
using std::cout;
using std::endl;
COpenningState::COpenningState(void)
{
}
COpenningState::~COpenningState(void)
{
}
void COpenningState::Open()
{
cout << "电梯门开启..." << endl;
}
void COpenningState::Close()
{
this->CLiftState::m_pContext->SetLiftState(CContext::pCloseingState);
this->CLiftState::m_pContext->GetLiftState()->Close();
}
void COpenningState::Run()
{
//do nothing
}
void COpenningState::Stop()
{
//do nothing
}
//RunningState.h
#pragma once
#include "liftstate.h"
class CRunningState :
public CLiftState
{
public:
CRunningState(void);
~CRunningState(void);
void Open();
void Close();
void Run();
void Stop();
};
//RunningState.cpp
#include "StdAfx.h"
#include "RunningState.h"
#include "Context.h"
#include <iostream>
using std::cout;
using std::endl;
CRunningState::CRunningState(void)
{
}
CRunningState::~CRunningState(void)
{
}
void CRunningState::Open()
{
//do nothing
}
void CRunningState::Close()
{
//do nothing
}
void CRunningState::Run()
{
cout << "电梯上下跑..." << endl;
}
void CRunningState::Stop()
{
this->CLiftState::m_pContext->SetLiftState(CContext::pStoppingState);
this->CLiftState::m_pContext->GetLiftState()->Stop();
}
//StoppingState.h
#pragma once
#include "liftstate.h"
class CStoppingState :
public CLiftState
{
public:
CStoppingState(void);
~CStoppingState(void);
void Open();
void Close();
void Run();
void Stop();
};
//StoppingState.cpp
#include "StdAfx.h"
#include "StoppingState.h"
#include "Context.h"
#include <iostream>
using std::cout;
using std::endl;
CStoppingState::CStoppingState(void)
{
}
CStoppingState::~CStoppingState(void)
{
}
void CStoppingState::Open()
{
this->CLiftState::m_pContext->SetLiftState(CContext::pOpenningState);
this->CLiftState::m_pContext->GetLiftState()->Open();
}
void CStoppingState::Close()
{
//do nothing
}
void CStoppingState::Run()
{
this->CLiftState::m_pContext->SetLiftState(CContext::pRunningState);
this->CLiftState::m_pContext->GetLiftState()->Run();
}
void CStoppingState::Stop()
{
cout << "电梯停止了..." << endl;
}
//Contex.h
#pragma once
#include "LiftState.h"
#include "OpenningState.h"
#include "CloseingState.h"
#include "RunningState.h"
#include "StoppingState.h"
class CContext
{
public:
CContext(void);
~CContext(void);
static COpenningState *pOpenningState;
static CCloseingState *pCloseingState;
static CRunningState *pRunningState;
static CStoppingState *pStoppingState;
CLiftState * GetLiftState();
void SetLiftState(CLiftState *pLiftState);
void Open();
void Close();
void Run();
void Stop();
private:
CLiftState *m_pLiftState;
};
//Context.cpp
#include "StdAfx.h"
#include "Context.h"
COpenningState* CContext::pOpenningState = NULL;
CCloseingState* CContext::pCloseingState = NULL;
CRunningState* CContext::pRunningState = NULL;
CStoppingState* CContext::pStoppingState = NULL;
CContext::CContext(void)
{
m_pLiftState = NULL;
pOpenningState = new COpenningState();
pCloseingState = new CCloseingState();
pRunningState = new CRunningState();
pStoppingState = new CStoppingState();
}
CContext::~CContext(void)
{
delete pOpenningState;
pOpenningState = NULL;
delete pCloseingState;
pCloseingState = NULL;
delete pRunningState;
pRunningState = NULL;
delete pStoppingState;
pStoppingState = NULL;
}
CLiftState * CContext::GetLiftState()
{
return m_pLiftState;
}
void CContext::SetLiftState(CLiftState *pLiftState)
{
this->m_pLiftState = pLiftState;
this->m_pLiftState->SetContext(this);
}
void CContext::Open()
{
this->m_pLiftState->Open();
}
void CContext::Close()
{
this->m_pLiftState->Close();
}
void CContext::Run()
{
this->m_pLiftState->Run();
}
void CContext::Stop()
{
this->m_pLiftState->Stop();
}
// State.cpp : 定义控制台应用程序的入口点。
#include "stdafx.h"
#include "ILift.h"
#include "Lift.h"
#include "Context.h"
#include "OpenningState.h"
#include "CloseingState.h"
#include "RunningState.h"
#include "StoppingState.h"
#include <iostream>
using std::cout;
using std::endl;
void DoIt()
{
//ILift.h, Lift.h, Lift.cpp
ILift *pLift = new CLift();
pLift->SetState(ILift::STOPPING_STATE);//电梯的初始条件是停止状态。
pLift->Open();//首先是电梯门开启,人进去
pLift->Close();//然后电梯门关闭
pLift->Run();//再然后,电梯跑起来,向上或者向下
pLift->Stop();//最后到达目的地,电梯停下来
delete pLift;
}
void DoNew()
{
//LiftState.h, LiftState.cpp, OpenningState.h, CloseingState.h, RunningState.h, StoppingState.h
//Context.h, Context.cpp
CContext context;
CCloseingState closeingState;
context.SetLiftState(&closeingState);
context.Close();
context.Open();
context.Run();
context.Stop();
}
int _tmain(int argc, _TCHAR* argv[])
{
cout << "----------使用模式之前----------" << endl;
DoIt();
cout << "----------使用模式之后----------" << endl;
DoNew();
_CrtSetDbgFlag(_CRTDBG_LEAK_CHECK_DF | _CRTDBG_ALLOC_MEM_DF);
_CrtDumpMemoryLeaks();
return 0;
}
状态模式也是行为型模式。写了好多天了,才发现如何在页面上插入代码。这样方便多了,看起来也清楚多了。博客园也许需要开个入门贴子,免得新来博客园的童鞋都不大会用。这几天还在学习数据结构中的排序,入排序入手来学习数据结构还是比较容易的。上学的时候只顾着考试了,该学的也都学了,但考完试就全忘掉,已经成为了一种习惯。现在再补回来。鼓励自己加油!一定要做一个学习型的程序员。
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