设计模式C++学习笔记之十九（State状态模式）

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 onceclass 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 onceclass 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。