设计模式之备忘录模式

备忘类

#pragma once
#include <string>

class Memento
{
private:
    friend class Originator;

    typedef std::string State;    // 作用域为类内

    Memento();
    ~Memento();

    Memento(const State &state);

    void SetState(const State &state);

    State GetState();

private:
    State m_state;
};

#include "Memento.h"

typedef std::string State;    // 作用域为这个cpp文件

Memento::Memento()
{
}


Memento::~Memento()
{
}

Memento::Memento(const State &state)
{
    m_state = state;
}

State Memento::GetState()
{
    return m_state;
}

void Memento::SetState(const State &state)
{
    m_state = state;
}

 

操作类

#pragma once
#include <string>

class Memento;

class Originator
{
public:
    typedef std::string State;

public:
    Originator();
    ~Originator();

    Originator(const State &state);

    Memento *GreateMemento();

    void SetMemento(Memento *men);

    void RestoreToMemento(Memento *men);

    State GetState();

    void SetState(const State &state);

    void PrintState();

private:
    State m_state;

    Memento *m_men;
};

#include "Originator.h"
#include "Memento.h"
#include <iostream>

typedef std::string State;    //作用域为这个cpp文件

Originator::Originator()
{
    m_state = "";
    m_men = 0;
}


Originator::~Originator()
{
    if (m_men)
    {
        delete m_men;
        m_men = NULL;
    }
}

Originator::Originator(const State &state)
{
    m_state = state;
    m_men = 0;
}

Memento *Originator::GreateMemento()
{
    m_men = new Memento(m_state);
    return m_men;
}

State Originator::GetState()
{
    return m_state;
}

void Originator::SetState(const State &state)
{
    m_state = state;
    return;
}

void Originator::PrintState()
{
    std::cout << this->m_state << "..." << std::endl;
    return;
}

void Originator::SetMemento(Memento *men)
{
    return;
}

void Originator::RestoreToMemento(Memento *men)
{
    this->m_state = men->GetState();
}

 

测试

#include <iostream>
#include "Originator.h"
#include "Memento.h"

#define _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>

int main()
{
    Originator *ori = new Originator();

    ori->SetState("old");

    ori->PrintState();

    Memento *men = ori->GreateMemento();

    ori->SetState("new");

    ori->PrintState();

    ori->RestoreToMemento(men);

    ori->PrintState();

    if (ori)
    {
        delete ori;
        ori = NULL;
    }

    _CrtDumpMemoryLeaks();
    std::cout << "Hello World!\n"; 
}