存档模式 Memento

定义：在不破坏封装性的前提下，捕获一个对象的内部状态，并在该对象之外保存这个状态。这样就可以将该对象恢复到原先保存的状态

类型：行为类

类图：

class Memento{
public:
    Memento(int level,int life,int time):m_level(level),m_life(life),m_time(time){}
    Memento * GetState(){
        return this;
    }
    int GetLevel(){
        return m_level;
    }
    int Getlife(){
        return m_life;
    }
    int Gettime(){
        return m_time;
    }
private:
    int m_level;
    int m_life;
    int m_time;
};

class Role{
public:
    Role(int level,int life,int time):m_level(level),m_life(life),m_time(time){}
    void LoadMem(Memento * pmem){
        m_level = pmem->GetLevel();
        m_life = pmem->Getlife();
        m_time = pmem->Gettime();
    }

    Memento * CreateMem(){
        return new Memento(m_level,m_life,m_time);
    }

    void Upgrade(){
        this->m_level += 1 ;
        this->m_life += 10;
        this->m_time += 10;
    }
    void show(){
        cout<<"~~~~~~~~state~~~~~~~~~~"<<endl;
        cout<<"level : "<<m_level<<endl;
        cout<<"life : "<<m_life<<endl;
        cout<<"time : "<<m_time<<endl;
    }
private:
    int m_level;
    int m_life;
    int m_time;
};

class ManagerMem{
public:
    void AddMem(Memento * p){
        memvec.push_back(p);
    }
    Memento * GetMem(int index){
        return memvec[index];
    }
    ~ManagerMem(){
        vector<Memento *>::iterator it = memvec.begin();
        for(; it != memvec.end();it++)
            delete *it;
    }
private:
    vector<Memento *>  memvec;
};

int main(int argc,char * argv[]){
    ManagerMem * pmanager = new ManagerMem;
    Role * prole = new Role(1,20,30);
    prole->show();

    prole->Upgrade();
    prole->show();
    
    cout<<"存档管理器添加存档："<<endl;
    pmanager->AddMem(prole->CreateMem());

    prole->Upgrade(); prole->show();
    prole->Upgrade(); prole->show();
    //断电了，升级失败，只能恢复原来的存档
    
    cout<<"加载存档："<<endl;
    prole->LoadMem(pmanager->GetMem(0));
    prole->show();

    delete prole;
    delete pmanager;
}