备忘录设计模式笔记

package Memento;


public class Memento {
    private String state;//状态

    public Memento(String state){//构造对象
        this.state=state;
    }
    public String getState() {//获得状态
        return state;
    }

    public void setState(String state) {//设置状态
        this.state = state;
    }
}

package Memento;


public class Caretaker {
    private Memento memento;//备忘录

    public Memento getMemento() {//获得备忘录
        return memento;
    }

    public void setMemento(Memento memento) {//设置备忘录
        this.memento = memento;
    }
}

package Memento;

public class Originator {
    private String statue;//状态

    public String getStatue() {//获得状态
        return statue;
    }

    public void setStatue(String statue) {//设置状态
        this.statue = statue;
    }

    public Memento createMemento(String statue){//构建备忘录存储状态
        return new Memento(statue);
    }

    public void restoreMemento(Memento memento){//从备忘录拿出状态恢复状态
        this.setStatue(memento.getState());
    }
}

package Memento;

public class Test {
    public static void main(String[] args) {    
        Originator or=new Originator();//发起对象
        Caretaker cr=new Caretaker();//备忘录管理对象
        or.setStatue("old");//发起设置状态
        System.out.println(or.getStatue());
        cr.setMemento(or.createMemento(or.getStatue()));//备忘录管理对象设置备忘录
        or.setStatue("new");//发起设置新状态
        System.out.println(or.getStatue());
        or.restoreMemento(cr.getMemento());//发起对象恢复状态
        System.out.println(or.getStatue());
    }
}