Java设计模式之备忘录模式实现对象状态的保存和恢复

@Data
public class Memento {
    /**
     * 攻击力
     */
    private int attack;
    /**
     * 防御力
     */
    private int defense;
    /**
     * 生命值
     */
    private int hp;
    public Memento(int attack, int defense, int hp) {
        this.attack = attack;
        this.defense = defense;
        this.hp = hp;
    }
}

@Data
public class Role {
    /**
     * 攻击力
     */
    private int attack;
    /**
     * 防御力
     */
    private int defense;
    /**
     * 生命值
     */
    private int hp;
    public Role(int attack, int defense, int hp) {
        this.attack = attack;
        this.defense = defense;
        this.hp = hp;
    }
    /**
     * 将当前对象储存值Memento中
     * @return
     */
    public Memento save(){
        return new Memento(attack,defense,hp);
    }
    /**
     * 从memento中获取状态;并恢复到当前状态
     * @param memento
     */
    public void restore(Memento memento){
        attack = memento.getAttack();
        defense = memento.getDefense();
        hp = memento.getHp();
    }
}

public class Caretaker {
    private List<Memento> mementos = new ArrayList<>();
    public void addMemento(Memento m){
        mementos.add(m);
    }
    public Memento getMemento(int index){
        return mementos.get(index);
    }
}

public class Demo {
    public static void main(String[] args) {
        Role role = new Role(100,50,20);
        Caretaker caretaker = new Caretaker();
        Memento memento = role.save();
        caretaker.addMemento(memento);
        // 攻击力+10
        role.setAttack(role.getAttack()+10);
        System.out.println(JSON.toJSONString(role));
        // 恢复
        role.restore(caretaker.getMemento(0));
        System.out.println(JSON.toJSONString(role));
    }
}