从保险柜的角度来看设计模式之备忘录模式

package memo;

//保险柜不能有任何开口（方法），只能做个保险柜
public interface SafeBox {

}

package memo;

public class Bank {
    //持有保险柜
    private SafeBox safeBox = null;

    //持有保险柜
    public void setSafeBox(SafeBox safeBox) {
        this.safeBox = safeBox;
    }
    
    //当主人要的时候返回保险柜
    public SafeBox getSafeBox() {
        return safeBox;
    }
    
}

package memo;

public class Me {
    private String money = "1000000000000000000000000$";
    
    
    //把存好钱的保险柜交给银行
    public SafeBox getBox()
    {
        return new SaveOrGetMoney(money);
    }
    
    //把钱拿出来
    public String getMoneyOfBox(SafeBox safeBox)
    {
        SaveOrGetMoney getMoney = (SaveOrGetMoney)safeBox;
        return getMoney.getMoney();
    }
    
    //存钱保险柜 拿钱出来
    class SaveOrGetMoney implements SafeBox
    {
        private String money;

        public SaveOrGetMoney(String money) {
            super();
            this.money = money;
        }
        //拿钱
        public String getMoney() {
            return money;
        }
        
        
    }
    
    
}