设计模式之备忘录模式

组成

• Originator（发起者）：需要对状态进行保存和读取的成员
• Memotor（备忘录）：备忘录对象中包含存储发起人状态的成员变量
• Caretaker（备忘录管理者）：用于管理备忘录对象的实现类

类图

实例类图

代码

/// <summary>
    /// 游戏场景
    /// </summary>
    class GameSence : IShow
    {
        public Hero GameHero { get; set; }
        public Monster GameMonster { get; set; }

        public void LoadMemento(GameMemento memento)
        {
            GameHero = memento.MementoHero;
            GameMonster = memento.MementoMonster;
        }

        public GameMemento SaveMemento()
        {
            return new GameMemento(GameHero, GameMonster);
        }

        public void AttackMonster()
        {
            GameHero.AttackMonster(GameMonster);
        }

        public void Show()
        {
            IShow show = GameHero;
            show.Show();
            show = GameMonster;
            show.Show();
        }
    }

  /// <summary>
    /// 怪物
    /// </summary>
    class Monster : IShow, ICloneable
    {
        private int _hp;
        public int HP
        {
            get
            {
                return _hp >= 0 ? _hp : 0;
            }
            set
            {
                _hp = value;
                if (_hp <= 0)
                {
                    Console.WriteLine("Monster Dead");
                    _hp = 0;
                }
            }
        }

        #region IShow

        public void Show()
        {
            Console.WriteLine("Monster HP : " + HP);
        }

        #endregion

        public object Clone()
        {
            return MemberwiseClone();
        }
    }

/// <summary>
    /// 角色
    /// </summary>
    class Hero : IShow, ICloneable
    {
        private int _hp;
        public int HP
        {
            get { return _hp; }
            set { _hp = value; }
        }

        private int _mp;
        public int MP
        {
            get { return _mp; }
            set
            {
                _mp = value;
            }
        }

        public int Attack { get; set; }

        public void AttackMonster(Monster monster)
        {
            if (MP > 0)
            {
                Console.WriteLine("Attack : " + Attack);
                monster.HP = monster.HP - Attack;
                MP--;
            }
            else
            {
                Console.WriteLine("No Enough MP");
            }
        }

        #region IShow
        public void Show()
        {
            var info = string.Format("HP : {0} | MP : {1} | Attact : {2}", HP, MP, Attack);
            Console.WriteLine("Hero " + info);
        }
        #endregion

        public object Clone()
        {
            return MemberwiseClone();
        }
    }

   /// <summary>
    /// 游戏存档
    /// </summary>
    class GameMemento
    {
        public Hero MementoHero { get; set; }
        public Monster MementoMonster { get; set; }

        public GameMemento(Hero hero, Monster monster)
        {
            MementoHero = hero.Clone() as Hero;
            MementoMonster = monster.Clone() as Monster;
        }
    }

 /// <summary>
    /// 存档管理类
    /// </summary>
    internal class Caretaker
    {
        private GameMemento _memento;

        public void SetMemento(GameMemento memento)
        {
            ConsoleHelper.WriteImportString("Save Memento");
            _memento = memento;
        }

        public GameMemento GetMemento()
        {
            ConsoleHelper.WriteImportString("Load Memento");
            return _memento;
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            GameSence game = new GameSence();

            var hero = new Hero
            {
                Attack = 5,
                HP = 100,
                MP = 100
            };
            game.GameHero = hero;

            var monster = new Monster { HP = 400 };
            game.GameMonster = monster;

            game.Show();
            game.AttackMonster();
            game.Show();
            game.AttackMonster();
            game.Show();
            var caretaker = new Caretaker();
            caretaker.SetMemento(game.SaveMemento());
            game.AttackMonster();
            game.Show();
            game.LoadMemento(caretaker.GetMemento());
            game.Show();

            Console.ReadLine();
        }
    }

运行结果

优点：待补充

缺点：待补充