設計模式（22）---備忘錄模式

時間 2019-12-12

標籤設計模式備忘錄简体版

原文原文鏈接

基本定義ide

備忘錄模式：在不破壞封裝性的前提下，捕獲一個對象的內部狀態，並在該對象以外保存這個狀態。這樣之後就能夠將該對象恢復到原先保存的狀態。this

解釋：簡單來講，就是保存一個對象在某一時刻的特定狀態，在之後須要的時候能夠將對象恢復到保存時的狀態。spa

基本代碼：code

class Originator
    {
        private string state;
        public string State
        {
            get { return state; }
            set { state = value; }
        }

        public Memento CreateMemento()
        {
            return new Memento(state);
        }

        public void SetMemento(Memento memento)
        {
            state = memento.State;
        }

        public void Display()
        {
            Console.WriteLine("State=" + state);
        }
    }

    class Memento
    {
        private string state;
        public string State
        {
            get { return state; }
        }

        public Memento(string state)
        {
            this.state = state;
        }
    }

    class Caretaker
    {
        private Memento memento1;
        public Memento Memento1
        {
            get { return memento1; }
            set { memento1 = value; }
        }
    }

客戶端調用：對象

Originator originator = new Originator();
            originator.State = "on";
            originator.Display();

            Caretaker caretaker = new Caretaker();
            caretaker.Memento1 = originator.CreateMemento();

            originator.State = "off";
            originator.Display();

            originator.SetMemento(caretaker.Memento1);
            originator.Display();

View Code

列舉具體實例：blog

打遊戲，保存一角色在打boss前的狀態，待打boss結束後再恢復到它以前的狀態。遊戲

class Program
    {
        static void Main(string[] args)
        {
            Role role = new Role(100, 100);
            Console.WriteLine("大戰前：");
            role.Display();

            Caretaker caretaker = new Caretaker();
            caretaker.memento = role.SaveMemento();

            role.SetBloodFlow(20);
            role.SetMagicPoint(20);
            Console.WriteLine("大戰");
            role.Display();

            role.RestoreMemento(caretaker.GetMemento());
            Console.WriteLine("恢復");
            role.Display();

            Console.Read();
        }
    }

    class Role
    {
        private int bloodFlow;
        private int magicPoint;

        public Role(int bloodFlow, int magicPoint)
        {
            this.bloodFlow = bloodFlow;
            this.magicPoint = magicPoint;
        }

        public int GetBloodFlow()
        {
            return bloodFlow;
        }

        public void SetBloodFlow(int bloodFlow)
        {
            this.bloodFlow = bloodFlow;
        }

        public int GetMagicPoint()
        {
            return magicPoint;
        }

        public void SetMagicPoint(int magicPoint)
        {
            this.magicPoint = magicPoint;
        }

        public void Display()
        {
            Console.WriteLine("用戶當前的狀態：");
            Console.WriteLine("血量：" + GetBloodFlow() + ";藍量：" + GetMagicPoint());
        }

        public Memento SaveMemento()
        {
            return new Memento(GetBloodFlow (),GetMagicPoint ());
        }

        public void RestoreMemento(Memento memento)
        {
            this.bloodFlow = memento.GetBloodFlow();
            this.magicPoint = memento.GetMagicPoint();
        }
    }

    class Memento
    {
        private int bloodFlow;
        private int magicPoint;

        public Memento(int bloodFlow, int magicPoint)
        {
            this.bloodFlow = bloodFlow;
            this.magicPoint = magicPoint;
        }

        public int GetBloodFlow()
        {
            return bloodFlow;
        }

        public void SetBloodFlow(int bloodFlow)
        {
            this.bloodFlow = bloodFlow;
        }

        public int GetMagicPoint()
        {
            return magicPoint;
        }

        public void SetMagicPoint(int magicPoint)
        {
            this.magicPoint = magicPoint;
        }
    }

    class Caretaker
    {
        public Memento memento;

        public Memento GetMemento()
        {
            return memento;
        }

        public void SetMemento(Memento memento)
        {
            this.memento = memento;
        }
    }