用Unity写设计模式-备忘录模式

备忘录模式介绍

在不破坏封装性的前提下，捕获一个对象的内部状态，并在该对象之外保存这个状态。这样以后就可将该对象恢复到原先保存的状态。

• Memento 纪念品(纪念品)

存储Originator对象的内部状态。 纪念品可以根据其发起人的自由裁量权，尽可能多地或尽可能少地存储发起人的内部状态。
防止除发起者以外的对象访问。 memento有两个有效的接口。 看管人看到了纪念品的一个狭窄的接口——它只能把纪念品传递给其他物体。 相比之下，发起者看到的是一个广泛的接口，一个允许它访问所有必要的数据来恢复自己到之前的状态。 理想情况下，只有产生纪念品的发起者才能访问纪念品的内部状态。

• Originator 发起者(SalesProspect)

创建一个包含当前内部状态快照的纪念品。
使用纪念品恢复其内部状态

• Caretaker 看守(Caretaker 临时)

负责保管纪念品
不要操作或检查纪念品的内容。

备忘录模式

using UnityEngine;
using System.Collections;

public class MementoStructure : MonoBehaviour
{
     
	void Start ( )
    {
     
        Originator o = new Originator();
        o.State = "On";

        // Store internal state
        Caretaker c = new Caretaker();
        c.Memento = o.CreateMemento();

        // Continue changing originator
        o.State = "Off";

        // Restore saved state
        o.SetMemento(c.Memento);

    }
}

/// 

/// The 'Originator' class
/// 
class Originator
{
     
    private string _state;

    // Property
    public string State
    {
     
        get {
      return _state; }
        set
        {
     
            _state = value;
            Debug.Log("State = " + _state);
        }
    }

    // Creates memento 
    public Memento CreateMemento()
    {
     
        return (new Memento(_state));
    }

    // Restores original state
    public void SetMemento(Memento memento)
    {
     
        Debug.Log("Restoring state...");
        State = memento.State;
    }
}

/// 

/// The 'Memento' class
/// 
class Memento
{
     
    private string _state;

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

    // Gets or sets state
    public string State
    {
     
        get {
      return _state; }
    }
}

/// 

/// The 'Caretaker' class
/// 
class Caretaker
{
     
    private Memento _memento;

    // Gets or sets memento
    public Memento Memento
    {
     
        set {
      _memento = value; }
        get {
      return _memento; }
    }
}

备忘录模式案例1

using UnityEngine;
using System.Collections;

//这段真实的代码演示了Memento模式，它暂时保存并恢复SalesProspect的内部状态。  

namespace MementoExample1
{
     
    public class MementoExample1 : MonoBehaviour
    {
     
        void Start()
        {
     
            SalesProspect s = new SalesProspect();
            s.Name = "Bruce";
            s.Phone = "(412) 256-6666";
            s.Budget = 25000.0;

            // Store internal state
            ProspectMemory m = new ProspectMemory();
            m.Memento = s.SaveMemento();

            // Continue changing originator
            s.Name = "Oliver";
            s.Phone = "(310) 209-8888";
            s.Budget = 1000000.0;

            // Restore saved state
            s.RestoreMemento(m.Memento);

        }
    }

    /// 

    /// The 'Originator' class
    /// 
    class SalesProspect
    {
     
        private string _name;
        private string _phone;
        private double _budget;

        // Gets or sets name
        public string Name
        {
     
            get {
      return _name; }
            set
            {
     
                _name = value;
                Debug.Log("Name:  " + _name);
            }
        }

        // Gets or sets phone
        public string Phone
        {
     
            get {
      return _phone; }
            set
            {
     
                _phone = value;
                Debug.Log("Phone: " + _phone);
            }
        }

        // Gets or sets budget
        public double Budget
        {
     
            get {
      return _budget; }
            set
            {
     
                _budget = value;
                Debug.Log("Budget: " + _budget);
            }
        }

        // Stores memento
        public Memento SaveMemento()
        {
     
            Debug.Log("\nSaving state --\n");
            return new Memento(_name, _phone, _budget);
        }

        // Restores memento
        public void RestoreMemento(Memento memento)
        {
     
            Debug.Log("\nRestoring state --\n");
            this.Name = memento.Name;
            this.Phone = memento.Phone;
            this.Budget = memento.Budget;
        }
    }

    /// 

    /// The 'Memento' class
    /// 
    class Memento
    {
     
        private string _name;
        private string _phone;
        private double _budget;

        // Constructor
        public Memento(string name, string phone, double budget)
        {
     
            this._name = name;
            this._phone = phone;
            this._budget = budget;
        }

        // Gets or sets name
        public string Name
        {
     
            get {
      return _name; }
            set {
      _name = value; }
        }

        // Gets or set phone
        public string Phone
        {
     
            get {
      return _phone; }
            set {
      _phone = value; }
        }

        // Gets or sets budget
        public double Budget
        {
     
            get {
      return _budget; }
            set {
      _budget = value; }
        }
    }

    /// 

    /// The 'Caretaker' class
    /// 
    class ProspectMemory
    {
     
        private Memento _memento;

        // Property
        public Memento Memento
        {
     
            set {
      _memento = value; }
            get {
      return _memento; }
        }
    }
}

备忘录模式案例2

/* 
提供一种方便地存储对象以前状态的方法  
＊  
*纪念品:存储在不同状态下的基本对象  
＊  
* originator:设置和获取当前目标纪念品的值。 创建新的备忘录并将当前值赋给它们  
＊  
*看守:持有一个列表，包含所有之前的版本的纪念品。 它可以存储和检索存储的纪念品  
 * 
 * */

namespace MementoExample2
{
     


    public class MementoExample2 : MonoBehaviour
    {
     

        Caretaker caretaker = new Caretaker();

        Originator originator = new Originator();

        int savedFiles = 0, currentArticle = 0;

        void Start()
        {
     
            // here we do some virtual typing and saving texts:
            Save("Tex1: Hello World, this is text example 1");
            Save("Text2: Ok here comes example number 2.");
            Save("Text3: And example number 3. Just testing.");
            Save("Text4: ....");

            // Here we do some virtual button pressing
            Debug.Log("Pressing Undo");
            Undo();
            Debug.Log("Pressing Undo");
            Undo();
            Debug.Log("Pressing Undo");
            Undo();
            Debug.Log("Pressing Redo");
            Redo();
        }


        // these methods below might get called when someone is pressing a button
        // you could easily implement it with unitys new ui system :)
        public void Save(string text)
        {
     
            originator.Set(text);
            caretaker.Add(originator.StoreInMemento());
            savedFiles = caretaker.GetCountOfSavedArticles();
            currentArticle = savedFiles;
        }

        public string Undo()
        {
     
            if (currentArticle > 0)
                currentArticle -= 1;

            Memento prev = caretaker.Get(currentArticle);
            string prevArticle = originator.RestoreFromMemento(prev);
            return prevArticle;
        }

        public string Redo()
        {
     
            if (currentArticle < savedFiles)
                currentArticle += 1;

            Memento next = caretaker.Get(currentArticle);
            string nextArticle = originator.RestoreFromMemento(next);
            return nextArticle;
        }

    }




    /// 

    /// the basic object that is stored in different states
    /// 
    public class Memento
    {
     
        public string article {
      get; protected set; }

        // Base Memento class that in this case just stores article strings!:)
        public Memento(string article)
        {
     
            this.article = article;
        }
    }


    /// 

    /// sets and gets values from the currently targeted memento. Creates new memenots and assigns current values to them.
    /// 
    public class Originator
    {
     
        public string article {
      get; protected set; }

        public void Set(string article)
        {
     
            Debug.Log("From Originator: Current Version of article is: [\"" + article + "\"]");
            this.article = article;
        }

        public Memento StoreInMemento()
        {
     
            Debug.Log("From Originator: Saving in Memento: [\"" + this.article + "\"]");
            return new Memento(this.article);
        }

        public string RestoreFromMemento(Memento memento)
        {
     
            article = memento.article;
            Debug.Log("From Originator: Previous Article saved in Memento: [\"" + article + "\"]");
            return article;
        }
    }


    /// 

    /// holds an list that contains all previous versions of the memento. it can store and retrieve stored mementos
    /// 
    public class Caretaker
    {
     
        List<Memento> savedArticles = new List<Memento>();

        public void Add(Memento m)
        {
     
            savedArticles.Add(m);
        }

        public Memento Get(int i)
        {
     
            return savedArticles[i];
        }

        public int GetCountOfSavedArticles()
        {
     
            return savedArticles.Count;
        }
    }


}