二十四种设计模式：原型模式(Prototype Pattern)

原型模式(Prototype Pattern)

介绍
用原型实例指定创建对象的种类，并且通过拷贝这个原型来创建新的对象。

示例
有一个Message实体类，现在要克隆它。

　　MessageModel

using System;
using System.Collections.Generic;
using System.Text;

namespace Pattern.Prototype
{
    /// <summary>
    /// Message实体类
    /// </summary>
    public class MessageModel
    {
        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="msg">Message内容</param>
        /// <param name="pt">Message发布时间</param>
        public MessageModel(string msg, DateTime pt)
        {
            this._message = msg;
            this._publishTime = pt;
        }

        private string _message;
        /// <summary>
        /// Message内容
        /// </summary>
        public string Message
        {
            get { return _message; }
            set { _message = value; }
        }

        private DateTime _publishTime;
        /// <summary>
        /// Message发布时间
        /// </summary>
        public DateTime PublishTime
        {
            get { return _publishTime; }
            set { _publishTime = value; }
        }
    }
}

　　ShallowCopy

using System;
using System.Collections.Generic;
using System.Text;

namespace Pattern.Prototype
{
    /// <summary>
    /// 浅拷贝
    /// </summary>
    public class ShallowCopy : ICloneable
    {
        /// <summary>
        /// 构造函数
        /// </summary>
        public ShallowCopy()
        {

        }

        /// <summary>
        /// 实现ICloneable的Clone()方法
        /// </summary>
        /// <returns></returns>
        public Object Clone()
        {
            return this.MemberwiseClone();
        }

        private MessageModel _mm;
        /// <summary>
        /// Message实体对象
        /// </summary>
        public MessageModel MessageModel
        {
            get { return _mm; }
            set { _mm = value; }
        }
    }
}

　　DeepCopy

using System;
using System.Collections.Generic;
using System.Text;

namespace Pattern.Prototype
{
    /// <summary>
    /// 深拷贝
    /// </summary>
    public class DeepCopy : ICloneable
    {
        /// <summary>
        /// 构造函数
        /// </summary>
        public DeepCopy()
        {

        }

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="mm">Message实体对象</param>
        public DeepCopy(MessageModel mm)
        {
            _mm = mm;
        }

        /// <summary>
        /// 实现ICloneable的Clone()方法
        /// </summary>
        /// <returns></returns>
        public Object Clone()
        {
            return new DeepCopy(new MessageModel(_mm.Message, _mm.PublishTime));
        }

        private MessageModel _mm;
        /// <summary>
        /// Message实体对象
        /// </summary>
        public MessageModel MessageModel
        {
            get { return _mm; }
            set { _mm = value; }
        }
    }
}

　　Client

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

using Pattern.Prototype;

public partial class Prototype : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        Response.Write("ShallowCopy演示如下：<br />");
        ShowShallowCopy();

        Response.Write("DeepCopy演示如下：<br />");
        ShowDeepCopy();
    }

    private void ShowShallowCopy()
    {
        ShallowCopy sc = new ShallowCopy();
        sc.MessageModel = new MessageModel("ShallowCopy", DateTime.Now);

        ShallowCopy sc2 = (ShallowCopy)sc.Clone();

        Response.Write(sc.MessageModel.Message);
        Response.Write("<br />");
        Response.Write(sc2.MessageModel.Message);
        Response.Write("<br />");

        sc.MessageModel.Message = "ShallowCopyShallowCopy";

        Response.Write(sc.MessageModel.Message);
        Response.Write("<br />");
        Response.Write(sc2.MessageModel.Message);
        Response.Write("<br />");
    }

    private void ShowDeepCopy()
    {
        DeepCopy sc = new DeepCopy();
        sc.MessageModel = new MessageModel("DeepCopy", DateTime.Now);

        DeepCopy sc2 = (DeepCopy)sc.Clone();

        Response.Write(sc.MessageModel.Message);
        Response.Write("<br />");
        Response.Write(sc2.MessageModel.Message);
        Response.Write("<br />");

        sc.MessageModel.Message = "DeepCopyDeepCopy";

        Response.Write(sc.MessageModel.Message);
        Response.Write("<br />");
        Response.Write(sc2.MessageModel.Message);
        Response.Write("<br />");
    }
}

　　运行结果
　　ShallowCopy演示如下：
　　ShallowCopy
　　ShallowCopy
　　ShallowCopyShallowCopy
　　ShallowCopyShallowCopy
　　DeepCopy演示如下：
　　DeepCopy
　　DeepCopy
　　DeepCopyDeepCopy
　　DeepCopy