你的位置:首页 > ASP.net教程

[ASP.net教程]《大话设计模式》学习笔记6:原型模式


  

说明:1..NET在System命名空间中提供了ICloneable接口,其中只有唯一的一个方法Clone(),只需要实现这个接口就可以完成原型模式。【即上图中Prototype用ICloneable代替】

   2.MemberwiseClone():创建一个浅表副本,方法是创建一个新对象,然后将当前对象的非静态字段复制到该新对象。 如果字段是值类型的,则对该字段执行逐位复制。 如果字段是引用类型,则复制引用但不复制引用的对象;因此,原始对象及其复本引用同一对象。【对于内部的Class对象和数组,则Copy一份地址;而对于其它内置的int/string/enum/struct/object类型,则Copy一份值(参考:C# 浅拷贝与深拷贝区别)】

 

一、简历复印示例:

  

1.具体原型类:

  public class Resume:ICloneable  {    private string name;    private string timeArea;    private string company;    public Resume(string name)    {      this.name = name;    }    public void SetWorkExperience(string timeArea,string company)    {      this.timeArea = timeArea;      this.company = company;    }    public void Display()    {      Console.WriteLine("{0} 工作经历:{1} {2}", name,timeArea, company);    }    public object Clone()    {      return (object)this.MemberwiseClone();    }  }

2.客户端调用:

  class Program  {    static void Main(string[] args)    {      Resume a = new Resume("a");      a.SetWorkExperience("1998-2000", "X公司");      Resume b = (Resume)a.Clone();      b.SetWorkExperience("1998-2006", "Y公司");      a.Display();      b.Display();    }  }

二、简历的深复制示例:

  

  说明:参考上图若Resume类中包含WorkExperience类,则在上面的[简历复印示例]中,Resume复制对WorkExperience的复制为浅复制,不同的Resume对象对WorkExperience指向同一个引用。

1.原型包含类:

  public class WorkExperience:ICloneable  {    public string WorkDate { get; set; }    public string Company { get; set; }    public object Clone()    {      return (object)this.MemberwiseClone();    }  }

2.具体原型类:

  public class Resume:ICloneable  {    private string name;    private WorkExperience workExperience;    public Resume(string name)    {      this.name = name;      workExperience = new WorkExperience();    }    //提供Clone方法调用的私有构造函数,以便克隆“工作经历”的数据    private Resume(WorkExperience workExperience)    {      this.workExperience = (WorkExperience)workExperience.Clone();    }    public void SetWorkExperience(string workDate,string company)    {      workExperience.WorkDate = workDate;      workExperience.Company = company;    }    public void Display()    {      Console.WriteLine("{0} 工作经历:{1} {2}", name,workExperience.WorkDate, workExperience.Company);    }    public object Clone()    {      Resume resume = new Resume(this.workExperience);      resume.name = this.name;      return resume;    }  }

3.客户端调用:

  class Program  {    static void Main(string[] args)    {      Resume a = new Resume("a");      a.SetWorkExperience("1998-2000", "X公司");      Resume b = (Resume)a.Clone();      b.SetWorkExperience("1998-2006", "Y公司");      a.Display();      b.Display();    }  }

 

原型模式其实就是从一个对象再创建另外一个可定制的对象,而不需要知道任何创建的细节。