乐在其中设计模式(C#) - 工厂方法模式(Factory Method Pattern)

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乐在其中设计模式(C#) - 工厂方法模式(Factory Method Pattern)

作者： webabcd


介绍
定义一个用于创建对象的接口，让子类决定将哪一个类实例化。Factory Method使一个类的实例化延迟到其子类。


示例
有SqlMessage和XmlMessage，用Factory Method来实例化它们。

MessageModel

using System; 
using System.Collections.Generic; 
using System.Text; 
 
namespace Pattern.FactoryMethod 
{ 
         /// <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; } 
                } 
        } 
}

 

AbstractMessage

using System; 
using System.Collections.Generic; 
using System.Text; 
 
namespace Pattern.FactoryMethod 
{ 
         /// <summary> 
         /// 操作Message抽象类（Product） 
         /// </summary> 
         public  abstract  class AbstractMessage 
        { 
                 /// <summary> 
                 /// 获取Message 
                 /// </summary> 
                 /// <returns></returns> 
                 public  abstract List<MessageModel> Get(); 
 
                 /// <summary> 
                 /// 插入Message 
                 /// </summary> 
                 /// <param name="mm">Message实体对象</param> 
                 /// <returns></returns> 
                 public  abstract  bool Insert(MessageModel mm); 
        } 
}

 

SqlMessage

using System; 
using System.Collections.Generic; 
using System.Text; 
 
namespace Pattern.FactoryMethod 
{ 
         /// <summary> 
         /// Sql方式操作Message（ConcreteProduct） 
         /// </summary> 
         public  class SqlMessage : AbstractMessage 
        { 
                 /// <summary> 
                 /// 获取Message 
                 /// </summary> 
                 /// <returns></returns> 
                 public  override List<MessageModel> Get() 
                { 
                        List<MessageModel> l =  new List<MessageModel>(); 
                        l.Add( new MessageModel( "SQL方式获取Message", DateTime.Now)); 
 
                         return l; 
                } 
 
                 /// <summary> 
                 /// 插入Message 
                 /// </summary> 
                 /// <param name="mm">Message实体对象</param> 
                 /// <returns></returns> 
                 public  override  bool Insert(MessageModel mm) 
                { 
                         // 代码略 
                         return  true; 
                } 
        } 
}

 

XmlMessage

using System; 
using System.Collections.Generic; 
using System.Text; 
 
namespace Pattern.FactoryMethod 
{ 
         /// <summary> 
         /// Xml方式操作Message（ConcreteProduct） 
         /// </summary> 
         public  class XmlMessage : AbstractMessage 
        { 
                 /// <summary> 
                 /// 获取Message 
                 /// </summary> 
                 /// <returns></returns> 
                 public  override List<MessageModel> Get() 
                { 
                        List<MessageModel> l =  new List<MessageModel>(); 
                        l.Add( new MessageModel( "XML方式获取Message", DateTime.Now)); 
 
                         return l; 
                } 
 
                 /// <summary> 
                 /// 插入Message 
                 /// </summary> 
                 /// <param name="mm">Message实体对象</param> 
                 /// <returns></returns> 
                 public  override  bool Insert(MessageModel mm) 
                { 
                         // 代码略 
                         return  true; 
                } 
        } 
}

 

AbstractMessageFactory

using System; 
using System.Collections.Generic; 
using System.Text; 
 
namespace Pattern.FactoryMethod 
{ 
         /// <summary> 
         /// 抽象Message工厂（Creator） 
         /// </summary> 
         public  abstract  class AbstractMessageFactory 
        { 
                 // An Operation 
 
                 /// <summary> 
                 /// 工厂方法 
                 /// </summary> 
                 /// <returns>AbstractMessage</returns> 
                 public  abstract AbstractMessage CreateMessage(); 
        } 
}

 

SqlMessageFactory

using System; 
using System.Collections.Generic; 
using System.Text; 
 
namespace Pattern.FactoryMethod 
{ 
         /// <summary> 
         /// SqlMessage工厂（ConcreteCreator） 
         /// </summary> 
         public  class SqlMessageFactory : AbstractMessageFactory 
        { 
                 /// <summary> 
                 /// 实现工厂方法，返回SqlMessage对象 
                 /// </summary> 
                 /// <returns></returns> 
                 public  override AbstractMessage CreateMessage() 
                { 
                         return  new SqlMessage(); 
                } 
        } 
}

 

XmlMessageFactory

using System; 
using System.Collections.Generic; 
using System.Text; 
 
namespace Pattern.FactoryMethod 
{ 
         /// <summary> 
         /// XmlMessage工厂（ConcreteCreator） 
         /// </summary> 
         public  class XmlMessageFactory : AbstractMessageFactory 
        { 
                 /// <summary> 
                 /// 实现工厂方法，返回XmlMessage对象 
                 /// </summary> 
                 /// <returns></returns> 
                 public  override AbstractMessage CreateMessage() 
                { 
                         return  new XmlMessage(); 
                } 
        } 
}

 

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.FactoryMethod; 
 
public partial  class FactoryMethod : System.Web.UI.Page 
{ 
         protected  void Page_Load( object sender, EventArgs e) 
        { 
                AbstractMessageFactory amf =  new SqlMessageFactory(); 
                AbstractMessage am = amf.CreateMessage(); 
 
                Response.Write(am.Insert( new MessageModel( "插入", DateTime.Now))); 
                Response.Write( "<br />"); 
                Response.Write(am.Get()[0].Message +  " " + am.Get()[0].PublishTime.ToString()); 
                Response.Write( "<br />"); 
 
 
                amf =  new XmlMessageFactory(); 
                am = amf.CreateMessage(); 
 
                Response.Write(am.Insert( new MessageModel( "插入", DateTime.Now))); 
                Response.Write( "<br />"); 
                Response.Write(am.Get()[0].Message +  " " + am.Get()[0].PublishTime.ToString()); 
        } 
}

 

 

运行结果
True
SQL方式获取Message 2007-5-4 22:34:39
True
XML方式获取Message 2007-5-4 22:34:39


参考
http://www.dofactory.com/Patterns/PatternFactory.aspx


OK
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     本文转自webabcd 51CTO博客，原文链接：http://blog.51cto.com/webabcd/344514 ，如需转载请自行联系原作者