原文:
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
[源码下载]
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

























































AbstractMessage































SqlMessage











































XmlMessage











































AbstractMessageFactory

























SqlMessageFactory



























XmlMessageFactory



























client





































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
[源码下载]