乐在其中设计模式(C#) - 中介者模式(Mediator Pattern)

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乐在其中设计模式(C#) - 中介者模式(Mediator Pattern)

作者： webabcd


介绍
用一个中介对象来封装一系列的对象交互。中介者使各对象不需要显式地相互引用，从而使其耦合松散，而且可以独立地改变它们之间的交互。


示例
有一个Message实体类，某个对象对它的操作有Send()和Insert()方法，现在用一个中介对象来封装这一系列的对象交互。

 

MessageModel

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

namespace Pattern.Mediator
{
         /// <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; }
                }
        }
}

 

AbstractMessageMediator

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

namespace Pattern.Mediator
{
         /// <summary>
         /// 抽象中介者（Mediator）
         /// </summary>
         public abstract class AbstractMessageMediator
        {
                 /// <summary>
                 /// 注册一个操作Message的对象
                 /// </summary>
                 /// <param name="AbstractMessage">AbstractMessage</param>
                 public abstract void Register(AbstractMessage AbstractMessage);

                 /// <summary>
                 /// 发送Message
                 /// </summary>
                 /// <param name="from">来自UserId</param>
                 /// <param name="to">发送到UserId</param>
                 /// <param name="mm">Message实体对象</param>
                 /// <returns></returns>
                 public abstract string Send( string from, string to, MessageModel mm);
        }
}

 

MessageMediator

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

namespace Pattern.Mediator
{
         /// <summary>
         /// 中介者（ConcreteMediator）
         /// </summary>
         public class MessageMediator : AbstractMessageMediator
        {
                 private Dictionary< string, AbstractMessage> _dictionary = new Dictionary< string, AbstractMessage>();

                 /// <summary>
                 /// 注册一个操作Message的对象
                 /// </summary>
                 /// <param name="abstractMessage">AbstractMessage</param>
                 public override void Register(AbstractMessage abstractMessage)
                {
                         if (!_dictionary.ContainsKey(abstractMessage.UserId))
                        {
                                _dictionary.Add(abstractMessage.UserId, abstractMessage);
                        }

                        abstractMessage.AbstractMessageMediator = this;
                }

                 /// <summary>
                 /// 发送Message
                 /// </summary>
                 /// <param name="from">来自UserId</param>
                 /// <param name="to">发送到UserId</param>
                 /// <param name="mm">Message实体对象</param>
                 /// <returns></returns>
                 public override string Send( string from, string to, MessageModel mm)
                {
                        AbstractMessage abstractMessage = _dictionary[to];
                         if (abstractMessage != null)
                        {
                                 return abstractMessage.Insert(from, mm);
                        }
                         else
                        {
                                 return null;
                        }
                }
        }
}

 

AbstractMessage

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

namespace Pattern.Mediator
{
         /// <summary>
         /// 操作Message抽象类（Colleague）
         /// </summary>
         public abstract class AbstractMessage
        {
                 private AbstractMessageMediator _abstractMessageMediator;
                 private string _userId;

                 /// <summary>
                 /// 构造函数
                 /// </summary>
                 /// <param name="userId">UserId</param>
                 public AbstractMessage( string userId)
                {
                         this._userId = userId;
                }

                 /// <summary>
                 /// UserId
                 /// </summary>
                 public string UserId
                {
                        get { return _userId; }
                }

                 /// <summary>
                 /// 中介者
                 /// </summary>
                 public AbstractMessageMediator AbstractMessageMediator
                {
                        get { return _abstractMessageMediator; }
                        set { _abstractMessageMediator = value; }
                }

                 /// <summary>
                 /// 发送Message（由客户端调用）
                 /// </summary>
                 /// <param name="to">发送到UserId</param>
                 /// <param name="mm">Message实体对象</param>
                 /// <returns></returns>
                 public string Send( string to, MessageModel mm)
                {
                         return _abstractMessageMediator.Send(_userId, to, mm);
                }

                 /// <summary>
                 /// 接受Message（由中介者调用）
                 /// </summary>
                 /// <param name="from">来自UserId</param>
                 /// <param name="mm">Message实体对象</param>
                 /// <returns></returns>
                 public abstract string Insert( string from, MessageModel mm);
        }
}

 

SqlMessage

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

namespace Pattern.Mediator
{
         /// <summary>
         /// Sql方式操作Message（ConcreteColleague）
         /// </summary>
         public class SqlMessage : AbstractMessage
        {
                 /// <summary>
                 /// 构造函数
                 /// </summary>
                 /// <param name="userId">UserId</param>
                 public SqlMessage( string userId)
                        : base(userId)
                {

                }

                 /// <summary>
                 /// 接受Message（由中介者调用）
                 /// </summary>
                 /// <param name="from">来自UserId</param>
                 /// <param name="mm">Message实体对象</param>
                 /// <returns></returns>
                 public override string Insert( string from, MessageModel mm)
                {
                         return "Sql方式插入Message（" + from + "发送给" + base.UserId + "）"
                                + " - 内容：" + mm.Message
                                + " - 时间：" + mm.PublishTime.ToString();
                }
        }
}

 

XmlMessage

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

namespace Pattern.Mediator
{
         /// <summary>
         /// Xml方式操作Message（ConcreteColleague）
         /// </summary>
         public class XmlMessage : AbstractMessage
        {
                 /// <summary>
                 /// 构造函数
                 /// </summary>
                 /// <param name="userId">UserId</param>
                 public XmlMessage( string userId)
                        : base(userId)
                {

                }

                 /// <summary>
                 /// 接受Message（由中介者调用）
                 /// </summary>
                 /// <param name="from">来自UserId</param>
                 /// <param name="mm">Message实体对象</param>
                 /// <returns></returns>
                 public override string Insert( string from, MessageModel mm)
                {
                         return "Xml方式插入Message（" + from + "发送给" + base.UserId + "）"
                                + " - 内容：" + mm.Message
                                + " - 时间：" + mm.PublishTime.ToString();
                }
        }
}

 

Test

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.Mediator;

public partial class Mediator : System.Web.UI.Page
{
         protected void Page_Load( object sender, EventArgs e)
        {
                AbstractMessageMediator messageMediator = new MessageMediator();

                AbstractMessage user1 = new SqlMessage( "user1");
                AbstractMessage user2 = new SqlMessage( "user2");
                AbstractMessage user3 = new XmlMessage( "user3");
                AbstractMessage user4 = new XmlMessage( "user4");

                messageMediator.Register(user1);
                messageMediator.Register(user2);
                messageMediator.Register(user3);
                messageMediator.Register(user4);

                Response.Write(user1.Send( "user2", new MessageModel( "你好！", DateTime.Now)));
                Response.Write( "<br />");
                Response.Write(user2.Send( "user1", new MessageModel( "我不好！", DateTime.Now)));
                Response.Write( "<br />");
                Response.Write(user1.Send( "user2", new MessageModel( "不好就不好吧。", DateTime.Now)));
                Response.Write( "<br />");
                Response.Write(user3.Send( "user4", new MessageModel( "吃了吗？", DateTime.Now)));
                Response.Write( "<br />");
                Response.Write(user4.Send( "user3", new MessageModel( "没吃，你请我？", DateTime.Now)));
                Response.Write( "<br />");
                Response.Write(user3.Send( "user4", new MessageModel( "不请。", DateTime.Now)));
                Response.Write( "<br />");
        }
}

 

 

运行结果
Sql方式插入Message（user1发送给user2） - 内容：你好！ - 时间：2007-5-19 23:43:19
Sql方式插入Message（user2发送给user1） - 内容：我不好！ - 时间：2007-5-19 23:43:19
Sql方式插入Message（user1发送给user2） - 内容：不好就不好吧。 - 时间：2007-5-19 23:43:19
Xml方式插入Message（user3发送给user4） - 内容：吃了吗？ - 时间：2007-5-19 23:43:19
Xml方式插入Message（user4发送给user3） - 内容：没吃，你请我？ - 时间：2007-5-19 23:43:19
Xml方式插入Message（user3发送给user4） - 内容：不请。 - 时间：2007-5-19 23:43:19


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


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