Mediator模式

using System;using System.Linq;using System.Text;namespace DesignPatterns.Mediator{    //MediatorR    abstract class AbstractChatroom    {        public abstract void Register(Participant participant);        public abstract void Send(string from, string to, string message);    }    //ConcreteMediator    class Chatroom : AbstractChatroom    {        private System.Collections.Hashtable participants = new System.Collections.Hashtable();        public override void Register(Participant participant)        {            if (participants[participant.Name] == null)            {                participants[participant.Name] = participant;            }            participant.Chatroom = this;        }        public override void Send(string from, string to, string message)        {            Participant pto = (Participant)participants[to];            if (pto != null)            {                pto.Receive(from, message);            }        }    }    /**********************************************************************************/    //AbstractColleague    class Participant    {        private Chatroom chatroom;        private string name;        //Constructor        public Participant(string name)        {            this.name = name;        }        //Properties        public string Name        {            get { return name; }        }        public Chatroom Chatroom        {            set { chatroom = value; }            get { return chatroom; }        }        public void Send(string to, string message)        {            chatroom.Send(name, to, message);        }        public virtual void Receive(string from, string message)        {            Console.WriteLine("{0} to {1}:'{2}'", from, name, message);        }    }    //ConcreteColleaguel    class Beatle : Participant    {        //Constructor        public Beatle(string name)            : base(name)        { }        public override void Receive(string from, string message)        {            Console.Write("To a Beatle: ");            base.Receive(from, message);        }    }    //ConcreteColleague2    class NonBeatle : Participant    {        //Constructor        public NonBeatle(string name)            : base(name)        { }        public override void Receive(string from, string message)        {            Console.Write("To a non-Beatle:");            base.Receive(from, message);        }    }    class Program    {        //客户端调用如下：        static void Main(string[] args)        {            //create chatroom            Chatroom chatroom = new Chatroom();            //Create participants and register them            Participant George = new Beatle("George");            Participant Paul = new Beatle("Paul");            Participant Ringo = new Beatle("Ringo");            Participant John = new NonBeatle("John");            Participant Yoko = new NonBeatle("Yoko");            chatroom.Register(George);            chatroom.Register(Paul);            chatroom.Register(Ringo);            chatroom.Register(John);            chatroom.Register(Yoko);            //chatting participants            George.Send("Yoko", "你说错话了");            Yoko.Send("George", "哪里说错了?");            //Yoko.Send("John", "Hi John");            //Paul.Send("Ringo", "All you need is love");            //Ringo.Send("George", "My sweet Lord");            //Paul.Send("John", "Can't buy me love");            //John.Send("Yoko", "My sweet love");            Console.ReadKey();        }    }}

from:http://www.uml.org.cn/sjms/200906113.asp