1、场景
实现一个聊天室功能，聊城室就是一个中介者，参与聊天的人就是同事对象,如下图所示
AbstractChatroom类：抽象聊天室类，做为Participant的交互的中介。
Register()方法:会员注册功能；Send()方法：发送消息功能。
Chatroom类：具体聊天室类，实现抽象聊天室类中的方法。
Participant类：参与者类，主要有发送消息Send()功能和接受消息Receive()功能。
Beatle类，NonBeatle类：参与者类的具体实现，实现父类Paticipant类中的方法。
2、代码
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1、抽象聊天室类AbstractChatroom及其具体聊天室Chatroom
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///<summary>
/// The 'Mediator' abstract class
///</summary>
abstract class AbstractChatroom
{
public abstract void Register(Participant participant);
public abstract void Send(string from, string to, string message);
}
///<summary>
/// The 'ConcreteMediator' class
///</summary>
class Chatroom : AbstractChatroom
{
private Dictionary<string, Participant> _participants =new Dictionary<string, Participant>();
public override void Register(Participant participant)
{
if (!_participants.ContainsValue(participant))
{
_participants[participant.Name] = participant;
}
participant.Chatroom = this;
}
public override void Send(string from, string to, string message)
{
Participant participant = _participants[to];
if (participant != null)
{
participant.Receive(from, message);
}
}
}
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2、参与者Participant类及其实现Beatle、NonBeatle
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///<summary>
/// The 'AbstractColleague' class
///</summary>
class Participant
{
private Chatroom _chatroom;
private string _name;
// Constructor
public Participant(string name)
{
this._name = name;
}
// Gets participant name
public string Name
{
get { return _name; }
}
// Gets chatroom
public Chatroom Chatroom
{
set { _chatroom = value; }
get { return _chatroom; }
}
// Sends message to given participant
public void Send(string to, string message)
{
_chatroom.Send(_name, to, message);
}
// Receives message from given participant
public virtual void Receive(string from, string message)
{
Console.WriteLine("{0} to {1}: '{2}'",from, Name, message);
}
}
///<summary>
/// A 'ConcreteColleague' class
///</summary>
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);
}
}
///<summary>
/// A 'ConcreteColleague' class
///</summary>
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);
}
}
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3、客户端代码
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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 Beatle("John");
Participant Yoko = new NonBeatle("Yoko");
chatroom.Register(George);
chatroom.Register(Paul);
chatroom.Register(Ringo);
chatroom.Register(John);
chatroom.Register(Yoko);
// Chatting participants
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");
// Wait for user
Console.ReadKey();
}
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3、运行结果
中介者模式（Mediator Pattern），定义一个中介对象来封装系列对象之间的交互。中介者使各个对象不需要显示地相互引用，从而使其耦合性松散，而且可以独立地改变他们之间的交互。中介者模式一般应用于一组对象以定义良好但是复杂的方法进行通信的场合，以及想定制一个分布在多个类中的行为，而不想生成太多的子类的场合。
本文转自 灵动生活 51CTO博客，原文链接：http://blog.51cto.com/smartlife/277270，如需转载请自行联系原作者