索引
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。
Define an object that encapsulates how a set of objects interact.
Mediator promotes loose coupling by keeping objects from referring to each other explicitly, and it lets you vary their interaction independently.
一个典型的对象结构：
Mediator
ConcreteMediator
Colleague
在以下情况下可以使用 Mediator 模式：
Colleague-Mediator 的通信中，当一个感兴趣的事件发生时，Colleague 必须与其 Mediator 通信。
一种方式是使用 Observer 模式，将 Mediator 实现为一个 Observer，各 Colleague 作为 Subject。
另一种方式是在 Mediator 中定义一个特殊的通知接口，各 Colleague 在通信时直接调用该接口。
1 namespace MediatorPattern.Implementation1 2 { 3 public abstract class Colleague 4 { 5 protected Mediator _mediator; 6 7 public Colleague(Mediator mediator) 8 { 9 _mediator = mediator; 10 } 11 12 public abstract void Send(string message); 13 public abstract void Notify(string message); 14 } 15 16 public abstract class Mediator 17 { 18 public abstract void SendMessage(Colleague sender, string message); 19 } 20 21 public class ConcreteMediator : Mediator 22 { 23 private ConcreteColleague1 _colleague1; 24 private ConcreteColleague2 _colleague2; 25 26 public ConcreteColleague1 Colleague1 27 { 28 set { _colleague1 = value; } 29 } 30 31 public ConcreteColleague2 Colleague2 32 { 33 set { _colleague2 = value; } 34 } 35 36 public override void SendMessage(Colleague sender, string message) 37 { 38 if (sender == _colleague1) 39 { 40 _colleague2.Notify(message); 41 } 42 else if (sender == _colleague2) 43 { 44 _colleague1.Notify(message); 45 } 46 } 47 } 48 49 public class ConcreteColleague1 : Colleague 50 { 51 public ConcreteColleague1(Mediator mediator) 52 : base(mediator) 53 { 54 } 55 56 public override void Send(string message) 57 { 58 _mediator.SendMessage(this, message); 59 } 60 61 public override void Notify(string message) 62 { 63 Console.WriteLine("Colleague1 gets message: " + message); 64 } 65 } 66 67 public class ConcreteColleague2 : Colleague 68 { 69 public ConcreteColleague2(Mediator mediator) 70 : base(mediator) 71 { 72 } 73 74 public override void Send(string message) 75 { 76 _mediator.SendMessage(this, message); 77 } 78 79 public override void Notify(string message) 80 { 81 Console.WriteLine("Colleague2 gets message: " + message); 82 } 83 } 84 85 public class Client 86 { 87 public void TestCase1() 88 { 89 var mediator = new ConcreteMediator(); 90 91 var colleague1 = new ConcreteColleague1(mediator); 92 var colleague2 = new ConcreteColleague2(mediator); 93 94 mediator.Colleague1 = colleague1; 95 mediator.Colleague2 = colleague2; 96 97 colleague1.Send("How are you?"); 98 colleague2.Send("Fine, Thank you!"); 99 } 100 } 101 }
《设计模式之美》为 Dennis Gao 发布于博客园的系列文章，任何未经作者本人同意的人为或爬虫转载均为耍流氓。
设计模式之美：Mediator（中介者）,布布扣,bubuko.com
原文：http://www.cnblogs.com/gaochundong/p/design_pattern_mediator.html