行为型设计模式之中介者模式(Mediator)

结构
意图	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。
适用性	一组对象以定义良好但是复杂的方式进行通信。产生的相互依赖关系结构混乱且难以理解。一个对象引用其他很多对象并且直接与这些对象通信,导致难以复用该对象。想定制一个分布在多个类中的行为，而又不想生成太多的子类。

 1 using System;
 2 
 3     class Mediator 
 4     {
 5         private DataProviderColleague dataProvider;
 6         private DataConsumerColleague dataConsumer;
 7         public void IntroduceColleagues(DataProviderColleague c1, DataConsumerColleague c2)
 8         {
 9             dataProvider = c1;
10             dataConsumer = c2;            
11         }
12         
13         public void DataChanged()
14         {
15             int i = dataProvider.MyData;
16             dataConsumer.NewValue(i);
17         }
18     }
19 
20     class DataConsumerColleague 
21     {
22         public void NewValue(int i)
23         {
24             Console.WriteLine("New value {0}", i);
25         }
26     }
27 
28     class DataProviderColleague
29     {
30         private Mediator mediator;
31         private int iMyData=0;
32         public int MyData 
33         {
34             get 
35             {
36                 return iMyData;
37             }
38             set 
39             {
40                 iMyData = value;
41             }
42         }
43         public DataProviderColleague(Mediator m)
44         {
45             mediator = m;
46         }
47 
48         public void ChangeData()
49         {
50             iMyData = 403;
51 
52             // Inform mediator that I have changed the data
53             if (mediator != null)
54                 mediator.DataChanged();    
55         }        
56     }
57 
58     /// <summary>
59     ///    Summary description for Client.
60     /// </summary>
61     public class Client
62     {
63         public static int Main(string[] args)
64         {            
65             Mediator m = new Mediator();
66             DataProviderColleague c1 = new DataProviderColleague(m);
67             DataConsumerColleague c2 = new DataConsumerColleague();
68             m.IntroduceColleagues(c1,c2);
69 
70             c1.ChangeData();
71 
72             return 0;
73         }
74     }

中介者模式