二十七.中介者模式

中介者模式：

       Mediator:用一个中介对象封装一系列的对象交互。中介者使各对象不需要显示的相互引用，从而使其耦合松散，而且可以独立改变他们之间的交互

注意：

       一般用于一组对象以定义良好但是复杂的方式进行通信的场合

       中介者很容易在系统中应用，也很容易在系统中误用。

       当系统出现“多对多“交互复杂的对象群时，不要急于使用中介者模式，而是先反思你的系统在设计上是不是合理。

Demo1:

       //抽象中介者类，定义了同事对象到中介者对象的接口

   abstract  class Mediator

    {

       //定义一个抽象的发送消息方法，得到同事对象和发送信息

       public abstract void Send(string message,Colleague colleague);

    }

       //具体中介者类

   class ConcreteMediator:Mediator

    {

       private ConcreteColleague1 colleague1;

       private ConcreteColleague2 colleague2;

       public ConcreteColleague1 Colleague1

       {

           set { colleague1 = value; }

       }

       public ConcreteColleague2 Colleague2

       {

           set { colleague2 = value; }

       }

       public override void Send(string message, Colleague colleague)

       {

           if (colleague == colleague1)

           {

                colleague2.Notify(message);

           }

           else

           {

                colleague1.Notify(message );

           }

       }

    }

       //抽象同事类

   abstract class Colleague

    {

       protected Mediator mediator;

       public Colleague(Mediator mediator)

       {

           this.mediator = mediator;//构造方法，得到中介者对象

       }

    }

       class ConcreteColleague1:Colleague

    {

       public ConcreteColleague1(Mediator mediator):base(mediator)

       {}

       public void Send(string message)

       {

           //发送消息时通常是中介者发送去的

           mediator.Send(message,this);

       }

       public void Notify(string message)

        {

           Console.WriteLine("同事1得到消息："+message);

       }

    }

   class ConcreteColleague2 : Colleague

    {

       public ConcreteColleague2(Mediator mediator)

           : base(mediator)

       { }

       public void Send(string message)

       {

           //发送消息时通常是中介者发送去的

           mediator.Send(message, this);

       }

       public void Notify(string message)

       {

           Console.WriteLine("同事2得到消息：" +message);

       }

    }

       static void Main(string[]args)

        {

           ConcreteMediator m = new ConcreteMediator();

           ConcreteColleague1 c1 =new ConcreteColleague1(m);

           ConcreteColleague2 c2 =new ConcreteColleague2(m);

           m.Colleague1 = c1;

           m.Colleague2 = c2;

            c1.Send("吃过饭了吗？");

           c2.Send("没有呢，你打算请客？");

           Console.ReadKey();

       }