Mediator

    Mediator模式主要是用于对象间的通信，我们知道任何对象都不能是单独存在的，通信对象之间的通信，需要有个执行体，如果是对象直接去进行通信势必会增加对象的负担，

除此之外，还会增加对象之间的耦合度，要有一个专门的类进行通信，降低系统的复杂性，也是一种更为艺术的做法，下面是Mediator的示意图

Mediator模式，其实不过就是在Mediator类当中记录下，要进行通信类的指针，然后通过指针，对这两个类对象进行某种操作，即为通信：

#include"string"
#include"iostream"
using namespace std;
class Mediator;
class Colleage
{
public:
 Colleage(Mediator*tmp)
   {
   _mdt=tmp;
   }
virtual  string getState() =0;
virtual   void setState(string state)=0;
virtual   void Action()=0;    
private:
 Mediator*_mdt;

};
class ConcreteColleageA:public Colleage
{
   public:
   ConcreteColleage(Mediator*tmp):Colleage(tmp)
   {;}
   void setState(string st) 
   {_st=st;}
   string getState()
    {return _st;  }
   void action()
    {_mdt->DoActionFromAtoB();}
   private:
   string  _st;
};
class ConcreteColleageB:public Colleage
{
   public:
   ConcreteColleageB(Mediator*tmp):Colleage(tmp)
   {;}
   void setState(string st)
   {_st=st;}
   string getState()
    {return _st;}
   void action()
    {_mdt->DoActionFromBtoA();}
   private:
   string _st;
};
class Mediator
{
  public:
   Mediator()
   {;}
   setMediator(Colleage*tmpa,Colleage*tmpb)
    {this->tmpa=tmpa;
     this->tmpb=tmpb;}
   void DoActionFromAtoB()
   {tmpa->setState(tmpb->getState()); 
    }
   void DoActionFromBtoA()
   {   
     tmpa->setState(tmpb->getState()) ;
   }   
  private:
   Colleage*tmpa;
   Colleage*tmpb;
};
int main()
{
    Mediator*m=new Mediator();
    ConcreteColleageA*c1=new ConcreteColleageA();
    ConcreteColleageB*c2=new ConcreteColleageB();
    m->setMediator(c1,c2);
    c1->setState("old");
    c2->setState("new");
    c1->action();
    cout<getState()<<endl;
    cout<getState()<
  
   action();
    cout<getState()<<endl;
    cout<getState()<<endl;
    
}

其实这也算是bridge模式的一种应用吧，毕竟是对象组合的方式