设计模式 - Mediator

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。

一般来说，只有对于那种同事类之间是网状结构的关系，才会考虑使用中介者模式。可以将网状结构变为星状结构，使同事类之间的关系变的清晰一些。

class Mediator
{
public:Mediator(){}~Mediator(){}virtual void Notify() = 0;
};class Colleague
{
public:Colleague(Mediator* mediator){this->mediator = mediator;}virtual ~Colleague(){}protected:Mediator* mediator;
};class ColleagueProvidor: public Colleague
{
public:ColleagueProvidor(Mediator* mediator): Colleague(mediator){}~ColleagueProvidor(){}void ChangeProvidor(){cout<<"ColleagueProvidor::ChangeProvidor()"<<endl;mediator->Notify();}
};class ColleagueConsumer: public Colleague
{
public:ColleagueConsumer(Mediator* mediator): Colleague(mediator){}~ColleagueConsumer(){}void ChangeConsumer(){cout<<"ColleagueConsumer::ChangeConsumer()"<<endl;}
};class ConcreteMediator: public Mediator
{
public:ConcreteMediator(){}~ConcreteMediator(){}void Introduce(ColleagueProvidor* providor, ColleagueConsumer* consumer){this->providor = providor;this->consumer = consumer;}void Notify(){consumer->ChangeConsumer();}private:ColleagueProvidor* providor;ColleagueConsumer* consumer;
};