设计模式笔记：中介者模式

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中介者模式：用中介对象来封装对象之间的交互行为。

中介者使对象之间不用显式的引用，降低类对象之间的耦合。

抽象中介者类（Mediator ）

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// 抽象中介者类
class Mediator {
public:
	virtual void SetCustomer(Person *person) = 0;	// 设置买家
	virtual void SetSeller(Person *person) = 0;		// 设置卖家
	virtual void SendMsg(std::string msg, Person *person) = 0; // 消息传递接口
}

具体中介者（ConMediator ）

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// 具体中介者类
class ConMediator : public Mediator {
public:
	void SetCustomer(Person *person)
	{
		customer_ = person;
	}

	void SetSeller(Person *person)
	{
		seller_ = person;
	}

	void SendMsg(std::string msg, Person *person)
	{
		//若保存改为数组，则该处可用数组遍历来传递消息
		if (person == customer_) {
			seller_->GetMsg(msg);
		} else {
			customer_->GetMsg(msg);
		}
	}

private:
	// 此处指针可用数组来代替，这样能够实现单对多的对象交互
	Person *customer_;
	Person *seller_;
}

抽象对象（Object ）

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// 抽象对象
class Person {
public:
	virtual void SendMsg(std::string msg) = 0;
	virtual void GetMsg(std::string msg) = 0;
	virtual void SetMediator(Mediator *mediator) = 0;
}

具体对象（ConObject ）

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// 具体买家
class ConCustomer: public Person {
public:
	void SetMediator(Mediator *mediator)
	{
		mediator_ = mediator;
	}

	void SendMsg(std::string msg)
	{
		mediator_->SendMsg(msg, this);
	}

	void GetMsg(std::string msg)
	{
		std::cout << "Customer get mssage from Mediator: "<< msg << std::endl;
	}

private:
	Meadiator *mediator_;
}

// 具体卖家
class ConSeller: public Person {
public:
	void SetMediator(Mediator *mediator)
	{
		mediator_ = mediator;
	}

	void SendMsg(std::string msg)
	{
		mediator_->SendMsg(msg, this);
	}

	void GetMsg(std::string msg)
	{
		std::cout << "Seller get mssage from Mediator: "<< msg << std::endl;
	}

private:
	Meadiator *mediator_;
}

客户端调用

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int main() {
	Mediator *mediator = new ConMediator();
	Person *customer = new ConCustomer();
	Person *seller = new ConSeller();

	seller->SetMediator(mediator);
	customer->SetMediator(mediator);

	seller->SendMsg("I want to sell my SU7");
	customer->SendMsg("I want to buy SU7");
	delete mediator;
    delete customer; 
    delete seller;
	return 0;
}