设计模式-中介者模式

使用情境:封装一系列对象的交互方式,使得各对象之间不用显示互相调用,降低耦合.

// person.h
#ifndef PERSON_H
#define PERSON_H

#include "mediator.h"

class Person
{
public:
    Person(Mediator* tmp);
    virtual void Send(std::string msg) = 0;
    virtual void GetMsg(std::string msg) = 0;
protected:
    Mediator* m_mediator;
};

#endif // PERSON_H

// person.cpp
#include "person.h"

Person::Person(Mediator *tmp)
{
    m_mediator = tmp;
}

// producer.h
#ifndef PRODUCER_H
#define PRODUCER_H

#include "person.h"

class Producer : public Person
{
public:
    Producer(Mediator* tmp);
    void Send(std::string msg);
    void GetMsg(std::string msg);
};

#endif // PRODUCER_H

// producer.cpp
#include "producer.h"
#include <iostream>

Producer::Producer(Mediator *tmp) : Person(tmp)
{}

void Producer::Send(std::__cxx11::string msg)
{
    m_mediator->Send(msg, this);
}

void Producer::GetMsg(std::__cxx11::string msg)
{
    std::cout << "producer get msg : " << msg << std::endl;
}

// consumer.h
#ifndef CONSUMER_H
#define CONSUMER_H

#include "person.h"

class Consumer : public Person
{
public:
    Consumer(Mediator* tmp);
    void Send(std::__cxx11::string msg);
    void GetMsg(std::string msg);
};

#endif // CONSUMER_H

// consumer.cpp
#include "consumer.h"
#include <iostream>

Consumer::Consumer(Mediator *tmp) : Person(tmp)
{}

void Consumer::Send(std::__cxx11::string msg)
{
    m_mediator->Send(msg, this);
}

void Consumer::GetMsg(std::__cxx11::string msg)
{
    std::cout << "Consumer get msg : " << msg << std::endl;
}

// mediator.h
#ifndef MEDIATOR_H
#define MEDIATOR_H

#include <string>

class Person;

class Mediator
{
public:
    virtual void Send(std::string msg, Person *p) = 0;
};

#endif // MEDIATOR_H

// mediator.cpp
#include "mediator.h"

// concretemediator.h
#ifndef CONCRETEMEDIATOR_H
#define CONCRETEMEDIATOR_H

#include "mediator.h"
#include "producer.h"
#include "consumer.h"

class ConcreteMediator : public Mediator
{
public:
    Producer* m_producer;
    Consumer* m_consumer;
public:
    virtual void Send(std::__cxx11::string msg, Person *p);
};

#endif // CONCRETEMEDIATOR_H

// concretemediator.cpp
#include "concretemediator.h"

void ConcreteMediator::Send(std::__cxx11::string msg, Person *p)
{
    if(p == m_producer)
    {
        m_consumer->GetMsg(msg);
    }
    else if(p == m_consumer)
    {
        m_producer->GetMsg(msg);
    }
}

客户端:

// main.cpp
#include <iostream>
#include "producer.h"
#include "consumer.h"
#include "concretemediator.h"

using namespace std;

int main(int argc, char *argv[])
{
    ConcreteMediator* mediator = new ConcreteMediator();

    Producer* producer = new Producer(mediator);
    Consumer* consumer = new Consumer(mediator);

    mediator->m_consumer = consumer;
    mediator->m_producer = producer;

    producer->Send("I am producer");
    consumer->Send("I am consumer");

    return 0;
}