Mediator pattern (C++)

definition

Use an intermediary object to encapsulate (encapsulate changes) a series of object interactions. The intermediary makes objects not need to explicitly refer to each other (compile-time dependency -> run-time dependency), thus making them loosely coupled (managing changes), and their interactions can be changed independently.

Application Scenario

In the process of software construction, multiple objects often interact with each other, and a complex reference relationship is often maintained between objects. If some requirements change, this direct reference relationship will face constant changes. .
In this case, we can use an "intermediary object" to manage the relationship between objects, avoid the tightly coupled reference relationship between interacting objects, and better resist changes.

structure

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code example

//Mediator.h
/****************************************************/
#ifndef MEDIATOR_H
#define MEDIATOR_H
#include <iostream>
using namespace std;
 
class User
{
    
    
public:
	User(string tname) {
    
     name = tname; };
	~User() {
    
    };
 
	string getName() {
    
     return name; };
	void setName(string tname) {
    
     name = tname; };
 
	void sendMessage(string message);
 
private:
	string name;
};
 
class ChatRoom
{
    
    
public:
	ChatRoom() {
    
    };
	~ChatRoom() {
    
    };
 
	static void showMessage(User *user, string message) {
    
    cout << " [" << user->getName() << "] : " << message << endl;};
};
 
void User::sendMessage(string message)
{
    
    
	ChatRoom::showMessage(this, message);
}


#endif

//test.cpp
/****************************************************/
#include "Mediator.h"
int main()
{
    
    
	User robert("Robert");
	User john("John");
	robert.sendMessage("Hi! John!");
	john.sendMessage("Hello! Robert!");
	
	return 0;
}

operation result