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C++中的中介者模式

news 来源：原创 2024/9/29 5:43:02

中介者模式（Mediator Pattern）

实际应用

聊天室

空中交通管制系统

智能家居控制系统

总结

中介者模式（Mediator Pattern）

中介者模式是一种行为型设计模式，它定义了一个对象来封装一系列对象之间的交互。通过使用中介者模式，减少了对象之间的直接依赖，使对象的交互变得松散耦合，从而提高系统的可维护性和可扩展性。

实际应用

聊天室

-- 管理用户之间的消息传递。

#include <iostream>
#include <string>
#include <vector>
#include <memory>// 中介者接口
class ChatMediator {
public:virtual void sendMessage(const std::string& message, class User* user) = 0;virtual void addUser(std::shared_ptr<User> user) = 0;
};// 用户类
class User {
protected:ChatMediator& mediator;std::string name;
public:User(ChatMediator& mediator, const std::string& name) : mediator(mediator), name(name) {}virtual void send(const std::string& message) = 0;virtual void receive(const std::string& message) = 0;std::string getName() const { return name; }
};// 具体中介者
class ChatRoom : public ChatMediator {
private:std::vector<std::shared_ptr<User>> users;
public:void addUser(std::shared_ptr<User> user) override {users.push_back(user);}void sendMessage(const std::string& message, User* user) override {for (const auto& u : users) {if (u.get() != user) {u->receive(message);}}}
};// 具体用户
class ConcreteUser : public User {
public:ConcreteUser(ChatMediator& mediator, const std::string& name) : User(mediator, name) {}void send(const std::string& message) override {std::cout << name << " sends: " << message << std::endl;mediator.sendMessage(message, this);}void receive(const std::string& message) override {std::cout << name << " received: " << message << std::endl;}
};// 客户端代码
int main() {ChatRoom chatRoom;auto user1 = std::make_shared<ConcreteUser>(chatRoom, "User1");auto user2 = std::make_shared<ConcreteUser>(chatRoom, "User2");auto user3 = std::make_shared<ConcreteUser>(chatRoom, "User3");chatRoom.addUser(user1);chatRoom.addUser(user2);chatRoom.addUser(user3);user1->send("Hello everyone!");user2->send("Hi User1!");user3->send("Good morning!");return 0;
}

空中交通管制系统

-- 管理飞机之间的通信。

#include <iostream>
#include <string>
#include <vector>
#include <memory>// 中介者接口
class ATCMediator {
public:virtual void sendMessage(const std::string& message, class Aircraft* aircraft) = 0;virtual void addAircraft(std::shared_ptr<Aircraft> aircraft) = 0;
};// 飞机类
class Aircraft {
protected:ATCMediator& mediator;std::string id;
public:Aircraft(ATCMediator& mediator, const std::string& id) : mediator(mediator), id(id) {}virtual void send(const std::string& message) = 0;virtual void receive(const std::string& message) = 0;std::string getId() const { return id; }
};// 具体中介者
class ATC : public ATCMediator {
private:std::vector<std::shared_ptr<Aircraft>> aircrafts;
public:void addAircraft(std::shared_ptr<Aircraft> aircraft) override {aircrafts.push_back(aircraft);}void sendMessage(const std::string& message, Aircraft* aircraft) override {for (const auto& a : aircrafts) {if (a.get() != aircraft) {a->receive(message);}}}
};// 具体飞机
class ConcreteAircraft : public Aircraft {
public:ConcreteAircraft(ATCMediator& mediator, const std::string& id) : Aircraft(mediator, id) {}void send(const std::string& message) override {std::cout << "Aircraft " << id << " sends: " << message << std::endl;mediator.sendMessage(message, this);}void receive(const std::string& message) override {std::cout << "Aircraft " << id << " received: " << message << std::endl;}
};// 客户端代码
int main() {ATC atc;auto aircraft1 = std::make_shared<ConcreteAircraft>(atc, "AC1");auto aircraft2 = std::make_shared<ConcreteAircraft>(atc, "AC2");auto aircraft3 = std::make_shared<ConcreteAircraft>(atc, "AC3");atc.addAircraft(aircraft1);atc.addAircraft(aircraft2);atc.addAircraft(aircraft3);aircraft1->send("Requesting landing clearance.");aircraft2->send("Acknowledged. Waiting for clearance.");aircraft3->send("Holding pattern at 5000 feet.");return 0;
}

智能家居控制系统

-- 用中介者模式来管理不同设备之间的通信。

#include <iostream>
#include <string>
#include <vector>
#include <memory>// 中介者接口
class SmartHomeMediator {
public:virtual void sendMessage(const std::string& message, class Device* device) = 0;virtual void addDevice(std::shared_ptr<Device> device) = 0;
};// 设备类
class Device {
protected:SmartHomeMediator& mediator;std::string name;
public:Device(SmartHomeMediator& mediator, const std::string& name) : mediator(mediator), name(name) {}virtual void send(const std::string& message) = 0;virtual void receive(const std::string& message) = 0;std::string getName() const { return name; }
};// 具体中介者
class SmartHomeController : public SmartHomeMediator {
private:std::vector<std::shared_ptr<Device>> devices;
public:void addDevice(std::shared_ptr<Device> device) override {devices.push_back(device);}void sendMessage(const std::string& message, Device* device) override {for (const auto& d : devices) {if (d.get() != device) {d->receive(message);}}}
};// 具体设备
class Light : public Device {
public:Light(SmartHomeMediator& mediator, const std::string& name) : Device(mediator, name) {}void send(const std::string& message) override {std::cout << "Light " << name << " sends: " << message << std::endl;mediator.sendMessage(message, this);}void receive(const std::string& message) override {std::cout << "Light " << name << " received: " << message << std::endl;}
};class Thermostat : public Device {
public:Thermostat(SmartHomeMediator& mediator, const std::string& name) : Device(mediator, name) {}void send(const std::string& message) override {std::cout << "Thermostat " << name << " sends: " << message << std::endl;mediator.sendMessage(message, this);}void receive(const std::string& message) override {std::cout << "Thermostat " << name << " received: " << message << std::endl;}
};class SecurityCamera : public Device {
public:SecurityCamera(SmartHomeMediator& mediator, const std::string& name) : Device(mediator, name) {}void send(const std::string& message) override {std::cout << "Security Camera " << name << " sends: " << message << std::endl;mediator.sendMessage(message, this);}void receive(const std::string& message) override {std::cout << "Security Camera " << name << " received: " << message << std::endl;}
};// 客户端代码
int main() {SmartHomeController controller;auto light = std::make_shared<Light>(controller, "Living Room");auto thermostat = std::make_shared<Thermostat>(controller, "Main");auto camera = std::make_shared<SecurityCamera>(controller, "Front Door");controller.addDevice(light);controller.addDevice(thermostat);controller.addDevice(camera);light->send("Turning on the lights.");thermostat->send("Setting temperature to 22 degrees.");camera->send("Motion detected.");return 0;
}