中介者模式

// Mediator接口
public interface Mediator {
    void sendMessage(String message, Colleague colleague);
    void addColleague(Colleague colleague);
}

// ConcreteMediator类
import java.util.ArrayList;
import java.util.List;

public class ChatMediator implements Mediator {
    private List<Colleague> colleagues;

    public ChatMediator(){
        colleagues = new ArrayList<>();
    }

    @Override
    public void addColleague(Colleague colleague){
        colleagues.add(colleague);
    }

    @Override
    public void sendMessage(String message, Colleague sender){
        for(Colleague colleague : colleagues){
            // 不发送给自己
            if(colleague != sender){
                colleague.receive(message);
            }
        }
    }
}

// Colleague抽象类
public abstract class Colleague {
    protected Mediator mediator;

    public Colleague(Mediator mediator){
        this.mediator = mediator;
    }

    public abstract void send(String message);
    public abstract void receive(String message);
}

// ConcreteColleague类
public class User extends Colleague {
    private String name;

    public User(Mediator mediator, String name){
        super(mediator);
        this.name = name;
        mediator.addColleague(this);
    }

    @Override
    public void send(String message){
        System.out.println(this.name + " 发送消息: " + message);
        mediator.sendMessage(message, this);
    }

    @Override
    public void receive(String message){
        System.out.println(this.name + " 接收到消息: " + message);
    }
}

// 客户端代码
public class MediatorPatternDemo {
    public static void main(String[] args) {
        Mediator mediator = new ChatMediator();

        Colleague user1 = new User(mediator, "Alice");
        Colleague user2 = new User(mediator, "Bob");
        Colleague user3 = new User(mediator, "Charlie");

        user1.send("大家好！");
        System.out.println();
        user2.send("你好，Alice！");
        System.out.println();
        user3.send("大家晚上好！");
    }
}

// Mediator接口
public interface Mediator {
    void sendMessage(String message, User colleague);
    void addUser(User user);
}

// ConcreteMediator类
import java.util.ArrayList;
import java.util.List;

public class ChatRoom implements Mediator {
    private List<User> users;

    public ChatRoom(){
        users = new ArrayList<>();
    }

    @Override
    public void addUser(User user){
        users.add(user);
    }

    @Override
    public void sendMessage(String message, User sender){
        for(User user : users){
            if(user != sender){
                user.receive(message);
            }
        }
    }
}

// Colleague类
public abstract class User {
    protected Mediator mediator;
    protected String name;

    public User(Mediator mediator, String name){
        this.mediator = mediator;
        this.name = name;
        mediator.addUser(this);
    }

    public abstract void send(String message);
    public abstract void receive(String message);
}

// ConcreteColleague类
public class ChatUser extends User {
    public ChatUser(Mediator mediator, String name){
        super(mediator, name);
    }

    @Override
    public void send(String message){
        System.out.println(this.name + " 发送消息: " + message);
        mediator.sendMessage(message, this);
    }

    @Override
    public void receive(String message){
        System.out.println(this.name + " 接收到消息: " + message);
    }
}

// 客户端代码
public class MediatorPatternDemo {
    public static void main(String[] args) {
        Mediator chatRoom = new ChatRoom();

        User user1 = new ChatUser(chatRoom, "Alice");
        User user2 = new ChatUser(chatRoom, "Bob");
        User user3 = new ChatUser(chatRoom, "Charlie");

        user1.send("大家好！");
        System.out.println();
        user2.send("你好，Alice！");
        System.out.println();
        user3.send("大家晚上好！");
    }
}

// Mediator接口
public interface Mediator {
    void registerAirplane(Airplane airplane);
    void sendMessage(String message, Airplane airplane);
}

// ConcreteMediator类
import java.util.ArrayList;
import java.util.List;

public class AirTrafficControl implements Mediator {
    private List<Airplane> airplanes;

    public AirTrafficControl(){
        airplanes = new ArrayList<>();
    }

    @Override
    public void registerAirplane(Airplane airplane){
        airplanes.add(airplane);
    }

    @Override
    public void sendMessage(String message, Airplane sender){
        System.out.println("控制塔接收到来自 " + sender.getName() + " 的消息: " + message);
        for(Airplane airplane : airplanes){
            if(airplane != sender){
                airplane.receive(message);
            }
        }
    }
}

// Colleague类
public abstract class Airplane {
    protected Mediator mediator;
    protected String name;

    public Airplane(Mediator mediator, String name){
        this.mediator = mediator;
        this.name = name;
        mediator.registerAirplane(this);
    }

    public abstract void send(String message);
    public abstract void receive(String message);

    public String getName(){
        return this.name;
    }
}

// ConcreteColleague类
public class CommercialAirplane extends Airplane {
    public CommercialAirplane(Mediator mediator, String name){
        super(mediator, name);
    }

    @Override
    public void send(String message){
        System.out.println(this.name + " 发送消息: " + message);
        mediator.sendMessage(message, this);
    }

    @Override
    public void receive(String message){
        System.out.println(this.name + " 接收到消息: " + message);
    }
}

// 客户端代码
public class MediatorPatternDemo {
    public static void main(String[] args) {
        Mediator mediator = new AirTrafficControl();

        Airplane plane1 = new CommercialAirplane(mediator, "航班A");
        Airplane plane2 = new CommercialAirplane(mediator, "航班B");
        Airplane plane3 = new CommercialAirplane(mediator, "航班C");

        plane1.send("请求起飞许可");
        System.out.println();
        plane2.send("请求降落许可");
        System.out.println();
        plane3.send("报告当前位置");
    }
}