定义
中介者模式是一种行为设计模式，它减少了类之间的通信复杂性。这种模式提供了一个中介类，该类通常处理所有的通信，并支持易维护的方式来协调多个类。
示例代码
以下是一个简单的Java代码示例，演示了中介者模式的使用：
首先，我们定义一个中介者接口：
public interface Mediator {void sendMessage(String message, Colleague colleague);
}
然后，我们创建实现中介者接口的具体中介者类：
import java.util.ArrayList;
import java.util.List;public class ConcreteMediator implements Mediator {private List<Colleague> colleagues;public ConcreteMediator() {this.colleagues = new ArrayList<>();}public void addColleague(Colleague colleague) {this.colleagues.add(colleague);}@Overridepublic void sendMessage(String message, Colleague originator) {for (Colleague colleague : colleagues) {//don't tell ourselvesif (colleague != originator) {colleague.receive(message);}}}
}
接着，我们定义一个同事类：
public abstract class Colleague {protected Mediator mediator;public Colleague(Mediator m) {mediator = m;}//send a message via the mediatorpublic void send(String message) {mediator.sendMessage(message, this);}//get access to the mediatorpublic Mediator getMediator() {return mediator;}public abstract void receive(String message);
}
然后，我们创建实现同事抽象类的具体同事类：
public class ConcreteColleague extends Colleague {public ConcreteColleague(Mediator m) {super(m);}public void receive(String message) {System.out.println("Colleague Received: " + message);}
}
最后，我们可以在客户端代码中使用这些类：
public class MediatorPatternDemo {public static void main(String[] args) {ConcreteMediator mediator = new ConcreteMediator();ConcreteColleague colleague1 = new ConcreteColleague(mediator);ConcreteColleague colleague2 = new ConcreteColleague(mediator);mediator.addColleague(colleague1);mediator.addColleague(colleague2);colleague1.send("Hello, from colleague1!");colleague2.send("Hello, from colleague2!");}
}
在这个例子中，MediatorPatternDemo类使用ConcreteMediator类和ConcreteColleague类来创建一个中介者模式的示例。
