如何实现Java监听器详解

package demo.listener;

/**
 * 监听器接口
 * dingwen
 * 2021/5/30 14:35
 **/
public interface DeveloperListener {
    /**
     * 工作
     *
     * @param event 事件
     */
    void work(Event event);

    /**
     * 研究
     *
     * @param event 事件
     */
    void study(Event event);
}

package demo.listener;

import java.util.Optional;
import java.util.function.Supplier;

/**
 * 开发者类
 * dingwen
 * 2021/5/30 14:34
 **/
public class Developer {
    private DeveloperListener developerListener;


    /**
     * 注册监听器
     *
     * @param developerListener 开发人员监听器
     */
    public void registerListener(DeveloperListener developerListener) {
        this.developerListener = developerListener;
    }

    /**
     * 工作
     */
    public void work() {
        if (developerListener != null) {
            this.developerListener.work(new Event(this));
        }
        System.out.println("developer work");
    }


    /**
     * 研究
     */
    public void study(){
        if (developerListener != null){
            this.developerListener.study(new Event(this));
            System.out.println("developer study");
        }
    }
}

package demo.listener;

/**
 * 事件对象
 * dingwen
 * 2021/5/30 14:32
 **/
public class Event {
    /**
     * 开发人员
     */
    private Developer developer;

    public Event(Developer developer) {
        this.developer = developer;
    }

    public Event() {
    }

    public Developer getDeveloper() {
        return developer;
    }

    public void setDeveloper(Developer developer) {
        this.developer = developer;
    }
}

package demo.listener;

/**
 * developer listener impl
 * dingwen
 * 2021/5/30 14:38
 **/
public class DeveloperListenerImpl implements DeveloperListener {
    @Override
    public void work(Event event) {
        Developer developer = event.getDeveloper();
        System.out.println("work developer impl listener");

    }

    @Override
    public void study(Event event) {
        Developer developer = event.getDeveloper();
        System.out.println("study developer impl listener");

    }
}

package demo.listener;

/**
 * 测试
 * dingwen
 * 2021/5/30 14:57
 **/
public class ListenerTest {
    public static void main(String[] args) {
        Developer developer = new Developer();
        developer.registerListener(new DeveloperListenerImpl());
        developer.study();
        developer.work();
    }
}