通过简易例子讲解Java回调机制

package callback;
//回调接口
public interface CallBack {
  public void beWakedUp();
}

package callback;

public class Customer implements CallBack {
  //顾客同时持有酒店类的对象，后面定义
  private Hotel hotel;

  public Customer(Hotel hotel) {
    this.hotel = hotel;
  }

  @Override
  public void beWakedUp() {
    System.out.println("被叫醒了");
  }

  // 客户预约使用酒店的叫醒功能
  public void bookWakeService() {
    hotel.wakeService(this);
  }
  // 省略get set
}

package callback;

public class Hotel {

  public void wakeService(CallBack callBack) {
    System.out.println("顾客预约了叫醒服务");
    try {
      // 模拟时间过了一晚上
      Thread.sleep(3000);
      System.out.println("时间过去了一夜");
      callBack.beWakedUp();
    } catch (InterruptedException e) {

      e.printStackTrace();
    }
  }
}

package callback;

public class Main {
  
  public static void main(String[] args) {
    Hotel hotel = new Hotel();
    Customer customer = new Customer(hotel);
    customer.bookWakeService();
  }
}