How to use the components of Java event handling mechanism?

1. Event, event object, describes the change of phase.

For example, click an action in the GUI to start and stop the container in Spring Framework, such as computer startup, shutdown, hibernation, cache expiration, WeChat official account follow, unblock, etc.

2. The event source can be any object and has the ability to trigger events.

Generally, a listener is registered (or released) in this object, and the event is usually triggered here. A source may generate many different types of events and register listeners for different types of events. One or more listeners can be registered for each type of event.

3. Event listener, a class that implements a specific interface, needs to implement specific processing methods for specific events and must be registered on specific events.

Example

package event;
 
import java.util.Observable;
 
/**
 * Created by Joe on 2018/4/11
 */
public class Student implements java.util.Observer {
 
    private String name;
 
    public Student(String name) {
        this.name = name;
    }
 
    @Override
    public void update(Observable o, Object arg) {
        Teacher teacher = (Teacher) o;
 
        System.out.printf("学生%s观察到（实际是被通知）%s布置了作业《%s》 \n", this.name, teacher.getName(), arg);
    }
}

The above is the detailed content of How to use the components of Java event handling mechanism?. For more information, please follow other related articles on the PHP Chinese website!