Event object has information about an event, that has happened. : Event « Swing Event « Java Tutorial

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.DateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class EventObject {
  public static void main(String[] args) {
    JFrame f = new JFrame();
    JButton ok = new JButton("Ok");

    ok.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent event) {
        Calendar cal = Calendar.getInstance();
        Locale locale = Locale.getDefault();
        String s = DateFormat.getTimeInstance(DateFormat.SHORT, locale).format(new Date());

        if (event.getID() == ActionEvent.ACTION_PERFORMED)
          System.out.println(" Event Id: ACTION_PERFORMED");

        System.out.println(" Time: " + s);

        String source = event.getSource().getClass().getName();
        System.out.println(" Source: " + source);

        int mod = event.getModifiers();
        if ((mod & ActionEvent.ALT_MASK) > 0)
          System.out.println("Alt ");

        if ((mod & ActionEvent.SHIFT_MASK) > 0)
          System.out.println("Shift ");

        if ((mod & ActionEvent.META_MASK) > 0)
          System.out.println("Meta ");

        if ((mod & ActionEvent.CTRL_MASK) > 0)
          System.out.println("Ctrl ");



    f.setSize(420, 250);

15.1.1.In the event model, there are three participants
15.1.2.Subclasses of AWTEvent
15.1.3.ActionEvent Example with One Button That Demonstrates Sources, Events, and Their ListenersActionEvent Example with One Button That Demonstrates Sources, Events, and Their Listeners
15.1.4.Enabling Other Low-level Events
15.1.5.Event maskEvent mask
15.1.6.Managing Listener Lists with AWTEventMulticasterManaging Listener Lists with AWTEventMulticaster
15.1.7.Semantic Events
15.1.8.Semantic Event Listeners
15.1.9.Managing Listener Lists with EventListenerListManaging Listener Lists with EventListenerList
15.1.10.Writing a Listener as an Anonymous ClassWriting a Listener as an Anonymous Class
15.1.11.Writing a listener as a nested class
15.1.12.Creating a Custom Event
15.1.13.Event object has information about an event, that has happened.
15.1.14.implements AWTEventListener
15.1.15.int java.awt.AWTEvent.getID()
15.1.16.Event source and listener
15.1.17.Process On Swing Event Thread