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

1. Java Tutorial
2. Swing Event
3. Event

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();
        cal.setTimeInMillis(event.getWhen());
        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.add(ok);

    f.setSize(420, 250);
    f.setLocationRelativeTo(null);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.setVisible(true);
  }
}

15.1.Event
	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 Listeners
	15.1.4.	Enabling Other Low-level Events
	15.1.5.	Event mask
	15.1.6.	Managing Listener Lists with AWTEventMulticaster
	15.1.7.	Semantic Events
	15.1.8.	Semantic Event Listeners
	15.1.9.	Managing Listener Lists with EventListenerList
	15.1.10.	Writing 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