Managing Listener Lists with EventListenerList : 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.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.EventListener;

import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.event.EventListenerList;

class KeyTextComponent extends JComponent {
  private EventListenerList actionListenerList = new EventListenerList();

  public KeyTextComponent() {
    KeyListener internalKeyListener = new KeyAdapter() {
      public void keyPressed(KeyEvent keyEvent) {
        System.out.println("keyPressed");
        if (actionListenerList != null) {
          int keyCode = keyEvent.getKeyCode();
          String keyText = KeyEvent.getKeyText(keyCode);
          ActionEvent actionEvent = new ActionEvent(this, ActionEvent.ACTION_PERFORMED, keyText);
          fireActionPerformed(actionEvent);
        }
      }
    };
    MouseListener internalMouseListener = new MouseAdapter() {
      public void mousePressed(MouseEvent mouseEvent) {
        requestFocusInWindow();
      }
    };

    addKeyListener(internalKeyListener);
    addMouseListener(internalMouseListener);
  }

  public void addActionListener(ActionListener actionListener) {
    actionListenerList.add(ActionListener.class, actionListener);
  }

  public void removeActionListener(ActionListener actionListener) {
    actionListenerList.remove(ActionListener.class, actionListener);
  }

  protected void fireActionPerformed(ActionEvent actionEvent) {
    EventListener listenerList[] = actionListenerList.getListeners(ActionListener.class);
    for (int i = 0, n = listenerList.length; i < n; i++) {
      ((ActionListener) listenerList[i]).actionPerformed(actionEvent);
    }
  }

  public boolean isFocusable() {
    return true;
  }
}

public class KeyTextComponentDemo {
  public static void main(String[] args) {
    JFrame aWindow = new JFrame();
    aWindow.setBounds(30, 30, 300, 300); // Size
    aWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    KeyTextComponent com = new KeyTextComponent();
    aWindow.add(com, "Center");
    com.addActionListener(new ActionListener() {

      public void actionPerformed(ActionEvent e) {
        System.out.println("action");

      }

    });

    aWindow.add(new JTextField(), "South");

    aWindow.setVisible(true); // Display the window
  }
}

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