Process key event for JTextField in Java

import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
/*  w  w  w  .  ja  v a  2  s  . c o  m*/
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.text.Document;

public class Main {
  // Test method
  public static void main(String[] args) {
    JFrame f = new JFrame();
    f.setLayout(new FlowLayout());
    final PassiveTextField ptf = new PassiveTextField(32);
    JTextField tf = new JTextField(32);
    JPanel p = new JPanel();
    JButton b = new JButton("OK");
    p.add(b);
    f.getContentPane().add(ptf);
    f.getContentPane().add(tf);
    f.getContentPane().add(p);

    ActionListener l = new ActionListener() {
      public void actionPerformed(ActionEvent evt) {
        System.out.println("Action event from a text field");
      }
    };
    ptf.addActionListener(l);
    tf.addActionListener(l);

    // Make the button the default button
    f.getRootPane().setDefaultButton(b);
    b.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent evt) {
        System.out.println("Content of text field: <" + ptf.getText() + ">");
      }
    });
    f.pack();
    f.setVisible(true);
  }
}

class PassiveTextField extends JTextField {
  public PassiveTextField() {
    this(null, null, 0);
  }

  public PassiveTextField(String text) {
    this(null, text, 0);
  }

  public PassiveTextField(int columns) {
    this(null, null, columns);
  }

  public PassiveTextField(String text, int columns) {
    this(null, text, columns);
  }

  public PassiveTextField(Document doc, String text, int columns) {
    super(doc, text, columns);
  }

  public void processComponentKeyEvent(KeyEvent evt) {
    switch (evt.getID()) {
    case KeyEvent.KEY_PRESSED:
    case KeyEvent.KEY_RELEASED:
      if (evt.getKeyCode() == KeyEvent.VK_ENTER) {
        return;
      }
      break;

    case KeyEvent.KEY_TYPED:
      if (evt.getKeyChar() == '\r') {
        return;
      }
      break;
    }

    super.processComponentKeyEvent(evt);
  }

}