import java.awt.*;
 import java.util.*;
 import java.awt.event.*;
 import javax.swing.*;

 // This program demonstrates the use of the Swing InputVerifier class.
 // It creates two text fields; the first of the text fields expects the
 // string "pass" as input, and will allow focus to advance out of it
 // only after that string is typed in by the user.
 // Author: SUN Microsystems, API-Doc: Java 2 Platform SE v1.4.2 (2003)
 // modified by R. Mayer

 public class VerifierTest extends JFrame {
     public VerifierTest() {
       JTextField tf1 = new JTextField ("Gib hier \"FHD-FbI\" ein");
 	   getContentPane().add (tf1, BorderLayout.NORTH);
 	   tf1.setInputVerifier(new PassVerifier());

 	   JTextField tf2 = new JTextField ("... hier weitere Eingabe");
 	   getContentPane().add (tf2, BorderLayout.SOUTH);

 	   WindowListener l = new WindowAdapter() {
 	       public void windowClosing(WindowEvent e) {
 	           System.exit(0);
 	       }
 	   };
 	   addWindowListener(l);
     }

     class PassVerifier extends InputVerifier {
         public boolean verify(JComponent input) {
 	       JTextField tf = (JTextField) input;
 	       boolean test = "FHD-FbI".equals(tf.getText());
 	       if (!test)
 	       		Toolkit.getDefaultToolkit().beep();
 	       return test;
         }
     }

     public static void main(String[] args) {
         Frame f = new VerifierTest();
 	   f.pack();
 	   f.setVisible(true);
     }
 }