🚀 go-pugleaf

Hi,

I'm using JBuilder 2 (latest patch) and Swing under Windows 95
(w/64MB RAM -- not the fastest thing in the world <s>).  

I'm trying to make it so that a JTextField will only accept valid
integer values (but I'd like to use a similar method for other kinds
of masked data entry).  I'm probably doing this the wrong way since
I'm still learning Java/Swing, but here is what I've done so far:

First, I've added the "implements DocumentListener" to the JDialog
class that contains the JTextFields in question.  

Then, I add the following event listeners to each fields (I know
that the event works because they do other things as well, such as
enable the "Save" button):

    txtST.getDocument().addDocumentListener(this);
    txtDX.getDocument().addDocumentListener(this);
    txtIQ.getDocument().addDocumentListener(this);
    txtHT.getDocument().addDocumentListener(this);

In the class itself, I handle the three events defined in the
DocumentListener interface (the first event handler -- ie the
insertUpdate event handler -- is the one I'm trying to use to
validate the number for now):

  public void insertUpdate(DocumentEvent e) {

    Document thisDoc = e.getDocument();
  
    if (thisDoc == txtDX.getDocument()) {
      try {
        int nValue = Integer.parseInt(txtDX.getText());
        // all is okay
      }
      catch (NumberFormatException exc) {
        // invalid number
        txtDX.setText("10");
      }
    } 
  
    pc.setModified(true);
    refreshButtons();
  }

  public void removeUpdate(DocumentEvent e) {
    pc.setModified(true);
    refreshButtons();
  }                          

  public void changedUpdate(DocumentEvent e) {
    pc.setModified(true);
    refreshButtons();
  }                          

When I run the application and enter an invalid value in the txtDX
JTextField control, the application freezes.

What am I doing wrong?  How should I implement this (and similar)
functionality?

Thanks,
Denis
The GURU guru                      
*New* GURPS tool now available at            
http://www.io.com/~denis/GURU.htm