something like this:

public class NumericDocument extends PlainDocument {

   public void insertString(int offs, String str, AttributeSet a) throws
BadLocationException {
       StringBuffer sb = new StringBuffer(str.length());

       for(int i = 0; i < str.length(); i++) {
           char c = srt.charAt(i);
           if(Character.isDigit(c)) {
               sb.append(c);
           }
       }
       String nstr = sb.toString();
       if(nstr.length() > 0) {
           super.insertString(nstr);
       }
   }
}

--

____________

http://reader.imagero.com the best java image reader.

...

'best' is difficult to define, it depends a lot on the context.

I used a simple method to ensure my Calculator
http://www.physci.org/launcher.jsp#Calculator

Particularly the 'formatNumber' method,
it is invoked by a 'key typed' event, and
attempts to parse the number as a double
(in this case) - it it is not a double, it is
rejected.

You might get some ideas from looking
at that code.

HTH

--
Andrew Thompson
* http://www.PhySci.org/ PhySci software suite
* http://www.1point1C.org/ 1.1C - Superluminal!
* http://www.AThompson.info/andrew/ personal site

Extend javax.swing.InputVerifier and write its/their verify() method(s) accordingly.
<code>
 public boolean verify(thisTextField){
   String str = thisTextField.getText();
   int i = 0;
   while (i < str.length()){
     if (! Character.isDigit(str.charAt(i))){
       showErrorMessage();
       return false;
     }
     ++i;
   }
   return true;
 }
Then,
<code>
 yourJTextField1.setInputVerifier(yourInputVerifier1);
 yourJTextField2.setInputVerifier(yourInputVerifier2);
 //etc.
</code>

http://java.sun.com/developer/JDCTechTips/2001/tt1120.html#tip1

____________

http://reader.imagero.com the best java image reader.