Does the JDK have anything in the API for determining numeric vs. alpabetic characters? In my client, I prevent the user from typing anything but numbers for the fields that require numbers. But I do this by manually running through a string array of numbers (0 - 9) and checking each character typed via a KeyListener. If the character typed is not a numeric, then the KeyEvent is consumed. It works fine functionally, but is there anything in the JDK that would decipher numeric from alphabetic characters for me? I have not seen anything that would do this.
If you want only to allow certain strings as valid input to a textfield, the standard way to achieve that, would be to use a JFormattedTextField with an appropriate AbstractFormatter-subclass or a Format-subclass.