How to prevent certain inputs in JSpinner?

[Biliang Zhou]

JSpinner provides us with both a display field and a pair of up and down buttons. Both are kept in sync with the SpinnerModel and are able to change the value.

Now the problem is: if the JSpinner is intended to be used to handle nothing but integers, how to prevent user from inputting characters?

I tried to use spinner.getEditor(), and added KeyEventListener to the editor, but it didn't turn out to be successful.

Gurus, help me...

[Michael Dunn]

((DefaultFormatter)((JSpinner.DefaultEditor)spinner.getEditor()).getTextField().getFormatter()).setAllowsInvalid(false);

[Biliang Zhou]

Man, I admire you...