import java.awt.event.KeyListener;


public class TextFilter implements KeyListener  {

    @Override

    public void keyTyped(KeyEvent e) {
	char c = e.getKeyChar();
	if ( ((c < '0') || (c > '9')) && (c != KeyEvent.VK_BACK_SPACE)) {
	    e.consume();  // ignorer l'événement
	}
    }
}