Listener for keypresses of menu mnemonics and accelerators

Question

Hello,
is it possible to intercept key events associated with instances of JMenu and JMenuItem? I mean: in case of a menu, a mnemonic is usually set by
menu.setMnemonic(KeyEvent.<whatever>));and in case of menu items both mnemonic and accelerator key stroke are set:
menuItem.setMnemonic(KeyEvent.<whatever>));
menuItem.setAccelerator(KeyStroke.getKeyStroke(
        KeyEvent.<whatever>, ActionEvent.<mask>));Is it possible to intercept events generated by pressing the set key combinations and consume them if necessary?
Thanks for any help.
Best regards,
vt

Answer 1

Dear Calypso,
here is a SSCCE (at least I hope it is correct ;) ).
package testmnemonic;
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import javax.swing.AbstractAction;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JTextField;
class MenuAction extends AbstractAction {
    MenuAction(String text, ImageIcon icon, String desc,
            Integer mnemonic) {
        super(text, icon);
        putValue(SHORT_DESCRIPTION, desc);
        putValue(MNEMONIC_KEY, mnemonic);
    public void actionPerformed(ActionEvent e) {
        // Is the condition met?
        if (!Main.field.getText().equals("x")) { // <-- BREAKPOINT HERE
            // If so, let's do something
            Main.label.setText("allowed");
public class Main {
    static JTextField field;
    static JLabel label;
    private static void createAndShowGUI() {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        // Menu
        JMenuBar menuBar = new JMenuBar();
        JMenu testMenu = new JMenu(new MenuAction("Test", null,
                "description", KeyEvent.VK_T));
        menuBar.add(testMenu);
        // Text field, actions are allowed according to its content
        field = new JTextField("x");
        // Info label
        label = new JLabel("---");
        frame.setJMenuBar(menuBar);
        Container pane = frame.getContentPane();
        pane.setLayout(new BorderLayout());
        pane.add(field, BorderLayout.PAGE_START);
        pane.add(label, BorderLayout.PAGE_END);
        frame.pack();
        frame.setVisible(true);
    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
}When I debug this code and press ALT+T (mnemonic for the menu), I would like the menu not to roll down (since the condition is "if the text in teh filed is not 'x'"). Nevertheless, in such a case the debugger never stops at the marked location ("if (!Main.field..." in actionPerformed(...)).
I guess I am probably doing something wrong, so any hints as to where should I catch the "mnemonic" events would be greatly appreciated.
Best regards,
vt