Java SE (Java Platform, Standard Edition)

Hi- I've got a single threaded JFrame-based application in which I want to change the mouse pointer to indicate 'busy' when it's doing stuff eg. loading a file. So within my extended JFrame method for handling menu selections I've got:

public class Layout extends JFrame
{
    // For items in the main menu
    // (the sub-class contains either a JMenuItem or JCheckBoxMenuItem).
    abstract class MenuItem implements ActionListener
    {
        abstract JMenuItem menuItemAbs(); // get the menu item component
        abstract void handlerAbs(); // perform the menu's action

        // Menu item has been selected.
        public void actionPerformed(ActionEvent e)
        {
            Cursor cursor = Layout.this.getCursor();
            
            Layout.this.setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
            handlerAbs();
            Layout.this.setCursor(cursor);
        }

But the mouse pointer doesn't always change. If handler() just does some processing without user interaction, the pointer does change. But in the case of loading a file, where first the user selects the file using a JFileChooser, it doesn't.

Is this because JFileChooser does its own setCursor()? But even if it does, presumably it does another setCursor() to restore my WAIT_CURSOR before it returns, so why don't I see the WAIT_CURSOR while the file is loading (which takes seconds)?

Cheers
John

EDIT: BTW running under Linux, Java v6 update 7

Edited by: matth1j on Nov 12, 2008 2:15 AM