/**
     * Notifies all listeners that have registered interest for
     * notification on this event type.  The event instance 
     * is lazily created using the <code>event</code> 
     * parameter.
     *
     * @param event  the <code>ActionEvent</code> object
     * @see EventListenerList
     */
    protected void fireActionPerformed(ActionEvent event) {
        // Guaranteed to return a non-null array
        Object[] listeners = listenerList.getListenerList();
        ActionEvent e = null;
        // Process the listeners last to first, notifying
        // those that are interested in this event
        for (int i = listeners.length-2; i>=0; i-=2) {
            if (listeners[i]==ActionListener.class) {
                // Lazily create the event:
                if (e == null) {
                      String actionCommand = event.getActionCommand();
                      if(actionCommand == null) {
                         actionCommand = getActionCommand();
                      }
                      e = new ActionEvent(AbstractButton.this,
                                          ActionEvent.ACTION_PERFORMED,
                                          actionCommand,
                                          event.getWhen(),
                                          event.getModifiers());
                }
                ((ActionListener)listeners[i+1]).actionPerformed(e);
            }          
        }
    }