abstract void selectValue(final BasicComboBoxUI ui);
public void actionPerformed(ActionEvent e) {
JComboBox comboBox = (JComboBox)e.getSource();
if (!comboBox.isPopupVisible()) {
comboBox.showPopup();
} else {
BasicComboBoxUI ui = ((BasicComboBoxUI)comboBox.getUI());
JList popupList = ui.popup.getList();
Action action = popupList.getActionMap().get(command);
if (action != null) {