How to enforce always sorting on a column in a TableView?

Question

Hello,
I have a requirement to always sort on a column in a TableView.
So basically, I need a TableColumn's SortType go from Ascending to Descending and back to Ascedning when user clicks on a column header repeatedly.
I guess that means making sure a TableView's SortOrder list is not empty. Am I right?
I tried to listen to SortOrder list changes like below:
tableView.getSortOrder().addListener(new ListChangeListener<TableColumn<String, ?>>() {
     @Override
     public void onChanged(final javafx.collections.ListChangeListener.Change<? extends TableColumn<String, ?>> arg0) {
if (tableView.getSortOrder().size() > 0) {
               // fine. nothing to do
          else {
// add the removed column back
Is this the right approach?
I'm not sure how to use arg0 and add the removed column back.
Can people with experience in this area provide some sample code?
Thanks.

Answer 1

The solution I came up with was to save the last column added to the SortOrder list to a map.
Whenever the SortOrder list becomes empty, I add the last saved column back to the SortOrder list.
That seems work.
Edited by: 925616 on Aug 3, 2012 3:33 PM
Edited by: 925616 on Aug 3, 2012 3:33 PM