Changing a JTable's model

Question

Hello everyone,
I dont have a whole lot of experience w/ JTables and this problem has been troubling me for a while now. I have a JTable that significantly changes when the user hits the calculate button, so instead of going through the trouble of completely reformatting the table by adding/removing columns and table headers, I simple make a new model and set the table's model to the new one, and then call table.updateUI(). The problem is that my custom cell renderer that displays a down or up arrow depending on how the given column is sorted stops working. The sorter works properly and the table displays properly, but the arrows do not change from up to down or vise versa when a column is resorted. The whole process works just fine the first time, but the more times the user pushes the calculate button the more off it gets. I have added a flag in the actionPerformed method in my cell renderer that tells me when the table header is clicked. Every time the calculate button is hit, more flags appear when the table header is clicked. Therefore the arrows change position on odd numbers and do not on evens (because the evens cancel eachother out and the arrow appears to sit still), however the sorter still works properly. It seems as though somehow a new mouse listener or cell renderer is added after each time the calculate button is pressed. Either that or the entire table is not being reset somehow and something is still invisible in the background.
Here is some of my code.
// The initial table with no data
String[] str = {"class 1", "class 2", "class 3", "class 4", "class 5", "= GPA"};
String[][]  data= {{"", "", "", "", "", ""},
pmModel = new ProjectionModel(str, data);
mainTable = new JTable(pmModel);
mainTable.getTableHeader().setDefaultRenderer(new SortButtonRenderer());
// After the calculate button has been pushed:
// The table is reset here. TableSorter extends TableMap
    ProjectionModel newModel = new ProjectionModel(courseList, charList);
    TableSorter sorter = new TableSorter(newModel);
    // this method is shown below
    sorter.addMouseListenerToHeaderInTable(mainTable);
    sorter.sortedUp = false;
    mainTable.addNotify();
    mainTable.setModel(sorter);
    // SortButtonRenderer extends TableCellRenderer
    SortButtonRenderer renderer = new SortButtonRenderer();
    mainTable.getTableHeader().setDefaultRenderer(renderer);
    // set the arrow to DOWN on the first column
    renderer.setSelectedColumn(0);
    renderer.setSelectedColumn(0);
    mainTable.updateUI();
// This is the addMouseListenerToTable(JTable table) found in the TableSorter class
    public void addMouseListenerToHeaderInTable(JTable table) {
        final TableSorter sorter = this;
        final JTable tableView = table;
        tableView.setColumnSelectionAllowed(false);
        MouseAdapter listMouseListener = new MouseAdapter() {
            public void mouseClicked(MouseEvent e) {
                TableColumnModel columnModel = tableView.getColumnModel();
                int viewColumn = columnModel.getColumnIndexAtX(e.getX());
                int column = tableView.convertColumnIndexToModel(viewColumn);
                if (e.getClickCount() == 1 && column != -1) {
                  SortButtonRenderer renderer =
                        (SortButtonRenderer)tableView.getTableHeader().getDefaultRenderer();
                    //int shiftPressed = e.getModifiers()&InputEvent.SHIFT_MASK;
                    //boolean ascending = (shiftPressed == 0);
                    boolean ascending = (renderer.getLastColumn() == column && !sortedUp);
                    renderer.setLastColumn(column);
                    sorter.sortByColumn(column, ascending);
                    if (ascending) sortedUp = true;
                    else sortedUp = false;
                    renderer.setSelectedColumn(column);
                    // the flag that prints the column that is pressed
                    System.out.println(column + " " + sortedUp);
        JTableHeader th = tableView.getTableHeader();
        th.addMouseListener(listMouseListener); // it seems like i need a way to remove any
// previous mouseListeners here, i think this would solve the problem
    }The flag's output looks something like this:
< first time calculate button is clicked >
< column 0 is clicked> 0 false
< column 0 is clicked again > 0 true
< second time calculate button is clicked >
< column 0 is clicked >
0 false
0 true
notice they cancel eachother out so the arrow stays in the same position
< third time calculate button is clicked >
< column 0 is clicked >
0 false
0 true
0 false
notice they dont cancel eachother out, so the arrow changes positions
This problem is really bugging me. I appreciate any help. Thanks.
-kc

Answer 1

Well I fixed my problem but I kind of cheated...
I used a static variable in the class that inits the GUI to keep track of the MouseListeners that are added to the table headers by the TableSorter. In the TableSorter class's addMouseListenerToTableHeader(JTable table) class I added a line of code before the "th.addMouseListener(listListener)" line: "th.removeMouseListener(Projector.lastListener))"
It works but it kind of sucks. If there is a better way to do it that would be great. I'm sorry if you read through all of that stuff and then I ended up fixing my own problem anyway :(
Thanks anyway.
-kc