Are TreePaths only valid in the TreeModel they originate from?

Question

I've got a JTree that lists our warehouse inventory, grouped by primary and secondary invenotry categories. (IE. "Printers" / "Laser" / "SomeLaserPrinter". ) The tree is populated through a SQL query.
I've got a checkbox that, when the value changes, decides if the tree should show or hide inventory categories that don't contain any inventory items at the moment.
What happens when I check/uncheck the box is that the tree is rebuilt from scratch according to it's value.
Now, if there is something selected in the tree when I click that checkbox, I want the same item to be selected and expanded when the tree is rebuilt. This is where I've been running in to problems.
The ActionListener for the checkbox is as follows:
//hideEmptyNodes is the JCheckBox
hideEmptyNodes.addActionListener( new ActionListener() {
      public void actionPerformed( ActionEvent e ) {
       try { //inventoryTree is the tree
            TreePath tp = inventoryTree.getSelectionPath();
             // the InventoryTree.fillWithInventory(boolean hideEmpty) method
             // clears and populates the tree from a SQL query.
       inventoryTree.fillWithInventory( hideEmptyNodes.isSelected() );
            inventoryTree.expandPath(tp);
            inventoryTree.setSelectionPath(tp);
     } catch ( SQLException ex ) {
       LGRUtils.debugErrln( "Error filling tree." );
    } );This, does NOT work, for some reason. I tried creating the TreePath from the new TreeModel, but still the same:
hideEmptyNodes.addActionListener( new ActionListener() {
      public void actionPerformed( ActionEvent e ) {
     try { //inventoryTree is the tree
          Object o = inventoryTree.getLastSelectedPathComponent();
           // the InventoryTree.fillWithInventory(boolean hideEmpty) method
           //clears and populates the tree from a SQL query.
       inventoryTree.fillWithInventory( hideEmptyNodes.isSelected() );
          TreePath tp = new TreePath(
              ((DefaultTreeModel)inventoryTree.getModel())
              //SimpleTreeNode extends DefaultMutableTreeNode and only
              //overrides the boolean equals(Object) method.
              .getPathToRoot((SimpleTreeNode)o));
          inventoryTree.setSelectionPath(tp);
     } catch ( SQLException ex ) {
       LGRUtils.debugErrln( "Error filling tree." );
    } );Quite frankly, I'm at a loss to how this stuff works. I've searched a bit around the forums, and I've found plenty of other people who have problems with setting the selection paths of trees. None of them have gotten their problems solved in any uniform way, it seems the solution varies from user to user.
Any pointers to a way of doing this, and making it work, would be greatly appreciated!
-christig

Answer 1

First thing I would tell you is that if you will not rebuild a tree from scratch, you will not have this problem!
Denis Krukovsky
http://dotuseful.sourceforge.net/