/**
   * Recursively rebuild the tree nodes.
   *
   * @param root The full abstract path to the root saved layout directory.
   * @param local The current directory relative to root (null if none).
   * @param tnode The current parent tree node.
   */
  private void rebuildTreeModel(Path root, Path local, DefaultMutableTreeNode tnode) {
    TreeSet<Path> subdirs = new TreeSet<Path>();
    TreeSet<String> layouts = new TreeSet<String>();
    {
      Path current = new Path(root, local);
      File files[] = current.toFile().listFiles();
      if (files != null) {
        int wk;
        for (wk = 0; wk < files.length; wk++) {
          String name = files[wk].getName();
          if (files[wk].isDirectory()) subdirs.add(new Path(local, name));
          else if (files[wk].isFile()) layouts.add(name);
        }
      }
    }

    for (Path subdir : subdirs) {
      TreeData data = new TreeData(subdir);
      DefaultMutableTreeNode child = new DefaultMutableTreeNode(data, true);
      tnode.add(child);

      rebuildTreeModel(root, subdir, child);
    }

    for (String lname : layouts) {
      TreeData data = new TreeData(new Path(local, lname), lname);
      DefaultMutableTreeNode child = new DefaultMutableTreeNode(data, false);
      tnode.add(child);
    }
  }
  /**
   * Update the layouts tree.
   *
   * @param current The name of the current layout or <CODE>null</CODE> if none.
   */
  public void updateLayouts(Path current) throws PipelineException {
    DefaultMutableTreeNode root = null;
    {
      root = new DefaultMutableTreeNode(new TreeData(), true);

      {
        Path path = new Path(PackageInfo.getSettingsPath(), "layouts");
        rebuildTreeModel(path, new Path("/"), root);
      }

      DefaultTreeModel model = (DefaultTreeModel) pTree.getModel();
      model.setRoot(root);

      {
        Enumeration e = root.depthFirstEnumeration();
        if (e != null) {
          while (e.hasMoreElements()) {
            DefaultMutableTreeNode tnode = (DefaultMutableTreeNode) e.nextElement();
            pTree.expandPath(new TreePath(tnode.getPath()));
          }
        }
      }
    }

    pTree.clearSelection();
    if (current != null) {
      TreePath tpath = null;
      DefaultMutableTreeNode tnode = root;
      for (String comp : current.getComponents()) {
        DefaultMutableTreeNode next = null;
        Enumeration e = tnode.children();
        if (e != null) {
          while (e.hasMoreElements()) {
            DefaultMutableTreeNode child = (DefaultMutableTreeNode) e.nextElement();
            TreeData data = (TreeData) child.getUserObject();
            if (data.toString().equals(comp)) {
              tpath = new TreePath(child.getPath());
              next = child;
              break;
            }
          }
        }

        if (next == null) break;

        tnode = next;
      }

      if (tpath != null) {
        pTree.setSelectionPath(tpath);
        pTree.makeVisible(tpath);
      }
    }
  }