_collapsedImage = "collapsed.gif"; _collapsedImageFramework = "Ajax"; _expandedImage = "expanded.gif"; _expandedImageFramework = "Ajax"; _leafImage = "leaf.gif"; _leafImageFramework = "Ajax"; _treeNodeRenderer = AjaxSimpleTreeNodeRenderer.class.getName();
  public AjaxTreeModel(ITreeNode rootTreeNode) {    _rootTreeNode = rootTreeNode;    _expandedTreeNodes = new NSMutableSet();  }