code: public static CmsTreeOpenState getVfsTreeState(HttpServletRequest request, String treeToken) {
  
          return (CmsTreeOpenState)request.getSession().getAttribute(
              getTreeOpenStateAttributeName(I_CmsGalleryProviderConstants.TREE_VFS, treeToken));
  
      }
docs: Convenience method for reading the saved VFS tree state from the session.<p>
  
  @param request the current request
  @param treeToken the tree token (may be null)
  
  @return the saved tree open state (may be null)