code: protected void doUpdate(final ItemData item, final WorkspaceStorageConnection con, ChangedSizeHandler sizeHandler)
        throws RepositoryException, InvalidItemStateException
     {
  
        if (item.isNode())
        {
           con.update((NodeData)item);
        }
        else
        {
           con.update((PropertyData)item, sizeHandler);
        }
     }
docs: Performs actual item data updating.
  
  @param item
  to update
  @param con
  connection
  @param sizeHandler
  @throws RepositoryException
  @throws InvalidItemStateException
  if the item not found