private function getColumns()
    {
        $columns = array();
        
        /**
         * Use call_user_func to make sure only public vars are returned
         */
        $vars = call_user_func('get_object_vars', $this);
        
        foreach ( $vars as $key => $value )
        {
            $columns[] = array(
                "name" => $key
            );
        }
        
        return $columns;
    }