public function getData($name, $default = null)
    {
        if (!isset($this->data[$name])) {
            $this->data[$name] = $default;
        } else {
            if (is_array($this->data[$name])) {
                $this->data[$name] = new GridState_Data($this->data[$name]);
            }
        }

        return $this->data[$name];
    }