protected function _getFilterData()
    {
        $rawFilterData = $this->request->getData();
        $filterData = [];
        foreach ($this->filterFields as $filterField => $options) {
            if (isset($rawFilterData[$filterField]) && $rawFilterData[$filterField] !== '') {
                $filterData[$filterField] = $rawFilterData[$filterField];
            }
        }

        return $filterData;
    }