protected function filtertextToArray(string $filter = null)
    {
        $resultArray = [];

        if (!empty($filter)) {
            $filterArray = explode(self::SEPARATOR_ENTRY, $filter);

            foreach ($filterArray as $key => $value) {
                $entryArray = explode(self::SEPARATOR_KEY_VALUE, $value);
                $resultArray[$entryArray[0]] = $entryArray[1];
            }
        }

        return $resultArray;
    }