/**
* @param array $parameters
*
* @return SortParameterInterface[]|null
*/
protected function getSortParameters(array $parameters)
{
$sortParams = null;
$sortParam = $this->getParamOrNull($parameters, self::PARAM_SORT);
if ($sortParam !== null) {
foreach (explode(',', $sortParam) as $param) {
$isDesc = false;
empty($param) === false ? $isDesc = $param[0] === '-' : $this->exceptionThrower->throwBadRequest();
$sortField = ltrim($param, '+-');
empty($sortField) === false ?: $this->exceptionThrower->throwBadRequest();
$sortParams[] = $this->factory->createSortParam($sortField, $isDesc === false);
}
}
return $sortParams;
}
