protected function getSortFieldName($sortField)
{
$class = new \ReflectionClass('\\eZ\\Publish\\API\\Repository\\Values\\Content\\Location');
foreach ($class->getConstants() as $constantName => $constantValue) {
if ($constantValue == $sortField && strpos($constantName, 'SORT_FIELD_') >= 0) {
return str_replace('SORT_FIELD_', '', $constantName);
}
}
return '';
}