BizProcDocument::getDocumentType

static function getDocumentType($documentId)
{
	if (mb_substr($documentId, 0, mb_strlen(self::DOCUMENT_TYPE_PREFIX)) == self::DOCUMENT_TYPE_PREFIX)
	{
		return $documentId;
	}

	$documentId = intval($documentId);
	if ($documentId <= 0)
	{
		throw new CBPArgumentNullException("documentId");
	}
	$fileRow = File::getList(array('select' => array('ID', 'STORAGE_ID'), 'filter' => array('ID' => $documentId)))->fetch();
	if (!$fileRow || empty($fileRow['STORAGE_ID']))
	{
		throw new SystemException("Element is not found");
	}

	return self::generateDocumentType($fileRow['STORAGE_ID']);
}