/**
* Sets or returns the current sort direction.
*
* @param integer $d The direction to sort by.
*
* @return integer If $d is null, returns the previously set value.
*/
public static function sortDir($d = null)
{
if (!is_null($d)) {
self::$_sortDir = $d;
} else {
return self::$_sortDir;
}
}
