public function getColumnDefaultSort($columnKey)
	{
		if (isset($this->default_sort[$columnKey])) {
			return $this->default_sort[$columnKey];
		}

		return NULL;
	}
public function getColumnDefaultSort($columnKey)
	{
		if (isset($this->default_sort[$columnKey])) {
			return $this->default_sort[$columnKey];
		}

		return NULL;
	}
public function getColumnDefaultSort ( $ columnKey ) { if ( isset ( $ this -> default_sort [ $ columnKey ] ) ) { return $ this -> default_sort [ $ columnKey ] ; } return NULL ; }
Return default sort for column, if specified
@param string $columnKey
@return string|NULL
Return default sort for column if specified