public function addRow($id, $cells = array(), $replace = false)
    {
        $returnValue = (bool) false;

        
		if(!$replace && isset($this->rows[$id])){
			throw new common_Exception('the row with the id '.$id.' already exists');
		}else{
			$this->rows[$id] = $cells;
			//@TODO: implement a sort funciton?

			$returnValue = true;
		}
        

        return (bool) $returnValue;
    }