public function getAttribute( $name, $nsPrefix = NULL )
	{
		$data	= $nsPrefix ? $this->attributes( $nsPrefix, TRUE ) : $this->attributes();
		if( !isset( $data[$name] ) )
			throw new RuntimeException( 'Attribute "'.( $nsPrefix ? $nsPrefix.':'.$name : $name ).'" is not set' );
		return (string) $data[$name];
	}