private function message( $message , $message_level )
	{
		if ( $message_level <= (int)$this->log_level )
		{
			if ( empty( $this->log_file_path ) )
			{
				error_log( $message );
			}
			else
			{
				if ( @file_put_contents( $this->log_file_path , $message . "\n" , FILE_APPEND ) === false )
				{
					$message = sprintf( "Unable to write to log file %s" , $this->log_file_path );

					error_log( self::getMessagePrefix( __CLASS__ , 'message' , 'fatal' ) . $message );

					throw new Exception( $message );
				}
			}

			return true;
		}

		return false;
	}