code: public void set_rolling_file_threshold (Logger logger, long rft) {
        if (logger == null) {
            return;
        }
        if (rft < LOGGING_MIN_RFT) {
            rft = LOGGING_MIN_RFT;
        } else if (rft > LOGGING_MAX_RFT) {
            rft = LOGGING_MAX_RFT;
        }
        String prefix = LOGGING_FILE_TARGET + LOGGING_SEPARATOR;
        Enumeration all_appenders = logger.getAllAppenders();
        while (all_appenders.hasMoreElements()) {
            Appender appender = (Appender)all_appenders.nextElement();
            if (appender.getName().indexOf(prefix) != -1) {
                TangoRollingFileAppender trfa = (TangoRollingFileAppender) appender;
                trfa.setMaximumFileSize(rft * 1024);
            }
        }
    }
docs: Set the specified logger's rolling threshold