code: static long parseParametersForPollingInterval(Map<String, String> parameters)
              throws JournalException {
          String intervalString =
                  parameters.get(PARAMETER_FOLLOW_POLLING_INTERVAL);
          if (intervalString == null) {
              intervalString = DEFAULT_FOLLOW_POLLING_INTERVAL;
          }
          Pattern p = Pattern.compile("([0-9]+)([HM]?)");
          Matcher m = p.matcher(intervalString);
          if (!m.matches()) {
              throw new JournalException("Parameter '"
                      + PARAMETER_FOLLOW_POLLING_INTERVAL
                      + "' must be an positive integer number of seconds, "
                      + "optionally followed by 'H'(hours), or 'M'(minutes)");
          }
          long interval = Long.parseLong(m.group(1)) * 1000;
          String factor = m.group(2);
          if ("H".equals(factor)) {
              interval *= 60 * 60;
          } else if ("M".equals(factor)) {
              interval *= 60;
          }
          return interval;
      }
docs: Find the polling interval that we will choose when checking for new
  journal files to appear.