code: private void sleepAndCheck(long backupFrequency) {
          long sleepTime = DEFAULT_SLEEP_TIME;
          for (long sleepCompleted = 0;
               continueBackup && sleepCompleted < backupFrequency;
               sleepCompleted += sleepTime) {
              sleep(sleepTime);
          }
      }
docs: /*
  Sleeps for a given amount of time, checking frequently
  to see if the process should be continued. This allows
  the the backup manager to wait between activity and also
  ensure that the higher level system shutdown process is
  not held up by waiting for a sleep to complete here.