public PeriodicityType getPeriodicityType() {
    return periodicityType;
  }
@Test
  public void testMillisecondPeriodicity() {
    // The length of the 'S' pattern letter matters on different platforms,
    // and can render different results on different versions of Android.
    // This test verifies that the periodicity is correct for different
    // pattern lengths.

    {
      RollingCalendar rc = new RollingCalendar("yyyy-MM-dd-S");
      assertEquals(PeriodicityType.TOP_OF_MILLISECOND, rc.getPeriodicityType());
    }

    {
      RollingCalendar rc = new RollingCalendar("yyyy-MM-dd-SS");
      assertEquals(PeriodicityType.TOP_OF_MILLISECOND, rc.getPeriodicityType());
    }

    {
      RollingCalendar rc = new RollingCalendar("yyyy-MM-dd-SSS");
      assertEquals(PeriodicityType.TOP_OF_MILLISECOND, rc.getPeriodicityType());
    }
  }