@Override public List<Period> generateRollingPeriods(Date date){
  Period period=createPeriod(date);
  List<Period> periods=Lists.newArrayList();
  periods.add(getPreviousPeriod(period));
  periods.add(period);
  return periods;
}

@ Override public List < Period > generateRollingPeriods ( Date date ) { Period period = createPeriod ( date ) ; List < Period > periods = Lists . newArrayList ( ) ; periods . add ( getPreviousPeriod ( period ) ) ; periods . add ( period ) ; return periods ; }
generates the last 2 six - months where the last one is the six - month which the given date is inside .
