question: @ Override public List < Period > generateRollingPeriods ( DateTimeUnit dateTimeUnit ) { Calendar calendar = getCalendar ( ) ; List < Period > periods = Lists . newArrayList ( ) ; dateTimeUnit = calendar . minusDays ( dateTimeUnit , calendar . weekday ( dateTimeUnit ) - 1 ) ; dateTimeUnit = calendar . minusDays ( dateTimeUnit , 357 ) ; for ( int i = 0 ; i < 52 ; i ++ ) { periods . add ( createPeriod ( dateTimeUnit , calendar ) ) ; dateTimeUnit = calendar . plusWeeks ( dateTimeUnit , 1 ) ; } return periods ; }
target:  Generates the last 52 weeks where the last one is the week which the given date is inside.