Set<WDate> (AllCalculationData acd) { // calculate days approved by daily approvals Set<WDate> approvedDays = new HashSet<WDate>(); for( WDate date : acd.getPayPeriodData().getActiveDates().getAllDates() ) { if( acd.isDayApproved(date) ) { approvedDays.add(date); } } return Collections.unmodifiableSet(approvedDays); }