Class URule

base/src/main/java/net/time4j/YOWElement.java:281–373

    }

    private static class URule<T extends ChronoEntity<T>>
        implements UnitRule<T> {

        //~ Methoden ------------------------------------------------------

        @Override
        public T addTo(
            T entity,
            long amount
        ) {

            if (amount == 0) {
                return entity;
            }

            int yow =
                MathUtils.safeCast(
                    MathUtils.safeAdd(
                        entity.get(YOWElement.INSTANCE).intValue(),
                        amount)
                    );

            PlainDate date = entity.get(CALENDAR_DATE);
            int woy = date.getWeekOfYear();
            Weekday dow = date.getDayOfWeek();

            if (woy == 53) {
                PlainDate test = PlainDate.of(yow, 26, dow);
                woy = test.getMaximum(Weekmodel.ISO.weekOfYear());
            }

            return entity.with(
                CALENDAR_DATE,
                PlainDate.of(yow, woy, dow));

        }

        @Override
        public long between(
            T start,
            T end
        ) {

            PlainDate startDate = start.get(CALENDAR_DATE);
            PlainDate endDate = end.get(CALENDAR_DATE);

            int startYOW = startDate.get(YOWElement.INSTANCE).intValue();
            int endYOW = endDate.get(YOWElement.INSTANCE).intValue();
            long delta = endYOW - startYOW;

            if (delta != 0) {
                int startWOY = getWeekOfYear(startDate);
                int endWOY = getWeekOfYear(endDate);

                if ((delta > 0) && (startWOY > endWOY)) {
                    delta--;
                } else if ((delta < 0) && (startWOY < endWOY)) {
                    delta++;