Method normalize

base/src/main/java/net/time4j/StdNormalizer.java:100–263

(TimeSpan<? extends U> timespan)

    }

    @SuppressWarnings("unchecked")
    @Override
    public Duration<U> normalize(TimeSpan<? extends U> timespan) {

        int count = timespan.getTotalLength().size();
        List<TimeSpan.Item<U>> items = new ArrayList<>(count);
        long years = 0, months = 0, weeks = 0, days = 0;
        long hours = 0, minutes = 0, seconds = 0, nanos = 0;

        for (int i = 0; i < count; i++) {
            TimeSpan.Item<? extends U> item = timespan.getTotalLength().get(i);
            long amount = item.getAmount();
            U unit = item.getUnit();

            if (unit instanceof CalendarUnit) {
                switch ((CalendarUnit.class.cast(unit))) {
                    case MILLENNIA:
                        years =
                            MathUtils.safeAdd(
                                MathUtils.safeMultiply(amount, 1000),
                                years
                            );
                        break;
                    case CENTURIES:
                        years =
                            MathUtils.safeAdd(
                                MathUtils.safeMultiply(amount, 100),
                                years
                            );
                        break;
                    case DECADES:
                        years =
                            MathUtils.safeAdd(
                                MathUtils.safeMultiply(amount, 10),
                                years
                            );
                        break;
                    case YEARS:
                        years = MathUtils.safeAdd(amount, years);
                        break;
                    case QUARTERS:
                        months =
                            MathUtils.safeAdd(
                                MathUtils.safeMultiply(amount, 3),
                                months
                            );
                        break;
                    case MONTHS:
                        months = MathUtils.safeAdd(amount, months);
                        break;
                    case WEEKS:
                        weeks = amount;
                        break;
                    case DAYS:
                        days = amount;
                        break;
                    default:
                        throw new UnsupportedOperationException(unit.toString());