Method parse

base/src/main/java/net/time4j/Duration.java:3535–3627

(
        String period,
        int from,
        int to,
        int typeID,
        List<Item<U>> items
    )

    }

    private static <U extends ChronoUnit> boolean parse(
        String period,
        int from,
        int to,
        int typeID,
        List<Item<U>> items
    ) throws ParseException {

        // alternative format?
        char ending = period.charAt(to - 1);

        if ((ending >= '0') && (ending <= '9') && (typeID != WEEK_BASED_TYPE)) {
            parseAlt(period, from, to, (typeID == CALENDAR_TYPE), items);
            return true;
        }

        if (from == to) {
            throw new ParseException(period, from);
        }

        StringBuilder num = null;
        boolean endOfItem = false;
        ChronoUnit last = null;
        int index = from;
        boolean decimal = false;

        for (int i = from; i < to; i++) {
            char c = period.charAt(i);

            if ((c >= '0') && (c <= '9')) {
                if (num == null) {
                    num = new StringBuilder();
                    endOfItem = false;
                    index = i;
                }
                num.append(c);
            } else if ((c == ',') || (c == '.')) {
                if ((num == null) || (typeID != CLOCK_TYPE)) {
                    throw new ParseException(
                        "Decimal separator misplaced: " + period, i);
                } else {
                    endOfItem = true;
                    long amount = parseAmount(period, num.toString(), index);
                    last = addParsedItem(SECONDS, last, amount, period, i, items);
                    num = null;
                    decimal = true;
                }
            } else if (endOfItem) {
                throw new ParseException(
                    "Unexpected char \'" + c + "\' found: " + period, i);
            } else if (decimal) {
                if (c != 'S') {
                    throw new ParseException("Second symbol expected: " + period, i);
                } else if (num == null) {
                    throw new ParseException("Decimal separator misplaced: " + period, i - 1);
                } else if (num.length() > 9) {
                    num.delete(9, num.length());
                }