Method Weekmodel

base/src/main/java/net/time4j/Weekmodel.java:175–235

(
        Weekday firstDayOfWeek,
        int minimalDaysInFirstWeek,
        final Weekday startOfWeekend,
        final Weekday endOfWeekend
    )

    //~ Konstruktoren -----------------------------------------------------

    private Weekmodel(
        Weekday firstDayOfWeek,
        int minimalDaysInFirstWeek,
        final Weekday startOfWeekend,
        final Weekday endOfWeekend
    ) {
        super();

        if (firstDayOfWeek == null) {
            throw new NullPointerException("Missing first day of week.");
        } else if (
            (minimalDaysInFirstWeek < 1)
            || (minimalDaysInFirstWeek > 7)
        ) {
            throw new IllegalArgumentException(
                "Minimal days in first week out of range: "
                + minimalDaysInFirstWeek);
        } else if (startOfWeekend == null) {
            throw new NullPointerException("Missing start of weekend.");
        } else if (endOfWeekend == null) {
            throw new NullPointerException("Missing end of weekend.");
        }

        this.firstDayOfWeek = firstDayOfWeek;
        this.minimalDaysInFirstWeek = minimalDaysInFirstWeek;
        this.startOfWeekend = startOfWeekend;
        this.endOfWeekend = endOfWeekend;

        this.woyElement =
            new CalendarWeekElement(
                "WEEK_OF_YEAR", CALENDAR_WEEK_OF_YEAR);
        this.womElement =
            new CalendarWeekElement(
                "WEEK_OF_MONTH", CALENDAR_WEEK_OF_MONTH);
        this.boundWoyElement =
            new CalendarWeekElement(
                "BOUNDED_WEEK_OF_YEAR", BOUNDED_WEEK_OF_YEAR);
        this.boundWomElement =
            new CalendarWeekElement(
                "BOUNDED_WEEK_OF_MONTH", BOUNDED_WEEK_OF_MONTH);
        this.dayOfWeekElement = new DayOfWeekElement();

        this.weekendCondition =
            context -> {
                int y = context.getYear();
                int m = context.getMonth();
                int dom = context.getDayOfMonth();
                Weekday wd =
                    Weekday.valueOf(GregorianMath.getDayOfWeek(y, m, dom));
                return ((wd == startOfWeekend) || (wd == endOfWeekend));
            };

        Set<ChronoElement<?>> set = new HashSet<>();
        set.add(this.woyElement);
        set.add(this.womElement);
        set.add(this.dayOfWeekElement);
        set.add(this.boundWoyElement);
        set.add(this.boundWomElement);