Java Utililty Methods Day of Week

List of utility methods to do Day of Week

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Description

The list of methods to do Day of Week are organized into topic(s).

Method

DategetFirstDayOfWeek(int year, int week)
get First Day Of Week 
Calendar cal = Calendar.getInstance();
cal.set(Calendar.YEAR, year);
cal.set(Calendar.MONTH, Calendar.JANUARY);
cal.set(Calendar.DATE, 1);
Calendar c = (Calendar) cal.clone();
c.add(Calendar.DATE, week * 7);
return getStartTimeOfWeek(c.getTime());
DategetFirstDayOfWeek(int year, int week)
get First Day Of Week 
Calendar c = new GregorianCalendar();
c.set(Calendar.YEAR, year);
c.set(Calendar.MONTH, Calendar.JANUARY);
c.set(Calendar.DATE, 1);
Calendar cal = (GregorianCalendar) c.clone();
cal.add(Calendar.DATE, week * 7);
return cal.getTime();
Date[]getFirstDayWeekly(final int year)
Returns an array of Dates starting with the first day of each week of the year. 
final GregorianCalendar cal = gregorianCalendarThreadLocal.get();
final GregorianCalendar testCal = new GregorianCalendar();
List<Date> dates = new ArrayList<>();
cal.setTime(trimDate(cal.getTime()));
cal.set(Calendar.YEAR, year);
cal.set(Calendar.MONTH, 0);
cal.set(Calendar.WEEK_OF_YEAR, 1);
cal.set(Calendar.DAY_OF_WEEK, cal.getFirstDayOfWeek());
...
DategetFirstMonthWeek(Date month)
Gets the first week which ends in specified month. 
Calendar firstWeek = Calendar.getInstance();
firstWeek.setTime(month);
firstWeek.set(Calendar.DATE, 1);
firstWeek.set(Calendar.HOUR, 0);
firstWeek.set(Calendar.MINUTE, 0);
firstWeek.set(Calendar.SECOND, 0);
firstWeek.set(Calendar.MILLISECOND, 0);
firstWeek.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
...
DategetFirstWeekdayBetween(Date fromDate, Date toDate, int dayOfWeek)
get First Weekday Between 
Calendar aDay = Calendar.getInstance();
aDay.setTime(fromDate);
while (aDay.getTime().before(toDate)) {
    if (aDay.get(Calendar.DAY_OF_WEEK) == dayOfWeek) {
        return aDay.getTime();
    aDay.add(Calendar.DATE, 1);
return null;
intgetFirstWeekofMonth(Date date1)
get First Weekof Month 
Calendar cld = Calendar.getInstance();
cld.setTime(date1);
cld.set(5, 1);
int week = cld.get(3);
return week;
intgetIntervalIncludeWeekend(Date date)
get Interval Include Weekend 
Calendar now = Calendar.getInstance();
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
int d = (int) ((now.getTimeInMillis() - calendar.getTimeInMillis()) / (24 * 60 * 60 * 1000));
return d;
intgetISO8601WeekOfYear(Date date)
Computes the ISO-8601 week of year for the given date See: http://stackoverflow.com/questions/147178/what-is-a-good-simple-way-to-compute-iso-8601-week-number 
Calendar calendar = Calendar.getInstance();
calendar.setMinimalDaysInFirstWeek(4);
calendar.setFirstDayOfWeek(Calendar.MONDAY);
calendar.setTime(date);
return calendar.get(Calendar.WEEK_OF_YEAR);
intgetIsoDayOfWeek(Date date)
Return the day of week. 
Calendar cal = Calendar.getInstance();
cal.setTimeInMillis(date.getTime());
int val = cal.get(Calendar.DAY_OF_WEEK) - 1;
return val == 0 ? 7 : val;
intgetIsoWeek(java.util.Date date)
Returns the week of the year according to the ISO 8601 specification. 
Calendar c = Calendar.getInstance();
c.setTimeInMillis(date.getTime());
c.setFirstDayOfWeek(Calendar.MONDAY);
c.setMinimalDaysInFirstWeek(4);
return c.get(Calendar.WEEK_OF_YEAR);