Java Utililty Methods Calendar Week

int temp = getDayOfWeek(currentDate);
String result = "";
switch (temp) {
case Calendar.MONDAY:
    result = "A";
    break;
case Calendar.TUESDAY:
    result = "B";
...

ensureStateValid(calendar, date);
calendar.setTime(date);
setDateToZeroHour(calendar);
do {
    calendar.add(Calendar.DATE, 1);
} while (calendar.get(Calendar.DAY_OF_WEEK) != dayStartOfWeek);
calendar.add(Calendar.MILLISECOND, -1);
return calendar.getTime();
...

Calendar tmpCal = new GregorianCalendar(cal.getTimeZone());
tmpCal.set(Calendar.YEAR, cal.get(Calendar.YEAR));
tmpCal.set(Calendar.MONTH, cal.get(Calendar.MONTH));
tmpCal.set(Calendar.DATE, 1);
int day = tmpCal.get(Calendar.DAY_OF_WEEK);
if (day == dayOfWeek) {
    return tmpCal.get(Calendar.DATE);
while (day != dayOfWeek) {
    tmpCal.add(Calendar.DATE, 1);
    day = tmpCal.get(Calendar.DAY_OF_WEEK);
return tmpCal.get(Calendar.DATE);

switch (cal.get(Calendar.DAY_OF_WEEK)) {
case 1:
    break;
case 2:
    cal.add(Calendar.DATE, -1);
    break;
case 3:
    cal.add(Calendar.DATE, -2);
...

Calendar ret = (Calendar) calendar.clone();
ret.add(Calendar.DAY_OF_MONTH, -((ret.get(Calendar.DAY_OF_WEEK) + 5) % 7));
return ret;

int currDom = aCalendar.get(Calendar.DAY_OF_MONTH);
aCalendar.set(Calendar.DAY_OF_MONTH, 1);
int firstDowInMonth = aCalendar.get(Calendar.DAY_OF_WEEK);
aCalendar.set(Calendar.DAY_OF_MONTH, currDom);
return firstDowInMonth;

Calendar immediateDayOfWeek = (Calendar) current.clone();
immediateDayOfWeek.add(Calendar.DAY_OF_MONTH, 1);
while (immediateDayOfWeek.get(Calendar.DAY_OF_WEEK) != dayOfWeek) {
    immediateDayOfWeek.add(Calendar.DAY_OF_MONTH, 1);
return immediateDayOfWeek;

int last = cal.getFirstDayOfWeek() - 1;
if (last == 0) {
    last = Calendar.SATURDAY;
return last;

int firstDayOfWeek = cal.getFirstDayOfWeek();
if (firstDayOfWeek == Calendar.SUNDAY) {
    return Calendar.SATURDAY;
} else if (firstDayOfWeek == Calendar.MONDAY) {
    return Calendar.SUNDAY;
} else if (firstDayOfWeek == Calendar.TUESDAY) {
    return Calendar.MONDAY;
} else if (firstDayOfWeek == Calendar.WEDNESDAY) {
...

return calendar.get(Calendar.WEEK_OF_YEAR);