protected Calendar firstIntervalDate(
DateIntervalType intervalType, Date minDate, ColumnGroup columnGroup) {
Calendar c = GregorianCalendar.getInstance();
c.setLenient(false);
c.setTime(minDate);
if (YEAR.equals(intervalType)) {
c.set(Calendar.MONTH, 0);
c.set(Calendar.DAY_OF_MONTH, 1);
c.set(Calendar.HOUR, 0);
c.set(Calendar.MINUTE, 0);
c.set(Calendar.SECOND, 0);
c.set(Calendar.MILLISECOND, 0);
}
if (QUARTER.equals(intervalType)) {
int currentMonth = c.get(Calendar.MONTH);
int firstMonthYear = columnGroup.getFirstMonthOfYear().getIndex();
int rest = Quarter.getPositionInQuarter(firstMonthYear, currentMonth + 1);
c.add(Calendar.MONTH, rest * -1);
c.set(Calendar.DAY_OF_MONTH, 1);
c.set(Calendar.HOUR, 0);
c.set(Calendar.MINUTE, 0);
c.set(Calendar.SECOND, 0);
c.set(Calendar.MILLISECOND, 0);
}
if (MONTH.equals(intervalType)) {
c.set(Calendar.DAY_OF_MONTH, 1);
c.set(Calendar.HOUR, 0);
c.set(Calendar.MINUTE, 0);
c.set(Calendar.SECOND, 0);
c.set(Calendar.MILLISECOND, 0);
}
if (DAY.equals(intervalType) || DAY_OF_WEEK.equals(intervalType) || WEEK.equals(intervalType)) {
c.set(Calendar.HOUR, 0);
c.set(Calendar.MINUTE, 0);
c.set(Calendar.SECOND, 0);
c.set(Calendar.MILLISECOND, 0);
}
if (HOUR.equals(intervalType)) {
c.set(Calendar.MINUTE, 0);
c.set(Calendar.SECOND, 0);
c.set(Calendar.MILLISECOND, 0);
}
if (MINUTE.equals(intervalType)) {
c.set(Calendar.SECOND, 0);
c.set(Calendar.MILLISECOND, 0);
}
if (SECOND.equals(intervalType)) {
c.set(Calendar.MILLISECOND, 0);
}
return c;
}