How to check a DateTime is an occurence of recurring event using Joda Time?

Question

I\'ve a DateTime that represent the beginning of a recurring event. A Days (daily period) will represent the recurring period. I assume that this rec

Answer 1

You can always use the add method in the Calendar class.

You could do the following -

Date date = "2013-06-27" ; 
Calendar cal = Calendar.getInstance();  
cal.setTime(date);  
cal.add(Calendar.DATE, 3); // add 3 days  
date = cal.getTime();  

And so on...

Answer 2

This runs all five checks in 180 ms seconds on my machine. Or about 27-checks/second, where you are checking a date 300 years in the future.

@Test
public void isOccurrence() {
    long startTime = System.currentTimeMillis();

    assertTrue(isOccurrence(new DateMidnight(2010, 1, 10), 3, new DateTime(2010, 1, 19, 0, 0)));
    assertFalse(isOccurrence(new DateMidnight(2010, 1, 10), 3, new DateTime(2010, 1, 18, 0, 0)));

    assertTrue(isOccurrence(new DateMidnight(2010, 1, 10), 3, new DateTime(2310, 1, 19, 0, 0)));
    assertFalse(isOccurrence(new DateMidnight(2010, 1, 10), 3, new DateTime(2310, 1, 20, 0, 0)));

    assertTrue(isOccurrence(new DateMidnight(2010, 1, 10), 3, new DateTime(2010, 1, 10, 0, 0)));

    System.out.println("elapsed=" + (System.currentTimeMillis() - startTime));
}

public boolean isOccurrence(DateMidnight startDate, int dayIncrement, DateTime testTime) {
    DateMidnight testDateMidnight = testTime.toDateMidnight();
    while (startDate.isBefore(testDateMidnight)) {
        startDate = startDate.plusDays(dayIncrement);
    }
    return startDate.equals(testDateMidnight);
}