Time: How to get the next friday?

How can I get the next friday with the Joda-Time API.

The LocalDate of today is today. It looks to me you have to decide whever you are before or after the friday of the current week. See this method:

private LocalDate calcNextFriday(LocalDate d) {
    LocalDate friday = d.dayOfWeek().setCopy(5);
    if (d.isBefore(friday)) {
        return d.dayOfWeek().setCopy(5);
    } else {
        return d.plusWeeks(1).dayOfWeek().setCopy(5);
    }
}

Is it possible to do it shorter or with a oneliner?

PS: Please don't advise me using JDKs date/time stuff. Joda-Time is a much better API.

Java 8 introduces java.time package (Tutorial) which is even better.

Solution 1:

java.time

With the java.time framework built into Java 8 and later (Tutorial) you can use TemporalAdjusters to get next or previous day-of-week.

private LocalDate calcNextFriday(LocalDate d) {
  return d.with(TemporalAdjusters.next(DayOfWeek.FRIDAY));
}

Solution 2:

It's possible to do it in a much easier to read way:

if (d.getDayOfWeek() < DateTimeConstants.FRIDAY) {
    return d.withDayOfWeek(DateTimeConstants.FRIDAY));
} else if (d.getDayOfWeek() == DateTimeConstants.FRIDAY) {
    // almost useless branch, could be merged with the one above
    return d;
} else {
    return d.plusWeeks(1).withDayOfWeek(DateTimeConstants.FRIDAY));
}

or in a bit shorter form

private LocalDate calcNextFriday(LocalDate d) {    
    if (d.getDayOfWeek() < DateTimeConstants.FRIDAY) {
        d = d.withDayOfWeek(DateTimeConstants.FRIDAY));
    } else {
        d = d.plusWeeks(1).withDayOfWeek(DateTimeConstants.FRIDAY));
    }    
    return d; // note that there's a possibility original object is returned
}

or even shorter

private LocalDate calcNextFriday(LocalDate d) {
    if (d.getDayOfWeek() >= DateTimeConstants.FRIDAY) {
        d = d.plusWeeks(1);
    }
    return d.withDayOfWeek(DateTimeConstants.FRIDAY);
}

PS. I didn't test the actual code! :)