Clean Code

Listing B-1 (continued)
SerialDate.Java

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360
Appendix B: 
org.jfree.date.SerialDate
661 
662 /**
663 * Returns the earliest date that falls on the specified day-of-the-week
664 * and is AFTER the base date.
665 *
666 * @param targetWeekday a code for the target day-of-the-week.
667 * @param base the base date.
668 *
669 * @return the earliest date that falls on the specified day-of-the-week 
670 * and is AFTER the base date.
671 */
672 public static SerialDate getFollowingDayOfWeek(final int targetWeekday, 
673 final SerialDate base) {
674 
675 // check arguments...
676 if (!SerialDate.isValidWeekdayCode(targetWeekday)) {
677 throw new IllegalArgumentException(
678 "Invalid day-of-the-week code."
679 );
680 }
681 
682 // find the date...
683 final int adjust;
684 final int baseDOW = base.getDayOfWeek();
685 if (baseDOW > targetWeekday) {
686 adjust = 7 + Math.min(0, targetWeekday - baseDOW);
687 }
688 else {
689 adjust = Math.max(0, targetWeekday - baseDOW);
690 }
691 
692 return SerialDate.addDays(adjust, base);
693 }
694 
695 /**
696 * Returns the date that falls on the specified day-of-the-week and is
697 * CLOSEST to the base date.
698 *
699 * @param targetDOW a code for the target day-of-the-week.
700 * @param base the base date.
701 *
702 * @return the date that falls on the specified day-of-the-week and is 
703 * CLOSEST to the base date.
704 */
705 public static SerialDate getNearestDayOfWeek(final int targetDOW,
706 final SerialDate base) {
707 
708 // check arguments...
709 if (!SerialDate.isValidWeekdayCode(targetDOW)) {
710 throw new IllegalArgumentException(
711 "Invalid day-of-the-week code."
712 );
713 }
714 
715 // find the date...
716 final int baseDOW = base.getDayOfWeek();
717 int adjust = -Math.abs(targetDOW - baseDOW);
718 if (adjust >= 4) {
719 adjust = 7 - adjust;
720 }
721 if (adjust <= -4) {
722 adjust = 7 + adjust;