Clean Code

Listing B-5 (continued)
SpreadsheetDate.java

---

389
Appendix B: 
org.jfree.date.SerialDate
436 if (SerialDate.isLeapYear(y)) {
437 mm = mm + 1;
438 }
439 }
440 final int dd = d;
441 return yy + mm + dd + 1;
442 }
443 
444 /**
445 * Calculate the day, month and year from the serial number.
446 */
447 private void calcDayMonthYear() {
448 
449 // get the year from the serial date
450 final int days = this.serial - SERIAL_LOWER_BOUND;
451 // overestimated because we ignored leap days
452 final int overestimatedYYYY = 1900 + (days / 365);
453 final int leaps = SerialDate.leapYearCount(overestimatedYYYY);
454 final int nonleapdays = days - leaps;
455 // underestimated because we overestimated years
456 int underestimatedYYYY = 1900 + (nonleapdays / 365);
457 
458 if (underestimatedYYYY == overestimatedYYYY) {
459 this.year = underestimatedYYYY;
460 }
461 else {
462 int ss1 = calcSerial(1, 1, underestimatedYYYY);
463 while (ss1 <= this.serial) {
464 underestimatedYYYY = underestimatedYYYY + 1;
465 ss1 = calcSerial(1, 1, underestimatedYYYY);
466 }
467 this.year = underestimatedYYYY - 1;
468 }
469 
470 final int ss2 = calcSerial(1, 1, this.year);
471 
472 int[] daysToEndOfPrecedingMonth
473 = AGGREGATE_DAYS_TO_END_OF_PRECEDING_MONTH;
474 
475 if (isLeapYear(this.year)) {
476 daysToEndOfPrecedingMonth
477 = LEAP_YEAR_AGGREGATE_DAYS_TO_END_OF_PRECEDING_MONTH;
478 }
479 
480 // get the month from the serial date
481 int mm = 1;
482 int sss = ss2 + daysToEndOfPrecedingMonth[mm] - 1;
483 while (sss < this.serial) {
484 mm = mm + 1;
485 sss = ss2 + daysToEndOfPrecedingMonth[mm] - 1;
486 }
487 this.month = mm - 1;
488 
489 // what's left is d(+1);
490 this.day = this.serial - ss2
491 - daysToEndOfPrecedingMonth[this.month] + 1;
492 
493 }
494 
495 }