1 /* Copyright 2002-2025 CS GROUP
2 * Licensed to CS GROUP (CS) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * CS licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.orekit.time;
18
19 import java.io.IOException;
20 import java.io.Serializable;
21 import java.util.regex.Matcher;
22 import java.util.regex.Pattern;
23
24 import org.orekit.errors.OrekitIllegalArgumentException;
25 import org.orekit.errors.OrekitInternalError;
26 import org.orekit.errors.OrekitMessages;
27 import org.orekit.utils.formatting.FastLongFormatter;
28
29 /** Class representing a date broken up as year, month and day components.
30 * <p>This class uses the astronomical convention for calendars,
31 * which is also the convention used by <code>java.util.Date</code>:
32 * a year zero is present between years -1 and +1, and 10 days are
33 * missing in 1582. The calendar used around these special dates are:</p>
34 * <ul>
35 * <li>up to 0000-12-31 : proleptic julian calendar</li>
36 * <li>from 0001-01-01 to 1582-10-04: julian calendar</li>
37 * <li>from 1582-10-15: gregorian calendar</li>
38 * </ul>
39 * <p>Instances of this class are guaranteed to be immutable.</p>
40 * @see TimeComponents
41 * @see DateTimeComponents
42 * @author Luc Maisonobe
43 */
44 public class DateComponents implements Serializable, Comparable<DateComponents> {
45
46 /** Reference epoch for julian dates: -4712-01-01.
47 * <p>Both <code>java.util.Date</code> and {@link DateComponents} classes
48 * follow the astronomical conventions and consider a year 0 between
49 * years -1 and +1, hence this reference date lies in year -4712 and not
50 * in year -4713 as can be seen in other documents or programs that obey
51 * a different convention (for example the <code>convcal</code> utility).</p>
52 */
53 public static final DateComponents JULIAN_EPOCH;
54
55 /** Reference epoch for modified julian dates: 1858-11-17. */
56 public static final DateComponents MODIFIED_JULIAN_EPOCH;
57
58 /** Reference epoch for 1950 dates: 1950-01-01. */
59 public static final DateComponents FIFTIES_EPOCH;
60
61 /** Reference epoch for CCSDS Time Code Format (CCSDS 301.0-B-4): 1958-01-01. */
62 public static final DateComponents CCSDS_EPOCH;
63
64 /** Reference epoch for Galileo System Time: 1999-08-22. */
65 public static final DateComponents GALILEO_EPOCH;
66
67 /** Reference epoch for GPS weeks: 1980-01-06. */
68 public static final DateComponents GPS_EPOCH;
69
70 /** Reference epoch for QZSS weeks: 1980-01-06. */
71 public static final DateComponents QZSS_EPOCH;
72
73 /** Reference epoch for NavIC weeks: 1999-08-22. */
74 public static final DateComponents NAVIC_EPOCH;
75
76 /** Reference epoch for BeiDou weeks: 2006-01-01. */
77 public static final DateComponents BEIDOU_EPOCH;
78
79 /** Reference epoch for GLONASS four-year interval number: 1996-01-01. */
80 public static final DateComponents GLONASS_EPOCH;
81
82 /** J2000.0 Reference epoch: 2000-01-01. */
83 public static final DateComponents J2000_EPOCH;
84
85 /** Java Reference epoch: 1970-01-01. */
86 public static final DateComponents JAVA_EPOCH;
87
88 /** Maximum supported date.
89 * <p>
90 * This is date 5881610-07-11 which corresponds to {@code Integer.MAX_VALUE}
91 * days after {@link #J2000_EPOCH}.
92 * </p>
93 * @since 9.0
94 */
95 public static final DateComponents MAX_EPOCH;
96
97 /** Maximum supported date.
98 * <p>
99 * This is date -5877490-03-03, which corresponds to {@code Integer.MIN_VALUE}
100 * days before {@link #J2000_EPOCH}.
101 * </p>
102 * @since 9.0
103 */
104 public static final DateComponents MIN_EPOCH;
105
106 /** Offset between julian day epoch and modified julian day epoch. */
107 public static final double JD_TO_MJD = 2400000.5;
108
109 /** Format for one 4 digits integer field.
110 * @since 13.0.3
111 */
112 private static final FastLongFormatter PADDED_FOUR_DIGITS_INTEGER = new FastLongFormatter(4, true);
113
114 /** Format for one 2 digits integer field.
115 * @since 13.0.3
116 */
117 private static final FastLongFormatter PADDED_TWO_DIGITS_INTEGER = new FastLongFormatter(2, true);
118
119 /** Serializable UID. */
120 private static final long serialVersionUID = -2462694707837970938L;
121
122 /** Factory for proleptic julian calendar (up to 0000-12-31). */
123 private static final YearFactory PROLEPTIC_JULIAN_FACTORY = new ProlepticJulianFactory();
124
125 /** Factory for julian calendar (from 0001-01-01 to 1582-10-04). */
126 private static final YearFactory JULIAN_FACTORY = new JulianFactory();
127
128 /** Factory for gregorian calendar (from 1582-10-15). */
129 private static final YearFactory GREGORIAN_FACTORY = new GregorianFactory();
130
131 /** Factory for leap years. */
132 private static final MonthDayFactory LEAP_YEAR_FACTORY = new LeapYearFactory();
133
134 /** Factory for non-leap years. */
135 private static final MonthDayFactory COMMON_YEAR_FACTORY = new CommonYearFactory();
136
137 /** Offset between J2000 epoch and modified julian day epoch. */
138 private static final int MJD_TO_J2000 = 51544;
139
140
141 /** Basic and extended format calendar date. */
142 private static final Pattern CALENDAR_FORMAT = Pattern.compile("^(-?\\d\\d\\d\\d)-?(\\d\\d)-?(\\d\\d)$");
143
144 /** Basic and extended format ordinal date. */
145 private static final Pattern ORDINAL_FORMAT = Pattern.compile("^(-?\\d\\d\\d\\d)-?(\\d\\d\\d)$");
146
147 /** Basic and extended format week date. */
148 private static final Pattern WEEK_FORMAT = Pattern.compile("^(-?\\d\\d\\d\\d)-?W(\\d\\d)-?(\\d)$");
149
150 static {
151 // this static statement makes sure the reference epoch are initialized
152 // once AFTER the various factories have been set up
153 JULIAN_EPOCH = new DateComponents(-4712, 1, 1);
154 MODIFIED_JULIAN_EPOCH = new DateComponents(1858, 11, 17);
155 FIFTIES_EPOCH = new DateComponents(1950, 1, 1);
156 CCSDS_EPOCH = new DateComponents(1958, 1, 1);
157 GALILEO_EPOCH = new DateComponents(1999, 8, 22);
158 GPS_EPOCH = new DateComponents(1980, 1, 6);
159 QZSS_EPOCH = new DateComponents(1980, 1, 6);
160 NAVIC_EPOCH = new DateComponents(1999, 8, 22);
161 BEIDOU_EPOCH = new DateComponents(2006, 1, 1);
162 GLONASS_EPOCH = new DateComponents(1996, 1, 1);
163 J2000_EPOCH = new DateComponents(2000, 1, 1);
164 JAVA_EPOCH = new DateComponents(1970, 1, 1);
165 MAX_EPOCH = new DateComponents(Integer.MAX_VALUE);
166 MIN_EPOCH = new DateComponents(Integer.MIN_VALUE);
167 }
168
169 /** Year number. */
170 private final int year;
171
172 /** Month number. */
173 private final int month;
174
175 /** Day number. */
176 private final int day;
177
178 /** Build a date from its components.
179 * @param year year number (may be 0 or negative for BC years)
180 * @param month month number from 1 to 12
181 * @param day day number from 1 to 31
182 * @exception IllegalArgumentException if inconsistent arguments
183 * are given (parameters out of range, february 29 for non-leap years,
184 * dates during the gregorian leap in 1582 ...)
185 */
186 public DateComponents(final int year, final int month, final int day)
187 throws IllegalArgumentException {
188
189 // very rough range check
190 // (just to avoid ArrayOutOfboundException in MonthDayFactory later)
191 if (month < 1 || month > 12) {
192 throw new OrekitIllegalArgumentException(OrekitMessages.NON_EXISTENT_MONTH, month);
193 }
194
195 // start by trusting the parameters
196 this.year = year;
197 this.month = month;
198 this.day = day;
199
200 // build a check date from the J2000 day
201 final DateComponents check = new DateComponents(getJ2000Day());
202
203 // check the parameters for mismatch
204 // (i.e. invalid date components, like 29 february on non-leap years)
205 if (year != check.year || month != check.month || day != check.day) {
206 throw new OrekitIllegalArgumentException(OrekitMessages.NON_EXISTENT_YEAR_MONTH_DAY,
207 year, month, day);
208 }
209
210 }
211
212 /** Build a date from its components.
213 * @param year year number (may be 0 or negative for BC years)
214 * @param month month enumerate
215 * @param day day number from 1 to 31
216 * @exception IllegalArgumentException if inconsistent arguments
217 * are given (parameters out of range, february 29 for non-leap years,
218 * dates during the gregorian leap in 1582 ...)
219 */
220 public DateComponents(final int year, final Month month, final int day)
221 throws IllegalArgumentException {
222 this(year, month.getNumber(), day);
223 }
224
225 /** Build a date from a year and day number.
226 * @param year year number (may be 0 or negative for BC years)
227 * @param dayNumber day number in the year from 1 to 366
228 * @exception IllegalArgumentException if dayNumber is out of range
229 * with respect to year
230 */
231 public DateComponents(final int year, final int dayNumber)
232 throws IllegalArgumentException {
233 this(J2000_EPOCH, new DateComponents(year - 1, 12, 31).getJ2000Day() + dayNumber);
234 if (dayNumber != getDayOfYear()) {
235 throw new OrekitIllegalArgumentException(OrekitMessages.NON_EXISTENT_DAY_NUMBER_IN_YEAR,
236 dayNumber, year);
237 }
238 }
239
240 /** Build a date from its offset with respect to a {@link #J2000_EPOCH}.
241 * @param offset offset with respect to a {@link #J2000_EPOCH}
242 * @see #getJ2000Day()
243 */
244 public DateComponents(final int offset) {
245
246 // we follow the astronomical convention for calendars:
247 // we consider a year zero and 10 days are missing in 1582
248 // from 1582-10-15: gregorian calendar
249 // from 0001-01-01 to 1582-10-04: julian calendar
250 // up to 0000-12-31 : proleptic julian calendar
251 YearFactory yFactory = GREGORIAN_FACTORY;
252 if (offset < -152384) {
253 if (offset > -730122) {
254 yFactory = JULIAN_FACTORY;
255 } else {
256 yFactory = PROLEPTIC_JULIAN_FACTORY;
257 }
258 }
259 year = yFactory.getYear(offset);
260 final int dayInYear = offset - yFactory.getLastJ2000DayOfYear(year - 1);
261
262 // handle month/day according to the year being a common or leap year
263 final MonthDayFactory mdFactory =
264 yFactory.isLeap(year) ? LEAP_YEAR_FACTORY : COMMON_YEAR_FACTORY;
265 month = mdFactory.getMonth(dayInYear);
266 day = mdFactory.getDay(dayInYear, month);
267
268 }
269
270 /** Build a date from its offset with respect to a reference epoch.
271 * <p>This constructor is mainly useful to build a date from a modified
272 * julian day (using {@link #MODIFIED_JULIAN_EPOCH}) or a GPS week number
273 * (using {@link #GPS_EPOCH}).</p>
274 * @param epoch reference epoch
275 * @param offset offset with respect to a reference epoch
276 * @see #DateComponents(int)
277 * @see #getMJD()
278 */
279 public DateComponents(final DateComponents epoch, final int offset) {
280 this(epoch.getJ2000Day() + offset);
281 }
282
283 /** Build a date from week components.
284 * <p>The calendar week number is a number between 1 and 52 or 53 depending
285 * on the year. Week 1 is defined by ISO as the one that includes the first
286 * Thursday of a year. Week 1 may therefore start the previous year and week
287 * 52 or 53 may end in the next year. As an example calendar date 1995-01-01
288 * corresponds to week date 1994-W52-7 (i.e. Sunday in the last week of 1994
289 * is in fact the first day of year 1995). This date would beAnother example is calendar date
290 * 1996-12-31 which corresponds to week date 1997-W01-2 (i.e. Tuesday in the
291 * first week of 1997 is in fact the last day of year 1996).</p>
292 * @param wYear year associated to week numbering
293 * @param week week number in year, from 1 to 52 or 53
294 * @param dayOfWeek day of week, from 1 (Monday) to 7 (Sunday)
295 * @return a builded date
296 * @exception IllegalArgumentException if inconsistent arguments
297 * are given (parameters out of range, week 53 on a 52 weeks year ...)
298 */
299 public static DateComponents createFromWeekComponents(final int wYear, final int week, final int dayOfWeek)
300 throws IllegalArgumentException {
301
302 final DateComponents firstWeekMonday = new DateComponents(getFirstWeekMonday(wYear));
303 final DateComponents d = new DateComponents(firstWeekMonday, 7 * week + dayOfWeek - 8);
304
305 // check the parameters for invalid date components
306 if (week != d.getCalendarWeek() || dayOfWeek != d.getDayOfWeek()) {
307 throw new OrekitIllegalArgumentException(OrekitMessages.NON_EXISTENT_WEEK_DATE,
308 wYear, week, dayOfWeek);
309 }
310
311 return d;
312
313 }
314
315 /** Parse a string in ISO-8601 format to build a date.
316 * <p>The supported formats are:
317 * <ul>
318 * <li>basic format calendar date: YYYYMMDD</li>
319 * <li>extended format calendar date: YYYY-MM-DD</li>
320 * <li>basic format ordinal date: YYYYDDD</li>
321 * <li>extended format ordinal date: YYYY-DDD</li>
322 * <li>basic format week date: YYYYWwwD</li>
323 * <li>extended format week date: YYYY-Www-D</li>
324 * </ul>
325 *
326 * <p> As shown by the list above, only the complete representations defined in section 4.1
327 * of ISO-8601 standard are supported, neither expended representations nor representations
328 * with reduced accuracy are supported.
329 *
330 * <p>
331 * Parsing a single integer as a julian day is <em>not</em> supported as it may be ambiguous
332 * with either the basic format calendar date or the basic format ordinal date depending
333 * on the number of digits.
334 * </p>
335 * @param string string to parse
336 * @return a parsed date
337 * @exception IllegalArgumentException if string cannot be parsed
338 */
339 public static DateComponents parseDate(final String string) {
340
341 // is the date a calendar date ?
342 final Matcher calendarMatcher = CALENDAR_FORMAT.matcher(string);
343 if (calendarMatcher.matches()) {
344 return new DateComponents(Integer.parseInt(calendarMatcher.group(1)),
345 Integer.parseInt(calendarMatcher.group(2)),
346 Integer.parseInt(calendarMatcher.group(3)));
347 }
348
349 // is the date an ordinal date ?
350 final Matcher ordinalMatcher = ORDINAL_FORMAT.matcher(string);
351 if (ordinalMatcher.matches()) {
352 return new DateComponents(Integer.parseInt(ordinalMatcher.group(1)),
353 Integer.parseInt(ordinalMatcher.group(2)));
354 }
355
356 // is the date a week date ?
357 final Matcher weekMatcher = WEEK_FORMAT.matcher(string);
358 if (weekMatcher.matches()) {
359 return createFromWeekComponents(Integer.parseInt(weekMatcher.group(1)),
360 Integer.parseInt(weekMatcher.group(2)),
361 Integer.parseInt(weekMatcher.group(3)));
362 }
363
364 throw new OrekitIllegalArgumentException(OrekitMessages.NON_EXISTENT_DATE, string);
365
366 }
367
368 /** Get the year number.
369 * @return year number (may be 0 or negative for BC years)
370 */
371 public int getYear() {
372 return year;
373 }
374
375 /** Get the month.
376 * @return month number from 1 to 12
377 */
378 public int getMonth() {
379 return month;
380 }
381
382 /** Get the month as an enumerate.
383 * @return month as an enumerate
384 */
385 public Month getMonthEnum() {
386 return Month.getMonth(month);
387 }
388
389 /** Get the day.
390 * @return day number from 1 to 31
391 */
392 public int getDay() {
393 return day;
394 }
395
396 /** Get the day number with respect to J2000 epoch.
397 * @return day number with respect to J2000 epoch
398 */
399 public int getJ2000Day() {
400 YearFactory yFactory = GREGORIAN_FACTORY;
401 if (year < 1583) {
402 if (year < 1) {
403 yFactory = PROLEPTIC_JULIAN_FACTORY;
404 } else if (year < 1582 || month < 10 || month < 11 && day < 5) {
405 yFactory = JULIAN_FACTORY;
406 }
407 }
408 final MonthDayFactory mdFactory =
409 yFactory.isLeap(year) ? LEAP_YEAR_FACTORY : COMMON_YEAR_FACTORY;
410 return yFactory.getLastJ2000DayOfYear(year - 1) +
411 mdFactory.getDayInYear(month, day);
412 }
413
414 /** Get the modified julian day.
415 * @return modified julian day
416 */
417 public int getMJD() {
418 return MJD_TO_J2000 + getJ2000Day();
419 }
420
421 /** Get the calendar week number.
422 * <p>The calendar week number is a number between 1 and 52 or 53 depending
423 * on the year. Week 1 is defined by ISO as the one that includes the first
424 * Thursday of a year. Week 1 may therefore start the previous year and week
425 * 52 or 53 may end in the next year. As an example calendar date 1995-01-01
426 * corresponds to week date 1994-W52-7 (i.e. Sunday in the last week of 1994
427 * is in fact the first day of year 1995). Another example is calendar date
428 * 1996-12-31 which corresponds to week date 1997-W01-2 (i.e. Tuesday in the
429 * first week of 1997 is in fact the last day of year 1996).</p>
430 * @return calendar week number
431 */
432 public int getCalendarWeek() {
433 final int firstWeekMonday = getFirstWeekMonday(year);
434 int daysSincefirstMonday = getJ2000Day() - firstWeekMonday;
435 if (daysSincefirstMonday < 0) {
436 // we are still in a week from previous year
437 daysSincefirstMonday += firstWeekMonday - getFirstWeekMonday(year - 1);
438 } else if (daysSincefirstMonday > 363) {
439 // up to three days at end of year may belong to first week of next year
440 // (by chance, there is no need for a specific check in year 1582 ...)
441 final int weekYearLength = getFirstWeekMonday(year + 1) - firstWeekMonday;
442 if (daysSincefirstMonday >= weekYearLength) {
443 daysSincefirstMonday -= weekYearLength;
444 }
445 }
446 return 1 + daysSincefirstMonday / 7;
447 }
448
449 /** Get the monday of a year first week.
450 * @param year year to consider
451 * @return day of the monday of the first weak of year
452 */
453 private static int getFirstWeekMonday(final int year) {
454 final int yearFirst = new DateComponents(year, 1, 1).getJ2000Day();
455 final int offsetToMonday = 4 - (yearFirst + 2) % 7;
456 return yearFirst + offsetToMonday + ((offsetToMonday > 3) ? -7 : 0);
457 }
458
459 /** Get the day of week.
460 * <p>Day of week is a number between 1 (Monday) and 7 (Sunday).</p>
461 * @return day of week
462 */
463 public int getDayOfWeek() {
464 final int dow = (getJ2000Day() + 6) % 7; // result is between -6 and +6
465 return (dow < 1) ? (dow + 7) : dow;
466 }
467
468 /** Get the day number in year.
469 * <p>Day number in year is between 1 (January 1st) and either 365 or
470 * 366 inclusive depending on year.</p>
471 * @return day number in year
472 */
473 public int getDayOfYear() {
474 return getJ2000Day() - new DateComponents(year - 1, 12, 31).getJ2000Day();
475 }
476
477 /** Get a string representation (ISO-8601) of the date.
478 * @return string representation of the date.
479 */
480 public String toString() {
481 try {
482 final StringBuilder builder = new StringBuilder();
483 PADDED_FOUR_DIGITS_INTEGER.appendTo(builder, year);
484 builder.append('-');
485 PADDED_TWO_DIGITS_INTEGER.appendTo(builder, month);
486 builder.append('-');
487 PADDED_TWO_DIGITS_INTEGER.appendTo(builder, day);
488 return builder.toString();
489 } catch (IOException ioe) {
490 // this should never happen
491 throw new OrekitInternalError(ioe);
492 }
493 }
494
495 /** {@inheritDoc} */
496 public int compareTo(final DateComponents other) {
497 final int j2000Day = getJ2000Day();
498 final int otherJ2000Day = other.getJ2000Day();
499 if (j2000Day < otherJ2000Day) {
500 return -1;
501 } else if (j2000Day > otherJ2000Day) {
502 return 1;
503 }
504 return 0;
505 }
506
507 /** {@inheritDoc} */
508 public boolean equals(final Object other) {
509 try {
510 final DateComponents otherDate = (DateComponents) other;
511 return otherDate != null && year == otherDate.year &&
512 month == otherDate.month && day == otherDate.day;
513 } catch (ClassCastException cce) {
514 return false;
515 }
516 }
517
518 /** {@inheritDoc} */
519 public int hashCode() {
520 return (year << 16) ^ (month << 8) ^ day;
521 }
522
523 /** Interface for dealing with years sequences according to some calendar. */
524 private interface YearFactory {
525
526 /** Get the year number for a given day number with respect to J2000 epoch.
527 * @param j2000Day day number with respect to J2000 epoch
528 * @return year number
529 */
530 int getYear(int j2000Day);
531
532 /** Get the day number with respect to J2000 epoch for new year's Eve.
533 * @param year year number
534 * @return day number with respect to J2000 epoch for new year's Eve
535 */
536 int getLastJ2000DayOfYear(int year);
537
538 /** Check if a year is a leap or common year.
539 * @param year year number
540 * @return true if year is a leap year
541 */
542 boolean isLeap(int year);
543
544 }
545
546 /** Class providing a years sequence compliant with the proleptic Julian calendar. */
547 private static class ProlepticJulianFactory implements YearFactory {
548
549 /** {@inheritDoc} */
550 public int getYear(final int j2000Day) {
551 return (int) -((-4L * j2000Day - 2920488L) / 1461L);
552 }
553
554 /** {@inheritDoc} */
555 public int getLastJ2000DayOfYear(final int year) {
556 return 365 * year + (year + 1) / 4 - 730123;
557 }
558
559 /** {@inheritDoc} */
560 public boolean isLeap(final int year) {
561 return (year % 4) == 0;
562 }
563
564 }
565
566 /** Class providing a years sequence compliant with the Julian calendar. */
567 private static class JulianFactory implements YearFactory {
568
569 /** {@inheritDoc} */
570 public int getYear(final int j2000Day) {
571 return (int) ((4L * j2000Day + 2921948L) / 1461L);
572 }
573
574 /** {@inheritDoc} */
575 public int getLastJ2000DayOfYear(final int year) {
576 return 365 * year + year / 4 - 730122;
577 }
578
579 /** {@inheritDoc} */
580 public boolean isLeap(final int year) {
581 return (year % 4) == 0;
582 }
583
584 }
585
586 /** Class providing a years sequence compliant with the Gregorian calendar. */
587 private static class GregorianFactory implements YearFactory {
588
589 /** {@inheritDoc} */
590 public int getYear(final int j2000Day) {
591
592 // year estimate
593 int year = (int) ((400L * j2000Day + 292194288L) / 146097L);
594
595 // the previous estimate is one unit too high in some rare cases
596 // (240 days in the 400 years gregorian cycle, about 0.16%)
597 if (j2000Day <= getLastJ2000DayOfYear(year - 1)) {
598 --year;
599 }
600
601 // exact year
602 return year;
603
604 }
605
606 /** {@inheritDoc} */
607 public int getLastJ2000DayOfYear(final int year) {
608 return 365 * year + year / 4 - year / 100 + year / 400 - 730120;
609 }
610
611 /** {@inheritDoc} */
612 public boolean isLeap(final int year) {
613 return (year % 4) == 0 && ((year % 400) == 0 || (year % 100) != 0);
614 }
615
616 }
617
618 /** Interface for dealing with months sequences according to leap/common years. */
619 private interface MonthDayFactory {
620
621 /** Get the month number for a given day number within year.
622 * @param dayInYear day number within year
623 * @return month number
624 */
625 int getMonth(int dayInYear);
626
627 /** Get the day number for given month and day number within year.
628 * @param dayInYear day number within year
629 * @param month month number
630 * @return day number
631 */
632 int getDay(int dayInYear, int month);
633
634 /** Get the day number within year for given month and day numbers.
635 * @param month month number
636 * @param day day number
637 * @return day number within year
638 */
639 int getDayInYear(int month, int day);
640
641 }
642
643 /** Class providing the months sequence for leap years. */
644 private static class LeapYearFactory implements MonthDayFactory {
645
646 /** Months succession definition. */
647 private static final int[] PREVIOUS_MONTH_END_DAY = {
648 0, 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335
649 };
650
651 /** {@inheritDoc} */
652 public int getMonth(final int dayInYear) {
653 return (dayInYear < 32) ? 1 : (10 * dayInYear + 313) / 306;
654 }
655
656 /** {@inheritDoc} */
657 public int getDay(final int dayInYear, final int month) {
658 return dayInYear - PREVIOUS_MONTH_END_DAY[month];
659 }
660
661 /** {@inheritDoc} */
662 public int getDayInYear(final int month, final int day) {
663 return day + PREVIOUS_MONTH_END_DAY[month];
664 }
665
666 }
667
668 /** Class providing the months sequence for common years. */
669 private static class CommonYearFactory implements MonthDayFactory {
670
671 /** Months succession definition. */
672 private static final int[] PREVIOUS_MONTH_END_DAY = {
673 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
674 };
675
676 /** {@inheritDoc} */
677 public int getMonth(final int dayInYear) {
678 return (dayInYear < 32) ? 1 : (10 * dayInYear + 323) / 306;
679 }
680
681 /** {@inheritDoc} */
682 public int getDay(final int dayInYear, final int month) {
683 return dayInYear - PREVIOUS_MONTH_END_DAY[month];
684 }
685
686 /** {@inheritDoc} */
687 public int getDayInYear(final int month, final int day) {
688 return day + PREVIOUS_MONTH_END_DAY[month];
689 }
690
691 }
692
693 }