1 /*
2 * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 /*
27 * This file is available under and governed by the GNU General Public
28 * License version 2 only, as published by the Free Software Foundation.
29 * However, the following notice accompanied the original version of this
30 * file:
31 *
32 * Copyright (c) 2012, Stephen Colebourne & Michael Nascimento Santos
33 *
34 * All rights reserved.
35 *
36 * Redistribution and use in source and binary forms, with or without
37 * modification, are permitted provided that the following conditions are met:
38 *
39 * * Redistributions of source code must retain the above copyright notice,
40 * this list of conditions and the following disclaimer.
41 *
42 * * Redistributions in binary form must reproduce the above copyright notice,
43 * this list of conditions and the following disclaimer in the documentation
44 * and/or other materials provided with the distribution.
45 *
46 * * Neither the name of JSR-310 nor the names of its contributors
47 * may be used to endorse or promote products derived from this software
48 * without specific prior written permission.
49 *
50 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
51 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
52 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
53 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
54 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
55 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
56 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
57 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
58 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
59 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
60 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
61 */
62 package java.time.chrono;
63
64 import java.io.InvalidObjectException;
65 import static java.time.temporal.ChronoField.DAY_OF_MONTH;
66 import static java.time.temporal.ChronoField.ERA;
67 import static java.time.temporal.ChronoField.MONTH_OF_YEAR;
68 import static java.time.temporal.ChronoField.PROLEPTIC_MONTH;
69 import static java.time.temporal.ChronoField.YEAR;
70 import static java.time.temporal.ChronoField.YEAR_OF_ERA;
71
72 import java.io.ObjectInputStream;
73 import java.io.Serializable;
74 import java.time.Clock;
75 import java.time.DateTimeException;
76 import java.time.Instant;
77 import java.time.LocalDate;
78 import java.time.LocalDateTime;
79 import java.time.Month;
80 import java.time.Period;
81 import java.time.Year;
82 import java.time.ZoneId;
83 import java.time.ZonedDateTime;
84 import java.time.format.ResolverStyle;
85 import java.time.temporal.ChronoField;
86 import java.time.temporal.TemporalAccessor;
87 import java.time.temporal.TemporalField;
88 import java.time.temporal.ValueRange;
89 import java.util.Arrays;
90 import java.util.List;
91 import java.util.Locale;
92 import java.util.Map;
93 import java.util.Objects;
94
95 /**
96 * The ISO calendar system.
97 * <p>
98 * This chronology defines the rules of the ISO calendar system.
99 * This calendar system is based on the ISO-8601 standard, which is the
100 * <i>de facto</i> world calendar.
101 * <p>
102 * The fields are defined as follows:
103 * <ul>
104 * <li>era - There are two eras, 'Current Era' (CE) and 'Before Current Era' (BCE).
105 * <li>year-of-era - The year-of-era is the same as the proleptic-year for the current CE era.
106 * For the BCE era before the ISO epoch the year increases from 1 upwards as time goes backwards.
107 * <li>proleptic-year - The proleptic year is the same as the year-of-era for the
108 * current era. For the previous era, years have zero, then negative values.
109 * <li>month-of-year - There are 12 months in an ISO year, numbered from 1 to 12.
110 * <li>day-of-month - There are between 28 and 31 days in each of the ISO month, numbered from 1 to 31.
111 * Months 4, 6, 9 and 11 have 30 days, Months 1, 3, 5, 7, 8, 10 and 12 have 31 days.
112 * Month 2 has 28 days, or 29 in a leap year.
113 * <li>day-of-year - There are 365 days in a standard ISO year and 366 in a leap year.
114 * The days are numbered from 1 to 365 or 1 to 366.
115 * <li>leap-year - Leap years occur every 4 years, except where the year is divisble by 100 and not divisble by 400.
116 * </ul>
117 *
118 * @implSpec
119 * This class is immutable and thread-safe.
120 *
121 * @since 1.8
122 */
123 public final class IsoChronology extends AbstractChronology implements Serializable {
124
125 /**
126 * Singleton instance of the ISO chronology.
127 */
128 public static final IsoChronology INSTANCE = new IsoChronology();
129
130 /**
131 * Serialization version.
132 */
133 private static final long serialVersionUID = -1440403870442975015L;
134
135 /**
136 * Restricted constructor.
137 */
138 private IsoChronology() {
139 }
140
141 //-----------------------------------------------------------------------
142 /**
143 * Gets the ID of the chronology - 'ISO'.
144 * <p>
145 * The ID uniquely identifies the {@code Chronology}.
146 * It can be used to lookup the {@code Chronology} using {@link Chronology#of(String)}.
147 *
148 * @return the chronology ID - 'ISO'
149 * @see #getCalendarType()
150 */
151 @Override
152 public String getId() {
153 return "ISO";
154 }
155
156 /**
157 * Gets the calendar type of the underlying calendar system - 'iso8601'.
158 * <p>
159 * The calendar type is an identifier defined by the
160 * <em>Unicode Locale Data Markup Language (LDML)</em> specification.
161 * It can be used to lookup the {@code Chronology} using {@link Chronology#of(String)}.
162 * It can also be used as part of a locale, accessible via
163 * {@link Locale#getUnicodeLocaleType(String)} with the key 'ca'.
164 *
165 * @return the calendar system type - 'iso8601'
166 * @see #getId()
167 */
168 @Override
169 public String getCalendarType() {
170 return "iso8601";
171 }
172
173 //-----------------------------------------------------------------------
174 /**
175 * Obtains an ISO local date from the era, year-of-era, month-of-year
176 * and day-of-month fields.
177 *
178 * @param era the ISO era, not null
179 * @param yearOfEra the ISO year-of-era
180 * @param month the ISO month-of-year
181 * @param dayOfMonth the ISO day-of-month
182 * @return the ISO local date, not null
183 * @throws DateTimeException if unable to create the date
184 * @throws ClassCastException if the type of {@code era} is not {@code IsoEra}
185 */
186 @Override // override with covariant return type
187 public LocalDate date(Era era, int yearOfEra, int month, int dayOfMonth) {
188 return date(prolepticYear(era, yearOfEra), month, dayOfMonth);
189 }
190
191 /**
192 * Obtains an ISO local date from the proleptic-year, month-of-year
193 * and day-of-month fields.
194 * <p>
195 * This is equivalent to {@link LocalDate#of(int, int, int)}.
196 *
197 * @param prolepticYear the ISO proleptic-year
198 * @param month the ISO month-of-year
199 * @param dayOfMonth the ISO day-of-month
200 * @return the ISO local date, not null
201 * @throws DateTimeException if unable to create the date
202 */
203 @Override // override with covariant return type
204 public LocalDate date(int prolepticYear, int month, int dayOfMonth) {
205 return LocalDate.of(prolepticYear, month, dayOfMonth);
206 }
207
208 /**
209 * Obtains an ISO local date from the era, year-of-era and day-of-year fields.
210 *
211 * @param era the ISO era, not null
212 * @param yearOfEra the ISO year-of-era
213 * @param dayOfYear the ISO day-of-year
214 * @return the ISO local date, not null
215 * @throws DateTimeException if unable to create the date
216 */
217 @Override // override with covariant return type
218 public LocalDate dateYearDay(Era era, int yearOfEra, int dayOfYear) {
219 return dateYearDay(prolepticYear(era, yearOfEra), dayOfYear);
220 }
221
222 /**
223 * Obtains an ISO local date from the proleptic-year and day-of-year fields.
224 * <p>
225 * This is equivalent to {@link LocalDate#ofYearDay(int, int)}.
226 *
227 * @param prolepticYear the ISO proleptic-year
228 * @param dayOfYear the ISO day-of-year
229 * @return the ISO local date, not null
230 * @throws DateTimeException if unable to create the date
231 */
232 @Override // override with covariant return type
233 public LocalDate dateYearDay(int prolepticYear, int dayOfYear) {
234 return LocalDate.ofYearDay(prolepticYear, dayOfYear);
235 }
236
237 /**
238 * Obtains an ISO local date from the epoch-day.
239 * <p>
240 * This is equivalent to {@link LocalDate#ofEpochDay(long)}.
241 *
242 * @param epochDay the epoch day
243 * @return the ISO local date, not null
244 * @throws DateTimeException if unable to create the date
245 */
246 @Override // override with covariant return type
247 public LocalDate dateEpochDay(long epochDay) {
248 return LocalDate.ofEpochDay(epochDay);
249 }
250
251 //-----------------------------------------------------------------------
252 /**
253 * Obtains an ISO local date from another date-time object.
254 * <p>
255 * This is equivalent to {@link LocalDate#from(TemporalAccessor)}.
256 *
257 * @param temporal the date-time object to convert, not null
258 * @return the ISO local date, not null
259 * @throws DateTimeException if unable to create the date
260 */
261 @Override // override with covariant return type
262 public LocalDate date(TemporalAccessor temporal) {
263 return LocalDate.from(temporal);
264 }
265
266 /**
267 * Obtains an ISO local date-time from another date-time object.
268 * <p>
269 * This is equivalent to {@link LocalDateTime#from(TemporalAccessor)}.
270 *
271 * @param temporal the date-time object to convert, not null
272 * @return the ISO local date-time, not null
273 * @throws DateTimeException if unable to create the date-time
274 */
275 @Override // override with covariant return type
276 public LocalDateTime localDateTime(TemporalAccessor temporal) {
277 return LocalDateTime.from(temporal);
278 }
279
280 /**
281 * Obtains an ISO zoned date-time from another date-time object.
282 * <p>
283 * This is equivalent to {@link ZonedDateTime#from(TemporalAccessor)}.
284 *
285 * @param temporal the date-time object to convert, not null
286 * @return the ISO zoned date-time, not null
287 * @throws DateTimeException if unable to create the date-time
288 */
289 @Override // override with covariant return type
290 public ZonedDateTime zonedDateTime(TemporalAccessor temporal) {
291 return ZonedDateTime.from(temporal);
292 }
293
294 /**
295 * Obtains an ISO zoned date-time in this chronology from an {@code Instant}.
296 * <p>
297 * This is equivalent to {@link ZonedDateTime#ofInstant(Instant, ZoneId)}.
298 *
299 * @param instant the instant to create the date-time from, not null
300 * @param zone the time-zone, not null
301 * @return the zoned date-time, not null
302 * @throws DateTimeException if the result exceeds the supported range
303 */
304 @Override
305 public ZonedDateTime zonedDateTime(Instant instant, ZoneId zone) {
306 return ZonedDateTime.ofInstant(instant, zone);
307 }
308
309 //-----------------------------------------------------------------------
310 /**
311 * Obtains the current ISO local date from the system clock in the default time-zone.
312 * <p>
313 * This will query the {@link Clock#systemDefaultZone() system clock} in the default
314 * time-zone to obtain the current date.
315 * <p>
316 * Using this method will prevent the ability to use an alternate clock for testing
317 * because the clock is hard-coded.
318 *
319 * @return the current ISO local date using the system clock and default time-zone, not null
320 * @throws DateTimeException if unable to create the date
321 */
322 @Override // override with covariant return type
323 public LocalDate dateNow() {
324 return dateNow(Clock.systemDefaultZone());
325 }
326
327 /**
328 * Obtains the current ISO local date from the system clock in the specified time-zone.
329 * <p>
330 * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current date.
331 * Specifying the time-zone avoids dependence on the default time-zone.
332 * <p>
333 * Using this method will prevent the ability to use an alternate clock for testing
334 * because the clock is hard-coded.
335 *
336 * @return the current ISO local date using the system clock, not null
337 * @throws DateTimeException if unable to create the date
338 */
339 @Override // override with covariant return type
340 public LocalDate dateNow(ZoneId zone) {
341 return dateNow(Clock.system(zone));
342 }
343
344 /**
345 * Obtains the current ISO local date from the specified clock.
346 * <p>
347 * This will query the specified clock to obtain the current date - today.
348 * Using this method allows the use of an alternate clock for testing.
349 * The alternate clock may be introduced using {@link Clock dependency injection}.
350 *
351 * @param clock the clock to use, not null
352 * @return the current ISO local date, not null
353 * @throws DateTimeException if unable to create the date
354 */
355 @Override // override with covariant return type
356 public LocalDate dateNow(Clock clock) {
357 Objects.requireNonNull(clock, "clock");
358 return date(LocalDate.now(clock));
359 }
360
361 //-----------------------------------------------------------------------
362 /**
363 * Checks if the year is a leap year, according to the ISO proleptic
364 * calendar system rules.
365 * <p>
366 * This method applies the current rules for leap years across the whole time-line.
367 * In general, a year is a leap year if it is divisible by four without
368 * remainder. However, years divisible by 100, are not leap years, with
369 * the exception of years divisible by 400 which are.
370 * <p>
371 * For example, 1904 is a leap year it is divisible by 4.
372 * 1900 was not a leap year as it is divisible by 100, however 2000 was a
373 * leap year as it is divisible by 400.
374 * <p>
375 * The calculation is proleptic - applying the same rules into the far future and far past.
376 * This is historically inaccurate, but is correct for the ISO-8601 standard.
377 *
378 * @param prolepticYear the ISO proleptic year to check
379 * @return true if the year is leap, false otherwise
380 */
381 @Override
382 public boolean isLeapYear(long prolepticYear) {
383 return ((prolepticYear & 3) == 0) && ((prolepticYear % 100) != 0 || (prolepticYear % 400) == 0);
384 }
385
386 @Override
387 public int prolepticYear(Era era, int yearOfEra) {
388 if (era instanceof IsoEra == false) {
389 throw new ClassCastException("Era must be IsoEra");
390 }
391 return (era == IsoEra.CE ? yearOfEra : 1 - yearOfEra);
392 }
393
394 @Override
395 public IsoEra eraOf(int eraValue) {
396 return IsoEra.of(eraValue);
397 }
398
399 @Override
400 public List<Era> eras() {
401 return Arrays.<Era>asList(IsoEra.values());
402 }
403
404 //-----------------------------------------------------------------------
405 /**
406 * Resolves parsed {@code ChronoField} values into a date during parsing.
407 * <p>
408 * Most {@code TemporalField} implementations are resolved using the
409 * resolve method on the field. By contrast, the {@code ChronoField} class
410 * defines fields that only have meaning relative to the chronology.
411 * As such, {@code ChronoField} date fields are resolved here in the
412 * context of a specific chronology.
413 * <p>
414 * {@code ChronoField} instances on the ISO calendar system are resolved
415 * as follows.
416 * <ul>
417 * <li>{@code EPOCH_DAY} - If present, this is converted to a {@code LocalDate}
418 * and all other date fields are then cross-checked against the date.
419 * <li>{@code PROLEPTIC_MONTH} - If present, then it is split into the
420 * {@code YEAR} and {@code MONTH_OF_YEAR}. If the mode is strict or smart
421 * then the field is validated.
422 * <li>{@code YEAR_OF_ERA} and {@code ERA} - If both are present, then they
423 * are combined to form a {@code YEAR}. In lenient mode, the {@code YEAR_OF_ERA}
424 * range is not validated, in smart and strict mode it is. The {@code ERA} is
425 * validated for range in all three modes. If only the {@code YEAR_OF_ERA} is
426 * present, and the mode is smart or lenient, then the current era (CE/AD)
427 * is assumed. In strict mode, no era is assumed and the {@code YEAR_OF_ERA} is
428 * left untouched. If only the {@code ERA} is present, then it is left untouched.
429 * <li>{@code YEAR}, {@code MONTH_OF_YEAR} and {@code DAY_OF_MONTH} -
430 * If all three are present, then they are combined to form a {@code LocalDate}.
431 * In all three modes, the {@code YEAR} is validated. If the mode is smart or strict,
432 * then the month and day are validated, with the day validated from 1 to 31.
433 * If the mode is lenient, then the date is combined in a manner equivalent to
434 * creating a date on the first of January in the requested year, then adding
435 * the difference in months, then the difference in days.
436 * If the mode is smart, and the day-of-month is greater than the maximum for
437 * the year-month, then the day-of-month is adjusted to the last day-of-month.
438 * If the mode is strict, then the three fields must form a valid date.
439 * <li>{@code YEAR} and {@code DAY_OF_YEAR} -
440 * If both are present, then they are combined to form a {@code LocalDate}.
441 * In all three modes, the {@code YEAR} is validated.
442 * If the mode is lenient, then the date is combined in a manner equivalent to
443 * creating a date on the first of January in the requested year, then adding
444 * the difference in days.
445 * If the mode is smart or strict, then the two fields must form a valid date.
446 * <li>{@code YEAR}, {@code MONTH_OF_YEAR}, {@code ALIGNED_WEEK_OF_MONTH} and
447 * {@code ALIGNED_DAY_OF_WEEK_IN_MONTH} -
448 * If all four are present, then they are combined to form a {@code LocalDate}.
449 * In all three modes, the {@code YEAR} is validated.
450 * If the mode is lenient, then the date is combined in a manner equivalent to
451 * creating a date on the first of January in the requested year, then adding
452 * the difference in months, then the difference in weeks, then in days.
453 * If the mode is smart or strict, then the all four fields are validated to
454 * their outer ranges. The date is then combined in a manner equivalent to
455 * creating a date on the first day of the requested year and month, then adding
456 * the amount in weeks and days to reach their values. If the mode is strict,
457 * the date is additionally validated to check that the day and week adjustment
458 * did not change the month.
459 * <li>{@code YEAR}, {@code MONTH_OF_YEAR}, {@code ALIGNED_WEEK_OF_MONTH} and
460 * {@code DAY_OF_WEEK} - If all four are present, then they are combined to
461 * form a {@code LocalDate}. The approach is the same as described above for
462 * years, months and weeks in {@code ALIGNED_DAY_OF_WEEK_IN_MONTH}.
463 * The day-of-week is adjusted as the next or same matching day-of-week once
464 * the years, months and weeks have been handled.
465 * <li>{@code YEAR}, {@code ALIGNED_WEEK_OF_YEAR} and {@code ALIGNED_DAY_OF_WEEK_IN_YEAR} -
466 * If all three are present, then they are combined to form a {@code LocalDate}.
467 * In all three modes, the {@code YEAR} is validated.
468 * If the mode is lenient, then the date is combined in a manner equivalent to
469 * creating a date on the first of January in the requested year, then adding
470 * the difference in weeks, then in days.
471 * If the mode is smart or strict, then the all three fields are validated to
472 * their outer ranges. The date is then combined in a manner equivalent to
473 * creating a date on the first day of the requested year, then adding
474 * the amount in weeks and days to reach their values. If the mode is strict,
475 * the date is additionally validated to check that the day and week adjustment
476 * did not change the year.
477 * <li>{@code YEAR}, {@code ALIGNED_WEEK_OF_YEAR} and {@code DAY_OF_WEEK} -
478 * If all three are present, then they are combined to form a {@code LocalDate}.
479 * The approach is the same as described above for years and weeks in
480 * {@code ALIGNED_DAY_OF_WEEK_IN_YEAR}. The day-of-week is adjusted as the
481 * next or same matching day-of-week once the years and weeks have been handled.
482 * </ul>
483 *
484 * @param fieldValues the map of fields to values, which can be updated, not null
485 * @param resolverStyle the requested type of resolve, not null
486 * @return the resolved date, null if insufficient information to create a date
487 * @throws DateTimeException if the date cannot be resolved, typically
488 * because of a conflict in the input data
489 */
490 @Override // override for performance
491 public LocalDate resolveDate(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
492 return (LocalDate) super.resolveDate(fieldValues, resolverStyle);
493 }
494
495 @Override // override for better proleptic algorithm
496 void resolveProlepticMonth(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
497 Long pMonth = fieldValues.remove(PROLEPTIC_MONTH);
498 if (pMonth != null) {
499 if (resolverStyle != ResolverStyle.LENIENT) {
500 PROLEPTIC_MONTH.checkValidValue(pMonth);
501 }
502 addFieldValue(fieldValues, MONTH_OF_YEAR, Math.floorMod(pMonth, 12) + 1);
503 addFieldValue(fieldValues, YEAR, Math.floorDiv(pMonth, 12));
504 }
505 }
506
507 @Override // override for enhanced behaviour
508 LocalDate resolveYearOfEra(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
509 Long yoeLong = fieldValues.remove(YEAR_OF_ERA);
510 if (yoeLong != null) {
511 if (resolverStyle != ResolverStyle.LENIENT) {
512 YEAR_OF_ERA.checkValidValue(yoeLong);
513 }
514 Long era = fieldValues.remove(ERA);
515 if (era == null) {
516 Long year = fieldValues.get(YEAR);
517 if (resolverStyle == ResolverStyle.STRICT) {
518 // do not invent era if strict, but do cross-check with year
519 if (year != null) {
520 addFieldValue(fieldValues, YEAR, (year > 0 ? yoeLong: Math.subtractExact(1, yoeLong)));
521 } else {
522 // reinstate the field removed earlier, no cross-check issues
523 fieldValues.put(YEAR_OF_ERA, yoeLong);
524 }
525 } else {
526 // invent era
527 addFieldValue(fieldValues, YEAR, (year == null || year > 0 ? yoeLong: Math.subtractExact(1, yoeLong)));
528 }
529 } else if (era.longValue() == 1L) {
530 addFieldValue(fieldValues, YEAR, yoeLong);
531 } else if (era.longValue() == 0L) {
532 addFieldValue(fieldValues, YEAR, Math.subtractExact(1, yoeLong));
533 } else {
534 throw new DateTimeException("Invalid value for era: " + era);
535 }
536 } else if (fieldValues.containsKey(ERA)) {
537 ERA.checkValidValue(fieldValues.get(ERA)); // always validated
538 }
539 return null;
540 }
541
542 @Override // override for performance
543 LocalDate resolveYMD(Map <TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
544 int y = YEAR.checkValidIntValue(fieldValues.remove(YEAR));
545 if (resolverStyle == ResolverStyle.LENIENT) {
546 long months = Math.subtractExact(fieldValues.remove(MONTH_OF_YEAR), 1);
547 long days = Math.subtractExact(fieldValues.remove(DAY_OF_MONTH), 1);
548 return LocalDate.of(y, 1, 1).plusMonths(months).plusDays(days);
549 }
550 int moy = MONTH_OF_YEAR.checkValidIntValue(fieldValues.remove(MONTH_OF_YEAR));
551 int dom = DAY_OF_MONTH.checkValidIntValue(fieldValues.remove(DAY_OF_MONTH));
552 if (resolverStyle == ResolverStyle.SMART) { // previous valid
553 if (moy == 4 || moy == 6 || moy == 9 || moy == 11) {
554 dom = Math.min(dom, 30);
555 } else if (moy == 2) {
556 dom = Math.min(dom, Month.FEBRUARY.length(Year.isLeap(y)));
557
558 }
559 }
560 return LocalDate.of(y, moy, dom);
561 }
562
563 //-----------------------------------------------------------------------
564 @Override
565 public ValueRange range(ChronoField field) {
566 return field.range();
567 }
568
569 //-----------------------------------------------------------------------
570 /**
571 * Obtains a period for this chronology based on years, months and days.
572 * <p>
573 * This returns a period tied to the ISO chronology using the specified
574 * years, months and days. See {@link Period} for further details.
575 *
576 * @param years the number of years, may be negative
577 * @param months the number of years, may be negative
578 * @param days the number of years, may be negative
579 * @return the period in terms of this chronology, not null
580 * @return the ISO period, not null
581 */
582 @Override // override with covariant return type
583 public Period period(int years, int months, int days) {
584 return Period.of(years, months, days);
585 }
586
587 //-----------------------------------------------------------------------
588 /**
589 * Writes the Chronology using a
590 * <a href="../../../serialized-form.html#java.time.chrono.Ser">dedicated serialized form</a>.
591 * @serialData
592 * <pre>
593 * out.writeByte(1); // identifies a Chronology
594 * out.writeUTF(getId());
595 * </pre>
596 *
597 * @return the instance of {@code Ser}, not null
598 */
599 @Override
600 Object writeReplace() {
601 return super.writeReplace();
602 }
603
604 /**
605 * Defend against malicious streams.
606 *
607 * @param s the stream to read
608 * @throws InvalidObjectException always
609 */
610 private void readObject(ObjectInputStream s) throws InvalidObjectException {
611 throw new InvalidObjectException("Deserialization via serialization delegate");
612 }
613 }