1 /*
2 * Copyright (c) 2012, 2023, 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 * Copyright (c) 2012, Stephen Colebourne & Michael Nascimento Santos
28 *
29 * All rights reserved.
30 *
31 * Redistribution and use in source and binary forms, with or without
32 * modification, are permitted provided that the following conditions are met:
33 *
34 * * Redistributions of source code must retain the above copyright notice,
35 * this list of conditions and the following disclaimer.
36 *
37 * * Redistributions in binary form must reproduce the above copyright notice,
38 * this list of conditions and the following disclaimer in the documentation
39 * and/or other materials provided with the distribution.
40 *
41 * * Neither the name of JSR-310 nor the names of its contributors
42 * may be used to endorse or promote products derived from this software
43 * without specific prior written permission.
44 *
45 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
46 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
47 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
48 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
49 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
50 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
51 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
52 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
53 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
54 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
55 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
56 */
57 package java.time.chrono;
58
59 import static java.time.temporal.ChronoField.ALIGNED_DAY_OF_WEEK_IN_MONTH;
60 import static java.time.temporal.ChronoField.ALIGNED_DAY_OF_WEEK_IN_YEAR;
61 import static java.time.temporal.ChronoField.ALIGNED_WEEK_OF_MONTH;
62 import static java.time.temporal.ChronoField.ALIGNED_WEEK_OF_YEAR;
63 import static java.time.temporal.ChronoField.DAY_OF_MONTH;
64 import static java.time.temporal.ChronoField.MONTH_OF_YEAR;
65 import static java.time.temporal.ChronoField.YEAR;
66
67 import java.io.DataInput;
68 import java.io.DataOutput;
69 import java.io.IOException;
70 import java.io.InvalidObjectException;
71 import java.io.ObjectInputStream;
72 import java.io.Serializable;
73 import java.time.Clock;
74 import java.time.DateTimeException;
75 import java.time.LocalDate;
76 import java.time.LocalTime;
77 import java.time.Period;
78 import java.time.ZoneId;
79 import java.time.temporal.ChronoField;
80 import java.time.temporal.TemporalAccessor;
81 import java.time.temporal.TemporalAdjuster;
82 import java.time.temporal.TemporalAmount;
83 import java.time.temporal.TemporalField;
84 import java.time.temporal.TemporalQuery;
85 import java.time.temporal.TemporalUnit;
86 import java.time.temporal.UnsupportedTemporalTypeException;
87 import java.time.temporal.ValueRange;
88 import java.util.Calendar;
89 import java.util.Objects;
90
91 import sun.util.calendar.CalendarDate;
92 import sun.util.calendar.LocalGregorianCalendar;
93
94 /**
95 * A date in the Japanese Imperial calendar system.
96 * <p>
97 * This date operates using the {@linkplain JapaneseChronology Japanese Imperial calendar}.
98 * This calendar system is primarily used in Japan.
99 * <p>
100 * The Japanese Imperial calendar system is the same as the ISO calendar system
101 * apart from the era-based year numbering. The proleptic-year is defined to be
102 * equal to the ISO proleptic-year.
103 * <p>
104 * Japan introduced the Gregorian calendar starting with Meiji 6.
105 * Only Meiji and later eras are supported;
106 * dates before Meiji 6, January 1 are not supported.
107 * <p>
108 * For example, the Japanese year "Heisei 24" corresponds to ISO year "2012".<br>
109 * Calling {@code japaneseDate.get(YEAR_OF_ERA)} will return 24.<br>
110 * Calling {@code japaneseDate.get(YEAR)} will return 2012.<br>
111 * Calling {@code japaneseDate.get(ERA)} will return 2, corresponding to
112 * {@code JapaneseChronology.ERA_HEISEI}.<br>
113 * <p>
114 * This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
115 * class; programmers should treat instances that are {@linkplain #equals(Object) equal}
116 * as interchangeable and should not use instances for synchronization, mutexes, or
117 * with {@linkplain java.lang.ref.Reference object references}.
118 *
119 * <div class="preview-block">
120 * <div class="preview-comment">
121 * When preview features are enabled, {@code JapaneseDate} is a {@linkplain Class#isValue value class}.
122 * Use of value class instances for synchronization, mutexes, or with
123 * {@linkplain java.lang.ref.Reference object references} result in
124 * {@link IdentityException}.
125 * </div>
126 * </div>
127 *
128 * @implSpec
129 * This class is immutable and thread-safe.
130 *
131 * @since 1.8
132 */
133 @jdk.internal.ValueBased
134 @jdk.internal.MigratedValueClass
135 public final class JapaneseDate
136 extends ChronoLocalDateImpl<JapaneseDate>
137 implements ChronoLocalDate, Serializable {
138
139 /**
140 * Serialization version.
141 */
142 @java.io.Serial
143 private static final long serialVersionUID = -305327627230580483L;
144
145 /**
146 * The underlying ISO local date.
147 */
148 private final transient LocalDate isoDate;
149 /**
150 * The JapaneseEra of this date.
151 */
152 private final transient JapaneseEra era;
153 /**
154 * The Japanese imperial calendar year of this date.
155 */
156 private final transient int yearOfEra;
157
158 /**
159 * The first day supported by the JapaneseChronology is Meiji 6, January 1st.
160 */
161 static final LocalDate MEIJI_6_ISODATE = LocalDate.of(1873, 1, 1);
162
163 //-----------------------------------------------------------------------
164 /**
165 * Obtains the current {@code JapaneseDate} from the system clock in the default time-zone.
166 * <p>
167 * This will query the {@link Clock#systemDefaultZone() system clock} in the default
168 * time-zone to obtain the current date.
169 * <p>
170 * Using this method will prevent the ability to use an alternate clock for testing
171 * because the clock is hard-coded.
172 *
173 * @return the current date using the system clock and default time-zone, not null
174 */
175 public static JapaneseDate now() {
176 return now(Clock.systemDefaultZone());
177 }
178
179 /**
180 * Obtains the current {@code JapaneseDate} from the system clock in the specified time-zone.
181 * <p>
182 * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current date.
183 * Specifying the time-zone avoids dependence on the default time-zone.
184 * <p>
185 * Using this method will prevent the ability to use an alternate clock for testing
186 * because the clock is hard-coded.
187 *
188 * @param zone the zone ID to use, not null
189 * @return the current date using the system clock, not null
190 */
191 public static JapaneseDate now(ZoneId zone) {
192 return now(Clock.system(zone));
193 }
194
195 /**
196 * Obtains the current {@code JapaneseDate} from the specified clock.
197 * <p>
198 * This will query the specified clock to obtain the current date - today.
199 * Using this method allows the use of an alternate clock for testing.
200 * The alternate clock may be introduced using {@linkplain Clock dependency injection}.
201 *
202 * @param clock the clock to use, not null
203 * @return the current date, not null
204 * @throws DateTimeException if the current date cannot be obtained
205 */
206 public static JapaneseDate now(Clock clock) {
207 return new JapaneseDate(LocalDate.now(clock));
208 }
209
210 /**
211 * Obtains a {@code JapaneseDate} representing a date in the Japanese calendar
212 * system from the era, year-of-era, month-of-year and day-of-month fields.
213 * <p>
214 * This returns a {@code JapaneseDate} with the specified fields.
215 * The day must be valid for the year and month, otherwise an exception will be thrown.
216 * <p>
217 * The Japanese month and day-of-month are the same as those in the
218 * ISO calendar system. They are not reset when the era changes.
219 * For example:
220 * <pre>
221 * 6th Jan Showa 64 = ISO 1989-01-06
222 * 7th Jan Showa 64 = ISO 1989-01-07
223 * 8th Jan Heisei 1 = ISO 1989-01-08
224 * 9th Jan Heisei 1 = ISO 1989-01-09
225 * </pre>
226 *
227 * @param era the Japanese era, not null
228 * @param yearOfEra the Japanese year-of-era
229 * @param month the Japanese month-of-year, from 1 to 12
230 * @param dayOfMonth the Japanese day-of-month, from 1 to 31
231 * @return the date in Japanese calendar system, not null
232 * @throws DateTimeException if the value of any field is out of range,
233 * or if the day-of-month is invalid for the month-year,
234 * or if the date is not a Japanese era
235 */
236 public static JapaneseDate of(JapaneseEra era, int yearOfEra, int month, int dayOfMonth) {
237 Objects.requireNonNull(era, "era");
238 LocalGregorianCalendar.Date jdate = JapaneseChronology.JCAL.newCalendarDate(null);
239 jdate.setEra(era.getPrivateEra()).setDate(yearOfEra, month, dayOfMonth);
240 if (!JapaneseChronology.JCAL.validate(jdate)) {
241 throw new DateTimeException("year, month, and day not valid for Era");
242 }
243 LocalDate date = LocalDate.of(jdate.getNormalizedYear(), month, dayOfMonth);
244 return new JapaneseDate(era, yearOfEra, date);
245 }
246
247 /**
248 * Obtains a {@code JapaneseDate} representing a date in the Japanese calendar
249 * system from the proleptic-year, month-of-year and day-of-month fields.
250 * <p>
251 * This returns a {@code JapaneseDate} with the specified fields.
252 * The day must be valid for the year and month, otherwise an exception will be thrown.
253 * <p>
254 * The Japanese proleptic year, month and day-of-month are the same as those
255 * in the ISO calendar system. They are not reset when the era changes.
256 *
257 * @param prolepticYear the Japanese proleptic-year
258 * @param month the Japanese month-of-year, from 1 to 12
259 * @param dayOfMonth the Japanese day-of-month, from 1 to 31
260 * @return the date in Japanese calendar system, not null
261 * @throws DateTimeException if the value of any field is out of range,
262 * or if the day-of-month is invalid for the month-year
263 */
264 public static JapaneseDate of(int prolepticYear, int month, int dayOfMonth) {
265 return new JapaneseDate(LocalDate.of(prolepticYear, month, dayOfMonth));
266 }
267
268 /**
269 * Obtains a {@code JapaneseDate} representing a date in the Japanese calendar
270 * system from the era, year-of-era and day-of-year fields.
271 * <p>
272 * This returns a {@code JapaneseDate} with the specified fields.
273 * The day must be valid for the year, otherwise an exception will be thrown.
274 * <p>
275 * The day-of-year in this factory is expressed relative to the start of the year-of-era.
276 * This definition changes the normal meaning of day-of-year only in those years
277 * where the year-of-era is reset to one due to a change in the era.
278 * For example:
279 * <pre>
280 * 6th Jan Showa 64 = day-of-year 6
281 * 7th Jan Showa 64 = day-of-year 7
282 * 8th Jan Heisei 1 = day-of-year 1
283 * 9th Jan Heisei 1 = day-of-year 2
284 * </pre>
285 *
286 * @param era the Japanese era, not null
287 * @param yearOfEra the Japanese year-of-era
288 * @param dayOfYear the chronology day-of-year, from 1 to 366
289 * @return the date in Japanese calendar system, not null
290 * @throws DateTimeException if the value of any field is out of range,
291 * or if the day-of-year is invalid for the year
292 */
293 static JapaneseDate ofYearDay(JapaneseEra era, int yearOfEra, int dayOfYear) {
294 Objects.requireNonNull(era, "era");
295 CalendarDate firstDay = era.getPrivateEra().getSinceDate();
296 LocalGregorianCalendar.Date jdate = JapaneseChronology.JCAL.newCalendarDate(null);
297 jdate.setEra(era.getPrivateEra());
298 if (yearOfEra == 1) {
299 jdate.setDate(yearOfEra, firstDay.getMonth(), firstDay.getDayOfMonth() + dayOfYear - 1);
300 } else {
301 jdate.setDate(yearOfEra, 1, dayOfYear);
302 }
303 JapaneseChronology.JCAL.normalize(jdate);
304 if (era.getPrivateEra() != jdate.getEra() || yearOfEra != jdate.getYear()) {
305 throw new DateTimeException("Invalid parameters");
306 }
307 LocalDate localdate = LocalDate.of(jdate.getNormalizedYear(),
308 jdate.getMonth(), jdate.getDayOfMonth());
309 return new JapaneseDate(era, yearOfEra, localdate);
310 }
311
312 /**
313 * Obtains a {@code JapaneseDate} from a temporal object.
314 * <p>
315 * This obtains a date in the Japanese calendar system based on the specified temporal.
316 * A {@code TemporalAccessor} represents an arbitrary set of date and time information,
317 * which this factory converts to an instance of {@code JapaneseDate}.
318 * <p>
319 * The conversion typically uses the {@link ChronoField#EPOCH_DAY EPOCH_DAY}
320 * field, which is standardized across calendar systems.
321 * <p>
322 * This method matches the signature of the functional interface {@link TemporalQuery}
323 * allowing it to be used as a query via method reference, {@code JapaneseDate::from}.
324 *
325 * @param temporal the temporal object to convert, not null
326 * @return the date in Japanese calendar system, not null
327 * @throws DateTimeException if unable to convert to a {@code JapaneseDate}
328 */
329 public static JapaneseDate from(TemporalAccessor temporal) {
330 return JapaneseChronology.INSTANCE.date(temporal);
331 }
332
333 //-----------------------------------------------------------------------
334 /**
335 * Creates an instance from an ISO date.
336 *
337 * @param isoDate the standard local date, validated not null
338 */
339 JapaneseDate(LocalDate isoDate) {
340 if (isoDate.isBefore(MEIJI_6_ISODATE)) {
341 throw new DateTimeException("JapaneseDate before Meiji 6 is not supported");
342 }
343 LocalGregorianCalendar.Date jdate = toPrivateJapaneseDate(isoDate);
344 this.era = JapaneseEra.toJapaneseEra(jdate.getEra());
345 this.yearOfEra = jdate.getYear();
346 this.isoDate = isoDate;
347 }
348
349 /**
350 * Constructs a {@code JapaneseDate}. This constructor does NOT validate the given parameters,
351 * and {@code era} and {@code year} must agree with {@code isoDate}.
352 *
353 * @param era the era, validated not null
354 * @param year the year-of-era, validated
355 * @param isoDate the standard local date, validated not null
356 */
357 JapaneseDate(JapaneseEra era, int year, LocalDate isoDate) {
358 if (isoDate.isBefore(MEIJI_6_ISODATE)) {
359 throw new DateTimeException("JapaneseDate before Meiji 6 is not supported");
360 }
361 this.era = era;
362 this.yearOfEra = year;
363 this.isoDate = isoDate;
364 }
365
366 //-----------------------------------------------------------------------
367 /**
368 * Gets the chronology of this date, which is the Japanese calendar system.
369 * <p>
370 * The {@code Chronology} represents the calendar system in use.
371 * The era and other fields in {@link ChronoField} are defined by the chronology.
372 *
373 * @return the Japanese chronology, not null
374 */
375 @Override
376 public JapaneseChronology getChronology() {
377 return JapaneseChronology.INSTANCE;
378 }
379
380 /**
381 * Gets the era applicable at this date.
382 * <p>
383 * The Japanese calendar system has multiple eras defined by {@link JapaneseEra}.
384 *
385 * @return the era applicable at this date, not null
386 */
387 @Override
388 public JapaneseEra getEra() {
389 return era;
390 }
391
392 /**
393 * Returns the length of the month represented by this date.
394 * <p>
395 * This returns the length of the month in days.
396 * Month lengths match those of the ISO calendar system.
397 *
398 * @return the length of the month in days
399 */
400 @Override
401 public int lengthOfMonth() {
402 return isoDate.lengthOfMonth();
403 }
404
405 @Override
406 public int lengthOfYear() {
407 Calendar jcal = Calendar.getInstance(JapaneseChronology.LOCALE);
408 jcal.set(Calendar.ERA, era.getValue() + JapaneseEra.ERA_OFFSET);
409 jcal.set(yearOfEra, isoDate.getMonthValue() - 1, isoDate.getDayOfMonth());
410 return jcal.getActualMaximum(Calendar.DAY_OF_YEAR);
411 }
412
413 //-----------------------------------------------------------------------
414 /**
415 * Checks if the specified field is supported.
416 * <p>
417 * This checks if this date can be queried for the specified field.
418 * If false, then calling the {@link #range(TemporalField) range} and
419 * {@link #get(TemporalField) get} methods will throw an exception.
420 * <p>
421 * If the field is a {@link ChronoField} then the query is implemented here.
422 * The supported fields are:
423 * <ul>
424 * <li>{@code DAY_OF_WEEK}
425 * <li>{@code DAY_OF_MONTH}
426 * <li>{@code DAY_OF_YEAR}
427 * <li>{@code EPOCH_DAY}
428 * <li>{@code MONTH_OF_YEAR}
429 * <li>{@code PROLEPTIC_MONTH}
430 * <li>{@code YEAR_OF_ERA}
431 * <li>{@code YEAR}
432 * <li>{@code ERA}
433 * </ul>
434 * All other {@code ChronoField} instances will return false.
435 * <p>
436 * If the field is not a {@code ChronoField}, then the result of this method
437 * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)}
438 * passing {@code this} as the argument.
439 * Whether the field is supported is determined by the field.
440 *
441 * @param field the field to check, null returns false
442 * @return true if the field is supported on this date, false if not
443 */
444 @Override
445 public boolean isSupported(TemporalField field) {
446 if (field == ALIGNED_DAY_OF_WEEK_IN_MONTH || field == ALIGNED_DAY_OF_WEEK_IN_YEAR ||
447 field == ALIGNED_WEEK_OF_MONTH || field == ALIGNED_WEEK_OF_YEAR) {
448 return false;
449 }
450 return super.isSupported(field);
451 }
452
453 @Override
454 public ValueRange range(TemporalField field) {
455 if (field instanceof ChronoField chronoField) {
456 if (isSupported(field)) {
457 return switch (chronoField) {
458 case DAY_OF_MONTH -> ValueRange.of(1, lengthOfMonth());
459 case DAY_OF_YEAR -> ValueRange.of(1, lengthOfYear());
460 case YEAR_OF_ERA -> {
461 Calendar jcal = Calendar.getInstance(JapaneseChronology.LOCALE);
462 jcal.set(Calendar.ERA, era.getValue() + JapaneseEra.ERA_OFFSET);
463 jcal.set(yearOfEra, isoDate.getMonthValue() - 1, isoDate.getDayOfMonth());
464 yield ValueRange.of(1, jcal.getActualMaximum(Calendar.YEAR));
465 }
466 default -> getChronology().range(chronoField);
467 };
468 }
469 throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
470 }
471 return field.rangeRefinedBy(this);
472 }
473
474 @Override
475 public long getLong(TemporalField field) {
476 if (field instanceof ChronoField cf) {
477 // same as ISO:
478 // DAY_OF_WEEK, DAY_OF_MONTH, EPOCH_DAY, MONTH_OF_YEAR, PROLEPTIC_MONTH, YEAR
479 //
480 // calendar specific fields
481 // DAY_OF_YEAR, YEAR_OF_ERA, ERA
482 switch (cf) {
483 case ALIGNED_DAY_OF_WEEK_IN_MONTH:
484 case ALIGNED_DAY_OF_WEEK_IN_YEAR:
485 case ALIGNED_WEEK_OF_MONTH:
486 case ALIGNED_WEEK_OF_YEAR:
487 throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
488 case YEAR_OF_ERA:
489 return yearOfEra;
490 case ERA:
491 return era.getValue();
492 case DAY_OF_YEAR:
493 Calendar jcal = Calendar.getInstance(JapaneseChronology.LOCALE);
494 jcal.set(Calendar.ERA, era.getValue() + JapaneseEra.ERA_OFFSET);
495 jcal.set(yearOfEra, isoDate.getMonthValue() - 1, isoDate.getDayOfMonth());
496 return jcal.get(Calendar.DAY_OF_YEAR);
497 }
498 return isoDate.getLong(field);
499 }
500 return field.getFrom(this);
501 }
502
503 /**
504 * Returns a {@code LocalGregorianCalendar.Date} converted from the given {@code isoDate}.
505 *
506 * @param isoDate the local date, not null
507 * @return a {@code LocalGregorianCalendar.Date}, not null
508 */
509 private static LocalGregorianCalendar.Date toPrivateJapaneseDate(LocalDate isoDate) {
510 LocalGregorianCalendar.Date jdate = JapaneseChronology.JCAL.newCalendarDate(null);
511 sun.util.calendar.Era sunEra = JapaneseEra.privateEraFrom(isoDate);
512 int year = isoDate.getYear();
513 if (sunEra != null) {
514 year -= sunEra.getSinceDate().getYear() - 1;
515 }
516 jdate.setEra(sunEra).setYear(year).setMonth(isoDate.getMonthValue()).setDayOfMonth(isoDate.getDayOfMonth());
517 JapaneseChronology.JCAL.normalize(jdate);
518 return jdate;
519 }
520
521 //-----------------------------------------------------------------------
522 @Override
523 public JapaneseDate with(TemporalField field, long newValue) {
524 if (field instanceof ChronoField chronoField) {
525 if (getLong(chronoField) == newValue) { // getLong() validates for supported fields
526 return this;
527 }
528 switch (chronoField) {
529 case YEAR_OF_ERA:
530 case YEAR:
531 case ERA: {
532 int nvalue = getChronology().range(chronoField).checkValidIntValue(newValue, chronoField);
533 switch (chronoField) {
534 case YEAR_OF_ERA:
535 return this.withYear(nvalue);
536 case YEAR:
537 return with(isoDate.withYear(nvalue));
538 case ERA: {
539 return this.withYear(JapaneseEra.of(nvalue), yearOfEra);
540 }
541 }
542 }
543 }
544 // YEAR, PROLEPTIC_MONTH and others are same as ISO
545 return with(isoDate.with(field, newValue));
546 }
547 return super.with(field, newValue);
548 }
549
550 /**
551 * {@inheritDoc}
552 * @throws DateTimeException {@inheritDoc}
553 * @throws ArithmeticException {@inheritDoc}
554 */
555 @Override
556 public JapaneseDate with(TemporalAdjuster adjuster) {
557 return super.with(adjuster);
558 }
559
560 /**
561 * {@inheritDoc}
562 * @throws DateTimeException {@inheritDoc}
563 * @throws ArithmeticException {@inheritDoc}
564 */
565 @Override
566 public JapaneseDate plus(TemporalAmount amount) {
567 return super.plus(amount);
568 }
569
570 /**
571 * {@inheritDoc}
572 * @throws DateTimeException {@inheritDoc}
573 * @throws ArithmeticException {@inheritDoc}
574 */
575 @Override
576 public JapaneseDate minus(TemporalAmount amount) {
577 return super.minus(amount);
578 }
579 //-----------------------------------------------------------------------
580 /**
581 * Returns a copy of this date with the year altered.
582 * <p>
583 * This method changes the year of the date.
584 * If the month-day is invalid for the year, then the previous valid day
585 * will be selected instead.
586 * <p>
587 * This instance is immutable and unaffected by this method call.
588 *
589 * @param era the era to set in the result, not null
590 * @param yearOfEra the year-of-era to set in the returned date
591 * @return a {@code JapaneseDate} based on this date with the requested year, never null
592 * @throws DateTimeException if {@code year} is invalid
593 */
594 private JapaneseDate withYear(JapaneseEra era, int yearOfEra) {
595 int year = JapaneseChronology.INSTANCE.prolepticYear(era, yearOfEra);
596 return with(isoDate.withYear(year));
597 }
598
599 /**
600 * Returns a copy of this date with the year-of-era altered.
601 * <p>
602 * This method changes the year-of-era of the date.
603 * If the month-day is invalid for the year, then the previous valid day
604 * will be selected instead.
605 * <p>
606 * This instance is immutable and unaffected by this method call.
607 *
608 * @param year the year to set in the returned date
609 * @return a {@code JapaneseDate} based on this date with the requested year-of-era, never null
610 * @throws DateTimeException if {@code year} is invalid
611 */
612 private JapaneseDate withYear(int year) {
613 return withYear(getEra(), year);
614 }
615
616 //-----------------------------------------------------------------------
617 @Override
618 JapaneseDate plusYears(long years) {
619 return with(isoDate.plusYears(years));
620 }
621
622 @Override
623 JapaneseDate plusMonths(long months) {
624 return with(isoDate.plusMonths(months));
625 }
626
627 @Override
628 JapaneseDate plusWeeks(long weeksToAdd) {
629 return with(isoDate.plusWeeks(weeksToAdd));
630 }
631
632 @Override
633 JapaneseDate plusDays(long days) {
634 return with(isoDate.plusDays(days));
635 }
636
637 @Override
638 public JapaneseDate plus(long amountToAdd, TemporalUnit unit) {
639 return super.plus(amountToAdd, unit);
640 }
641
642 @Override
643 public JapaneseDate minus(long amountToSubtract, TemporalUnit unit) {
644 return super.minus(amountToSubtract, unit);
645 }
646
647 @Override
648 JapaneseDate minusYears(long yearsToSubtract) {
649 return super.minusYears(yearsToSubtract);
650 }
651
652 @Override
653 JapaneseDate minusMonths(long monthsToSubtract) {
654 return super.minusMonths(monthsToSubtract);
655 }
656
657 @Override
658 JapaneseDate minusWeeks(long weeksToSubtract) {
659 return super.minusWeeks(weeksToSubtract);
660 }
661
662 @Override
663 JapaneseDate minusDays(long daysToSubtract) {
664 return super.minusDays(daysToSubtract);
665 }
666
667 private JapaneseDate with(LocalDate newDate) {
668 return (newDate.equals(isoDate) ? this : new JapaneseDate(newDate));
669 }
670
671 @Override // for javadoc and covariant return type
672 @SuppressWarnings("unchecked")
673 public final ChronoLocalDateTime<JapaneseDate> atTime(LocalTime localTime) {
674 return (ChronoLocalDateTime<JapaneseDate>)super.atTime(localTime);
675 }
676
677 @Override
678 public ChronoPeriod until(ChronoLocalDate endDate) {
679 Period period = isoDate.until(endDate);
680 return getChronology().period(period.getYears(), period.getMonths(), period.getDays());
681 }
682
683 @Override // override for performance
684 public long toEpochDay() {
685 return isoDate.toEpochDay();
686 }
687
688 //-------------------------------------------------------------------------
689 /**
690 * Compares this date to another date, including the chronology.
691 * <p>
692 * Compares this {@code JapaneseDate} with another ensuring that the date is the same.
693 * <p>
694 * Only objects of type {@code JapaneseDate} are compared, other types return false.
695 * To compare the dates of two {@code TemporalAccessor} instances, including dates
696 * in two different chronologies, use {@link ChronoField#EPOCH_DAY} as a comparator.
697 *
698 * @param obj the object to check, null returns false
699 * @return true if this is equal to the other date
700 */
701 @Override // override for performance
702 public boolean equals(Object obj) {
703 if (this == obj) {
704 return true;
705 }
706 return (obj instanceof JapaneseDate otherDate)
707 && this.isoDate.equals(otherDate.isoDate);
708 }
709
710 /**
711 * A hash code for this date.
712 *
713 * @return a suitable hash code based only on the Chronology and the date
714 */
715 @Override // override for performance
716 public int hashCode() {
717 return getChronology().getId().hashCode() ^ isoDate.hashCode();
718 }
719
720 //-----------------------------------------------------------------------
721 /**
722 * Defend against malicious streams.
723 *
724 * @param s the stream to read
725 * @throws InvalidObjectException always
726 */
727 @java.io.Serial
728 private void readObject(ObjectInputStream s) throws InvalidObjectException {
729 throw new InvalidObjectException("Deserialization via serialization delegate");
730 }
731
732 /**
733 * Writes the object using a
734 * <a href="{@docRoot}/serialized-form.html#java.time.chrono.Ser">dedicated serialized form</a>.
735 * @serialData
736 * <pre>
737 * out.writeByte(4); // identifies a JapaneseDate
738 * out.writeInt(get(YEAR));
739 * out.writeByte(get(MONTH_OF_YEAR));
740 * out.writeByte(get(DAY_OF_MONTH));
741 * </pre>
742 *
743 * @return the instance of {@code Ser}, not null
744 */
745 @java.io.Serial
746 private Object writeReplace() {
747 return new Ser(Ser.JAPANESE_DATE_TYPE, this);
748 }
749
750 void writeExternal(DataOutput out) throws IOException {
751 // JapaneseChronology is implicit in the JAPANESE_DATE_TYPE
752 out.writeInt(get(YEAR));
753 out.writeByte(get(MONTH_OF_YEAR));
754 out.writeByte(get(DAY_OF_MONTH));
755 }
756
757 static JapaneseDate readExternal(DataInput in) throws IOException {
758 int year = in.readInt();
759 int month = in.readByte();
760 int dayOfMonth = in.readByte();
761 return JapaneseChronology.INSTANCE.date(year, month, dayOfMonth);
762 }
763
764 }