1 /*
  2  * Copyright (c) 2012, 2019, 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.IOException;
 68 import java.io.InvalidObjectException;
 69 import java.io.ObjectInput;
 70 import java.io.ObjectInputStream;
 71 import java.io.ObjectOutput;
 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.ZoneId;
 78 import java.time.temporal.ChronoField;
 79 import java.time.temporal.TemporalAccessor;
 80 import java.time.temporal.TemporalAdjuster;
 81 import java.time.temporal.TemporalAmount;
 82 import java.time.temporal.TemporalField;
 83 import java.time.temporal.TemporalQuery;
 84 import java.time.temporal.TemporalUnit;
 85 import java.time.temporal.UnsupportedTemporalTypeException;
 86 import java.time.temporal.ValueRange;
 87 
 88 /**
 89  * A date in the Hijrah calendar system.
 90  * <p>
 91  * This date operates using one of several variants of the
 92  * {@linkplain HijrahChronology Hijrah calendar}.
 93  * <p>
 94  * The Hijrah calendar has a different total of days in a year than
 95  * Gregorian calendar, and the length of each month is based on the period
 96  * of a complete revolution of the moon around the earth
 97  * (as between successive new moons).
 98  * Refer to the {@link HijrahChronology} for details of supported variants.
 99  * <p>
100  * Each HijrahDate is created bound to a particular HijrahChronology,
101  * The same chronology is propagated to each HijrahDate computed from the date.
102  * To use a different Hijrah variant, its HijrahChronology can be used
103  * to create new HijrahDate instances.
104  * Alternatively, the {@link #withVariant} method can be used to convert
105  * to a new HijrahChronology.
106  * <p>
107  * This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
108  * class; programmers should treat instances that are {@linkplain #equals(Object) equal}
109  * as interchangeable and should not use instances for synchronization, mutexes, or
110  * with {@linkplain java.lang.ref.Reference object references}.
111  *
112  * <div class="preview-block">
113  *      <div class="preview-comment">
114  *          When preview features are enabled, {@code HijrahDate} is a {@linkplain Class#isValue value class}.
115  *          Use of value class instances for synchronization, mutexes, or with
116  *          {@linkplain java.lang.ref.Reference object references} result in
117  *          {@link IdentityException}.
118  *      </div>
119  * </div>
120  *
121  * @implSpec
122  * This class is immutable and thread-safe.
123  *
124  * @since 1.8
125  */
126 @jdk.internal.ValueBased
127 @jdk.internal.MigratedValueClass
128 public final class HijrahDate
129         extends ChronoLocalDateImpl<HijrahDate>
130         implements ChronoLocalDate, Serializable {
131 
132     /**
133      * Serialization version.
134      */
135     @java.io.Serial
136     private static final long serialVersionUID = -5207853542612002020L;
137     /**
138      * The Chronology of this HijrahDate.
139      */
140     private final transient HijrahChronology chrono;
141     /**
142      * The proleptic year.
143      */
144     private final transient int prolepticYear;
145     /**
146      * The month-of-year.
147      */
148     private final transient int monthOfYear;
149     /**
150      * The day-of-month.
151      */
152     private final transient int dayOfMonth;
153 
154     //-------------------------------------------------------------------------
155     /**
156      * Obtains an instance of {@code HijrahDate} from the Hijrah proleptic year,
157      * month-of-year and day-of-month.
158      *
159      * @param prolepticYear  the proleptic year to represent in the Hijrah calendar
160      * @param monthOfYear  the month-of-year to represent, from 1 to 12
161      * @param dayOfMonth  the day-of-month to represent, from 1 to 30
162      * @return the Hijrah date, never null
163      * @throws DateTimeException if the value of any field is out of range
164      */
165     static HijrahDate of(HijrahChronology chrono, int prolepticYear, int monthOfYear, int dayOfMonth) {
166         return new HijrahDate(chrono, prolepticYear, monthOfYear, dayOfMonth);
167     }
168 
169     /**
170      * Returns a HijrahDate for the chronology and epochDay.
171      * @param chrono The Hijrah chronology
172      * @param epochDay the epoch day
173      * @return a HijrahDate for the epoch day; non-null
174      */
175     static HijrahDate ofEpochDay(HijrahChronology chrono, long epochDay) {
176         return new HijrahDate(chrono, epochDay);
177     }
178 
179     //-----------------------------------------------------------------------
180     /**
181      * Obtains the current {@code HijrahDate} of the Islamic Umm Al-Qura calendar
182      * in the default time-zone.
183      * <p>
184      * This will query the {@link Clock#systemDefaultZone() system clock} in the default
185      * time-zone to obtain the current date.
186      * <p>
187      * Using this method will prevent the ability to use an alternate clock for testing
188      * because the clock is hard-coded.
189      *
190      * @return the current date using the system clock and default time-zone, not null
191      */
192     public static HijrahDate now() {
193         return now(Clock.systemDefaultZone());
194     }
195 
196     /**
197      * Obtains the current {@code HijrahDate} of the Islamic Umm Al-Qura calendar
198      * in the specified time-zone.
199      * <p>
200      * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current date.
201      * Specifying the time-zone avoids dependence on the default time-zone.
202      * <p>
203      * Using this method will prevent the ability to use an alternate clock for testing
204      * because the clock is hard-coded.
205      *
206      * @param zone  the zone ID to use, not null
207      * @return the current date using the system clock, not null
208      */
209     public static HijrahDate now(ZoneId zone) {
210         return now(Clock.system(zone));
211     }
212 
213     /**
214      * Obtains the current {@code HijrahDate} of the Islamic Umm Al-Qura calendar
215      * from the specified clock.
216      * <p>
217      * This will query the specified clock to obtain the current date - today.
218      * Using this method allows the use of an alternate clock for testing.
219      * The alternate clock may be introduced using {@linkplain Clock dependency injection}.
220      *
221      * @param clock  the clock to use, not null
222      * @return the current date, not null
223      * @throws DateTimeException if the current date cannot be obtained
224      */
225     public static HijrahDate now(Clock clock) {
226         return HijrahDate.ofEpochDay(HijrahChronology.INSTANCE, LocalDate.now(clock).toEpochDay());
227     }
228 
229     /**
230      * Obtains a {@code HijrahDate} of the Islamic Umm Al-Qura calendar
231      * from the proleptic-year, month-of-year and day-of-month fields.
232      * <p>
233      * This returns a {@code HijrahDate} with the specified fields.
234      * The day must be valid for the year and month, otherwise an exception will be thrown.
235      *
236      * @param prolepticYear  the Hijrah proleptic-year
237      * @param month  the Hijrah month-of-year, from 1 to 12
238      * @param dayOfMonth  the Hijrah day-of-month, from 1 to 30
239      * @return the date in Hijrah calendar system, not null
240      * @throws DateTimeException if the value of any field is out of range,
241      *  or if the day-of-month is invalid for the month-year
242      */
243     public static HijrahDate of(int prolepticYear, int month, int dayOfMonth) {
244         return HijrahChronology.INSTANCE.date(prolepticYear, month, dayOfMonth);
245     }
246 
247     /**
248      * Obtains a {@code HijrahDate} of the Islamic Umm Al-Qura calendar from a temporal object.
249      * <p>
250      * This obtains a date in the Hijrah calendar system based on the specified temporal.
251      * A {@code TemporalAccessor} represents an arbitrary set of date and time information,
252      * which this factory converts to an instance of {@code HijrahDate}.
253      * <p>
254      * The conversion typically uses the {@link ChronoField#EPOCH_DAY EPOCH_DAY}
255      * field, which is standardized across calendar systems.
256      * <p>
257      * This method matches the signature of the functional interface {@link TemporalQuery}
258      * allowing it to be used as a query via method reference, {@code HijrahDate::from}.
259      *
260      * @param temporal  the temporal object to convert, not null
261      * @return the date in Hijrah calendar system, not null
262      * @throws DateTimeException if unable to convert to a {@code HijrahDate}
263      */
264     public static HijrahDate from(TemporalAccessor temporal) {
265         return HijrahChronology.INSTANCE.date(temporal);
266     }
267 
268     //-----------------------------------------------------------------------
269     /**
270      * Constructs an {@code HijrahDate} with the proleptic-year, month-of-year and
271      * day-of-month fields.
272      *
273      * @param chrono The chronology to create the date with
274      * @param prolepticYear the proleptic year
275      * @param monthOfYear the month of year
276      * @param dayOfMonth the day of month
277      */
278     private HijrahDate(HijrahChronology chrono, int prolepticYear, int monthOfYear, int dayOfMonth) {
279         // Computing the Gregorian day checks the valid ranges
280         chrono.getEpochDay(prolepticYear, monthOfYear, dayOfMonth);
281 
282         this.chrono = chrono;
283         this.prolepticYear = prolepticYear;
284         this.monthOfYear = monthOfYear;
285         this.dayOfMonth = dayOfMonth;
286     }
287 
288     /**
289      * Constructs an instance with the Epoch Day.
290      *
291      * @param epochDay  the epochDay
292      */
293     private HijrahDate(HijrahChronology chrono, long epochDay) {
294         int[] dateInfo = chrono.getHijrahDateInfo((int)epochDay);
295 
296         this.chrono = chrono;
297         this.prolepticYear = dateInfo[0];
298         this.monthOfYear = dateInfo[1];
299         this.dayOfMonth = dateInfo[2];
300     }
301 
302     //-----------------------------------------------------------------------
303     /**
304      * Gets the chronology of this date, which is the Hijrah calendar system.
305      * <p>
306      * The {@code Chronology} represents the calendar system in use.
307      * The era and other fields in {@link ChronoField} are defined by the chronology.
308      *
309      * @return the Hijrah chronology, not null
310      */
311     @Override
312     public HijrahChronology getChronology() {
313         return chrono;
314     }
315 
316     /**
317      * Gets the era applicable at this date.
318      * <p>
319      * The Hijrah calendar system has one era, 'AH',
320      * defined by {@link HijrahEra}.
321      *
322      * @return the era applicable at this date, not null
323      */
324     @Override
325     public HijrahEra getEra() {
326         return HijrahEra.AH;
327     }
328 
329     /**
330      * Returns the length of the month represented by this date.
331      * <p>
332      * This returns the length of the month in days.
333      * Month lengths in the Hijrah calendar system vary between 29 and 30 days.
334      *
335      * @return the length of the month in days
336      */
337     @Override
338     public int lengthOfMonth() {
339         return chrono.getMonthLength(prolepticYear, monthOfYear);
340     }
341 
342     /**
343      * Returns the length of the year represented by this date.
344      * <p>
345      * This returns the length of the year in days.
346      * A Hijrah calendar system year is typically shorter than
347      * that of the ISO calendar system.
348      *
349      * @return the length of the year in days
350      */
351     @Override
352     public int lengthOfYear() {
353         return chrono.getYearLength(prolepticYear);
354     }
355 
356     //-----------------------------------------------------------------------
357     @Override
358     public ValueRange range(TemporalField field) {
359         if (field instanceof ChronoField) {
360             if (isSupported(field)) {
361                 ChronoField f = (ChronoField) field;
362                 return switch (f) {
363                     case DAY_OF_MONTH -> ValueRange.of(1, lengthOfMonth());
364                     case DAY_OF_YEAR -> ValueRange.of(1, lengthOfYear());
365                     case ALIGNED_WEEK_OF_MONTH -> ValueRange.of(1, 5); // TODO
366                     // TODO does the limited range of valid years cause years to
367                     // start/end part way through? that would affect range
368                     default -> getChronology().range(f);
369                 };
370             }
371             throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
372         }
373         return field.rangeRefinedBy(this);
374     }
375 
376     @Override
377     public long getLong(TemporalField field) {
378         if (field instanceof ChronoField) {
379             return switch ((ChronoField) field) {
380                 case DAY_OF_WEEK                  ->  getDayOfWeek();
381                 case ALIGNED_DAY_OF_WEEK_IN_MONTH ->  ((dayOfMonth - 1) % 7) + 1;
382                 case ALIGNED_DAY_OF_WEEK_IN_YEAR  ->  ((getDayOfYear() - 1) % 7) + 1;
383                 case DAY_OF_MONTH                 ->  this.dayOfMonth;
384                 case DAY_OF_YEAR                  ->  this.getDayOfYear();
385                 case EPOCH_DAY                    ->  toEpochDay();
386                 case ALIGNED_WEEK_OF_MONTH        ->  ((dayOfMonth - 1) / 7) + 1;
387                 case ALIGNED_WEEK_OF_YEAR         ->  ((getDayOfYear() - 1) / 7) + 1;
388                 case MONTH_OF_YEAR                ->  monthOfYear;
389                 case PROLEPTIC_MONTH              ->  getProlepticMonth();
390                 case YEAR_OF_ERA                  ->  prolepticYear;
391                 case YEAR                         ->  prolepticYear;
392                 case ERA                          ->  getEraValue();
393                 default -> throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
394             };
395         }
396         return field.getFrom(this);
397     }
398 
399     private long getProlepticMonth() {
400         return prolepticYear * 12L + monthOfYear - 1;
401     }
402 
403     @Override
404     public HijrahDate with(TemporalField field, long newValue) {
405         if (field instanceof ChronoField chronoField) {
406             // not using checkValidIntValue so EPOCH_DAY and PROLEPTIC_MONTH work
407             chrono.range(chronoField).checkValidValue(newValue, chronoField);    // TODO: validate value
408             int nvalue = (int) newValue;
409             return switch (chronoField) {
410                 case DAY_OF_WEEK                  ->  plusDays(newValue - getDayOfWeek());
411                 case ALIGNED_DAY_OF_WEEK_IN_MONTH ->  plusDays(newValue - getLong(ALIGNED_DAY_OF_WEEK_IN_MONTH));
412                 case ALIGNED_DAY_OF_WEEK_IN_YEAR  ->  plusDays(newValue - getLong(ALIGNED_DAY_OF_WEEK_IN_YEAR));
413                 case DAY_OF_MONTH                 ->  resolvePreviousValid(prolepticYear, monthOfYear, nvalue);
414                 case DAY_OF_YEAR                  ->  plusDays(Math.min(nvalue, lengthOfYear()) - getDayOfYear());
415                 case EPOCH_DAY                    ->  new HijrahDate(chrono, newValue);
416                 case ALIGNED_WEEK_OF_MONTH        ->  plusDays((newValue - getLong(ALIGNED_WEEK_OF_MONTH)) * 7);
417                 case ALIGNED_WEEK_OF_YEAR         ->  plusDays((newValue - getLong(ALIGNED_WEEK_OF_YEAR)) * 7);
418                 case MONTH_OF_YEAR                ->  resolvePreviousValid(prolepticYear, nvalue, dayOfMonth);
419                 case PROLEPTIC_MONTH              ->  plusMonths(newValue - getProlepticMonth());
420                 case YEAR_OF_ERA                  ->  resolvePreviousValid(prolepticYear >= 1 ? nvalue : 1 - nvalue, monthOfYear, dayOfMonth);
421                 case YEAR                         ->  resolvePreviousValid(nvalue, monthOfYear, dayOfMonth);
422                 case ERA                          ->  resolvePreviousValid(1 - prolepticYear, monthOfYear, dayOfMonth);
423                 default -> throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
424             };
425         }
426         return super.with(field, newValue);
427     }
428 
429     private HijrahDate resolvePreviousValid(int prolepticYear, int month, int day) {
430         int monthDays = chrono.getMonthLength(prolepticYear, month);
431         if (day > monthDays) {
432             day = monthDays;
433         }
434         return HijrahDate.of(chrono, prolepticYear, month, day);
435     }
436 
437     /**
438      * {@inheritDoc}
439      * @throws DateTimeException if unable to make the adjustment.
440      *     For example, if the adjuster requires an ISO chronology
441      * @throws ArithmeticException {@inheritDoc}
442      */
443     @Override
444     public  HijrahDate with(TemporalAdjuster adjuster) {
445         return super.with(adjuster);
446     }
447 
448     /**
449      * Returns a {@code HijrahDate} with the Chronology requested.
450      * <p>
451      * The year, month, and day are checked against the new requested
452      * HijrahChronology.  If the chronology has a shorter month length
453      * for the month, the day is reduced to be the last day of the month.
454      *
455      * @param chronology the new HijrahChonology, non-null
456      * @return a HijrahDate with the requested HijrahChronology, non-null
457      */
458     public HijrahDate withVariant(HijrahChronology chronology) {
459         if (chrono == chronology) {
460             return this;
461         }
462         // Like resolvePreviousValid the day is constrained to stay in the same month
463         int monthDays = chronology.getDayOfYear(prolepticYear, monthOfYear);
464         return HijrahDate.of(chronology, prolepticYear, monthOfYear,(dayOfMonth > monthDays) ? monthDays : dayOfMonth );
465     }
466 
467     /**
468      * {@inheritDoc}
469      * @throws DateTimeException {@inheritDoc}
470      * @throws ArithmeticException {@inheritDoc}
471      */
472     @Override
473     public HijrahDate plus(TemporalAmount amount) {
474         return super.plus(amount);
475     }
476 
477     /**
478      * {@inheritDoc}
479      * @throws DateTimeException {@inheritDoc}
480      * @throws ArithmeticException {@inheritDoc}
481      */
482     @Override
483     public HijrahDate minus(TemporalAmount amount) {
484         return super.minus(amount);
485     }
486 
487     @Override
488     public long toEpochDay() {
489         return chrono.getEpochDay(prolepticYear, monthOfYear, dayOfMonth);
490     }
491 
492     /**
493      * Gets the day-of-year field.
494      * <p>
495      * This method returns the primitive {@code int} value for the day-of-year.
496      *
497      * @return the day-of-year
498      */
499     private int getDayOfYear() {
500         return chrono.getDayOfYear(prolepticYear, monthOfYear) + dayOfMonth;
501     }
502 
503     /**
504      * Gets the day-of-week value.
505      *
506      * @return the day-of-week; computed from the epochday
507      */
508     private int getDayOfWeek() {
509         int dow0 = Math.floorMod(toEpochDay() + 3, 7);
510         return dow0 + 1;
511     }
512 
513     /**
514      * Gets the Era of this date.
515      *
516      * @return the Era of this date; computed from epochDay
517      */
518     private int getEraValue() {
519         return (prolepticYear > 1 ? 1 : 0);
520     }
521 
522     //-----------------------------------------------------------------------
523     /**
524      * Checks if the year is a leap year, according to the Hijrah calendar system rules.
525      *
526      * @return true if this date is in a leap year
527      */
528     @Override
529     public boolean isLeapYear() {
530         return chrono.isLeapYear(prolepticYear);
531     }
532 
533     //-----------------------------------------------------------------------
534     @Override
535     HijrahDate plusYears(long years) {
536         if (years == 0) {
537             return this;
538         }
539         int newYear = Math.addExact(this.prolepticYear, (int)years);
540         return resolvePreviousValid(newYear, monthOfYear, dayOfMonth);
541     }
542 
543     @Override
544     HijrahDate plusMonths(long monthsToAdd) {
545         if (monthsToAdd == 0) {
546             return this;
547         }
548         long monthCount = prolepticYear * 12L + (monthOfYear - 1);
549         long calcMonths = monthCount + monthsToAdd;  // safe overflow
550         int newYear = chrono.checkValidYear(Math.floorDiv(calcMonths, 12L));
551         int newMonth = (int)Math.floorMod(calcMonths, 12L) + 1;
552         return resolvePreviousValid(newYear, newMonth, dayOfMonth);
553     }
554 
555     @Override
556     HijrahDate plusWeeks(long weeksToAdd) {
557         return super.plusWeeks(weeksToAdd);
558     }
559 
560     @Override
561     HijrahDate plusDays(long days) {
562         return new HijrahDate(chrono, toEpochDay() + days);
563     }
564 
565     @Override
566     public HijrahDate plus(long amountToAdd, TemporalUnit unit) {
567         return super.plus(amountToAdd, unit);
568     }
569 
570     @Override
571     public HijrahDate minus(long amountToSubtract, TemporalUnit unit) {
572         return super.minus(amountToSubtract, unit);
573     }
574 
575     @Override
576     HijrahDate minusYears(long yearsToSubtract) {
577         return super.minusYears(yearsToSubtract);
578     }
579 
580     @Override
581     HijrahDate minusMonths(long monthsToSubtract) {
582         return super.minusMonths(monthsToSubtract);
583     }
584 
585     @Override
586     HijrahDate minusWeeks(long weeksToSubtract) {
587         return super.minusWeeks(weeksToSubtract);
588     }
589 
590     @Override
591     HijrahDate minusDays(long daysToSubtract) {
592         return super.minusDays(daysToSubtract);
593     }
594 
595     @Override        // for javadoc and covariant return type
596     @SuppressWarnings("unchecked")
597     public final ChronoLocalDateTime<HijrahDate> atTime(LocalTime localTime) {
598         return (ChronoLocalDateTime<HijrahDate>)super.atTime(localTime);
599     }
600 
601     @Override
602     public ChronoPeriod until(ChronoLocalDate endDate) {
603         // TODO: untested
604         HijrahDate end = getChronology().date(endDate);
605         long totalMonths = (end.prolepticYear - this.prolepticYear) * 12 + (end.monthOfYear - this.monthOfYear);  // safe
606         int days = end.dayOfMonth - this.dayOfMonth;
607         if (totalMonths > 0 && days < 0) {
608             totalMonths--;
609             HijrahDate calcDate = this.plusMonths(totalMonths);
610             days = (int) (end.toEpochDay() - calcDate.toEpochDay());  // safe
611         } else if (totalMonths < 0 && days > 0) {
612             totalMonths++;
613             days -= end.lengthOfMonth();
614         }
615         long years = totalMonths / 12;  // safe
616         int months = (int) (totalMonths % 12);  // safe
617         return getChronology().period(Math.toIntExact(years), months, days);
618     }
619 
620     //-------------------------------------------------------------------------
621     /**
622      * Compares this date to another date, including the chronology.
623      * <p>
624      * Compares this {@code HijrahDate} with another ensuring that the date is the same.
625      * <p>
626      * Only objects of type {@code HijrahDate} are compared, other types return false.
627      * To compare the dates of two {@code TemporalAccessor} instances, including dates
628      * in two different chronologies, use {@link ChronoField#EPOCH_DAY} as a comparator.
629      *
630      * @param obj  the object to check, null returns false
631      * @return true if this is equal to the other date and the Chronologies are equal
632      */
633     @Override  // override for performance
634     public boolean equals(Object obj) {
635         if (this == obj) {
636             return true;
637         }
638         return (obj instanceof HijrahDate otherDate)
639                 && prolepticYear == otherDate.prolepticYear
640                 && this.monthOfYear == otherDate.monthOfYear
641                 && this.dayOfMonth == otherDate.dayOfMonth
642                 && getChronology().equals(otherDate.getChronology());
643     }
644 
645     /**
646      * A hash code for this date.
647      *
648      * @return a suitable hash code based only on the Chronology and the date
649      */
650     @Override  // override for performance
651     public int hashCode() {
652         int yearValue = prolepticYear;
653         int monthValue = monthOfYear;
654         int dayValue = dayOfMonth;
655         return getChronology().getId().hashCode() ^ (yearValue & 0xFFFFF800)
656                 ^ ((yearValue << 11) + (monthValue << 6) + (dayValue));
657     }
658 
659     //-----------------------------------------------------------------------
660     /**
661      * Defend against malicious streams.
662      *
663      * @param s the stream to read
664      * @throws InvalidObjectException always
665      */
666     @java.io.Serial
667     private void readObject(ObjectInputStream s) throws InvalidObjectException {
668         throw new InvalidObjectException("Deserialization via serialization delegate");
669     }
670 
671     /**
672      * Writes the object using a
673      * <a href="{@docRoot}/serialized-form.html#java.time.chrono.Ser">dedicated serialized form</a>.
674      * @serialData
675      * <pre>
676      *  out.writeByte(6);                 // identifies a HijrahDate
677      *  out.writeObject(chrono);          // the HijrahChronology variant
678      *  out.writeInt(get(YEAR));
679      *  out.writeByte(get(MONTH_OF_YEAR));
680      *  out.writeByte(get(DAY_OF_MONTH));
681      * </pre>
682      *
683      * @return the instance of {@code Ser}, not null
684      */
685     @java.io.Serial
686     private Object writeReplace() {
687         return new Ser(Ser.HIJRAH_DATE_TYPE, this);
688     }
689 
690     void writeExternal(ObjectOutput out) throws IOException {
691         // HijrahChronology is implicit in the Hijrah_DATE_TYPE
692         out.writeObject(getChronology());
693         out.writeInt(get(YEAR));
694         out.writeByte(get(MONTH_OF_YEAR));
695         out.writeByte(get(DAY_OF_MONTH));
696     }
697 
698     static HijrahDate readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
699         HijrahChronology chrono = (HijrahChronology) in.readObject();
700         int year = in.readInt();
701         int month = in.readByte();
702         int dayOfMonth = in.readByte();
703         return chrono.date(year, month, dayOfMonth);
704     }
705 
706 }