content: /*
   * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  /*
   * Copyright (c) 2012, Stephen Colebourne & Michael Nascimento Santos
   *
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *
   *  * Redistributions of source code must retain the above copyright notice,
   *    this list of conditions and the following disclaimer.
   *
   *  * Redistributions in binary form must reproduce the above copyright notice,
   *    this list of conditions and the following disclaimer in the documentation
   *    and/or other materials provided with the distribution.
   *
   *  * Neither the name of JSR-310 nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  package java.time.chrono;
  
  import static java.time.temporal.ChronoField.ALIGNED_DAY_OF_WEEK_IN_MONTH;
  import static java.time.temporal.ChronoField.ALIGNED_DAY_OF_WEEK_IN_YEAR;
  import static java.time.temporal.ChronoField.ALIGNED_WEEK_OF_MONTH;
  import static java.time.temporal.ChronoField.ALIGNED_WEEK_OF_YEAR;
  import static java.time.temporal.ChronoField.DAY_OF_MONTH;
  import static java.time.temporal.ChronoField.MONTH_OF_YEAR;
  import static java.time.temporal.ChronoField.YEAR;
  
  import java.io.IOException;
  import java.io.InvalidObjectException;
  import java.io.ObjectInput;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutput;
  import java.io.Serializable;
  import java.time.Clock;
  import java.time.DateTimeException;
  import java.time.LocalDate;
  import java.time.LocalTime;
  import java.time.ZoneId;
  import java.time.temporal.ChronoField;
  import java.time.temporal.TemporalAccessor;
  import java.time.temporal.TemporalAdjuster;
  import java.time.temporal.TemporalAmount;
  import java.time.temporal.TemporalField;
  import java.time.temporal.TemporalQuery;
  import java.time.temporal.TemporalUnit;
  import java.time.temporal.UnsupportedTemporalTypeException;
  import java.time.temporal.ValueRange;
  
  // Android-changed: removed ValueBased paragraph.
  
  /**
   * A date in the Hijrah calendar system.
   * <p>
   * This date operates using one of several variants of the
   * {@linkplain HijrahChronology Hijrah calendar}.
   * <p>
   * The Hijrah calendar has a different total of days in a year than
   * Gregorian calendar, and the length of each month is based on the period
   * of a complete revolution of the moon around the earth
   * (as between successive new moons).
   * Refer to the {@link HijrahChronology} for details of supported variants.
   * <p>
   * Each HijrahDate is created bound to a particular HijrahChronology,
   * The same chronology is propagated to each HijrahDate computed from the date.
   * To use a different Hijrah variant, its HijrahChronology can be used
   * to create new HijrahDate instances.
   * Alternatively, the {@link #withVariant} method can be used to convert
   * to a new HijrahChronology.
   *
   * @implSpec
   * This class is immutable and thread-safe.
   *
   * @since 1.8
   */
  public final class HijrahDate
          extends ChronoLocalDateImpl<HijrahDate>
          implements ChronoLocalDate, Serializable {
  
      /**
       * Serialization version.
       */
      private static final long serialVersionUID = -5207853542612002020L;
      /**
       * The Chronology of this HijrahDate.
       */
      private final transient HijrahChronology chrono;
      /**
       * The proleptic year.
       */
      private final transient int prolepticYear;
      /**
       * The month-of-year.
       */
      private final transient int monthOfYear;
      /**
       * The day-of-month.
       */
      private final transient int dayOfMonth;
  
      //-------------------------------------------------------------------------
      /**
       * Obtains an instance of {@code HijrahDate} from the Hijrah proleptic year,
       * month-of-year and day-of-month.
       *
       * @param prolepticYear  the proleptic year to represent in the Hijrah calendar
       * @param monthOfYear  the month-of-year to represent, from 1 to 12
       * @param dayOfMonth  the day-of-month to represent, from 1 to 30
       * @return the Hijrah date, never null
       * @throws DateTimeException if the value of any field is out of range
       */
      static HijrahDate of(HijrahChronology chrono, int prolepticYear, int monthOfYear, int dayOfMonth) {
          return new HijrahDate(chrono, prolepticYear, monthOfYear, dayOfMonth);
      }
  
      /**
       * Returns a HijrahDate for the chronology and epochDay.
       * @param chrono The Hijrah chronology
       * @param epochDay the epoch day
       * @return a HijrahDate for the epoch day; non-null
       */
      static HijrahDate ofEpochDay(HijrahChronology chrono, long epochDay) {
          return new HijrahDate(chrono, epochDay);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Obtains the current {@code HijrahDate} of the Islamic Umm Al-Qura calendar
       * in the default time-zone.
       * <p>
       * This will query the {@link Clock#systemDefaultZone() system clock} in the default
       * time-zone to obtain the current date.
       * <p>
       * Using this method will prevent the ability to use an alternate clock for testing
       * because the clock is hard-coded.
       *
       * @return the current date using the system clock and default time-zone, not null
       */
      public static HijrahDate now() {
          return now(Clock.systemDefaultZone());
      }
  
      /**
       * Obtains the current {@code HijrahDate} of the Islamic Umm Al-Qura calendar
       * in the specified time-zone.
       * <p>
       * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current date.
       * Specifying the time-zone avoids dependence on the default time-zone.
       * <p>
       * Using this method will prevent the ability to use an alternate clock for testing
       * because the clock is hard-coded.
       *
       * @param zone  the zone ID to use, not null
       * @return the current date using the system clock, not null
       */
      public static HijrahDate now(ZoneId zone) {
          return now(Clock.system(zone));
      }
  
      /**
       * Obtains the current {@code HijrahDate} of the Islamic Umm Al-Qura calendar
       * from the specified clock.
       * <p>
       * This will query the specified clock to obtain the current date - today.
       * Using this method allows the use of an alternate clock for testing.
       * The alternate clock may be introduced using {@linkplain Clock dependency injection}.
       *
       * @param clock  the clock to use, not null
       * @return the current date, not null
       * @throws DateTimeException if the current date cannot be obtained
       */
      public static HijrahDate now(Clock clock) {
          return HijrahDate.ofEpochDay(HijrahChronology.INSTANCE, LocalDate.now(clock).toEpochDay());
      }
  
      /**
       * Obtains a {@code HijrahDate} of the Islamic Umm Al-Qura calendar
       * from the proleptic-year, month-of-year and day-of-month fields.
       * <p>
       * This returns a {@code HijrahDate} with the specified fields.
       * The day must be valid for the year and month, otherwise an exception will be thrown.
       *
       * @param prolepticYear  the Hijrah proleptic-year
       * @param month  the Hijrah month-of-year, from 1 to 12
       * @param dayOfMonth  the Hijrah day-of-month, from 1 to 30
       * @return the date in Hijrah calendar system, not null
       * @throws DateTimeException if the value of any field is out of range,
       *  or if the day-of-month is invalid for the month-year
       */
      public static HijrahDate of(int prolepticYear, int month, int dayOfMonth) {
          return HijrahChronology.INSTANCE.date(prolepticYear, month, dayOfMonth);
      }
  
      /**
       * Obtains a {@code HijrahDate} of the Islamic Umm Al-Qura calendar from a temporal object.
       * <p>
       * This obtains a date in the Hijrah calendar system based on the specified temporal.
       * A {@code TemporalAccessor} represents an arbitrary set of date and time information,
       * which this factory converts to an instance of {@code HijrahDate}.
       * <p>
       * The conversion typically uses the {@link ChronoField#EPOCH_DAY EPOCH_DAY}
       * field, which is standardized across calendar systems.
       * <p>
       * This method matches the signature of the functional interface {@link TemporalQuery}
       * allowing it to be used as a query via method reference, {@code HijrahDate::from}.
       *
       * @param temporal  the temporal object to convert, not null
       * @return the date in Hijrah calendar system, not null
       * @throws DateTimeException if unable to convert to a {@code HijrahDate}
       */
      public static HijrahDate from(TemporalAccessor temporal) {
          return HijrahChronology.INSTANCE.date(temporal);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Constructs an {@code HijrahDate} with the proleptic-year, month-of-year and
       * day-of-month fields.
       *
       * @param chrono The chronology to create the date with
       * @param prolepticYear the proleptic year
       * @param monthOfYear the month of year
       * @param dayOfMonth the day of month
       */
      private HijrahDate(HijrahChronology chrono, int prolepticYear, int monthOfYear, int dayOfMonth) {
          // Computing the Gregorian day checks the valid ranges
          chrono.getEpochDay(prolepticYear, monthOfYear, dayOfMonth);
  
          this.chrono = chrono;
          this.prolepticYear = prolepticYear;
          this.monthOfYear = monthOfYear;
          this.dayOfMonth = dayOfMonth;
      }
  
      /**
       * Constructs an instance with the Epoch Day.
       *
       * @param epochDay  the epochDay
       */
      private HijrahDate(HijrahChronology chrono, long epochDay) {
          int[] dateInfo = chrono.getHijrahDateInfo((int)epochDay);
  
          this.chrono = chrono;
          this.prolepticYear = dateInfo[0];
          this.monthOfYear = dateInfo[1];
          this.dayOfMonth = dateInfo[2];
      }
  
      //-----------------------------------------------------------------------
      /**
       * Gets the chronology of this date, which is the Hijrah calendar system.
       * <p>
       * The {@code Chronology} represents the calendar system in use.
       * The era and other fields in {@link ChronoField} are defined by the chronology.
       *
       * @return the Hijrah chronology, not null
       */
      @Override
      public HijrahChronology getChronology() {
          return chrono;
      }
  
      /**
       * Gets the era applicable at this date.
       * <p>
       * The Hijrah calendar system has one era, 'AH',
       * defined by {@link HijrahEra}.
       *
       * @return the era applicable at this date, not null
       */
      @Override
      public HijrahEra getEra() {
          return HijrahEra.AH;
      }
  
      /**
       * Returns the length of the month represented by this date.
       * <p>
       * This returns the length of the month in days.
       * Month lengths in the Hijrah calendar system vary between 29 and 30 days.
       *
       * @return the length of the month in days
       */
      @Override
      public int lengthOfMonth() {
          return chrono.getMonthLength(prolepticYear, monthOfYear);
      }
  
      /**
       * Returns the length of the year represented by this date.
       * <p>
       * This returns the length of the year in days.
       * A Hijrah calendar system year is typically shorter than
       * that of the ISO calendar system.
       *
       * @return the length of the year in days
       */
      @Override
      public int lengthOfYear() {
          return chrono.getYearLength(prolepticYear);
      }
  
      //-----------------------------------------------------------------------
      @Override
      public ValueRange range(TemporalField field) {
          if (field instanceof ChronoField) {
              if (isSupported(field)) {
                  ChronoField f = (ChronoField) field;
                  switch (f) {
                      case DAY_OF_MONTH: return ValueRange.of(1, lengthOfMonth());
                      case DAY_OF_YEAR: return ValueRange.of(1, lengthOfYear());
                      case ALIGNED_WEEK_OF_MONTH: return ValueRange.of(1, 5);  // TODO
                      // TODO does the limited range of valid years cause years to
                      // start/end part way through? that would affect range
                  }
                  return getChronology().range(f);
              }
              throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
          }
          return field.rangeRefinedBy(this);
      }
  
      @Override
      public long getLong(TemporalField field) {
          if (field instanceof ChronoField) {
              switch ((ChronoField) field) {
                  case DAY_OF_WEEK: return getDayOfWeek();
                  case ALIGNED_DAY_OF_WEEK_IN_MONTH: return ((getDayOfWeek() - 1) % 7) + 1;
                  case ALIGNED_DAY_OF_WEEK_IN_YEAR: return ((getDayOfYear() - 1) % 7) + 1;
                  case DAY_OF_MONTH: return this.dayOfMonth;
                  case DAY_OF_YEAR: return this.getDayOfYear();
                  case EPOCH_DAY: return toEpochDay();
                  case ALIGNED_WEEK_OF_MONTH: return ((dayOfMonth - 1) / 7) + 1;
                  case ALIGNED_WEEK_OF_YEAR: return ((getDayOfYear() - 1) / 7) + 1;
                  case MONTH_OF_YEAR: return monthOfYear;
                  case PROLEPTIC_MONTH: return getProlepticMonth();
                  case YEAR_OF_ERA: return prolepticYear;
                  case YEAR: return prolepticYear;
                  case ERA: return getEraValue();
              }
              throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
          }
          return field.getFrom(this);
      }
  
      private long getProlepticMonth() {
          return prolepticYear * 12L + monthOfYear - 1;
      }
  
      @Override
      public HijrahDate with(TemporalField field, long newValue) {
          if (field instanceof ChronoField) {
              ChronoField f = (ChronoField) field;
              // not using checkValidIntValue so EPOCH_DAY and PROLEPTIC_MONTH work
              chrono.range(f).checkValidValue(newValue, f);    // TODO: validate value
              int nvalue = (int) newValue;
              switch (f) {
                  case DAY_OF_WEEK: return plusDays(newValue - getDayOfWeek());
                  case ALIGNED_DAY_OF_WEEK_IN_MONTH: return plusDays(newValue - getLong(ALIGNED_DAY_OF_WEEK_IN_MONTH));
                  case ALIGNED_DAY_OF_WEEK_IN_YEAR: return plusDays(newValue - getLong(ALIGNED_DAY_OF_WEEK_IN_YEAR));
                  case DAY_OF_MONTH: return resolvePreviousValid(prolepticYear, monthOfYear, nvalue);
                  case DAY_OF_YEAR: return plusDays(Math.min(nvalue, lengthOfYear()) - getDayOfYear());
                  case EPOCH_DAY: return new HijrahDate(chrono, newValue);
                  case ALIGNED_WEEK_OF_MONTH: return plusDays((newValue - getLong(ALIGNED_WEEK_OF_MONTH)) * 7);
                  case ALIGNED_WEEK_OF_YEAR: return plusDays((newValue - getLong(ALIGNED_WEEK_OF_YEAR)) * 7);
                  case MONTH_OF_YEAR: return resolvePreviousValid(prolepticYear, nvalue, dayOfMonth);
                  case PROLEPTIC_MONTH: return plusMonths(newValue - getProlepticMonth());
                  case YEAR_OF_ERA: return resolvePreviousValid(prolepticYear >= 1 ? nvalue : 1 - nvalue, monthOfYear, dayOfMonth);
                  case YEAR: return resolvePreviousValid(nvalue, monthOfYear, dayOfMonth);
                  case ERA: return resolvePreviousValid(1 - prolepticYear, monthOfYear, dayOfMonth);
              }
              throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
          }
          return super.with(field, newValue);
      }
  
      private HijrahDate resolvePreviousValid(int prolepticYear, int month, int day) {
          int monthDays = chrono.getMonthLength(prolepticYear, month);
          if (day > monthDays) {
              day = monthDays;
          }
          return HijrahDate.of(chrono, prolepticYear, month, day);
      }
  
      /**
       * {@inheritDoc}
       * @throws DateTimeException if unable to make the adjustment.
       *     For example, if the adjuster requires an ISO chronology
       * @throws ArithmeticException {@inheritDoc}
       */
      @Override
      public  HijrahDate with(TemporalAdjuster adjuster) {
          return super.with(adjuster);
      }
  
      /**
       * Returns a {@code HijrahDate} with the Chronology requested.
       * <p>
       * The year, month, and day are checked against the new requested
       * HijrahChronology.  If the chronology has a shorter month length
       * for the month, the day is reduced to be the last day of the month.
       *
       * @param chronology the new HijrahChonology, non-null
       * @return a HijrahDate with the requested HijrahChronology, non-null
       */
      public HijrahDate withVariant(HijrahChronology chronology) {
          if (chrono == chronology) {
              return this;
          }
          // Like resolvePreviousValid the day is constrained to stay in the same month
          int monthDays = chronology.getDayOfYear(prolepticYear, monthOfYear);
          return HijrahDate.of(chronology, prolepticYear, monthOfYear,(dayOfMonth > monthDays) ? monthDays : dayOfMonth );
      }
  
      /**
       * {@inheritDoc}
       * @throws DateTimeException {@inheritDoc}
       * @throws ArithmeticException {@inheritDoc}
       */
      @Override
      public HijrahDate plus(TemporalAmount amount) {
          return super.plus(amount);
      }
  
      /**
       * {@inheritDoc}
       * @throws DateTimeException {@inheritDoc}
       * @throws ArithmeticException {@inheritDoc}
       */
      @Override
      public HijrahDate minus(TemporalAmount amount) {
          return super.minus(amount);
      }
  
      @Override
      public long toEpochDay() {
          return chrono.getEpochDay(prolepticYear, monthOfYear, dayOfMonth);
      }
  
      /**
       * Gets the day-of-year field.
       * <p>
       * This method returns the primitive {@code int} value for the day-of-year.
       *
       * @return the day-of-year
       */
      private int getDayOfYear() {
          return chrono.getDayOfYear(prolepticYear, monthOfYear) + dayOfMonth;
      }
  
      /**
       * Gets the day-of-week value.
       *
       * @return the day-of-week; computed from the epochday
       */
      private int getDayOfWeek() {
          int dow0 = (int)Math.floorMod(toEpochDay() + 3, 7);
          return dow0 + 1;
      }
  
      /**
       * Gets the Era of this date.
       *
       * @return the Era of this date; computed from epochDay
       */
      private int getEraValue() {
          return (prolepticYear > 1 ? 1 : 0);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Checks if the year is a leap year, according to the Hijrah calendar system rules.
       *
       * @return true if this date is in a leap year
       */
      @Override
      public boolean isLeapYear() {
          return chrono.isLeapYear(prolepticYear);
      }
  
      //-----------------------------------------------------------------------
      @Override
      HijrahDate plusYears(long years) {
          if (years == 0) {
              return this;
          }
          int newYear = Math.addExact(this.prolepticYear, (int)years);
          return resolvePreviousValid(newYear, monthOfYear, dayOfMonth);
      }
  
      @Override
      HijrahDate plusMonths(long monthsToAdd) {
          if (monthsToAdd == 0) {
              return this;
          }
          long monthCount = prolepticYear * 12L + (monthOfYear - 1);
          long calcMonths = monthCount + monthsToAdd;  // safe overflow
          int newYear = chrono.checkValidYear(Math.floorDiv(calcMonths, 12L));
          int newMonth = (int)Math.floorMod(calcMonths, 12L) + 1;
          return resolvePreviousValid(newYear, newMonth, dayOfMonth);
      }
  
      @Override
      HijrahDate plusWeeks(long weeksToAdd) {
          return super.plusWeeks(weeksToAdd);
      }
  
      @Override
      HijrahDate plusDays(long days) {
          return new HijrahDate(chrono, toEpochDay() + days);
      }
  
      @Override
      public HijrahDate plus(long amountToAdd, TemporalUnit unit) {
          return super.plus(amountToAdd, unit);
      }
  
      @Override
      public HijrahDate minus(long amountToSubtract, TemporalUnit unit) {
          return super.minus(amountToSubtract, unit);
      }
  
      @Override
      HijrahDate minusYears(long yearsToSubtract) {
          return super.minusYears(yearsToSubtract);
      }
  
      @Override
      HijrahDate minusMonths(long monthsToSubtract) {
          return super.minusMonths(monthsToSubtract);
      }
  
      @Override
      HijrahDate minusWeeks(long weeksToSubtract) {
          return super.minusWeeks(weeksToSubtract);
      }
  
      @Override
      HijrahDate minusDays(long daysToSubtract) {
          return super.minusDays(daysToSubtract);
      }
  
      @Override        // for javadoc and covariant return type
      @SuppressWarnings("unchecked")
      public final ChronoLocalDateTime<HijrahDate> atTime(LocalTime localTime) {
          return (ChronoLocalDateTime<HijrahDate>)super.atTime(localTime);
      }
  
      @Override
      public ChronoPeriod until(ChronoLocalDate endDate) {
          // TODO: untested
          HijrahDate end = getChronology().date(endDate);
          long totalMonths = (end.prolepticYear - this.prolepticYear) * 12 + (end.monthOfYear - this.monthOfYear);  // safe
          int days = end.dayOfMonth - this.dayOfMonth;
          if (totalMonths > 0 && days < 0) {
              totalMonths--;
              HijrahDate calcDate = this.plusMonths(totalMonths);
              days = (int) (end.toEpochDay() - calcDate.toEpochDay());  // safe
          } else if (totalMonths < 0 && days > 0) {
              totalMonths++;
              days -= end.lengthOfMonth();
          }
          long years = totalMonths / 12;  // safe
          int months = (int) (totalMonths % 12);  // safe
          return getChronology().period(Math.toIntExact(years), months, days);
      }
  
      //-------------------------------------------------------------------------
      /**
       * Compares this date to another date, including the chronology.
       * <p>
       * Compares this {@code HijrahDate} with another ensuring that the date is the same.
       * <p>
       * Only objects of type {@code HijrahDate} are compared, other types return false.
       * To compare the dates of two {@code TemporalAccessor} instances, including dates
       * in two different chronologies, use {@link ChronoField#EPOCH_DAY} as a comparator.
       *
       * @param obj  the object to check, null returns false
       * @return true if this is equal to the other date and the Chronologies are equal
       */
      @Override  // override for performance
      public boolean equals(Object obj) {
          if (this == obj) {
              return true;
          }
          if (obj instanceof HijrahDate) {
              HijrahDate otherDate = (HijrahDate) obj;
              return prolepticYear == otherDate.prolepticYear
                  && this.monthOfYear == otherDate.monthOfYear
                  && this.dayOfMonth == otherDate.dayOfMonth
                  && getChronology().equals(otherDate.getChronology());
          }
          return false;
      }
  
      /**
       * A hash code for this date.
       *
       * @return a suitable hash code based only on the Chronology and the date
       */
      @Override  // override for performance
      public int hashCode() {
          int yearValue = prolepticYear;
          int monthValue = monthOfYear;
          int dayValue = dayOfMonth;
          return getChronology().getId().hashCode() ^ (yearValue & 0xFFFFF800)
                  ^ ((yearValue << 11) + (monthValue << 6) + (dayValue));
      }
  
      //-----------------------------------------------------------------------
      /**
       * Defend against malicious streams.
       *
       * @param s the stream to read
       * @throws InvalidObjectException always
       */
      private void readObject(ObjectInputStream s) throws InvalidObjectException {
          throw new InvalidObjectException("Deserialization via serialization delegate");
      }
  
      /**
       * Writes the object using a
       * <a href="../../../serialized-form.html#java.time.chrono.Ser">dedicated serialized form</a>.
       * @serialData
       * <pre>
       *  out.writeByte(6);                 // identifies a HijrahDate
       *  out.writeObject(chrono);          // the HijrahChronology variant
       *  out.writeInt(get(YEAR));
       *  out.writeByte(get(MONTH_OF_YEAR));
       *  out.writeByte(get(DAY_OF_MONTH));
       * </pre>
       *
       * @return the instance of {@code Ser}, not null
       */
      private Object writeReplace() {
          return new Ser(Ser.HIJRAH_DATE_TYPE, this);
      }
  
      void writeExternal(ObjectOutput out) throws IOException {
          // HijrahChronology is implicit in the Hijrah_DATE_TYPE
          out.writeObject(getChronology());
          out.writeInt(get(YEAR));
          out.writeByte(get(MONTH_OF_YEAR));
          out.writeByte(get(DAY_OF_MONTH));
      }
  
      static HijrahDate readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
          HijrahChronology chrono = (HijrahChronology) in.readObject();
          int year = in.readInt();
          int month = in.readByte();
          int dayOfMonth = in.readByte();
          return chrono.date(year, month, dayOfMonth);
      }
  
  }
  