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   * Copyright (c) 2012, 2015, 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.
   */
  
  /*
   * This file is available under and governed by the GNU General Public
   * License version 2 only, as published by the Free Software Foundation.
   * However, the following notice accompanied the original version of this
   * file:
   *
   * Copyright (c) 2007-2012, 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;
  
  import static java.time.LocalTime.SECONDS_PER_DAY;
  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.DAY_OF_YEAR;
  import static java.time.temporal.ChronoField.EPOCH_DAY;
  import static java.time.temporal.ChronoField.ERA;
  import static java.time.temporal.ChronoField.MONTH_OF_YEAR;
  import static java.time.temporal.ChronoField.PROLEPTIC_MONTH;
  import static java.time.temporal.ChronoField.YEAR;
  
  import java.io.DataInput;
  import java.io.DataOutput;
  import java.io.IOException;
  import java.io.InvalidObjectException;
  import java.io.ObjectInputStream;
  import java.io.Serializable;
  import java.time.chrono.ChronoLocalDate;
  import java.time.chrono.Era;
  import java.time.chrono.IsoChronology;
  import java.time.format.DateTimeFormatter;
  import java.time.format.DateTimeParseException;
  import java.time.temporal.ChronoField;
  import java.time.temporal.ChronoUnit;
  import java.time.temporal.Temporal;
  import java.time.temporal.TemporalAccessor;
  import java.time.temporal.TemporalAdjuster;
  import java.time.temporal.TemporalAmount;
  import java.time.temporal.TemporalField;
  import java.time.temporal.TemporalQueries;
  import java.time.temporal.TemporalQuery;
  import java.time.temporal.TemporalUnit;
  import java.time.temporal.UnsupportedTemporalTypeException;
  import java.time.temporal.ValueRange;
  import java.time.zone.ZoneOffsetTransition;
  import java.time.zone.ZoneRules;
  import java.util.Objects;
  
  // Android-changed: removed ValueBased paragraph.
  
  /**
   * A date without a time-zone in the ISO-8601 calendar system,
   * such as {@code 2007-12-03}.
   * <p>
   * {@code LocalDate} is an immutable date-time object that represents a date,
   * often viewed as year-month-day. Other date fields, such as day-of-year,
   * day-of-week and week-of-year, can also be accessed.
   * For example, the value "2nd October 2007" can be stored in a {@code LocalDate}.
   * <p>
   * This class does not store or represent a time or time-zone.
   * Instead, it is a description of the date, as used for birthdays.
   * It cannot represent an instant on the time-line without additional information
   * such as an offset or time-zone.
   * <p>
   * The ISO-8601 calendar system is the modern civil calendar system used today
   * in most of the world. It is equivalent to the proleptic Gregorian calendar
   * system, in which today's rules for leap years are applied for all time.
   * For most applications written today, the ISO-8601 rules are entirely suitable.
   * However, any application that makes use of historical dates, and requires them
   * to be accurate will find the ISO-8601 approach unsuitable.
   *
   * @implSpec
   * This class is immutable and thread-safe.
   *
   * @since 1.8
   */
  public final class LocalDate
          implements Temporal, TemporalAdjuster, ChronoLocalDate, Serializable {
  
      /**
       * The minimum supported {@code LocalDate}, '-999999999-01-01'.
       * This could be used by an application as a "far past" date.
       */
      public static final LocalDate MIN = LocalDate.of(Year.MIN_VALUE, 1, 1);
      /**
       * The maximum supported {@code LocalDate}, '+999999999-12-31'.
       * This could be used by an application as a "far future" date.
       */
      public static final LocalDate MAX = LocalDate.of(Year.MAX_VALUE, 12, 31);
  
      /**
       * Serialization version.
       */
      private static final long serialVersionUID = 2942565459149668126L;
      /**
       * The number of days in a 400 year cycle.
       */
      private static final int DAYS_PER_CYCLE = 146097;
      /**
       * The number of days from year zero to year 1970.
       * There are five 400 year cycles from year zero to 2000.
       * There are 7 leap years from 1970 to 2000.
       */
      static final long DAYS_0000_TO_1970 = (DAYS_PER_CYCLE * 5L) - (30L * 365L + 7L);
  
      /**
       * The year.
       */
      private final int year;
      /**
       * The month-of-year.
       */
      private final short month;
      /**
       * The day-of-month.
       */
      private final short day;
  
      //-----------------------------------------------------------------------
      /**
       * Obtains the current date from the system clock 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 LocalDate now() {
          return now(Clock.systemDefaultZone());
      }
  
      /**
       * Obtains the current date from the system clock 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 LocalDate now(ZoneId zone) {
          return now(Clock.system(zone));
      }
  
      /**
       * Obtains the current date 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 {@link Clock dependency injection}.
       *
       * @param clock  the clock to use, not null
       * @return the current date, not null
       */
      public static LocalDate now(Clock clock) {
          Objects.requireNonNull(clock, "clock");
          // inline to avoid creating object and Instant checks
          final Instant now = clock.instant();  // called once
          ZoneOffset offset = clock.getZone().getRules().getOffset(now);
          long epochSec = now.getEpochSecond() + offset.getTotalSeconds();  // overflow caught later
          long epochDay = Math.floorDiv(epochSec, SECONDS_PER_DAY);
          return LocalDate.ofEpochDay(epochDay);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Obtains an instance of {@code LocalDate} from a year, month and day.
       * <p>
       * This returns a {@code LocalDate} with the specified year, month and day-of-month.
       * The day must be valid for the year and month, otherwise an exception will be thrown.
       *
       * @param year  the year to represent, from MIN_YEAR to MAX_YEAR
       * @param month  the month-of-year to represent, not null
       * @param dayOfMonth  the day-of-month to represent, from 1 to 31
       * @return the local date, 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 LocalDate of(int year, Month month, int dayOfMonth) {
          YEAR.checkValidValue(year);
          Objects.requireNonNull(month, "month");
          DAY_OF_MONTH.checkValidValue(dayOfMonth);
          return create(year, month.getValue(), dayOfMonth);
      }
  
      /**
       * Obtains an instance of {@code LocalDate} from a year, month and day.
       * <p>
       * This returns a {@code LocalDate} with the specified year, month and day-of-month.
       * The day must be valid for the year and month, otherwise an exception will be thrown.
       *
       * @param year  the year to represent, from MIN_YEAR to MAX_YEAR
       * @param month  the month-of-year to represent, from 1 (January) to 12 (December)
       * @param dayOfMonth  the day-of-month to represent, from 1 to 31
       * @return the local date, 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 LocalDate of(int year, int month, int dayOfMonth) {
          YEAR.checkValidValue(year);
          MONTH_OF_YEAR.checkValidValue(month);
          DAY_OF_MONTH.checkValidValue(dayOfMonth);
          return create(year, month, dayOfMonth);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Obtains an instance of {@code LocalDate} from a year and day-of-year.
       * <p>
       * This returns a {@code LocalDate} with the specified year and day-of-year.
       * The day-of-year must be valid for the year, otherwise an exception will be thrown.
       *
       * @param year  the year to represent, from MIN_YEAR to MAX_YEAR
       * @param dayOfYear  the day-of-year to represent, from 1 to 366
       * @return the local date, not null
       * @throws DateTimeException if the value of any field is out of range,
       *  or if the day-of-year is invalid for the year
       */
      public static LocalDate ofYearDay(int year, int dayOfYear) {
          YEAR.checkValidValue(year);
          DAY_OF_YEAR.checkValidValue(dayOfYear);
          boolean leap = IsoChronology.INSTANCE.isLeapYear(year);
          if (dayOfYear == 366 && leap == false) {
              throw new DateTimeException("Invalid date 'DayOfYear 366' as '" + year + "' is not a leap year");
          }
          Month moy = Month.of((dayOfYear - 1) / 31 + 1);
          int monthEnd = moy.firstDayOfYear(leap) + moy.length(leap) - 1;
          if (dayOfYear > monthEnd) {
              moy = moy.plus(1);
          }
          int dom = dayOfYear - moy.firstDayOfYear(leap) + 1;
          return new LocalDate(year, moy.getValue(), dom);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Obtains an instance of {@code LocalDate} from the epoch day count.
       * <p>
       * This returns a {@code LocalDate} with the specified epoch-day.
       * The {@link ChronoField#EPOCH_DAY EPOCH_DAY} is a simple incrementing count
       * of days where day 0 is 1970-01-01. Negative numbers represent earlier days.
       *
       * @param epochDay  the Epoch Day to convert, based on the epoch 1970-01-01
       * @return the local date, not null
       * @throws DateTimeException if the epoch day exceeds the supported date range
       */
      public static LocalDate ofEpochDay(long epochDay) {
          long zeroDay = epochDay + DAYS_0000_TO_1970;
          // find the march-based year
          zeroDay -= 60;  // adjust to 0000-03-01 so leap day is at end of four year cycle
          long adjust = 0;
          if (zeroDay < 0) {
              // adjust negative years to positive for calculation
              long adjustCycles = (zeroDay + 1) / DAYS_PER_CYCLE - 1;
              adjust = adjustCycles * 400;
              zeroDay += -adjustCycles * DAYS_PER_CYCLE;
          }
          long yearEst = (400 * zeroDay + 591) / DAYS_PER_CYCLE;
          long doyEst = zeroDay - (365 * yearEst + yearEst / 4 - yearEst / 100 + yearEst / 400);
          if (doyEst < 0) {
              // fix estimate
              yearEst--;
              doyEst = zeroDay - (365 * yearEst + yearEst / 4 - yearEst / 100 + yearEst / 400);
          }
          yearEst += adjust;  // reset any negative year
          int marchDoy0 = (int) doyEst;
  
          // convert march-based values back to january-based
          int marchMonth0 = (marchDoy0 * 5 + 2) / 153;
          int month = (marchMonth0 + 2) % 12 + 1;
          int dom = marchDoy0 - (marchMonth0 * 306 + 5) / 10 + 1;
          yearEst += marchMonth0 / 10;
  
          // check year now we are certain it is correct
          int year = YEAR.checkValidIntValue(yearEst);
          return new LocalDate(year, month, dom);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Obtains an instance of {@code LocalDate} from a temporal object.
       * <p>
       * This obtains a local date 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 LocalDate}.
       * <p>
       * The conversion uses the {@link TemporalQueries#localDate()} query, which relies
       * on extracting the {@link ChronoField#EPOCH_DAY EPOCH_DAY} field.
       * <p>
       * This method matches the signature of the functional interface {@link TemporalQuery}
       * allowing it to be used as a query via method reference, {@code LocalDate::from}.
       *
       * @param temporal  the temporal object to convert, not null
       * @return the local date, not null
       * @throws DateTimeException if unable to convert to a {@code LocalDate}
       */
      public static LocalDate from(TemporalAccessor temporal) {
          Objects.requireNonNull(temporal, "temporal");
          LocalDate date = temporal.query(TemporalQueries.localDate());
          if (date == null) {
              throw new DateTimeException("Unable to obtain LocalDate from TemporalAccessor: " +
                      temporal + " of type " + temporal.getClass().getName());
          }
          return date;
      }
  
      //-----------------------------------------------------------------------
      /**
       * Obtains an instance of {@code LocalDate} from a text string such as {@code 2007-12-03}.
       * <p>
       * The string must represent a valid date and is parsed using
       * {@link DateTimeFormatter#ISO_LOCAL_DATE}.
       *
       * @param text  the text to parse such as "2007-12-03", not null
       * @return the parsed local date, not null
       * @throws DateTimeParseException if the text cannot be parsed
       */
      public static LocalDate parse(CharSequence text) {
          return parse(text, DateTimeFormatter.ISO_LOCAL_DATE);
      }
  
      /**
       * Obtains an instance of {@code LocalDate} from a text string using a specific formatter.
       * <p>
       * The text is parsed using the formatter, returning a date.
       *
       * @param text  the text to parse, not null
       * @param formatter  the formatter to use, not null
       * @return the parsed local date, not null
       * @throws DateTimeParseException if the text cannot be parsed
       */
      public static LocalDate parse(CharSequence text, DateTimeFormatter formatter) {
          Objects.requireNonNull(formatter, "formatter");
          return formatter.parse(text, LocalDate::from);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Creates a local date from the year, month and day fields.
       *
       * @param year  the year to represent, validated from MIN_YEAR to MAX_YEAR
       * @param month  the month-of-year to represent, from 1 to 12, validated
       * @param dayOfMonth  the day-of-month to represent, validated from 1 to 31
       * @return the local date, not null
       * @throws DateTimeException if the day-of-month is invalid for the month-year
       */
      private static LocalDate create(int year, int month, int dayOfMonth) {
          if (dayOfMonth > 28) {
              int dom = 31;
              switch (month) {
                  case 2:
                      dom = (IsoChronology.INSTANCE.isLeapYear(year) ? 29 : 28);
                      break;
                  case 4:
                  case 6:
                  case 9:
                  case 11:
                      dom = 30;
                      break;
              }
              if (dayOfMonth > dom) {
                  if (dayOfMonth == 29) {
                      throw new DateTimeException("Invalid date 'February 29' as '" + year + "' is not a leap year");
                  } else {
                      throw new DateTimeException("Invalid date '" + Month.of(month).name() + " " + dayOfMonth + "'");
                  }
              }
          }
          return new LocalDate(year, month, dayOfMonth);
      }
  
      /**
       * Resolves the date, resolving days past the end of month.
       *
       * @param year  the year to represent, validated from MIN_YEAR to MAX_YEAR
       * @param month  the month-of-year to represent, validated from 1 to 12
       * @param day  the day-of-month to represent, validated from 1 to 31
       * @return the resolved date, not null
       */
      private static LocalDate resolvePreviousValid(int year, int month, int day) {
          switch (month) {
              case 2:
                  day = Math.min(day, IsoChronology.INSTANCE.isLeapYear(year) ? 29 : 28);
                  break;
              case 4:
              case 6:
              case 9:
              case 11:
                  day = Math.min(day, 30);
                  break;
          }
          return new LocalDate(year, month, day);
      }
  
      /**
       * Constructor, previously validated.
       *
       * @param year  the year to represent, from MIN_YEAR to MAX_YEAR
       * @param month  the month-of-year to represent, not null
       * @param dayOfMonth  the day-of-month to represent, valid for year-month, from 1 to 31
       */
      private LocalDate(int year, int month, int dayOfMonth) {
          this.year = year;
          this.month = (short) month;
          this.day = (short) dayOfMonth;
      }
  
      //-----------------------------------------------------------------------
      /**
       * Checks if the specified field is supported.
       * <p>
       * This checks if this date can be queried for the specified field.
       * If false, then calling the {@link #range(TemporalField) range},
       * {@link #get(TemporalField) get} and {@link #with(TemporalField, long)}
       * methods will throw an exception.
       * <p>
       * If the field is a {@link ChronoField} then the query is implemented here.
       * The supported fields are:
       * <ul>
       * <li>{@code DAY_OF_WEEK}
       * <li>{@code ALIGNED_DAY_OF_WEEK_IN_MONTH}
       * <li>{@code ALIGNED_DAY_OF_WEEK_IN_YEAR}
       * <li>{@code DAY_OF_MONTH}
       * <li>{@code DAY_OF_YEAR}
       * <li>{@code EPOCH_DAY}
       * <li>{@code ALIGNED_WEEK_OF_MONTH}
       * <li>{@code ALIGNED_WEEK_OF_YEAR}
       * <li>{@code MONTH_OF_YEAR}
       * <li>{@code PROLEPTIC_MONTH}
       * <li>{@code YEAR_OF_ERA}
       * <li>{@code YEAR}
       * <li>{@code ERA}
       * </ul>
       * All other {@code ChronoField} instances will return false.
       * <p>
       * If the field is not a {@code ChronoField}, then the result of this method
       * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)}
       * passing {@code this} as the argument.
       * Whether the field is supported is determined by the field.
       *
       * @param field  the field to check, null returns false
       * @return true if the field is supported on this date, false if not
       */
      @Override  // override for Javadoc
      public boolean isSupported(TemporalField field) {
          return ChronoLocalDate.super.isSupported(field);
      }
  
      /**
       * Checks if the specified unit is supported.
       * <p>
       * This checks if the specified unit can be added to, or subtracted from, this date.
       * If false, then calling the {@link #plus(long, TemporalUnit)} and
       * {@link #minus(long, TemporalUnit) minus} methods will throw an exception.
       * <p>
       * If the unit is a {@link ChronoUnit} then the query is implemented here.
       * The supported units are:
       * <ul>
       * <li>{@code DAYS}
       * <li>{@code WEEKS}
       * <li>{@code MONTHS}
       * <li>{@code YEARS}
       * <li>{@code DECADES}
       * <li>{@code CENTURIES}
       * <li>{@code MILLENNIA}
       * <li>{@code ERAS}
       * </ul>
       * All other {@code ChronoUnit} instances will return false.
       * <p>
       * If the unit is not a {@code ChronoUnit}, then the result of this method
       * is obtained by invoking {@code TemporalUnit.isSupportedBy(Temporal)}
       * passing {@code this} as the argument.
       * Whether the unit is supported is determined by the unit.
       *
       * @param unit  the unit to check, null returns false
       * @return true if the unit can be added/subtracted, false if not
       */
      @Override  // override for Javadoc
      public boolean isSupported(TemporalUnit unit) {
          return ChronoLocalDate.super.isSupported(unit);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Gets the range of valid values for the specified field.
       * <p>
       * The range object expresses the minimum and maximum valid values for a field.
       * This date is used to enhance the accuracy of the returned range.
       * If it is not possible to return the range, because the field is not supported
       * or for some other reason, an exception is thrown.
       * <p>
       * If the field is a {@link ChronoField} then the query is implemented here.
       * The {@link #isSupported(TemporalField) supported fields} will return
       * appropriate range instances.
       * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
       * <p>
       * If the field is not a {@code ChronoField}, then the result of this method
       * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)}
       * passing {@code this} as the argument.
       * Whether the range can be obtained is determined by the field.
       *
       * @param field  the field to query the range for, not null
       * @return the range of valid values for the field, not null
       * @throws DateTimeException if the range for the field cannot be obtained
       * @throws UnsupportedTemporalTypeException if the field is not supported
       */
      @Override
      public ValueRange range(TemporalField field) {
          if (field instanceof ChronoField) {
              ChronoField f = (ChronoField) field;
              if (f.isDateBased()) {
                  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, getMonth() == Month.FEBRUARY && isLeapYear() == false ? 4 : 5);
                      case YEAR_OF_ERA:
                          return (getYear() <= 0 ? ValueRange.of(1, Year.MAX_VALUE + 1) : ValueRange.of(1, Year.MAX_VALUE));
                  }
                  return field.range();
              }
              throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
          }
          return field.rangeRefinedBy(this);
      }
  
      /**
       * Gets the value of the specified field from this date as an {@code int}.
       * <p>
       * This queries this date for the value of the specified field.
       * The returned value will always be within the valid range of values for the field.
       * If it is not possible to return the value, because the field is not supported
       * or for some other reason, an exception is thrown.
       * <p>
       * If the field is a {@link ChronoField} then the query is implemented here.
       * The {@link #isSupported(TemporalField) supported fields} will return valid
       * values based on this date, except {@code EPOCH_DAY} and {@code PROLEPTIC_MONTH}
       * which are too large to fit in an {@code int} and throw a {@code DateTimeException}.
       * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
       * <p>
       * If the field is not a {@code ChronoField}, then the result of this method
       * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
       * passing {@code this} as the argument. Whether the value can be obtained,
       * and what the value represents, is determined by the field.
       *
       * @param field  the field to get, not null
       * @return the value for the field
       * @throws DateTimeException if a value for the field cannot be obtained or
       *         the value is outside the range of valid values for the field
       * @throws UnsupportedTemporalTypeException if the field is not supported or
       *         the range of values exceeds an {@code int}
       * @throws ArithmeticException if numeric overflow occurs
       */
      @Override  // override for Javadoc and performance
      public int get(TemporalField field) {
          if (field instanceof ChronoField) {
              return get0(field);
          }
          return ChronoLocalDate.super.get(field);
      }
  
      /**
       * Gets the value of the specified field from this date as a {@code long}.
       * <p>
       * This queries this date for the value of the specified field.
       * If it is not possible to return the value, because the field is not supported
       * or for some other reason, an exception is thrown.
       * <p>
       * If the field is a {@link ChronoField} then the query is implemented here.
       * The {@link #isSupported(TemporalField) supported fields} will return valid
       * values based on this date.
       * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
       * <p>
       * If the field is not a {@code ChronoField}, then the result of this method
       * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
       * passing {@code this} as the argument. Whether the value can be obtained,
       * and what the value represents, is determined by the field.
       *
       * @param field  the field to get, not null
       * @return the value for the field
       * @throws DateTimeException if a value for the field cannot be obtained
       * @throws UnsupportedTemporalTypeException if the field is not supported
       * @throws ArithmeticException if numeric overflow occurs
       */
      @Override
      public long getLong(TemporalField field) {
          if (field instanceof ChronoField) {
              if (field == EPOCH_DAY) {
                  return toEpochDay();
              }
              if (field == PROLEPTIC_MONTH) {
                  return getProlepticMonth();
              }
              return get0(field);
          }
          return field.getFrom(this);
      }
  
      private int get0(TemporalField field) {
          switch ((ChronoField) field) {
              case DAY_OF_WEEK: return getDayOfWeek().getValue();
              case ALIGNED_DAY_OF_WEEK_IN_MONTH: return ((day - 1) % 7) + 1;
              case ALIGNED_DAY_OF_WEEK_IN_YEAR: return ((getDayOfYear() - 1) % 7) + 1;
              case DAY_OF_MONTH: return day;
              case DAY_OF_YEAR: return getDayOfYear();
              case EPOCH_DAY: throw new UnsupportedTemporalTypeException("Invalid field 'EpochDay' for get() method, use getLong() instead");
              case ALIGNED_WEEK_OF_MONTH: return ((day - 1) / 7) + 1;
              case ALIGNED_WEEK_OF_YEAR: return ((getDayOfYear() - 1) / 7) + 1;
              case MONTH_OF_YEAR: return month;
              case PROLEPTIC_MONTH: throw new UnsupportedTemporalTypeException("Invalid field 'ProlepticMonth' for get() method, use getLong() instead");
              case YEAR_OF_ERA: return (year >= 1 ? year : 1 - year);
              case YEAR: return year;
              case ERA: return (year >= 1 ? 1 : 0);
          }
          throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
      }
  
      private long getProlepticMonth() {
          return (year * 12L + month - 1);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Gets the chronology of this date, which is the ISO calendar system.
       * <p>
       * The {@code Chronology} represents the calendar system in use.
       * The ISO-8601 calendar system is the modern civil calendar system used today
       * in most of the world. It is equivalent to the proleptic Gregorian calendar
       * system, in which today's rules for leap years are applied for all time.
       *
       * @return the ISO chronology, not null
       */
      @Override
      public IsoChronology getChronology() {
          return IsoChronology.INSTANCE;
      }
  
      /**
       * Gets the era applicable at this date.
       * <p>
       * The official ISO-8601 standard does not define eras, however {@code IsoChronology} does.
       * It defines two eras, 'CE' from year one onwards and 'BCE' from year zero backwards.
       * Since dates before the Julian-Gregorian cutover are not in line with history,
       * the cutover between 'BCE' and 'CE' is also not aligned with the commonly used
       * eras, often referred to using 'BC' and 'AD'.
       * <p>
       * Users of this class should typically ignore this method as it exists primarily
       * to fulfill the {@link ChronoLocalDate} contract where it is necessary to support
       * the Japanese calendar system.
       * <p>
       * The returned era will be a singleton capable of being compared with the constants
       * in {@link IsoChronology} using the {@code ==} operator.
       *
       * @return the {@code IsoChronology} era constant applicable at this date, not null
       */
      @Override // override for Javadoc
      public Era getEra() {
          return ChronoLocalDate.super.getEra();
      }
  
      /**
       * Gets the year field.
       * <p>
       * This method returns the primitive {@code int} value for the year.
       * <p>
       * The year returned by this method is proleptic as per {@code get(YEAR)}.
       * To obtain the year-of-era, use {@code get(YEAR_OF_ERA)}.
       *
       * @return the year, from MIN_YEAR to MAX_YEAR
       */
      public int getYear() {
          return year;
      }
  
      /**
       * Gets the month-of-year field from 1 to 12.
       * <p>
       * This method returns the month as an {@code int} from 1 to 12.
       * Application code is frequently clearer if the enum {@link Month}
       * is used by calling {@link #getMonth()}.
       *
       * @return the month-of-year, from 1 to 12
       * @see #getMonth()
       */
      public int getMonthValue() {
          return month;
      }
  
      /**
       * Gets the month-of-year field using the {@code Month} enum.
       * <p>
       * This method returns the enum {@link Month} for the month.
       * This avoids confusion as to what {@code int} values mean.
       * If you need access to the primitive {@code int} value then the enum
       * provides the {@link Month#getValue() int value}.
       *
       * @return the month-of-year, not null
       * @see #getMonthValue()
       */
      public Month getMonth() {
          return Month.of(month);
      }
  
      /**
       * Gets the day-of-month field.
       * <p>
       * This method returns the primitive {@code int} value for the day-of-month.
       *
       * @return the day-of-month, from 1 to 31
       */
      public int getDayOfMonth() {
          return day;
      }
  
      /**
       * 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, from 1 to 365, or 366 in a leap year
       */
      public int getDayOfYear() {
          return getMonth().firstDayOfYear(isLeapYear()) + day - 1;
      }
  
      /**
       * Gets the day-of-week field, which is an enum {@code DayOfWeek}.
       * <p>
       * This method returns the enum {@link DayOfWeek} for the day-of-week.
       * This avoids confusion as to what {@code int} values mean.
       * If you need access to the primitive {@code int} value then the enum
       * provides the {@link DayOfWeek#getValue() int value}.
       * <p>
       * Additional information can be obtained from the {@code DayOfWeek}.
       * This includes textual names of the values.
       *
       * @return the day-of-week, not null
       */
      public DayOfWeek getDayOfWeek() {
          int dow0 = (int)Math.floorMod(toEpochDay() + 3, 7);
          return DayOfWeek.of(dow0 + 1);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Checks if the year is a leap year, according to the ISO proleptic
       * calendar system rules.
       * <p>
       * This method applies the current rules for leap years across the whole time-line.
       * In general, a year is a leap year if it is divisible by four without
       * remainder. However, years divisible by 100, are not leap years, with
       * the exception of years divisible by 400 which are.
       * <p>
       * For example, 1904 is a leap year it is divisible by 4.
       * 1900 was not a leap year as it is divisible by 100, however 2000 was a
       * leap year as it is divisible by 400.
       * <p>
       * The calculation is proleptic - applying the same rules into the far future and far past.
       * This is historically inaccurate, but is correct for the ISO-8601 standard.
       *
       * @return true if the year is leap, false otherwise
       */
      @Override // override for Javadoc and performance
      public boolean isLeapYear() {
          return IsoChronology.INSTANCE.isLeapYear(year);
      }
  
      /**
       * Returns the length of the month represented by this date.
       * <p>
       * This returns the length of the month in days.
       * For example, a date in January would return 31.
       *
       * @return the length of the month in days
       */
      @Override
      public int lengthOfMonth() {
          switch (month) {
              case 2:
                  return (isLeapYear() ? 29 : 28);
              case 4:
              case 6:
              case 9:
              case 11:
                  return 30;
              default:
                  return 31;
          }
      }
  
      /**
       * Returns the length of the year represented by this date.
       * <p>
       * This returns the length of the year in days, either 365 or 366.
       *
       * @return 366 if the year is leap, 365 otherwise
       */
      @Override // override for Javadoc and performance
      public int lengthOfYear() {
          return (isLeapYear() ? 366 : 365);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Returns an adjusted copy of this date.
       * <p>
       * This returns a {@code LocalDate}, based on this one, with the date adjusted.
       * The adjustment takes place using the specified adjuster strategy object.
       * Read the documentation of the adjuster to understand what adjustment will be made.
       * <p>
       * A simple adjuster might simply set the one of the fields, such as the year field.
       * A more complex adjuster might set the date to the last day of the month.
       * <p>
       * A selection of common adjustments is provided in
       * {@link java.time.temporal.TemporalAdjusters TemporalAdjusters}.
       * These include finding the "last day of the month" and "next Wednesday".
       * Key date-time classes also implement the {@code TemporalAdjuster} interface,
       * such as {@link Month} and {@link MonthDay MonthDay}.
       * The adjuster is responsible for handling special cases, such as the varying
       * lengths of month and leap years.
       * <p>
       * For example this code returns a date on the last day of July:
       * <pre>
       *  import static java.time.Month.*;
       *  import static java.time.temporal.TemporalAdjusters.*;
       *
       *  result = localDate.with(JULY).with(lastDayOfMonth());
       * </pre>
       * <p>
       * The result of this method is obtained by invoking the
       * {@link TemporalAdjuster#adjustInto(Temporal)} method on the
       * specified adjuster passing {@code this} as the argument.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param adjuster the adjuster to use, not null
       * @return a {@code LocalDate} based on {@code this} with the adjustment made, not null
       * @throws DateTimeException if the adjustment cannot be made
       * @throws ArithmeticException if numeric overflow occurs
       */
      @Override
      public LocalDate with(TemporalAdjuster adjuster) {
          // optimizations
          if (adjuster instanceof LocalDate) {
              return (LocalDate) adjuster;
          }
          return (LocalDate) adjuster.adjustInto(this);
      }
  
      /**
       * Returns a copy of this date with the specified field set to a new value.
       * <p>
       * This returns a {@code LocalDate}, based on this one, with the value
       * for the specified field changed.
       * This can be used to change any supported field, such as the year, month or day-of-month.
       * If it is not possible to set the value, because the field is not supported or for
       * some other reason, an exception is thrown.
       * <p>
       * In some cases, changing the specified field can cause the resulting date to become invalid,
       * such as changing the month from 31st January to February would make the day-of-month invalid.
       * In cases like this, the field is responsible for resolving the date. Typically it will choose
       * the previous valid date, which would be the last valid day of February in this example.
       * <p>
       * If the field is a {@link ChronoField} then the adjustment is implemented here.
       * The supported fields behave as follows:
       * <ul>
       * <li>{@code DAY_OF_WEEK} -
       *  Returns a {@code LocalDate} with the specified day-of-week.
       *  The date is adjusted up to 6 days forward or backward within the boundary
       *  of a Monday to Sunday week.
       * <li>{@code ALIGNED_DAY_OF_WEEK_IN_MONTH} -
       *  Returns a {@code LocalDate} with the specified aligned-day-of-week.
       *  The date is adjusted to the specified month-based aligned-day-of-week.
       *  Aligned weeks are counted such that the first week of a given month starts
       *  on the first day of that month.
       *  This may cause the date to be moved up to 6 days into the following month.
       * <li>{@code ALIGNED_DAY_OF_WEEK_IN_YEAR} -
       *  Returns a {@code LocalDate} with the specified aligned-day-of-week.
       *  The date is adjusted to the specified year-based aligned-day-of-week.
       *  Aligned weeks are counted such that the first week of a given year starts
       *  on the first day of that year.
       *  This may cause the date to be moved up to 6 days into the following year.
       * <li>{@code DAY_OF_MONTH} -
       *  Returns a {@code LocalDate} with the specified day-of-month.
       *  The month and year will be unchanged. If the day-of-month is invalid for the
       *  year and month, then a {@code DateTimeException} is thrown.
       * <li>{@code DAY_OF_YEAR} -
       *  Returns a {@code LocalDate} with the specified day-of-year.
       *  The year will be unchanged. If the day-of-year is invalid for the
       *  year, then a {@code DateTimeException} is thrown.
       * <li>{@code EPOCH_DAY} -
       *  Returns a {@code LocalDate} with the specified epoch-day.
       *  This completely replaces the date and is equivalent to {@link #ofEpochDay(long)}.
       * <li>{@code ALIGNED_WEEK_OF_MONTH} -
       *  Returns a {@code LocalDate} with the specified aligned-week-of-month.
       *  Aligned weeks are counted such that the first week of a given month starts
       *  on the first day of that month.
       *  This adjustment moves the date in whole week chunks to match the specified week.
       *  The result will have the same day-of-week as this date.
       *  This may cause the date to be moved into the following month.
       * <li>{@code ALIGNED_WEEK_OF_YEAR} -
       *  Returns a {@code LocalDate} with the specified aligned-week-of-year.
       *  Aligned weeks are counted such that the first week of a given year starts
       *  on the first day of that year.
       *  This adjustment moves the date in whole week chunks to match the specified week.
       *  The result will have the same day-of-week as this date.
       *  This may cause the date to be moved into the following year.
       * <li>{@code MONTH_OF_YEAR} -
       *  Returns a {@code LocalDate} with the specified month-of-year.
       *  The year will be unchanged. The day-of-month will also be unchanged,
       *  unless it would be invalid for the new month and year. In that case, the
       *  day-of-month is adjusted to the maximum valid value for the new month and year.
       * <li>{@code PROLEPTIC_MONTH} -
       *  Returns a {@code LocalDate} with the specified proleptic-month.
       *  The day-of-month will be unchanged, unless it would be invalid for the new month
       *  and year. In that case, the day-of-month is adjusted to the maximum valid value
       *  for the new month and year.
       * <li>{@code YEAR_OF_ERA} -
       *  Returns a {@code LocalDate} with the specified year-of-era.
       *  The era and month will be unchanged. The day-of-month will also be unchanged,
       *  unless it would be invalid for the new month and year. In that case, the
       *  day-of-month is adjusted to the maximum valid value for the new month and year.
       * <li>{@code YEAR} -
       *  Returns a {@code LocalDate} with the specified year.
       *  The month will be unchanged. The day-of-month will also be unchanged,
       *  unless it would be invalid for the new month and year. In that case, the
       *  day-of-month is adjusted to the maximum valid value for the new month and year.
       * <li>{@code ERA} -
       *  Returns a {@code LocalDate} with the specified era.
       *  The year-of-era and month will be unchanged. The day-of-month will also be unchanged,
       *  unless it would be invalid for the new month and year. In that case, the
       *  day-of-month is adjusted to the maximum valid value for the new month and year.
       * </ul>
       * <p>
       * In all cases, if the new value is outside the valid range of values for the field
       * then a {@code DateTimeException} will be thrown.
       * <p>
       * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
       * <p>
       * If the field is not a {@code ChronoField}, then the result of this method
       * is obtained by invoking {@code TemporalField.adjustInto(Temporal, long)}
       * passing {@code this} as the argument. In this case, the field determines
       * whether and how to adjust the instant.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param field  the field to set in the result, not null
       * @param newValue  the new value of the field in the result
       * @return a {@code LocalDate} based on {@code this} with the specified field set, not null
       * @throws DateTimeException if the field cannot be set
       * @throws UnsupportedTemporalTypeException if the field is not supported
       * @throws ArithmeticException if numeric overflow occurs
       */
      @Override
      public LocalDate with(TemporalField field, long newValue) {
          if (field instanceof ChronoField) {
              ChronoField f = (ChronoField) field;
              f.checkValidValue(newValue);
              switch (f) {
                  case DAY_OF_WEEK: return plusDays(newValue - getDayOfWeek().getValue());
                  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 withDayOfMonth((int) newValue);
                  case DAY_OF_YEAR: return withDayOfYear((int) newValue);
                  case EPOCH_DAY: return LocalDate.ofEpochDay(newValue);
                  case ALIGNED_WEEK_OF_MONTH: return plusWeeks(newValue - getLong(ALIGNED_WEEK_OF_MONTH));
                  case ALIGNED_WEEK_OF_YEAR: return plusWeeks(newValue - getLong(ALIGNED_WEEK_OF_YEAR));
                  case MONTH_OF_YEAR: return withMonth((int) newValue);
                  case PROLEPTIC_MONTH: return plusMonths(newValue - getProlepticMonth());
                  case YEAR_OF_ERA: return withYear((int) (year >= 1 ? newValue : 1 - newValue));
                  case YEAR: return withYear((int) newValue);
                  case ERA: return (getLong(ERA) == newValue ? this : withYear(1 - year));
              }
              throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
          }
          return field.adjustInto(this, newValue);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Returns a copy of this {@code LocalDate} with the year altered.
       * <p>
       * If the day-of-month is invalid for the year, it will be changed to the last valid day of the month.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param year  the year to set in the result, from MIN_YEAR to MAX_YEAR
       * @return a {@code LocalDate} based on this date with the requested year, not null
       * @throws DateTimeException if the year value is invalid
       */
      public LocalDate withYear(int year) {
          if (this.year == year) {
              return this;
          }
          YEAR.checkValidValue(year);
          return resolvePreviousValid(year, month, day);
      }
  
      /**
       * Returns a copy of this {@code LocalDate} with the month-of-year altered.
       * <p>
       * If the day-of-month is invalid for the year, it will be changed to the last valid day of the month.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param month  the month-of-year to set in the result, from 1 (January) to 12 (December)
       * @return a {@code LocalDate} based on this date with the requested month, not null
       * @throws DateTimeException if the month-of-year value is invalid
       */
      public LocalDate withMonth(int month) {
          if (this.month == month) {
              return this;
          }
          MONTH_OF_YEAR.checkValidValue(month);
          return resolvePreviousValid(year, month, day);
      }
  
      /**
       * Returns a copy of this {@code LocalDate} with the day-of-month altered.
       * <p>
       * If the resulting date is invalid, an exception is thrown.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param dayOfMonth  the day-of-month to set in the result, from 1 to 28-31
       * @return a {@code LocalDate} based on this date with the requested day, not null
       * @throws DateTimeException if the day-of-month value is invalid,
       *  or if the day-of-month is invalid for the month-year
       */
      public LocalDate withDayOfMonth(int dayOfMonth) {
          if (this.day == dayOfMonth) {
              return this;
          }
          return of(year, month, dayOfMonth);
      }
  
      /**
       * Returns a copy of this {@code LocalDate} with the day-of-year altered.
       * <p>
       * If the resulting date is invalid, an exception is thrown.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param dayOfYear  the day-of-year to set in the result, from 1 to 365-366
       * @return a {@code LocalDate} based on this date with the requested day, not null
       * @throws DateTimeException if the day-of-year value is invalid,
       *  or if the day-of-year is invalid for the year
       */
      public LocalDate withDayOfYear(int dayOfYear) {
          if (this.getDayOfYear() == dayOfYear) {
              return this;
          }
          return ofYearDay(year, dayOfYear);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Returns a copy of this date with the specified amount added.
       * <p>
       * This returns a {@code LocalDate}, based on this one, with the specified amount added.
       * The amount is typically {@link Period} but may be any other type implementing
       * the {@link TemporalAmount} interface.
       * <p>
       * The calculation is delegated to the amount object by calling
       * {@link TemporalAmount#addTo(Temporal)}. The amount implementation is free
       * to implement the addition in any way it wishes, however it typically
       * calls back to {@link #plus(long, TemporalUnit)}. Consult the documentation
       * of the amount implementation to determine if it can be successfully added.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param amountToAdd  the amount to add, not null
       * @return a {@code LocalDate} based on this date with the addition made, not null
       * @throws DateTimeException if the addition cannot be made
       * @throws ArithmeticException if numeric overflow occurs
       */
      @Override
      public LocalDate plus(TemporalAmount amountToAdd) {
          if (amountToAdd instanceof Period) {
              Period periodToAdd = (Period) amountToAdd;
              return plusMonths(periodToAdd.toTotalMonths()).plusDays(periodToAdd.getDays());
          }
          Objects.requireNonNull(amountToAdd, "amountToAdd");
          return (LocalDate) amountToAdd.addTo(this);
      }
  
      /**
       * Returns a copy of this date with the specified amount added.
       * <p>
       * This returns a {@code LocalDate}, based on this one, with the amount
       * in terms of the unit added. If it is not possible to add the amount, because the
       * unit is not supported or for some other reason, an exception is thrown.
       * <p>
       * In some cases, adding the amount can cause the resulting date to become invalid.
       * For example, adding one month to 31st January would result in 31st February.
       * In cases like this, the unit is responsible for resolving the date.
       * Typically it will choose the previous valid date, which would be the last valid
       * day of February in this example.
       * <p>
       * If the field is a {@link ChronoUnit} then the addition is implemented here.
       * The supported fields behave as follows:
       * <ul>
       * <li>{@code DAYS} -
       *  Returns a {@code LocalDate} with the specified number of days added.
       *  This is equivalent to {@link #plusDays(long)}.
       * <li>{@code WEEKS} -
       *  Returns a {@code LocalDate} with the specified number of weeks added.
       *  This is equivalent to {@link #plusWeeks(long)} and uses a 7 day week.
       * <li>{@code MONTHS} -
       *  Returns a {@code LocalDate} with the specified number of months added.
       *  This is equivalent to {@link #plusMonths(long)}.
       *  The day-of-month will be unchanged unless it would be invalid for the new
       *  month and year. In that case, the day-of-month is adjusted to the maximum
       *  valid value for the new month and year.
       * <li>{@code YEARS} -
       *  Returns a {@code LocalDate} with the specified number of years added.
       *  This is equivalent to {@link #plusYears(long)}.
       *  The day-of-month will be unchanged unless it would be invalid for the new
       *  month and year. In that case, the day-of-month is adjusted to the maximum
       *  valid value for the new month and year.
       * <li>{@code DECADES} -
       *  Returns a {@code LocalDate} with the specified number of decades added.
       *  This is equivalent to calling {@link #plusYears(long)} with the amount
       *  multiplied by 10.
       *  The day-of-month will be unchanged unless it would be invalid for the new
       *  month and year. In that case, the day-of-month is adjusted to the maximum
       *  valid value for the new month and year.
       * <li>{@code CENTURIES} -
       *  Returns a {@code LocalDate} with the specified number of centuries added.
       *  This is equivalent to calling {@link #plusYears(long)} with the amount
       *  multiplied by 100.
       *  The day-of-month will be unchanged unless it would be invalid for the new
       *  month and year. In that case, the day-of-month is adjusted to the maximum
       *  valid value for the new month and year.
       * <li>{@code MILLENNIA} -
       *  Returns a {@code LocalDate} with the specified number of millennia added.
       *  This is equivalent to calling {@link #plusYears(long)} with the amount
       *  multiplied by 1,000.
       *  The day-of-month will be unchanged unless it would be invalid for the new
       *  month and year. In that case, the day-of-month is adjusted to the maximum
       *  valid value for the new month and year.
       * <li>{@code ERAS} -
       *  Returns a {@code LocalDate} with the specified number of eras added.
       *  Only two eras are supported so the amount must be one, zero or minus one.
       *  If the amount is non-zero then the year is changed such that the year-of-era
       *  is unchanged.
       *  The day-of-month will be unchanged unless it would be invalid for the new
       *  month and year. In that case, the day-of-month is adjusted to the maximum
       *  valid value for the new month and year.
       * </ul>
       * <p>
       * All other {@code ChronoUnit} instances will throw an {@code UnsupportedTemporalTypeException}.
       * <p>
       * If the field is not a {@code ChronoUnit}, then the result of this method
       * is obtained by invoking {@code TemporalUnit.addTo(Temporal, long)}
       * passing {@code this} as the argument. In this case, the unit determines
       * whether and how to perform the addition.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param amountToAdd  the amount of the unit to add to the result, may be negative
       * @param unit  the unit of the amount to add, not null
       * @return a {@code LocalDate} based on this date with the specified amount added, not null
       * @throws DateTimeException if the addition cannot be made
       * @throws UnsupportedTemporalTypeException if the unit is not supported
       * @throws ArithmeticException if numeric overflow occurs
       */
      @Override
      public LocalDate plus(long amountToAdd, TemporalUnit unit) {
          if (unit instanceof ChronoUnit) {
              ChronoUnit f = (ChronoUnit) unit;
              switch (f) {
                  case DAYS: return plusDays(amountToAdd);
                  case WEEKS: return plusWeeks(amountToAdd);
                  case MONTHS: return plusMonths(amountToAdd);
                  case YEARS: return plusYears(amountToAdd);
                  case DECADES: return plusYears(Math.multiplyExact(amountToAdd, 10));
                  case CENTURIES: return plusYears(Math.multiplyExact(amountToAdd, 100));
                  case MILLENNIA: return plusYears(Math.multiplyExact(amountToAdd, 1000));
                  case ERAS: return with(ERA, Math.addExact(getLong(ERA), amountToAdd));
              }
              throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit);
          }
          return unit.addTo(this, amountToAdd);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Returns a copy of this {@code LocalDate} with the specified number of years added.
       * <p>
       * This method adds the specified amount to the years field in three steps:
       * <ol>
       * <li>Add the input years to the year field</li>
       * <li>Check if the resulting date would be invalid</li>
       * <li>Adjust the day-of-month to the last valid day if necessary</li>
       * </ol>
       * <p>
       * For example, 2008-02-29 (leap year) plus one year would result in the
       * invalid date 2009-02-29 (standard year). Instead of returning an invalid
       * result, the last valid day of the month, 2009-02-28, is selected instead.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param yearsToAdd  the years to add, may be negative
       * @return a {@code LocalDate} based on this date with the years added, not null
       * @throws DateTimeException if the result exceeds the supported date range
       */
      public LocalDate plusYears(long yearsToAdd) {
          if (yearsToAdd == 0) {
              return this;
          }
          int newYear = YEAR.checkValidIntValue(year + yearsToAdd);  // safe overflow
          return resolvePreviousValid(newYear, month, day);
      }
  
      /**
       * Returns a copy of this {@code LocalDate} with the specified number of months added.
       * <p>
       * This method adds the specified amount to the months field in three steps:
       * <ol>
       * <li>Add the input months to the month-of-year field</li>
       * <li>Check if the resulting date would be invalid</li>
       * <li>Adjust the day-of-month to the last valid day if necessary</li>
       * </ol>
       * <p>
       * For example, 2007-03-31 plus one month would result in the invalid date
       * 2007-04-31. Instead of returning an invalid result, the last valid day
       * of the month, 2007-04-30, is selected instead.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param monthsToAdd  the months to add, may be negative
       * @return a {@code LocalDate} based on this date with the months added, not null
       * @throws DateTimeException if the result exceeds the supported date range
       */
      public LocalDate plusMonths(long monthsToAdd) {
          if (monthsToAdd == 0) {
              return this;
          }
          long monthCount = year * 12L + (month - 1);
          long calcMonths = monthCount + monthsToAdd;  // safe overflow
          int newYear = YEAR.checkValidIntValue(Math.floorDiv(calcMonths, 12));
          int newMonth = (int)Math.floorMod(calcMonths, 12) + 1;
          return resolvePreviousValid(newYear, newMonth, day);
      }
  
      /**
       * Returns a copy of this {@code LocalDate} with the specified number of weeks added.
       * <p>
       * This method adds the specified amount in weeks to the days field incrementing
       * the month and year fields as necessary to ensure the result remains valid.
       * The result is only invalid if the maximum/minimum year is exceeded.
       * <p>
       * For example, 2008-12-31 plus one week would result in 2009-01-07.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param weeksToAdd  the weeks to add, may be negative
       * @return a {@code LocalDate} based on this date with the weeks added, not null
       * @throws DateTimeException if the result exceeds the supported date range
       */
      public LocalDate plusWeeks(long weeksToAdd) {
          return plusDays(Math.multiplyExact(weeksToAdd, 7));
      }
  
      /**
       * Returns a copy of this {@code LocalDate} with the specified number of days added.
       * <p>
       * This method adds the specified amount to the days field incrementing the
       * month and year fields as necessary to ensure the result remains valid.
       * The result is only invalid if the maximum/minimum year is exceeded.
       * <p>
       * For example, 2008-12-31 plus one day would result in 2009-01-01.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param daysToAdd  the days to add, may be negative
       * @return a {@code LocalDate} based on this date with the days added, not null
       * @throws DateTimeException if the result exceeds the supported date range
       */
      public LocalDate plusDays(long daysToAdd) {
          if (daysToAdd == 0) {
              return this;
          }
          long mjDay = Math.addExact(toEpochDay(), daysToAdd);
          return LocalDate.ofEpochDay(mjDay);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Returns a copy of this date with the specified amount subtracted.
       * <p>
       * This returns a {@code LocalDate}, based on this one, with the specified amount subtracted.
       * The amount is typically {@link Period} but may be any other type implementing
       * the {@link TemporalAmount} interface.
       * <p>
       * The calculation is delegated to the amount object by calling
       * {@link TemporalAmount#subtractFrom(Temporal)}. The amount implementation is free
       * to implement the subtraction in any way it wishes, however it typically
       * calls back to {@link #minus(long, TemporalUnit)}. Consult the documentation
       * of the amount implementation to determine if it can be successfully subtracted.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param amountToSubtract  the amount to subtract, not null
       * @return a {@code LocalDate} based on this date with the subtraction made, not null
       * @throws DateTimeException if the subtraction cannot be made
       * @throws ArithmeticException if numeric overflow occurs
       */
      @Override
      public LocalDate minus(TemporalAmount amountToSubtract) {
          if (amountToSubtract instanceof Period) {
              Period periodToSubtract = (Period) amountToSubtract;
              return minusMonths(periodToSubtract.toTotalMonths()).minusDays(periodToSubtract.getDays());
          }
          Objects.requireNonNull(amountToSubtract, "amountToSubtract");
          return (LocalDate) amountToSubtract.subtractFrom(this);
      }
  
      /**
       * Returns a copy of this date with the specified amount subtracted.
       * <p>
       * This returns a {@code LocalDate}, based on this one, with the amount
       * in terms of the unit subtracted. If it is not possible to subtract the amount,
       * because the unit is not supported or for some other reason, an exception is thrown.
       * <p>
       * This method is equivalent to {@link #plus(long, TemporalUnit)} with the amount negated.
       * See that method for a full description of how addition, and thus subtraction, works.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param amountToSubtract  the amount of the unit to subtract from the result, may be negative
       * @param unit  the unit of the amount to subtract, not null
       * @return a {@code LocalDate} based on this date with the specified amount subtracted, not null
       * @throws DateTimeException if the subtraction cannot be made
       * @throws UnsupportedTemporalTypeException if the unit is not supported
       * @throws ArithmeticException if numeric overflow occurs
       */
      @Override
      public LocalDate minus(long amountToSubtract, TemporalUnit unit) {
          return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit));
      }
  
      //-----------------------------------------------------------------------
      /**
       * Returns a copy of this {@code LocalDate} with the specified number of years subtracted.
       * <p>
       * This method subtracts the specified amount from the years field in three steps:
       * <ol>
       * <li>Subtract the input years from the year field</li>
       * <li>Check if the resulting date would be invalid</li>
       * <li>Adjust the day-of-month to the last valid day if necessary</li>
       * </ol>
       * <p>
       * For example, 2008-02-29 (leap year) minus one year would result in the
       * invalid date 2007-02-29 (standard year). Instead of returning an invalid
       * result, the last valid day of the month, 2007-02-28, is selected instead.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param yearsToSubtract  the years to subtract, may be negative
       * @return a {@code LocalDate} based on this date with the years subtracted, not null
       * @throws DateTimeException if the result exceeds the supported date range
       */
      public LocalDate minusYears(long yearsToSubtract) {
          return (yearsToSubtract == Long.MIN_VALUE ? plusYears(Long.MAX_VALUE).plusYears(1) : plusYears(-yearsToSubtract));
      }
  
      /**
       * Returns a copy of this {@code LocalDate} with the specified number of months subtracted.
       * <p>
       * This method subtracts the specified amount from the months field in three steps:
       * <ol>
       * <li>Subtract the input months from the month-of-year field</li>
       * <li>Check if the resulting date would be invalid</li>
       * <li>Adjust the day-of-month to the last valid day if necessary</li>
       * </ol>
       * <p>
       * For example, 2007-03-31 minus one month would result in the invalid date
       * 2007-02-31. Instead of returning an invalid result, the last valid day
       * of the month, 2007-02-28, is selected instead.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param monthsToSubtract  the months to subtract, may be negative
       * @return a {@code LocalDate} based on this date with the months subtracted, not null
       * @throws DateTimeException if the result exceeds the supported date range
       */
      public LocalDate minusMonths(long monthsToSubtract) {
          return (monthsToSubtract == Long.MIN_VALUE ? plusMonths(Long.MAX_VALUE).plusMonths(1) : plusMonths(-monthsToSubtract));
      }
  
      /**
       * Returns a copy of this {@code LocalDate} with the specified number of weeks subtracted.
       * <p>
       * This method subtracts the specified amount in weeks from the days field decrementing
       * the month and year fields as necessary to ensure the result remains valid.
       * The result is only invalid if the maximum/minimum year is exceeded.
       * <p>
       * For example, 2009-01-07 minus one week would result in 2008-12-31.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param weeksToSubtract  the weeks to subtract, may be negative
       * @return a {@code LocalDate} based on this date with the weeks subtracted, not null
       * @throws DateTimeException if the result exceeds the supported date range
       */
      public LocalDate minusWeeks(long weeksToSubtract) {
          return (weeksToSubtract == Long.MIN_VALUE ? plusWeeks(Long.MAX_VALUE).plusWeeks(1) : plusWeeks(-weeksToSubtract));
      }
  
      /**
       * Returns a copy of this {@code LocalDate} with the specified number of days subtracted.
       * <p>
       * This method subtracts the specified amount from the days field decrementing the
       * month and year fields as necessary to ensure the result remains valid.
       * The result is only invalid if the maximum/minimum year is exceeded.
       * <p>
       * For example, 2009-01-01 minus one day would result in 2008-12-31.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param daysToSubtract  the days to subtract, may be negative
       * @return a {@code LocalDate} based on this date with the days subtracted, not null
       * @throws DateTimeException if the result exceeds the supported date range
       */
      public LocalDate minusDays(long daysToSubtract) {
          return (daysToSubtract == Long.MIN_VALUE ? plusDays(Long.MAX_VALUE).plusDays(1) : plusDays(-daysToSubtract));
      }
  
      //-----------------------------------------------------------------------
      /**
       * Queries this date using the specified query.
       * <p>
       * This queries this date using the specified query strategy object.
       * The {@code TemporalQuery} object defines the logic to be used to
       * obtain the result. Read the documentation of the query to understand
       * what the result of this method will be.
       * <p>
       * The result of this method is obtained by invoking the
       * {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the
       * specified query passing {@code this} as the argument.
       *
       * @param <R> the type of the result
       * @param query  the query to invoke, not null
       * @return the query result, null may be returned (defined by the query)
       * @throws DateTimeException if unable to query (defined by the query)
       * @throws ArithmeticException if numeric overflow occurs (defined by the query)
       */
      @SuppressWarnings("unchecked")
      @Override
      public <R> R query(TemporalQuery<R> query) {
          if (query == TemporalQueries.localDate()) {
              return (R) this;
          }
          return ChronoLocalDate.super.query(query);
      }
  
      /**
       * Adjusts the specified temporal object to have the same date as this object.
       * <p>
       * This returns a temporal object of the same observable type as the input
       * with the date changed to be the same as this.
       * <p>
       * The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)}
       * passing {@link ChronoField#EPOCH_DAY} as the field.
       * <p>
       * In most cases, it is clearer to reverse the calling pattern by using
       * {@link Temporal#with(TemporalAdjuster)}:
       * <pre>
       *   // these two lines are equivalent, but the second approach is recommended
       *   temporal = thisLocalDate.adjustInto(temporal);
       *   temporal = temporal.with(thisLocalDate);
       * </pre>
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param temporal  the target object to be adjusted, not null
       * @return the adjusted object, not null
       * @throws DateTimeException if unable to make the adjustment
       * @throws ArithmeticException if numeric overflow occurs
       */
      @Override  // override for Javadoc
      public Temporal adjustInto(Temporal temporal) {
          return ChronoLocalDate.super.adjustInto(temporal);
      }
  
      /**
       * Calculates the amount of time until another date in terms of the specified unit.
       * <p>
       * This calculates the amount of time between two {@code LocalDate}
       * objects in terms of a single {@code TemporalUnit}.
       * The start and end points are {@code this} and the specified date.
       * The result will be negative if the end is before the start.
       * The {@code Temporal} passed to this method is converted to a
       * {@code LocalDate} using {@link #from(TemporalAccessor)}.
       * For example, the amount in days between two dates can be calculated
       * using {@code startDate.until(endDate, DAYS)}.
       * <p>
       * The calculation returns a whole number, representing the number of
       * complete units between the two dates.
       * For example, the amount in months between 2012-06-15 and 2012-08-14
       * will only be one month as it is one day short of two months.
       * <p>
       * There are two equivalent ways of using this method.
       * The first is to invoke this method.
       * The second is to use {@link TemporalUnit#between(Temporal, Temporal)}:
       * <pre>
       *   // these two lines are equivalent
       *   amount = start.until(end, MONTHS);
       *   amount = MONTHS.between(start, end);
       * </pre>
       * The choice should be made based on which makes the code more readable.
       * <p>
       * The calculation is implemented in this method for {@link ChronoUnit}.
       * The units {@code DAYS}, {@code WEEKS}, {@code MONTHS}, {@code YEARS},
       * {@code DECADES}, {@code CENTURIES}, {@code MILLENNIA} and {@code ERAS}
       * are supported. Other {@code ChronoUnit} values will throw an exception.
       * <p>
       * If the unit is not a {@code ChronoUnit}, then the result of this method
       * is obtained by invoking {@code TemporalUnit.between(Temporal, Temporal)}
       * passing {@code this} as the first argument and the converted input temporal
       * as the second argument.
       * <p>
       * This instance is immutable and unaffected by this method call.
       *
       * @param endExclusive  the end date, exclusive, which is converted to a {@code LocalDate}, not null
       * @param unit  the unit to measure the amount in, not null
       * @return the amount of time between this date and the end date
       * @throws DateTimeException if the amount cannot be calculated, or the end
       *  temporal cannot be converted to a {@code LocalDate}
       * @throws UnsupportedTemporalTypeException if the unit is not supported
       * @throws ArithmeticException if numeric overflow occurs
       */
      @Override
      public long until(Temporal endExclusive, TemporalUnit unit) {
          LocalDate end = LocalDate.from(endExclusive);
          if (unit instanceof ChronoUnit) {
              switch ((ChronoUnit) unit) {
                  case DAYS: return daysUntil(end);
                  case WEEKS: return daysUntil(end) / 7;
                  case MONTHS: return monthsUntil(end);
                  case YEARS: return monthsUntil(end) / 12;
                  case DECADES: return monthsUntil(end) / 120;
                  case CENTURIES: return monthsUntil(end) / 1200;
                  case MILLENNIA: return monthsUntil(end) / 12000;
                  case ERAS: return end.getLong(ERA) - getLong(ERA);
              }
              throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit);
          }
          return unit.between(this, end);
      }
  
      long daysUntil(LocalDate end) {
          return end.toEpochDay() - toEpochDay();  // no overflow
      }
  
      private long monthsUntil(LocalDate end) {
          long packed1 = getProlepticMonth() * 32L + getDayOfMonth();  // no overflow
          long packed2 = end.getProlepticMonth() * 32L + end.getDayOfMonth();  // no overflow
          return (packed2 - packed1) / 32;
      }
  
      /**
       * Calculates the period between this date and another date as a {@code Period}.
       * <p>
       * This calculates the period between two dates in terms of years, months and days.
       * The start and end points are {@code this} and the specified date.
       * The result will be negative if the end is before the start.
       * The negative sign will be the same in each of year, month and day.
       * <p>
       * The calculation is performed using the ISO calendar system.
       * If necessary, the input date will be converted to ISO.
       * <p>
       * The start date is included, but the end date is not.
       * The period is calculated by removing complete months, then calculating
       * the remaining number of days, adjusting to ensure that both have the same sign.
       * The number of months is then normalized into years and months based on a 12 month year.
       * A month is considered to be complete if the end day-of-month is greater
       * than or equal to the start day-of-month.
       * For example, from {@code 2010-01-15} to {@code 2011-03-18} is "1 year, 2 months and 3 days".
       * <p>
       * There are two equivalent ways of using this method.
       * The first is to invoke this method.
       * The second is to use {@link Period#between(LocalDate, LocalDate)}:
       * <pre>
       *   // these two lines are equivalent
       *   period = start.until(end);
       *   period = Period.between(start, end);
       * </pre>
       * The choice should be made based on which makes the code more readable.
       *
       * @param endDateExclusive  the end date, exclusive, which may be in any chronology, not null
       * @return the period between this date and the end date, not null
       */
      @Override
      public Period until(ChronoLocalDate endDateExclusive) {
          LocalDate end = LocalDate.from(endDateExclusive);
          long totalMonths = end.getProlepticMonth() - this.getProlepticMonth();  // safe
          int days = end.day - this.day;
          if (totalMonths > 0 && days < 0) {
              totalMonths--;
              LocalDate 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 Period.of(Math.toIntExact(years), months, days);
      }
  
      /**
       * Formats this date using the specified formatter.
       * <p>
       * This date will be passed to the formatter to produce a string.
       *
       * @param formatter  the formatter to use, not null
       * @return the formatted date string, not null
       * @throws DateTimeException if an error occurs during printing
       */
      @Override  // override for Javadoc and performance
      public String format(DateTimeFormatter formatter) {
          Objects.requireNonNull(formatter, "formatter");
          return formatter.format(this);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Combines this date with a time to create a {@code LocalDateTime}.
       * <p>
       * This returns a {@code LocalDateTime} formed from this date at the specified time.
       * All possible combinations of date and time are valid.
       *
       * @param time  the time to combine with, not null
       * @return the local date-time formed from this date and the specified time, not null
       */
      @Override
      public LocalDateTime atTime(LocalTime time) {
          return LocalDateTime.of(this, time);
      }
  
      /**
       * Combines this date with a time to create a {@code LocalDateTime}.
       * <p>
       * This returns a {@code LocalDateTime} formed from this date at the
       * specified hour and minute.
       * The seconds and nanosecond fields will be set to zero.
       * The individual time fields must be within their valid range.
       * All possible combinations of date and time are valid.
       *
       * @param hour  the hour-of-day to use, from 0 to 23
       * @param minute  the minute-of-hour to use, from 0 to 59
       * @return the local date-time formed from this date and the specified time, not null
       * @throws DateTimeException if the value of any field is out of range
       */
      public LocalDateTime atTime(int hour, int minute) {
          return atTime(LocalTime.of(hour, minute));
      }
  
      /**
       * Combines this date with a time to create a {@code LocalDateTime}.
       * <p>
       * This returns a {@code LocalDateTime} formed from this date at the
       * specified hour, minute and second.
       * The nanosecond field will be set to zero.
       * The individual time fields must be within their valid range.
       * All possible combinations of date and time are valid.
       *
       * @param hour  the hour-of-day to use, from 0 to 23
       * @param minute  the minute-of-hour to use, from 0 to 59
       * @param second  the second-of-minute to represent, from 0 to 59
       * @return the local date-time formed from this date and the specified time, not null
       * @throws DateTimeException if the value of any field is out of range
       */
      public LocalDateTime atTime(int hour, int minute, int second) {
          return atTime(LocalTime.of(hour, minute, second));
      }
  
      /**
       * Combines this date with a time to create a {@code LocalDateTime}.
       * <p>
       * This returns a {@code LocalDateTime} formed from this date at the
       * specified hour, minute, second and nanosecond.
       * The individual time fields must be within their valid range.
       * All possible combinations of date and time are valid.
       *
       * @param hour  the hour-of-day to use, from 0 to 23
       * @param minute  the minute-of-hour to use, from 0 to 59
       * @param second  the second-of-minute to represent, from 0 to 59
       * @param nanoOfSecond  the nano-of-second to represent, from 0 to 999,999,999
       * @return the local date-time formed from this date and the specified time, not null
       * @throws DateTimeException if the value of any field is out of range
       */
      public LocalDateTime atTime(int hour, int minute, int second, int nanoOfSecond) {
          return atTime(LocalTime.of(hour, minute, second, nanoOfSecond));
      }
  
      /**
       * Combines this date with an offset time to create an {@code OffsetDateTime}.
       * <p>
       * This returns an {@code OffsetDateTime} formed from this date at the specified time.
       * All possible combinations of date and time are valid.
       *
       * @param time  the time to combine with, not null
       * @return the offset date-time formed from this date and the specified time, not null
       */
      public OffsetDateTime atTime(OffsetTime time) {
          return OffsetDateTime.of(LocalDateTime.of(this, time.toLocalTime()), time.getOffset());
      }
  
      /**
       * Combines this date with the time of midnight to create a {@code LocalDateTime}
       * at the start of this date.
       * <p>
       * This returns a {@code LocalDateTime} formed from this date at the time of
       * midnight, 00:00, at the start of this date.
       *
       * @return the local date-time of midnight at the start of this date, not null
       */
      public LocalDateTime atStartOfDay() {
          return LocalDateTime.of(this, LocalTime.MIDNIGHT);
      }
  
      /**
       * Returns a zoned date-time from this date at the earliest valid time according
       * to the rules in the time-zone.
       * <p>
       * Time-zone rules, such as daylight savings, mean that not every local date-time
       * is valid for the specified zone, thus the local date-time may not be midnight.
       * <p>
       * In most cases, there is only one valid offset for a local date-time.
       * In the case of an overlap, there are two valid offsets, and the earlier one is used,
       * corresponding to the first occurrence of midnight on the date.
       * In the case of a gap, the zoned date-time will represent the instant just after the gap.
       * <p>
       * If the zone ID is a {@link ZoneOffset}, then the result always has a time of midnight.
       * <p>
       * To convert to a specific time in a given time-zone call {@link #atTime(LocalTime)}
       * followed by {@link LocalDateTime#atZone(ZoneId)}.
       *
       * @param zone  the zone ID to use, not null
       * @return the zoned date-time formed from this date and the earliest valid time for the zone, not null
       */
      public ZonedDateTime atStartOfDay(ZoneId zone) {
          Objects.requireNonNull(zone, "zone");
          // need to handle case where there is a gap from 11:30 to 00:30
          // standard ZDT factory would result in 01:00 rather than 00:30
          LocalDateTime ldt = atTime(LocalTime.MIDNIGHT);
          if (zone instanceof ZoneOffset == false) {
              ZoneRules rules = zone.getRules();
              ZoneOffsetTransition trans = rules.getTransition(ldt);
              if (trans != null && trans.isGap()) {
                  ldt = trans.getDateTimeAfter();
              }
          }
          return ZonedDateTime.of(ldt, zone);
      }
  
      //-----------------------------------------------------------------------
      @Override
      public long toEpochDay() {
          long y = year;
          long m = month;
          long total = 0;
          total += 365 * y;
          if (y >= 0) {
              total += (y + 3) / 4 - (y + 99) / 100 + (y + 399) / 400;
          } else {
              total -= y / -4 - y / -100 + y / -400;
          }
          total += ((367 * m - 362) / 12);
          total += day - 1;
          if (m > 2) {
              total--;
              if (isLeapYear() == false) {
                  total--;
              }
          }
          return total - DAYS_0000_TO_1970;
      }
  
      //-----------------------------------------------------------------------
      /**
       * Compares this date to another date.
       * <p>
       * The comparison is primarily based on the date, from earliest to latest.
       * It is "consistent with equals", as defined by {@link Comparable}.
       * <p>
       * If all the dates being compared are instances of {@code LocalDate},
       * then the comparison will be entirely based on the date.
       * If some dates being compared are in different chronologies, then the
       * chronology is also considered, see {@link ChronoLocalDate#compareTo}.
       *
       * @param other  the other date to compare to, not null
       * @return the comparator value, negative if less, positive if greater
       */
      @Override  // override for Javadoc and performance
      public int compareTo(ChronoLocalDate other) {
          if (other instanceof LocalDate) {
              return compareTo0((LocalDate) other);
          }
          return ChronoLocalDate.super.compareTo(other);
      }
  
      int compareTo0(LocalDate otherDate) {
          int cmp = (year - otherDate.year);
          if (cmp == 0) {
              cmp = (month - otherDate.month);
              if (cmp == 0) {
                  cmp = (day - otherDate.day);
              }
          }
          return cmp;
      }
  
      /**
       * Checks if this date is after the specified date.
       * <p>
       * This checks to see if this date represents a point on the
       * local time-line after the other date.
       * <pre>
       *   LocalDate a = LocalDate.of(2012, 6, 30);
       *   LocalDate b = LocalDate.of(2012, 7, 1);
       *   a.isAfter(b) == false
       *   a.isAfter(a) == false
       *   b.isAfter(a) == true
       * </pre>
       * <p>
       * This method only considers the position of the two dates on the local time-line.
       * It does not take into account the chronology, or calendar system.
       * This is different from the comparison in {@link #compareTo(ChronoLocalDate)},
       * but is the same approach as {@link ChronoLocalDate#timeLineOrder()}.
       *
       * @param other  the other date to compare to, not null
       * @return true if this date is after the specified date
       */
      @Override  // override for Javadoc and performance
      public boolean isAfter(ChronoLocalDate other) {
          if (other instanceof LocalDate) {
              return compareTo0((LocalDate) other) > 0;
          }
          return ChronoLocalDate.super.isAfter(other);
      }
  
      /**
       * Checks if this date is before the specified date.
       * <p>
       * This checks to see if this date represents a point on the
       * local time-line before the other date.
       * <pre>
       *   LocalDate a = LocalDate.of(2012, 6, 30);
       *   LocalDate b = LocalDate.of(2012, 7, 1);
       *   a.isBefore(b) == true
       *   a.isBefore(a) == false
       *   b.isBefore(a) == false
       * </pre>
       * <p>
       * This method only considers the position of the two dates on the local time-line.
       * It does not take into account the chronology, or calendar system.
       * This is different from the comparison in {@link #compareTo(ChronoLocalDate)},
       * but is the same approach as {@link ChronoLocalDate#timeLineOrder()}.
       *
       * @param other  the other date to compare to, not null
       * @return true if this date is before the specified date
       */
      @Override  // override for Javadoc and performance
      public boolean isBefore(ChronoLocalDate other) {
          if (other instanceof LocalDate) {
              return compareTo0((LocalDate) other) < 0;
          }
          return ChronoLocalDate.super.isBefore(other);
      }
  
      /**
       * Checks if this date is equal to the specified date.
       * <p>
       * This checks to see if this date represents the same point on the
       * local time-line as the other date.
       * <pre>
       *   LocalDate a = LocalDate.of(2012, 6, 30);
       *   LocalDate b = LocalDate.of(2012, 7, 1);
       *   a.isEqual(b) == false
       *   a.isEqual(a) == true
       *   b.isEqual(a) == false
       * </pre>
       * <p>
       * This method only considers the position of the two dates on the local time-line.
       * It does not take into account the chronology, or calendar system.
       * This is different from the comparison in {@link #compareTo(ChronoLocalDate)}
       * but is the same approach as {@link ChronoLocalDate#timeLineOrder()}.
       *
       * @param other  the other date to compare to, not null
       * @return true if this date is equal to the specified date
       */
      @Override  // override for Javadoc and performance
      public boolean isEqual(ChronoLocalDate other) {
          if (other instanceof LocalDate) {
              return compareTo0((LocalDate) other) == 0;
          }
          return ChronoLocalDate.super.isEqual(other);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Checks if this date is equal to another date.
       * <p>
       * Compares this {@code LocalDate} with another ensuring that the date is the same.
       * <p>
       * Only objects of type {@code LocalDate} 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
       */
      @Override
      public boolean equals(Object obj) {
          if (this == obj) {
              return true;
          }
          if (obj instanceof LocalDate) {
              return compareTo0((LocalDate) obj) == 0;
          }
          return false;
      }
  
      /**
       * A hash code for this date.
       *
       * @return a suitable hash code
       */
      @Override
      public int hashCode() {
          int yearValue = year;
          int monthValue = month;
          int dayValue = day;
          return (yearValue & 0xFFFFF800) ^ ((yearValue << 11) + (monthValue << 6) + (dayValue));
      }
  
      //-----------------------------------------------------------------------
      /**
       * Outputs this date as a {@code String}, such as {@code 2007-12-03}.
       * <p>
       * The output will be in the ISO-8601 format {@code uuuu-MM-dd}.
       *
       * @return a string representation of this date, not null
       */
      @Override
      public String toString() {
          int yearValue = year;
          int monthValue = month;
          int dayValue = day;
          int absYear = Math.abs(yearValue);
          StringBuilder buf = new StringBuilder(10);
          if (absYear < 1000) {
              if (yearValue < 0) {
                  buf.append(yearValue - 10000).deleteCharAt(1);
              } else {
                  buf.append(yearValue + 10000).deleteCharAt(0);
              }
          } else {
              if (yearValue > 9999) {
                  buf.append('+');
              }
              buf.append(yearValue);
          }
          return buf.append(monthValue < 10 ? "-0" : "-")
              .append(monthValue)
              .append(dayValue < 10 ? "-0" : "-")
              .append(dayValue)
              .toString();
      }
  
      //-----------------------------------------------------------------------
      /**
       * Writes the object using a
       * <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>.
       * @serialData
       * <pre>
       *  out.writeByte(3);  // identifies a LocalDate
       *  out.writeInt(year);
       *  out.writeByte(month);
       *  out.writeByte(day);
       * </pre>
       *
       * @return the instance of {@code Ser}, not null
       */
      private Object writeReplace() {
          return new Ser(Ser.LOCAL_DATE_TYPE, this);
      }
  
      /**
       * 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");
      }
  
      void writeExternal(DataOutput out) throws IOException {
          out.writeInt(year);
          out.writeByte(month);
          out.writeByte(day);
      }
  
      static LocalDate readExternal(DataInput in) throws IOException {
          int year = in.readInt();
          int month = in.readByte();
          int dayOfMonth = in.readByte();
          return LocalDate.of(year, month, dayOfMonth);
      }
  
  }
  