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	/*
	* Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	/*
	* Copyright (c) 2012, Stephen Colebourne & Michael Nascimento Santos
	*
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are met:
	*
	* * Redistributions of source code must retain the above copyright notice,
	* this list of conditions and the following disclaimer.
	*
	* * Redistributions in binary form must reproduce the above copyright notice,
	* this list of conditions and the following disclaimer in the documentation
	* and/or other materials provided with the distribution.
	*
	* * Neither the name of JSR-310 nor the names of its contributors
	* may be used to endorse or promote products derived from this software
	* without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
	* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
	* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
	* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
	* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
	* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
	* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/
	package java.time.chrono;

	import static java.time.temporal.ChronoField.ALIGNED_DAY_OF_WEEK_IN_MONTH;
	import static java.time.temporal.ChronoField.ALIGNED_DAY_OF_WEEK_IN_YEAR;
	import static java.time.temporal.ChronoField.ALIGNED_WEEK_OF_MONTH;
	import static java.time.temporal.ChronoField.ALIGNED_WEEK_OF_YEAR;
	import static java.time.temporal.ChronoField.DAY_OF_MONTH;
	import static java.time.temporal.ChronoField.MONTH_OF_YEAR;
	import static java.time.temporal.ChronoField.YEAR;

	import java.io.DataInput;
	import java.io.DataOutput;
	import java.io.IOException;
	import java.io.InvalidObjectException;
	import java.io.ObjectInputStream;
	import java.io.Serializable;
	import java.time.Clock;
	import java.time.DateTimeException;
	import java.time.LocalDate;
	import java.time.LocalTime;
	import java.time.Period;
	import java.time.ZoneId;
	import java.time.temporal.ChronoField;
	import java.time.temporal.TemporalAccessor;
	import java.time.temporal.TemporalAdjuster;
	import java.time.temporal.TemporalAmount;
	import java.time.temporal.TemporalField;
	import java.time.temporal.TemporalQuery;
	import java.time.temporal.TemporalUnit;
	import java.time.temporal.UnsupportedTemporalTypeException;
	import java.time.temporal.ValueRange;
	import java.util.Calendar;
	import java.util.Objects;

	import sun.util.calendar.CalendarDate;
	import sun.util.calendar.LocalGregorianCalendar;

	/**
	* A date in the Japanese Imperial calendar system.
	* <p>
	* This date operates using the {@linkplain JapaneseChronology Japanese Imperial calendar}.
	* This calendar system is primarily used in Japan.
	* <p>
	* The Japanese Imperial calendar system is the same as the ISO calendar system
	* apart from the era-based year numbering. The proleptic-year is defined to be
	* equal to the ISO proleptic-year.
	* <p>
	* Japan introduced the Gregorian calendar starting with Meiji 6.
	* Only Meiji and later eras are supported;
	* dates before Meiji 6, January 1 are not supported.
	* <p>
	* For example, the Japanese year "Heisei 24" corresponds to ISO year "2012".<br>
	* Calling {@code japaneseDate.get(YEAR_OF_ERA)} will return 24.<br>
	* Calling {@code japaneseDate.get(YEAR)} will return 2012.<br>
	* Calling {@code japaneseDate.get(ERA)} will return 2, corresponding to
	* {@code JapaneseChronology.ERA_HEISEI}.<br>
	*
	* <p>
	* This is a <a href="{@docRoot}/java/lang/doc-files/ValueBased.html">value-based</a>
	* class; use of identity-sensitive operations (including reference equality
	* ({@code ==}), identity hash code, or synchronization) on instances of
	* {@code JapaneseDate} may have unpredictable results and should be avoided.
	* The {@code equals} method should be used for comparisons.
	*
	* @implSpec
	* This class is immutable and thread-safe.
	*
	* @since 1.8
	*/
	public final class JapaneseDate
	extends ChronoLocalDateImpl<JapaneseDate>
	implements ChronoLocalDate, Serializable {

	/**
	* Serialization version.
	*/
	private static final long serialVersionUID = -305327627230580483L;

	/**
	* The underlying ISO local date.
	*/
	private final transient LocalDate isoDate;
	/**
	* The JapaneseEra of this date.
	*/
	private transient JapaneseEra era;
	/**
	* The Japanese imperial calendar year of this date.
	*/
	private transient int yearOfEra;

	/**
	* The first day supported by the JapaneseChronology is Meiji 6, January 1st.
	*/
	static final LocalDate MEIJI_6_ISODATE = LocalDate.of(1873, 1, 1);

	//-----------------------------------------------------------------------
	/**
	* Obtains the current {@code JapaneseDate} 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 JapaneseDate now() {
	return now(Clock.systemDefaultZone());
	}

	/**
	* Obtains the current {@code JapaneseDate} 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 JapaneseDate now(ZoneId zone) {
	return now(Clock.system(zone));
	}

	/**
	* Obtains the current {@code JapaneseDate} from the specified clock.
	* <p>
	* This will query the specified clock to obtain the current date - today.
	* Using this method allows the use of an alternate clock for testing.
	* The alternate clock may be introduced using {@linkplain Clock dependency injection}.
	*
	* @param clock the clock to use, not null
	* @return the current date, not null
	* @throws DateTimeException if the current date cannot be obtained
	*/
	public static JapaneseDate now(Clock clock) {
	return new JapaneseDate(LocalDate.now(clock));
	}

	/**
	* Obtains a {@code JapaneseDate} representing a date in the Japanese calendar
	* system from the era, year-of-era, month-of-year and day-of-month fields.
	* <p>
	* This returns a {@code JapaneseDate} with the specified fields.
	* The day must be valid for the year and month, otherwise an exception will be thrown.
	* <p>
	* The Japanese month and day-of-month are the same as those in the
	* ISO calendar system. They are not reset when the era changes.
	* For example:
	* <pre>
	* 6th Jan Showa 64 = ISO 1989-01-06
	* 7th Jan Showa 64 = ISO 1989-01-07
	* 8th Jan Heisei 1 = ISO 1989-01-08
	* 9th Jan Heisei 1 = ISO 1989-01-09
	* </pre>
	*
	* @param era the Japanese era, not null
	* @param yearOfEra the Japanese year-of-era
	* @param month the Japanese month-of-year, from 1 to 12
	* @param dayOfMonth the Japanese day-of-month, from 1 to 31
	* @return the date in Japanese calendar system, not null
	* @throws DateTimeException if the value of any field is out of range,
	* or if the day-of-month is invalid for the month-year,
	* or if the date is not a Japanese era
	*/
	public static JapaneseDate of(JapaneseEra era, int yearOfEra, int month, int dayOfMonth) {
	Objects.requireNonNull(era, "era");
	LocalGregorianCalendar.Date jdate = JapaneseChronology.JCAL.newCalendarDate(null);
	jdate.setEra(era.getPrivateEra()).setDate(yearOfEra, month, dayOfMonth);
	if (!JapaneseChronology.JCAL.validate(jdate)) {
	throw new DateTimeException("year, month, and day not valid for Era");
	}
	LocalDate date = LocalDate.of(jdate.getNormalizedYear(), month, dayOfMonth);
	return new JapaneseDate(era, yearOfEra, date);
	}

	/**
	* Obtains a {@code JapaneseDate} representing a date in the Japanese calendar
	* system from the proleptic-year, month-of-year and day-of-month fields.
	* <p>
	* This returns a {@code JapaneseDate} with the specified fields.
	* The day must be valid for the year and month, otherwise an exception will be thrown.
	* <p>
	* The Japanese proleptic year, month and day-of-month are the same as those
	* in the ISO calendar system. They are not reset when the era changes.
	*
	* @param prolepticYear the Japanese proleptic-year
	* @param month the Japanese month-of-year, from 1 to 12
	* @param dayOfMonth the Japanese day-of-month, from 1 to 31
	* @return the date in Japanese calendar system, not null
	* @throws DateTimeException if the value of any field is out of range,
	* or if the day-of-month is invalid for the month-year
	*/
	public static JapaneseDate of(int prolepticYear, int month, int dayOfMonth) {
	return new JapaneseDate(LocalDate.of(prolepticYear, month, dayOfMonth));
	}

	/**
	* Obtains a {@code JapaneseDate} representing a date in the Japanese calendar
	* system from the era, year-of-era and day-of-year fields.
	* <p>
	* This returns a {@code JapaneseDate} with the specified fields.
	* The day must be valid for the year, otherwise an exception will be thrown.
	* <p>
	* The day-of-year in this factory is expressed relative to the start of the year-of-era.
	* This definition changes the normal meaning of day-of-year only in those years
	* where the year-of-era is reset to one due to a change in the era.
	* For example:
	* <pre>
	* 6th Jan Showa 64 = day-of-year 6
	* 7th Jan Showa 64 = day-of-year 7
	* 8th Jan Heisei 1 = day-of-year 1
	* 9th Jan Heisei 1 = day-of-year 2
	* </pre>
	*
	* @param era the Japanese era, not null
	* @param yearOfEra the Japanese year-of-era
	* @param dayOfYear the chronology day-of-year, from 1 to 366
	* @return the date in Japanese calendar system, 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
	*/
	static JapaneseDate ofYearDay(JapaneseEra era, int yearOfEra, int dayOfYear) {
	Objects.requireNonNull(era, "era");
	CalendarDate firstDay = era.getPrivateEra().getSinceDate();
	LocalGregorianCalendar.Date jdate = JapaneseChronology.JCAL.newCalendarDate(null);
	jdate.setEra(era.getPrivateEra());
	if (yearOfEra == 1) {
	jdate.setDate(yearOfEra, firstDay.getMonth(), firstDay.getDayOfMonth() + dayOfYear - 1);
	} else {
	jdate.setDate(yearOfEra, 1, dayOfYear);
	}
	JapaneseChronology.JCAL.normalize(jdate);
	if (era.getPrivateEra() != jdate.getEra() \|\| yearOfEra != jdate.getYear()) {
	throw new DateTimeException("Invalid parameters");
	}
	LocalDate localdate = LocalDate.of(jdate.getNormalizedYear(),
	jdate.getMonth(), jdate.getDayOfMonth());
	return new JapaneseDate(era, yearOfEra, localdate);
	}

	/**
	* Obtains a {@code JapaneseDate} from a temporal object.
	* <p>
	* This obtains a date in the Japanese calendar system based on the specified temporal.
	* A {@code TemporalAccessor} represents an arbitrary set of date and time information,
	* which this factory converts to an instance of {@code JapaneseDate}.
	* <p>
	* The conversion typically uses the {@link ChronoField#EPOCH_DAY EPOCH_DAY}
	* field, which is standardized across calendar systems.
	* <p>
	* This method matches the signature of the functional interface {@link TemporalQuery}
	* allowing it to be used as a query via method reference, {@code JapaneseDate::from}.
	*
	* @param temporal the temporal object to convert, not null
	* @return the date in Japanese calendar system, not null
	* @throws DateTimeException if unable to convert to a {@code JapaneseDate}
	*/
	public static JapaneseDate from(TemporalAccessor temporal) {
	return JapaneseChronology.INSTANCE.date(temporal);
	}

	//-----------------------------------------------------------------------
	/**
	* Creates an instance from an ISO date.
	*
	* @param isoDate the standard local date, validated not null
	*/
	JapaneseDate(LocalDate isoDate) {
	if (isoDate.isBefore(MEIJI_6_ISODATE)) {
	throw new DateTimeException("JapaneseDate before Meiji 6 is not supported");
	}
	LocalGregorianCalendar.Date jdate = toPrivateJapaneseDate(isoDate);
	this.era = JapaneseEra.toJapaneseEra(jdate.getEra());
	this.yearOfEra = jdate.getYear();
	this.isoDate = isoDate;
	}

	/**
	* Constructs a {@code JapaneseDate}. This constructor does NOT validate the given parameters,
	* and {@code era} and {@code year} must agree with {@code isoDate}.
	*
	* @param era the era, validated not null
	* @param year the year-of-era, validated
	* @param isoDate the standard local date, validated not null
	*/
	JapaneseDate(JapaneseEra era, int year, LocalDate isoDate) {
	if (isoDate.isBefore(MEIJI_6_ISODATE)) {
	throw new DateTimeException("JapaneseDate before Meiji 6 is not supported");
	}
	this.era = era;
	this.yearOfEra = year;
	this.isoDate = isoDate;
	}

	//-----------------------------------------------------------------------
	/**
	* Gets the chronology of this date, which is the Japanese calendar system.
	* <p>
	* The {@code Chronology} represents the calendar system in use.
	* The era and other fields in {@link ChronoField} are defined by the chronology.
	*
	* @return the Japanese chronology, not null
	*/
	@Override
	public JapaneseChronology getChronology() {
	return JapaneseChronology.INSTANCE;
	}

	/**
	* Gets the era applicable at this date.
	* <p>
	* The Japanese calendar system has multiple eras defined by {@link JapaneseEra}.
	*
	* @return the era applicable at this date, not null
	*/
	@Override
	public JapaneseEra getEra() {
	return era;
	}

	/**
	* Returns the length of the month represented by this date.
	* <p>
	* This returns the length of the month in days.
	* Month lengths match those of the ISO calendar system.
	*
	* @return the length of the month in days
	*/
	@Override
	public int lengthOfMonth() {
	return isoDate.lengthOfMonth();
	}

	@Override
	public int lengthOfYear() {
	Calendar jcal = Calendar.getInstance(JapaneseChronology.LOCALE);
	jcal.set(Calendar.ERA, era.getValue() + JapaneseEra.ERA_OFFSET);
	jcal.set(yearOfEra, isoDate.getMonthValue() - 1, isoDate.getDayOfMonth());
	return jcal.getActualMaximum(Calendar.DAY_OF_YEAR);
	}

	//-----------------------------------------------------------------------
	/**
	* 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} and
	* {@link #get(TemporalField) get} 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 DAY_OF_MONTH}
	* <li>{@code DAY_OF_YEAR}
	* <li>{@code EPOCH_DAY}
	* <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
	public boolean isSupported(TemporalField field) {
	if (field == ALIGNED_DAY_OF_WEEK_IN_MONTH \|\| field == ALIGNED_DAY_OF_WEEK_IN_YEAR \|\|
	field == ALIGNED_WEEK_OF_MONTH \|\| field == ALIGNED_WEEK_OF_YEAR) {
	return false;
	}
	return ChronoLocalDate.super.isSupported(field);
	}

	@Override
	public ValueRange range(TemporalField field) {
	if (field instanceof ChronoField) {
	if (isSupported(field)) {
	ChronoField f = (ChronoField) field;
	switch (f) {
	case DAY_OF_MONTH: return ValueRange.of(1, lengthOfMonth());
	case DAY_OF_YEAR: return ValueRange.of(1, lengthOfYear());
	case YEAR_OF_ERA: {
	Calendar jcal = Calendar.getInstance(JapaneseChronology.LOCALE);
	jcal.set(Calendar.ERA, era.getValue() + JapaneseEra.ERA_OFFSET);
	jcal.set(yearOfEra, isoDate.getMonthValue() - 1, isoDate.getDayOfMonth());
	return ValueRange.of(1, jcal.getActualMaximum(Calendar.YEAR));
	}
	}
	return getChronology().range(f);
	}
	throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
	}
	return field.rangeRefinedBy(this);
	}

	@Override
	public long getLong(TemporalField field) {
	if (field instanceof ChronoField) {
	// same as ISO:
	// DAY_OF_WEEK, DAY_OF_MONTH, EPOCH_DAY, MONTH_OF_YEAR, PROLEPTIC_MONTH, YEAR
	//
	// calendar specific fields
	// DAY_OF_YEAR, YEAR_OF_ERA, ERA
	switch ((ChronoField) field) {
	case ALIGNED_DAY_OF_WEEK_IN_MONTH:
	case ALIGNED_DAY_OF_WEEK_IN_YEAR:
	case ALIGNED_WEEK_OF_MONTH:
	case ALIGNED_WEEK_OF_YEAR:
	throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
	case YEAR_OF_ERA:
	return yearOfEra;
	case ERA:
	return era.getValue();
	case DAY_OF_YEAR:
	Calendar jcal = Calendar.getInstance(JapaneseChronology.LOCALE);
	jcal.set(Calendar.ERA, era.getValue() + JapaneseEra.ERA_OFFSET);
	jcal.set(yearOfEra, isoDate.getMonthValue() - 1, isoDate.getDayOfMonth());
	return jcal.get(Calendar.DAY_OF_YEAR);
	}
	return isoDate.getLong(field);
	}
	return field.getFrom(this);
	}

	/**
	* Returns a {@code LocalGregorianCalendar.Date} converted from the given {@code isoDate}.
	*
	* @param isoDate the local date, not null
	* @return a {@code LocalGregorianCalendar.Date}, not null
	*/
	private static LocalGregorianCalendar.Date toPrivateJapaneseDate(LocalDate isoDate) {
	LocalGregorianCalendar.Date jdate = JapaneseChronology.JCAL.newCalendarDate(null);
	sun.util.calendar.Era sunEra = JapaneseEra.privateEraFrom(isoDate);
	int year = isoDate.getYear();
	if (sunEra != null) {
	year -= sunEra.getSinceDate().getYear() - 1;
	}
	jdate.setEra(sunEra).setYear(year).setMonth(isoDate.getMonthValue()).setDayOfMonth(isoDate.getDayOfMonth());
	JapaneseChronology.JCAL.normalize(jdate);
	return jdate;
	}

	//-----------------------------------------------------------------------
	@Override
	public JapaneseDate with(TemporalField field, long newValue) {
	if (field instanceof ChronoField) {
	ChronoField f = (ChronoField) field;
	if (getLong(f) == newValue) { // getLong() validates for supported fields
	return this;
	}
	switch (f) {
	case YEAR_OF_ERA:
	case YEAR:
	case ERA: {
	int nvalue = getChronology().range(f).checkValidIntValue(newValue, f);
	switch (f) {
	case YEAR_OF_ERA:
	return this.withYear(nvalue);
	case YEAR:
	return with(isoDate.withYear(nvalue));
	case ERA: {
	return this.withYear(JapaneseEra.of(nvalue), yearOfEra);
	}
	}
	}
	}
	// YEAR, PROLEPTIC_MONTH and others are same as ISO
	return with(isoDate.with(field, newValue));
	}
	return super.with(field, newValue);
	}

	/**
	* {@inheritDoc}
	* @throws DateTimeException {@inheritDoc}
	* @throws ArithmeticException {@inheritDoc}
	*/
	@Override
	public JapaneseDate with(TemporalAdjuster adjuster) {
	return super.with(adjuster);
	}

	/**
	* {@inheritDoc}
	* @throws DateTimeException {@inheritDoc}
	* @throws ArithmeticException {@inheritDoc}
	*/
	@Override
	public JapaneseDate plus(TemporalAmount amount) {
	return super.plus(amount);
	}

	/**
	* {@inheritDoc}
	* @throws DateTimeException {@inheritDoc}
	* @throws ArithmeticException {@inheritDoc}
	*/
	@Override
	public JapaneseDate minus(TemporalAmount amount) {
	return super.minus(amount);
	}
	//-----------------------------------------------------------------------
	/**
	* Returns a copy of this date with the year altered.
	* <p>
	* This method changes the year of the date.
	* If the month-day is invalid for the year, then the previous valid day
	* will be selected instead.
	* <p>
	* This instance is immutable and unaffected by this method call.
	*
	* @param era the era to set in the result, not null
	* @param yearOfEra the year-of-era to set in the returned date
	* @return a {@code JapaneseDate} based on this date with the requested year, never null
	* @throws DateTimeException if {@code year} is invalid
	*/
	private JapaneseDate withYear(JapaneseEra era, int yearOfEra) {
	int year = JapaneseChronology.INSTANCE.prolepticYear(era, yearOfEra);
	return with(isoDate.withYear(year));
	}

	/**
	* Returns a copy of this date with the year-of-era altered.
	* <p>
	* This method changes the year-of-era of the date.
	* If the month-day is invalid for the year, then the previous valid day
	* will be selected instead.
	* <p>
	* This instance is immutable and unaffected by this method call.
	*
	* @param year the year to set in the returned date
	* @return a {@code JapaneseDate} based on this date with the requested year-of-era, never null
	* @throws DateTimeException if {@code year} is invalid
	*/
	private JapaneseDate withYear(int year) {
	return withYear(getEra(), year);
	}

	//-----------------------------------------------------------------------
	@Override
	JapaneseDate plusYears(long years) {
	return with(isoDate.plusYears(years));
	}

	@Override
	JapaneseDate plusMonths(long months) {
	return with(isoDate.plusMonths(months));
	}

	@Override
	JapaneseDate plusWeeks(long weeksToAdd) {
	return with(isoDate.plusWeeks(weeksToAdd));
	}

	@Override
	JapaneseDate plusDays(long days) {
	return with(isoDate.plusDays(days));
	}

	@Override
	public JapaneseDate plus(long amountToAdd, TemporalUnit unit) {
	return super.plus(amountToAdd, unit);
	}

	@Override
	public JapaneseDate minus(long amountToAdd, TemporalUnit unit) {
	return super.minus(amountToAdd, unit);
	}

	@Override
	JapaneseDate minusYears(long yearsToSubtract) {
	return super.minusYears(yearsToSubtract);
	}

	@Override
	JapaneseDate minusMonths(long monthsToSubtract) {
	return super.minusMonths(monthsToSubtract);
	}

	@Override
	JapaneseDate minusWeeks(long weeksToSubtract) {
	return super.minusWeeks(weeksToSubtract);
	}

	@Override
	JapaneseDate minusDays(long daysToSubtract) {
	return super.minusDays(daysToSubtract);
	}

	private JapaneseDate with(LocalDate newDate) {
	return (newDate.equals(isoDate) ? this : new JapaneseDate(newDate));
	}

	@Override // for javadoc and covariant return type
	@SuppressWarnings("unchecked")
	public final ChronoLocalDateTime<JapaneseDate> atTime(LocalTime localTime) {
	return (ChronoLocalDateTime<JapaneseDate>)super.atTime(localTime);
	}

	@Override
	public ChronoPeriod until(ChronoLocalDate endDate) {
	Period period = isoDate.until(endDate);
	return getChronology().period(period.getYears(), period.getMonths(), period.getDays());
	}

	@Override // override for performance
	public long toEpochDay() {
	return isoDate.toEpochDay();
	}

	//-------------------------------------------------------------------------
	/**
	* Compares this date to another date, including the chronology.
	* <p>
	* Compares this {@code JapaneseDate} with another ensuring that the date is the same.
	* <p>
	* Only objects of type {@code JapaneseDate} 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 // override for performance
	public boolean equals(Object obj) {
	if (this == obj) {
	return true;
	}
	if (obj instanceof JapaneseDate) {
	JapaneseDate otherDate = (JapaneseDate) obj;
	return this.isoDate.equals(otherDate.isoDate);
	}
	return false;
	}

	/**
	* A hash code for this date.
	*
	* @return a suitable hash code based only on the Chronology and the date
	*/
	@Override // override for performance
	public int hashCode() {
	return getChronology().getId().hashCode() ^ isoDate.hashCode();
	}

	//-----------------------------------------------------------------------
	/**
	* Defend against malicious streams.
	*
	* @param s the stream to read
	* @throws InvalidObjectException always
	*/
	private void readObject(ObjectInputStream s) throws InvalidObjectException {
	throw new InvalidObjectException("Deserialization via serialization delegate");
	}

	/**
	* Writes the object using a
	* <a href="../../../serialized-form.html#java.time.chrono.Ser">dedicated serialized form</a>.
	* @serialData
	* <pre>
	* out.writeByte(4); // identifies a JapaneseDate
	* out.writeInt(get(YEAR));
	* out.writeByte(get(MONTH_OF_YEAR));
	* out.writeByte(get(DAY_OF_MONTH));
	* </pre>
	*
	* @return the instance of {@code Ser}, not null
	*/
	private Object writeReplace() {
	return new Ser(Ser.JAPANESE_DATE_TYPE, this);
	}

	void writeExternal(DataOutput out) throws IOException {
	// JapaneseChronology is implicit in the JAPANESE_DATE_TYPE
	out.writeInt(get(YEAR));
	out.writeByte(get(MONTH_OF_YEAR));
	out.writeByte(get(DAY_OF_MONTH));
	}

	static JapaneseDate readExternal(DataInput in) throws IOException {
	int year = in.readInt();
	int month = in.readByte();
	int dayOfMonth = in.readByte();
	return JapaneseChronology.INSTANCE.date(year, month, dayOfMonth);
	}

	}

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