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/*
 * This file is available under and governed by the GNU General Public
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 * However, the following notice accompanied the original version of this
 * file:
 *
 * Copyright (c) 2012, Stephen Colebourne & Michael Nascimento Santos
 *
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package java.time.chrono;

import static java.time.temporal.ChronoField.DAY_OF_MONTH;
import static java.time.temporal.ChronoField.ERA;
import static java.time.temporal.ChronoField.HOUR_OF_DAY;
import static java.time.temporal.ChronoField.MINUTE_OF_HOUR;
import static java.time.temporal.ChronoField.MONTH_OF_YEAR;
import static java.time.temporal.ChronoField.PROLEPTIC_MONTH;
import static java.time.temporal.ChronoField.SECOND_OF_MINUTE;
import static java.time.temporal.ChronoField.YEAR;
import static java.time.temporal.ChronoField.YEAR_OF_ERA;

import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.time.Clock;
import java.time.DateTimeException;
import java.time.Instant;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.Month;
import java.time.Period;
import java.time.Year;
import java.time.ZonedDateTime;
import java.time.ZoneId;
import java.time.ZoneOffset;
import java.time.format.ResolverStyle;
import java.time.temporal.ChronoField;
import java.time.temporal.TemporalAccessor;
import java.time.temporal.TemporalField;
import java.time.temporal.ValueRange;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Objects;

The ISO calendar system.

This chronology defines the rules of the ISO calendar system.
This calendar system is based on the ISO-8601 standard, which is the
de facto world calendar.

The fields are defined as follows:

era - There are two eras, 'Current Era' (CE) and 'Before Current Era' (BCE).
year-of-era - The year-of-era is the same as the proleptic-year for the current CE era.
 For the BCE era before the ISO epoch the year increases from 1 upwards as time goes backwards.
proleptic-year - The proleptic year is the same as the year-of-era for the
 current era. For the previous era, years have zero, then negative values.
month-of-year - There are 12 months in an ISO year, numbered from 1 to 12.
day-of-month - There are between 28 and 31 days in each of the ISO month, numbered from 1 to 31.
 Months 4, 6, 9 and 11 have 30 days, Months 1, 3, 5, 7, 8, 10 and 12 have 31 days.
 Month 2 has 28 days, or 29 in a leap year.
day-of-year - There are 365 days in a standard ISO year and 366 in a leap year.
 The days are numbered from 1 to 365 or 1 to 366.
leap-year - Leap years occur every 4 years, except where the year is divisble by 100 and not divisble by 400.

Implementation Requirements:

This class is immutable and thread-safe.
Since:
1.8/**
 * The ISO calendar system.
 * <p>
 * This chronology defines the rules of the ISO calendar system.
 * This calendar system is based on the ISO-8601 standard, which is the
 * <i>de facto</i> world calendar.
 * <p>
 * The fields are defined as follows:
 * <ul>
 * <li>era - There are two eras, 'Current Era' (CE) and 'Before Current Era' (BCE).
 * <li>year-of-era - The year-of-era is the same as the proleptic-year for the current CE era.
 *  For the BCE era before the ISO epoch the year increases from 1 upwards as time goes backwards.
 * <li>proleptic-year - The proleptic year is the same as the year-of-era for the
 *  current era. For the previous era, years have zero, then negative values.
 * <li>month-of-year - There are 12 months in an ISO year, numbered from 1 to 12.
 * <li>day-of-month - There are between 28 and 31 days in each of the ISO month, numbered from 1 to 31.
 *  Months 4, 6, 9 and 11 have 30 days, Months 1, 3, 5, 7, 8, 10 and 12 have 31 days.
 *  Month 2 has 28 days, or 29 in a leap year.
 * <li>day-of-year - There are 365 days in a standard ISO year and 366 in a leap year.
 *  The days are numbered from 1 to 365 or 1 to 366.
 * <li>leap-year - Leap years occur every 4 years, except where the year is divisble by 100 and not divisble by 400.
 * </ul>
 *
 * @implSpec
 * This class is immutable and thread-safe.
 *
 * @since 1.8
 */
public final class IsoChronology extends AbstractChronology implements Serializable {

    
Singleton instance of the ISO chronology.
/**
     * Singleton instance of the ISO chronology.
     */
    public static final IsoChronology INSTANCE = new IsoChronology();

    
Serialization version.
/**
     * Serialization version.
     */
    private static final long serialVersionUID = -1440403870442975015L;

    private static final long DAYS_0000_TO_1970 = (146097 * 5L) - (30L * 365L + 7L); // taken from LocalDate

    
Restricted constructor.
/**
     * Restricted constructor.
     */
    private IsoChronology() {
    }

    //-----------------------------------------------------------------------
    
Gets the ID of the chronology - 'ISO'.
 The ID uniquely identifies the Chronology. It can be used to lookup the Chronology using Chronology.of(String). 
See Also:
getCalendarType()
Returns:
the chronology ID - 'ISO'/**
     * Gets the ID of the chronology - 'ISO'.
     * <p>
     * The ID uniquely identifies the {@code Chronology}.
     * It can be used to lookup the {@code Chronology} using {@link Chronology#of(String)}.
     *
     * @return the chronology ID - 'ISO'
     * @see #getCalendarType()
     */
    @Override
    public String getId() {
        return "ISO";
    }

    
Gets the calendar type of the underlying calendar system - 'iso8601'.

The calendar type is an identifier defined by the
Unicode Locale Data Markup Language (LDML) specification. It can be used to lookup the Chronology using Chronology.of(String). It can also be used as part of a locale, accessible via Locale.getUnicodeLocaleType(String) with the key 'ca'. 
See Also:
getId()
Returns:
the calendar system type - 'iso8601'/**
     * Gets the calendar type of the underlying calendar system - 'iso8601'.
     * <p>
     * The calendar type is an identifier defined by the
     * <em>Unicode Locale Data Markup Language (LDML)</em> specification.
     * It can be used to lookup the {@code Chronology} using {@link Chronology#of(String)}.
     * It can also be used as part of a locale, accessible via
     * {@link Locale#getUnicodeLocaleType(String)} with the key 'ca'.
     *
     * @return the calendar system type - 'iso8601'
     * @see #getId()
     */
    @Override
    public String getCalendarType() {
        return "iso8601";
    }

    //-----------------------------------------------------------------------
    
Obtains an ISO local date from the era, year-of-era, month-of-year
and day-of-month fields.
Params:
era –  the ISO era, not null
yearOfEra –  the ISO year-of-era
month –  the ISO month-of-year
dayOfMonth –  the ISO day-of-month
Throws:
DateTimeException – if unable to create the date
ClassCastException – if the type of era is not IsoEra
Returns:
the ISO local date, not null/**
     * Obtains an ISO local date from the era, year-of-era, month-of-year
     * and day-of-month fields.
     *
     * @param era  the ISO era, not null
     * @param yearOfEra  the ISO year-of-era
     * @param month  the ISO month-of-year
     * @param dayOfMonth  the ISO day-of-month
     * @return the ISO local date, not null
     * @throws DateTimeException if unable to create the date
     * @throws ClassCastException if the type of {@code era} is not {@code IsoEra}
     */
    @Override  // override with covariant return type
    public LocalDate date(Era era, int yearOfEra, int month, int dayOfMonth) {
        return date(prolepticYear(era, yearOfEra), month, dayOfMonth);
    }

    
Obtains an ISO local date from the proleptic-year, month-of-year
and day-of-month fields.
 This is equivalent to LocalDate.of(int, int, int). 
Params:
prolepticYear –  the ISO proleptic-year
month –  the ISO month-of-year
dayOfMonth –  the ISO day-of-month
Throws:
DateTimeException – if unable to create the date
Returns:
the ISO local date, not null/**
     * Obtains an ISO local date from the proleptic-year, month-of-year
     * and day-of-month fields.
     * <p>
     * This is equivalent to {@link LocalDate#of(int, int, int)}.
     *
     * @param prolepticYear  the ISO proleptic-year
     * @param month  the ISO month-of-year
     * @param dayOfMonth  the ISO day-of-month
     * @return the ISO local date, not null
     * @throws DateTimeException if unable to create the date
     */
    @Override  // override with covariant return type
    public LocalDate date(int prolepticYear, int month, int dayOfMonth) {
        return LocalDate.of(prolepticYear, month, dayOfMonth);
    }

    
Obtains an ISO local date from the era, year-of-era and day-of-year fields.
Params:
era –  the ISO era, not null
yearOfEra –  the ISO year-of-era
dayOfYear –  the ISO day-of-year
Throws:
DateTimeException – if unable to create the date
Returns:
the ISO local date, not null/**
     * Obtains an ISO local date from the era, year-of-era and day-of-year fields.
     *
     * @param era  the ISO era, not null
     * @param yearOfEra  the ISO year-of-era
     * @param dayOfYear  the ISO day-of-year
     * @return the ISO local date, not null
     * @throws DateTimeException if unable to create the date
     */
    @Override  // override with covariant return type
    public LocalDate dateYearDay(Era era, int yearOfEra, int dayOfYear) {
        return dateYearDay(prolepticYear(era, yearOfEra), dayOfYear);
    }

    
Obtains an ISO local date from the proleptic-year and day-of-year fields.
 This is equivalent to LocalDate.ofYearDay(int, int). 
Params:
prolepticYear –  the ISO proleptic-year
dayOfYear –  the ISO day-of-year
Throws:
DateTimeException – if unable to create the date
Returns:
the ISO local date, not null/**
     * Obtains an ISO local date from the proleptic-year and day-of-year fields.
     * <p>
     * This is equivalent to {@link LocalDate#ofYearDay(int, int)}.
     *
     * @param prolepticYear  the ISO proleptic-year
     * @param dayOfYear  the ISO day-of-year
     * @return the ISO local date, not null
     * @throws DateTimeException if unable to create the date
     */
    @Override  // override with covariant return type
    public LocalDate dateYearDay(int prolepticYear, int dayOfYear) {
        return LocalDate.ofYearDay(prolepticYear, dayOfYear);
    }

    
Obtains an ISO local date from the epoch-day.
 This is equivalent to LocalDate.ofEpochDay(long). 
Params:
epochDay –  the epoch day
Throws:
DateTimeException – if unable to create the date
Returns:
the ISO local date, not null/**
     * Obtains an ISO local date from the epoch-day.
     * <p>
     * This is equivalent to {@link LocalDate#ofEpochDay(long)}.
     *
     * @param epochDay  the epoch day
     * @return the ISO local date, not null
     * @throws DateTimeException if unable to create the date
     */
    @Override  // override with covariant return type
    public LocalDate dateEpochDay(long epochDay) {
        return LocalDate.ofEpochDay(epochDay);
    }

    //-----------------------------------------------------------------------
    
Obtains an ISO local date from another date-time object.
 This is equivalent to LocalDate.from(TemporalAccessor). 
Params:
temporal –  the date-time object to convert, not null
Throws:
DateTimeException – if unable to create the date
Returns:
the ISO local date, not null/**
     * Obtains an ISO local date from another date-time object.
     * <p>
     * This is equivalent to {@link LocalDate#from(TemporalAccessor)}.
     *
     * @param temporal  the date-time object to convert, not null
     * @return the ISO local date, not null
     * @throws DateTimeException if unable to create the date
     */
    @Override  // override with covariant return type
    public LocalDate date(TemporalAccessor temporal) {
        return LocalDate.from(temporal);
    }

    //-----------------------------------------------------------------------
    
Gets the number of seconds from the epoch of 1970-01-01T00:00:00Z.

The number of seconds is calculated using the year,
month, day-of-month, hour, minute, second, and zoneOffset.
Params:
prolepticYear –  the year, from MIN_YEAR to MAX_YEAR
month –  the month-of-year, from 1 to 12
dayOfMonth –  the day-of-month, from 1 to 31
hour –  the hour-of-day, from 0 to 23
minute –  the minute-of-hour, from 0 to 59
second –  the second-of-minute, from 0 to 59
zoneOffset – the zone offset, not null
Throws:
DateTimeException – if the value of any argument is out of range,
        or if the day-of-month is invalid for the month-of-year
Returns:
the number of seconds relative to 1970-01-01T00:00:00Z, may be negative
Since:
9/**
     * Gets the number of seconds from the epoch of 1970-01-01T00:00:00Z.
     * <p>
     * The number of seconds is calculated using the year,
     * month, day-of-month, hour, minute, second, and zoneOffset.
     *
     * @param prolepticYear  the year, from MIN_YEAR to MAX_YEAR
     * @param month  the month-of-year, from 1 to 12
     * @param dayOfMonth  the day-of-month, from 1 to 31
     * @param hour  the hour-of-day, from 0 to 23
     * @param minute  the minute-of-hour, from 0 to 59
     * @param second  the second-of-minute, from 0 to 59
     * @param zoneOffset the zone offset, not null
     * @return the number of seconds relative to 1970-01-01T00:00:00Z, may be negative
     * @throws DateTimeException if the value of any argument is out of range,
     *         or if the day-of-month is invalid for the month-of-year
     * @since 9
     */
    @Override
    public long epochSecond(int prolepticYear, int month, int dayOfMonth,
                            int hour, int minute, int second, ZoneOffset zoneOffset) {
        YEAR.checkValidValue(prolepticYear);
        MONTH_OF_YEAR.checkValidValue(month);
        DAY_OF_MONTH.checkValidValue(dayOfMonth);
        HOUR_OF_DAY.checkValidValue(hour);
        MINUTE_OF_HOUR.checkValidValue(minute);
        SECOND_OF_MINUTE.checkValidValue(second);
        Objects.requireNonNull(zoneOffset, "zoneOffset");
        if (dayOfMonth > 28) {
            int dom = numberOfDaysOfMonth(prolepticYear, month);
            if (dayOfMonth > dom) {
                if (dayOfMonth == 29) {
                    throw new DateTimeException("Invalid date 'February 29' as '" + prolepticYear + "' is not a leap year");
                } else {
                    throw new DateTimeException("Invalid date '" + Month.of(month).name() + " " + dayOfMonth + "'");
                }
            }
        }

        long totalDays = 0;
        int timeinSec = 0;
        totalDays += 365L * prolepticYear;
        if (prolepticYear >= 0) {
            totalDays += (prolepticYear + 3L) / 4 - (prolepticYear + 99L) / 100 + (prolepticYear + 399L) / 400;
        } else {
            totalDays -= prolepticYear / -4 - prolepticYear / -100 + prolepticYear / -400;
        }
        totalDays += (367 * month - 362) / 12;
        totalDays += dayOfMonth - 1;
        if (month > 2) {
            totalDays--;
            if (IsoChronology.INSTANCE.isLeapYear(prolepticYear) == false) {
                totalDays--;
            }
        }
        totalDays -= DAYS_0000_TO_1970;
        timeinSec = (hour * 60 + minute ) * 60 + second;
        return Math.addExact(Math.multiplyExact(totalDays, 86400L), timeinSec - zoneOffset.getTotalSeconds());
     }

    
Gets the number of days for the given month in the given year.
Params:
year – the year to represent, from MIN_YEAR to MAX_YEAR
month – the month-of-year to represent, from 1 to 12
Returns:
the number of days for the given month in the given year/**
     * Gets the number of days for the given month in the given year.
     *
     * @param year the year to represent, from MIN_YEAR to MAX_YEAR
     * @param month the month-of-year to represent, from 1 to 12
     * @return the number of days for the given month in the given year
     */
    private int numberOfDaysOfMonth(int year, int month) {
        int dom;
        switch (month) {
            case 2:
                dom = (IsoChronology.INSTANCE.isLeapYear(year) ? 29 : 28);
                break;
            case 4:
            case 6:
            case 9:
            case 11:
                dom = 30;
                break;
            default:
                dom = 31;
                break;
        }
        return dom;
    }


    
Obtains an ISO local date-time from another date-time object.
 This is equivalent to LocalDateTime.from(TemporalAccessor). 
Params:
temporal –  the date-time object to convert, not null
Throws:
DateTimeException – if unable to create the date-time
Returns:
the ISO local date-time, not null/**
     * Obtains an ISO local date-time from another date-time object.
     * <p>
     * This is equivalent to {@link LocalDateTime#from(TemporalAccessor)}.
     *
     * @param temporal  the date-time object to convert, not null
     * @return the ISO local date-time, not null
     * @throws DateTimeException if unable to create the date-time
     */
    @Override  // override with covariant return type
    public LocalDateTime localDateTime(TemporalAccessor temporal) {
        return LocalDateTime.from(temporal);
    }

    
Obtains an ISO zoned date-time from another date-time object.
 This is equivalent to ZonedDateTime.from(TemporalAccessor). 
Params:
temporal –  the date-time object to convert, not null
Throws:
DateTimeException – if unable to create the date-time
Returns:
the ISO zoned date-time, not null/**
     * Obtains an ISO zoned date-time from another date-time object.
     * <p>
     * This is equivalent to {@link ZonedDateTime#from(TemporalAccessor)}.
     *
     * @param temporal  the date-time object to convert, not null
     * @return the ISO zoned date-time, not null
     * @throws DateTimeException if unable to create the date-time
     */
    @Override  // override with covariant return type
    public ZonedDateTime zonedDateTime(TemporalAccessor temporal) {
        return ZonedDateTime.from(temporal);
    }

    
Obtains an ISO zoned date-time in this chronology from an Instant. 
 This is equivalent to ZonedDateTime.ofInstant(Instant, ZoneId). 
Params:
instant –  the instant to create the date-time from, not null
zone –  the time-zone, not null
Throws:
DateTimeException – if the result exceeds the supported range
Returns:
the zoned date-time, not null/**
     * Obtains an ISO zoned date-time in this chronology from an {@code Instant}.
     * <p>
     * This is equivalent to {@link ZonedDateTime#ofInstant(Instant, ZoneId)}.
     *
     * @param instant  the instant to create the date-time from, not null
     * @param zone  the time-zone, not null
     * @return the zoned date-time, not null
     * @throws DateTimeException if the result exceeds the supported range
     */
    @Override
    public ZonedDateTime zonedDateTime(Instant instant, ZoneId zone) {
        return ZonedDateTime.ofInstant(instant, zone);
    }

    //-----------------------------------------------------------------------
    
Obtains the current ISO local date from the system clock in the default time-zone.
 This will query the system clock in the default time-zone to obtain the current date. 

Using this method will prevent the ability to use an alternate clock for testing
because the clock is hard-coded.
Throws:
DateTimeException – if unable to create the date
Returns:
the current ISO local date using the system clock and default time-zone, not null/**
     * Obtains the current ISO local 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 ISO local date using the system clock and default time-zone, not null
     * @throws DateTimeException if unable to create the date
     */
    @Override  // override with covariant return type
    public LocalDate dateNow() {
        return dateNow(Clock.systemDefaultZone());
    }

    
Obtains the current ISO local date from the system clock in the specified time-zone.
 This will query the system clock to obtain the current date. Specifying the time-zone avoids dependence on the default time-zone. 

Using this method will prevent the ability to use an alternate clock for testing
because the clock is hard-coded.
Throws:
DateTimeException – if unable to create the date
Returns:
the current ISO local date using the system clock, not null/**
     * Obtains the current ISO local 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.
     *
     * @return the current ISO local date using the system clock, not null
     * @throws DateTimeException if unable to create the date
     */
    @Override  // override with covariant return type
    public LocalDate dateNow(ZoneId zone) {
        return dateNow(Clock.system(zone));
    }

    
Obtains the current ISO local date from the specified clock.
 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 dependency injection. 
Params:
clock –  the clock to use, not null
Throws:
DateTimeException – if unable to create the date
Returns:
the current ISO local date, not null/**
     * Obtains the current ISO local 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 ISO local date, not null
     * @throws DateTimeException if unable to create the date
     */
    @Override  // override with covariant return type
    public LocalDate dateNow(Clock clock) {
        Objects.requireNonNull(clock, "clock");
        return date(LocalDate.now(clock));
    }

    //-----------------------------------------------------------------------
    
Checks if the year is a leap year, according to the ISO proleptic
calendar system rules.

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.

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.

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.
Params:
prolepticYear –  the ISO proleptic year to check
Returns:
true if the year is leap, false otherwise/**
     * 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.
     *
     * @param prolepticYear  the ISO proleptic year to check
     * @return true if the year is leap, false otherwise
     */
    @Override
    public boolean isLeapYear(long prolepticYear) {
        return ((prolepticYear & 3) == 0) && ((prolepticYear % 100) != 0 || (prolepticYear % 400) == 0);
    }

    @Override
    public int prolepticYear(Era era, int yearOfEra) {
        if (era instanceof IsoEra == false) {
            throw new ClassCastException("Era must be IsoEra");
        }
        return (era == IsoEra.CE ? yearOfEra : 1 - yearOfEra);
    }

    @Override
    public IsoEra eraOf(int eraValue) {
        return IsoEra.of(eraValue);
    }

    @Override
    public List<Era> eras() {
        return List.of(IsoEra.values());
    }

    //-----------------------------------------------------------------------
    
Resolves parsed ChronoField values into a date during parsing. 
 Most TemporalField implementations are resolved using the resolve method on the field. By contrast, the ChronoField class defines fields that only have meaning relative to the chronology. As such, ChronoField date fields are resolved here in the context of a specific chronology. 
 ChronoField instances on the ISO calendar system are resolved as follows. 

EPOCH_DAY - If present, this is converted to a LocalDate and all other date fields are then cross-checked against the date. 
PROLEPTIC_MONTH - If present, then it is split into the YEAR and MONTH_OF_YEAR. If the mode is strict or smart then the field is validated. 
YEAR_OF_ERA and ERA - If both are present, then they are combined to form a YEAR. In lenient mode, the YEAR_OF_ERA range is not validated, in smart and strict mode it is. The ERA is validated for range in all three modes. If only the YEAR_OF_ERA is present, and the mode is smart or lenient, then the current era (CE/AD) is assumed. In strict mode, no era is assumed and the YEAR_OF_ERA is left untouched. If only the ERA is present, then it is left untouched. 
YEAR, MONTH_OF_YEAR and DAY_OF_MONTH - If all three are present, then they are combined to form a LocalDate. In all three modes, the YEAR is validated. If the mode is smart or strict, then the month and day are validated, with the day validated from 1 to 31. If the mode is lenient, then the date is combined in a manner equivalent to creating a date on the first of January in the requested year, then adding the difference in months, then the difference in days. If the mode is smart, and the day-of-month is greater than the maximum for the year-month, then the day-of-month is adjusted to the last day-of-month. If the mode is strict, then the three fields must form a valid date. 
YEAR and DAY_OF_YEAR - If both are present, then they are combined to form a LocalDate. In all three modes, the YEAR is validated. If the mode is lenient, then the date is combined in a manner equivalent to creating a date on the first of January in the requested year, then adding the difference in days. If the mode is smart or strict, then the two fields must form a valid date. 
YEAR, MONTH_OF_YEAR, ALIGNED_WEEK_OF_MONTH and ALIGNED_DAY_OF_WEEK_IN_MONTH - If all four are present, then they are combined to form a LocalDate. In all three modes, the YEAR is validated. If the mode is lenient, then the date is combined in a manner equivalent to creating a date on the first of January in the requested year, then adding the difference in months, then the difference in weeks, then in days. If the mode is smart or strict, then the all four fields are validated to their outer ranges. The date is then combined in a manner equivalent to creating a date on the first day of the requested year and month, then adding the amount in weeks and days to reach their values. If the mode is strict, the date is additionally validated to check that the day and week adjustment did not change the month. 
YEAR, MONTH_OF_YEAR, ALIGNED_WEEK_OF_MONTH and DAY_OF_WEEK - If all four are present, then they are combined to form a LocalDate. The approach is the same as described above for years, months and weeks in ALIGNED_DAY_OF_WEEK_IN_MONTH. The day-of-week is adjusted as the next or same matching day-of-week once the years, months and weeks have been handled. 
YEAR, ALIGNED_WEEK_OF_YEAR and ALIGNED_DAY_OF_WEEK_IN_YEAR - If all three are present, then they are combined to form a LocalDate. In all three modes, the YEAR is validated. If the mode is lenient, then the date is combined in a manner equivalent to creating a date on the first of January in the requested year, then adding the difference in weeks, then in days. If the mode is smart or strict, then the all three fields are validated to their outer ranges. The date is then combined in a manner equivalent to creating a date on the first day of the requested year, then adding the amount in weeks and days to reach their values. If the mode is strict, the date is additionally validated to check that the day and week adjustment did not change the year. 
YEAR, ALIGNED_WEEK_OF_YEAR and DAY_OF_WEEK - If all three are present, then they are combined to form a LocalDate. The approach is the same as described above for years and weeks in ALIGNED_DAY_OF_WEEK_IN_YEAR. The day-of-week is adjusted as the next or same matching day-of-week once the years and weeks have been handled. 
Params:
fieldValues –  the map of fields to values, which can be updated, not null
resolverStyle –  the requested type of resolve, not null
Throws:
DateTimeException – if the date cannot be resolved, typically
 because of a conflict in the input data
Returns:
the resolved date, null if insufficient information to create a date/**
     * Resolves parsed {@code ChronoField} values into a date during parsing.
     * <p>
     * Most {@code TemporalField} implementations are resolved using the
     * resolve method on the field. By contrast, the {@code ChronoField} class
     * defines fields that only have meaning relative to the chronology.
     * As such, {@code ChronoField} date fields are resolved here in the
     * context of a specific chronology.
     * <p>
     * {@code ChronoField} instances on the ISO calendar system are resolved
     * as follows.
     * <ul>
     * <li>{@code EPOCH_DAY} - If present, this is converted to a {@code LocalDate}
     *  and all other date fields are then cross-checked against the date.
     * <li>{@code PROLEPTIC_MONTH} - If present, then it is split into the
     *  {@code YEAR} and {@code MONTH_OF_YEAR}. If the mode is strict or smart
     *  then the field is validated.
     * <li>{@code YEAR_OF_ERA} and {@code ERA} - If both are present, then they
     *  are combined to form a {@code YEAR}. In lenient mode, the {@code YEAR_OF_ERA}
     *  range is not validated, in smart and strict mode it is. The {@code ERA} is
     *  validated for range in all three modes. If only the {@code YEAR_OF_ERA} is
     *  present, and the mode is smart or lenient, then the current era (CE/AD)
     *  is assumed. In strict mode, no era is assumed and the {@code YEAR_OF_ERA} is
     *  left untouched. If only the {@code ERA} is present, then it is left untouched.
     * <li>{@code YEAR}, {@code MONTH_OF_YEAR} and {@code DAY_OF_MONTH} -
     *  If all three are present, then they are combined to form a {@code LocalDate}.
     *  In all three modes, the {@code YEAR} is validated. If the mode is smart or strict,
     *  then the month and day are validated, with the day validated from 1 to 31.
     *  If the mode is lenient, then the date is combined in a manner equivalent to
     *  creating a date on the first of January in the requested year, then adding
     *  the difference in months, then the difference in days.
     *  If the mode is smart, and the day-of-month is greater than the maximum for
     *  the year-month, then the day-of-month is adjusted to the last day-of-month.
     *  If the mode is strict, then the three fields must form a valid date.
     * <li>{@code YEAR} and {@code DAY_OF_YEAR} -
     *  If both are present, then they are combined to form a {@code LocalDate}.
     *  In all three modes, the {@code YEAR} is validated.
     *  If the mode is lenient, then the date is combined in a manner equivalent to
     *  creating a date on the first of January in the requested year, then adding
     *  the difference in days.
     *  If the mode is smart or strict, then the two fields must form a valid date.
     * <li>{@code YEAR}, {@code MONTH_OF_YEAR}, {@code ALIGNED_WEEK_OF_MONTH} and
     *  {@code ALIGNED_DAY_OF_WEEK_IN_MONTH} -
     *  If all four are present, then they are combined to form a {@code LocalDate}.
     *  In all three modes, the {@code YEAR} is validated.
     *  If the mode is lenient, then the date is combined in a manner equivalent to
     *  creating a date on the first of January in the requested year, then adding
     *  the difference in months, then the difference in weeks, then in days.
     *  If the mode is smart or strict, then the all four fields are validated to
     *  their outer ranges. The date is then combined in a manner equivalent to
     *  creating a date on the first day of the requested year and month, then adding
     *  the amount in weeks and days to reach their values. If the mode is strict,
     *  the date is additionally validated to check that the day and week adjustment
     *  did not change the month.
     * <li>{@code YEAR}, {@code MONTH_OF_YEAR}, {@code ALIGNED_WEEK_OF_MONTH} and
     *  {@code DAY_OF_WEEK} - If all four are present, then they are combined to
     *  form a {@code LocalDate}. The approach is the same as described above for
     *  years, months and weeks in {@code ALIGNED_DAY_OF_WEEK_IN_MONTH}.
     *  The day-of-week is adjusted as the next or same matching day-of-week once
     *  the years, months and weeks have been handled.
     * <li>{@code YEAR}, {@code ALIGNED_WEEK_OF_YEAR} and {@code ALIGNED_DAY_OF_WEEK_IN_YEAR} -
     *  If all three are present, then they are combined to form a {@code LocalDate}.
     *  In all three modes, the {@code YEAR} is validated.
     *  If the mode is lenient, then the date is combined in a manner equivalent to
     *  creating a date on the first of January in the requested year, then adding
     *  the difference in weeks, then in days.
     *  If the mode is smart or strict, then the all three fields are validated to
     *  their outer ranges. The date is then combined in a manner equivalent to
     *  creating a date on the first day of the requested year, then adding
     *  the amount in weeks and days to reach their values. If the mode is strict,
     *  the date is additionally validated to check that the day and week adjustment
     *  did not change the year.
     * <li>{@code YEAR}, {@code ALIGNED_WEEK_OF_YEAR} and {@code DAY_OF_WEEK} -
     *  If all three are present, then they are combined to form a {@code LocalDate}.
     *  The approach is the same as described above for years and weeks in
     *  {@code ALIGNED_DAY_OF_WEEK_IN_YEAR}. The day-of-week is adjusted as the
     *  next or same matching day-of-week once the years and weeks have been handled.
     * </ul>
     *
     * @param fieldValues  the map of fields to values, which can be updated, not null
     * @param resolverStyle  the requested type of resolve, not null
     * @return the resolved date, null if insufficient information to create a date
     * @throws DateTimeException if the date cannot be resolved, typically
     *  because of a conflict in the input data
     */
    @Override  // override for performance
    public LocalDate resolveDate(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
        return (LocalDate) super.resolveDate(fieldValues, resolverStyle);
    }

    @Override  // override for better proleptic algorithm
    void resolveProlepticMonth(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
        Long pMonth = fieldValues.remove(PROLEPTIC_MONTH);
        if (pMonth != null) {
            if (resolverStyle != ResolverStyle.LENIENT) {
                PROLEPTIC_MONTH.checkValidValue(pMonth);
            }
            addFieldValue(fieldValues, MONTH_OF_YEAR, Math.floorMod(pMonth, 12) + 1);
            addFieldValue(fieldValues, YEAR, Math.floorDiv(pMonth, 12));
        }
    }

    @Override  // override for enhanced behaviour
    LocalDate resolveYearOfEra(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
        Long yoeLong = fieldValues.remove(YEAR_OF_ERA);
        if (yoeLong != null) {
            if (resolverStyle != ResolverStyle.LENIENT) {
                YEAR_OF_ERA.checkValidValue(yoeLong);
            }
            Long era = fieldValues.remove(ERA);
            if (era == null) {
                Long year = fieldValues.get(YEAR);
                if (resolverStyle == ResolverStyle.STRICT) {
                    // do not invent era if strict, but do cross-check with year
                    if (year != null) {
                        addFieldValue(fieldValues, YEAR, (year > 0 ? yoeLong: Math.subtractExact(1, yoeLong)));
                    } else {
                        // reinstate the field removed earlier, no cross-check issues
                        fieldValues.put(YEAR_OF_ERA, yoeLong);
                    }
                } else {
                    // invent era
                    addFieldValue(fieldValues, YEAR, (year == null || year > 0 ? yoeLong: Math.subtractExact(1, yoeLong)));
                }
            } else if (era.longValue() == 1L) {
                addFieldValue(fieldValues, YEAR, yoeLong);
            } else if (era.longValue() == 0L) {
                addFieldValue(fieldValues, YEAR, Math.subtractExact(1, yoeLong));
            } else {
                throw new DateTimeException("Invalid value for era: " + era);
            }
        } else if (fieldValues.containsKey(ERA)) {
            ERA.checkValidValue(fieldValues.get(ERA));  // always validated
        }
        return null;
    }

    @Override  // override for performance
    LocalDate resolveYMD(Map <TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
        int y = YEAR.checkValidIntValue(fieldValues.remove(YEAR));
        if (resolverStyle == ResolverStyle.LENIENT) {
            long months = Math.subtractExact(fieldValues.remove(MONTH_OF_YEAR), 1);
            long days = Math.subtractExact(fieldValues.remove(DAY_OF_MONTH), 1);
            return LocalDate.of(y, 1, 1).plusMonths(months).plusDays(days);
        }
        int moy = MONTH_OF_YEAR.checkValidIntValue(fieldValues.remove(MONTH_OF_YEAR));
        int dom = DAY_OF_MONTH.checkValidIntValue(fieldValues.remove(DAY_OF_MONTH));
        if (resolverStyle == ResolverStyle.SMART) {  // previous valid
            if (moy == 4 || moy == 6 || moy == 9 || moy == 11) {
                dom = Math.min(dom, 30);
            } else if (moy == 2) {
                dom = Math.min(dom, Month.FEBRUARY.length(Year.isLeap(y)));

            }
        }
        return LocalDate.of(y, moy, dom);
    }

    //-----------------------------------------------------------------------
    @Override
    public ValueRange range(ChronoField field) {
        return field.range();
    }

    //-----------------------------------------------------------------------
    
Obtains a period for this chronology based on years, months and days.
 This returns a period tied to the ISO chronology using the specified years, months and days. See Period for further details. 
Params:
years –  the number of years, may be negative
months –  the number of years, may be negative
days –  the number of years, may be negative
Returns:
the period in terms of this chronology, not null
Returns:
the ISO period, not null/**
     * Obtains a period for this chronology based on years, months and days.
     * <p>
     * This returns a period tied to the ISO chronology using the specified
     * years, months and days. See {@link Period} for further details.
     *
     * @param years  the number of years, may be negative
     * @param months  the number of years, may be negative
     * @param days  the number of years, may be negative
     * @return the period in terms of this chronology, not null
     * @return the ISO period, not null
     */
    @Override  // override with covariant return type
    public Period period(int years, int months, int days) {
        return Period.of(years, months, days);
    }

    //-----------------------------------------------------------------------
    
Writes the Chronology using a
dedicated serialized form.
@serialData

 out.writeByte(1);     // identifies a Chronology
 out.writeUTF(getId());
Returns:
the instance of Ser, not null/**
     * Writes the Chronology using a
     * <a href="../../../serialized-form.html#java.time.chrono.Ser">dedicated serialized form</a>.
     * @serialData
     * <pre>
     *  out.writeByte(1);     // identifies a Chronology
     *  out.writeUTF(getId());
     * </pre>
     *
     * @return the instance of {@code Ser}, not null
     */
    @Override
    Object writeReplace() {
        return super.writeReplace();
    }

    
Defend against malicious streams.
Params:
s – the stream to read
Throws:
InvalidObjectException – always/**
     * 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");
    }
}