openjdk/jdk/src/share/classes/java/time/chrono/Chronology.java

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/*
 * 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) 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.
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 *  * Redistributions in binary form must reproduce the above copyright notice,
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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.DAY_OF_WEEK;
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 static java.time.temporal.ChronoField.YEAR_OF_ERA;
import static java.time.temporal.ChronoUnit.DAYS;
import static java.time.temporal.ChronoUnit.MONTHS;
import static java.time.temporal.ChronoUnit.WEEKS;
import static java.time.temporal.TemporalAdjuster.nextOrSame;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectStreamException;
import java.io.Serializable;
import java.time.Clock;
import java.time.DateTimeException;
import java.time.DayOfWeek;
import java.time.Instant;
import java.time.LocalDate;
import java.time.LocalTime;
import java.time.Month;
import java.time.Year;
import java.time.ZoneId;
import java.time.format.DateTimeFormatterBuilder;
import java.time.format.ResolverStyle;
import java.time.format.TextStyle;
import java.time.temporal.ChronoField;
import java.time.temporal.Temporal;
import java.time.temporal.TemporalAccessor;
import java.time.temporal.TemporalAdjuster;
import java.time.temporal.TemporalField;
import java.time.temporal.TemporalQuery;
import java.time.temporal.UnsupportedTemporalTypeException;
import java.time.temporal.ValueRange;
import java.util.Comparator;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Objects;
import java.util.ServiceLoader;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;

import sun.util.logging.PlatformLogger;

/**
 * A calendar system, used to organize and identify dates.
 * <p>
 * The main date and time API is built on the ISO calendar system.
 * This class operates behind the scenes to represent the general concept of a calendar system.
 * For example, the Japanese, Minguo, Thai Buddhist and others.
 * <p>
 * Most other calendar systems also operate on the shared concepts of year, month and day,
 * linked to the cycles of the Earth around the Sun, and the Moon around the Earth.
 * These shared concepts are defined by {@link ChronoField} and are available
 * for use by any {@code Chronology} implementation:
 * <pre>
 *   LocalDate isoDate = ...
 *   ThaiBuddhistDate thaiDate = ...
 *   int isoYear = isoDate.get(ChronoField.YEAR);
 *   int thaiYear = thaiDate.get(ChronoField.YEAR);
 * </pre>
 * As shown, although the date objects are in different calendar systems, represented by different
 * {@code Chronology} instances, both can be queried using the same constant on {@code ChronoField}.
 * For a full discussion of the implications of this, see {@link ChronoLocalDate}.
 * In general, the advice is to use the known ISO-based {@code LocalDate}, rather than
 * {@code ChronoLocalDate}.
 * <p>
 * While a {@code Chronology} object typically uses {@code ChronoField} and is based on
 * an era, year-of-era, month-of-year, day-of-month model of a date, this is not required.
 * A {@code Chronology} instance may represent a totally different kind of calendar system,
 * such as the Mayan.
 * <p>
 * In practical terms, the {@code Chronology} instance also acts as a factory.
 * The {@link #of(String)} method allows an instance to be looked up by identifier,
 * while the {@link #ofLocale(Locale)} method allows lookup by locale.
 * <p>
 * The {@code Chronology} instance provides a set of methods to create {@code ChronoLocalDate} instances.
 * The date classes are used to manipulate specific dates.
 * <p><ul>
 * <li> {@link #dateNow() dateNow()}
 * <li> {@link #dateNow(Clock) dateNow(clock)}
 * <li> {@link #dateNow(ZoneId) dateNow(zone)}
 * <li> {@link #date(int, int, int) date(yearProleptic, month, day)}
 * <li> {@link #date(Era, int, int, int) date(era, yearOfEra, month, day)}
 * <li> {@link #dateYearDay(int, int) dateYearDay(yearProleptic, dayOfYear)}
 * <li> {@link #dateYearDay(Era, int, int) dateYearDay(era, yearOfEra, dayOfYear)}
 * <li> {@link #date(TemporalAccessor) date(TemporalAccessor)}
 * </ul><p>
 *
 * <h3 id="addcalendars">Adding New Calendars</h3>
 * The set of available chronologies can be extended by applications.
 * Adding a new calendar system requires the writing of an implementation of
 * {@code Chronology}, {@code ChronoLocalDate} and {@code Era}.
 * The majority of the logic specific to the calendar system will be in
 * {@code ChronoLocalDate}. The {@code Chronology} subclass acts as a factory.
 * <p>
 * To permit the discovery of additional chronologies, the {@link java.util.ServiceLoader ServiceLoader}
 * is used. A file must be added to the {@code META-INF/services} directory with the
 * name 'java.time.chrono.Chronology' listing the implementation classes.
 * See the ServiceLoader for more details on service loading.
 * For lookup by id or calendarType, the system provided calendars are found
 * first followed by application provided calendars.
 * <p>
 * Each chronology must define a chronology ID that is unique within the system.
 * If the chronology represents a calendar system defined by the
 * CLDR specification then the calendar type is the concatenation of the
 * CLDR type and, if applicable, the CLDR variant,
 *
 * @implSpec
 * This class must be implemented with care to ensure other classes operate correctly.
 * All implementations that can be instantiated must be final, immutable and thread-safe.
 * Subclasses should be Serializable wherever possible.
 *
 * @since 1.8
 */
public abstract class Chronology implements Comparable<Chronology> {

    /**
     * ChronoLocalDate order constant.
     */
    static final Comparator<ChronoLocalDate> DATE_ORDER =
        (Comparator<ChronoLocalDate> & Serializable) (date1, date2) -> {
            return Long.compare(date1.toEpochDay(), date2.toEpochDay());
        };
    /**
     * ChronoLocalDateTime order constant.
     */
    static final Comparator<ChronoLocalDateTime<?>> DATE_TIME_ORDER =
        (Comparator<ChronoLocalDateTime<?>> & Serializable) (dateTime1, dateTime2) -> {
            int cmp = Long.compare(dateTime1.toLocalDate().toEpochDay(), dateTime2.toLocalDate().toEpochDay());
            if (cmp == 0) {
                cmp = Long.compare(dateTime1.toLocalTime().toNanoOfDay(), dateTime2.toLocalTime().toNanoOfDay());
            }
            return cmp;
        };
    /**
     * ChronoZonedDateTime order constant.
     */
    static final Comparator<ChronoZonedDateTime<?>> INSTANT_ORDER =
            (Comparator<ChronoZonedDateTime<?>> & Serializable) (dateTime1, dateTime2) -> {
                int cmp = Long.compare(dateTime1.toEpochSecond(), dateTime2.toEpochSecond());
                if (cmp == 0) {
                    cmp = Long.compare(dateTime1.toLocalTime().getNano(), dateTime2.toLocalTime().getNano());
                }
                return cmp;
            };

    /**
     * Map of available calendars by ID.
     */
    private static final ConcurrentHashMap<String, Chronology> CHRONOS_BY_ID = new ConcurrentHashMap<>();
    /**
     * Map of available calendars by calendar type.
     */
    private static final ConcurrentHashMap<String, Chronology> CHRONOS_BY_TYPE = new ConcurrentHashMap<>();

    /**
     * Register a Chronology by its ID and type for lookup by {@link #of(java.lang.String)}.
     * Chronologies must not be registered until they are completely constructed.
     * Specifically, not in the constructor of Chronology.
     *
     * @param chrono the chronology to register; not null
     * @return the already registered Chronology if any, may be null
     */
    static Chronology registerChrono(Chronology chrono) {
        return registerChrono(chrono, chrono.getId());
    }

    /**
     * Register a Chronology by ID and type for lookup by {@link #of(java.lang.String)}.
     * Chronos must not be registered until they are completely constructed.
     * Specifically, not in the constructor of Chronology.
     *
     * @param chrono the chronology to register; not null
     * @param id the ID to register the chronology; not null
     * @return the already registered Chronology if any, may be null
     */
    static Chronology registerChrono(Chronology chrono, String id) {
        Chronology prev = CHRONOS_BY_ID.putIfAbsent(id, chrono);
        if (prev == null) {
            String type = chrono.getCalendarType();
            if (type != null) {
                CHRONOS_BY_TYPE.putIfAbsent(type, chrono);
            }
        }
        return prev;
    }

    /**
     * Initialization of the maps from id and type to Chronology.
     * The ServiceLoader is used to find and register any implementations
     * of {@link java.time.chrono.Chronology} found in the bootclass loader.
     * The built-in chronologies are registered explicitly.
     * Calendars configured via the Thread's context classloader are local
     * to that thread and are ignored.
     * <p>
     * The initialization is done only once using the registration
     * of the IsoChronology as the test and the final step.
     * Multiple threads may perform the initialization concurrently.
     * Only the first registration of each Chronology is retained by the
     * ConcurrentHashMap.
     * @return true if the cache was initialized
     */
    private static boolean initCache() {
        if (CHRONOS_BY_ID.get("ISO") == null) {
            // Initialization is incomplete

            // Register built-in Chronologies
            registerChrono(HijrahChronology.INSTANCE);
            registerChrono(JapaneseChronology.INSTANCE);
            registerChrono(MinguoChronology.INSTANCE);
            registerChrono(ThaiBuddhistChronology.INSTANCE);

            // Register Chronologies from the ServiceLoader
            @SuppressWarnings("rawtypes")
            ServiceLoader<Chronology> loader =  ServiceLoader.load(Chronology.class, null);
            for (Chronology chrono : loader) {
                String id = chrono.getId();
                if (id.equals("ISO") || registerChrono(chrono) != null) {
                    // Log the attempt to replace an existing Chronology
                    PlatformLogger logger = PlatformLogger.getLogger("java.time.chrono");
                    logger.warning("Ignoring duplicate Chronology, from ServiceLoader configuration "  + id);
                }
            }

            // finally, register IsoChronology to mark initialization is complete
            registerChrono(IsoChronology.INSTANCE);
            return true;
        }
        return false;
    }

    //-----------------------------------------------------------------------
    /**
     * Obtains an instance of {@code Chronology} from a temporal object.
     * <p>
     * This obtains a chronology 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 Chronology}.
     * <p>
     * The conversion will obtain the chronology using {@link TemporalQuery#chronology()}.
     * If the specified temporal object does not have a chronology, {@link IsoChronology} is returned.
     * <p>
     * This method matches the signature of the functional interface {@link TemporalQuery}
     * allowing it to be used in queries via method reference, {@code Chronology::from}.
     *
     * @param temporal  the temporal to convert, not null
     * @return the chronology, not null
     * @throws DateTimeException if unable to convert to an {@code Chronology}
     */
    public static Chronology from(TemporalAccessor temporal) {
        Objects.requireNonNull(temporal, "temporal");
        Chronology obj = temporal.query(TemporalQuery.chronology());
        return (obj != null ? obj : IsoChronology.INSTANCE);
    }

    //-----------------------------------------------------------------------
    /**
     * Obtains an instance of {@code Chronology} from a locale.
     * <p>
     * This returns a {@code Chronology} based on the specified locale,
     * typically returning {@code IsoChronology}. Other calendar systems
     * are only returned if they are explicitly selected within the locale.
     * <p>
     * The {@link Locale} class provide access to a range of information useful
     * for localizing an application. This includes the language and region,
     * such as "en-GB" for English as used in Great Britain.
     * <p>
     * The {@code Locale} class also supports an extension mechanism that
     * can be used to identify a calendar system. The mechanism is a form
     * of key-value pairs, where the calendar system has the key "ca".
     * For example, the locale "en-JP-u-ca-japanese" represents the English
     * language as used in Japan with the Japanese calendar system.
     * <p>
     * This method finds the desired calendar system by in a manner equivalent
     * to passing "ca" to {@link Locale#getUnicodeLocaleType(String)}.
     * If the "ca" key is not present, then {@code IsoChronology} is returned.
     * <p>
     * Note that the behavior of this method differs from the older
     * {@link java.util.Calendar#getInstance(Locale)} method.
     * If that method receives a locale of "th_TH" it will return {@code BuddhistCalendar}.
     * By contrast, this method will return {@code IsoChronology}.
     * Passing the locale "th-TH-u-ca-buddhist" into either method will
     * result in the Thai Buddhist calendar system and is therefore the
     * recommended approach going forward for Thai calendar system localization.
     * <p>
     * A similar, but simpler, situation occurs for the Japanese calendar system.
     * The locale "jp_JP_JP" has previously been used to access the calendar.
     * However, unlike the Thai locale, "ja_JP_JP" is automatically converted by
     * {@code Locale} to the modern and recommended form of "ja-JP-u-ca-japanese".
     * Thus, there is no difference in behavior between this method and
     * {@code Calendar#getInstance(Locale)}.
     *
     * @param locale  the locale to use to obtain the calendar system, not null
     * @return the calendar system associated with the locale, not null
     * @throws DateTimeException if the locale-specified calendar cannot be found
     */
    public static Chronology ofLocale(Locale locale) {
        Objects.requireNonNull(locale, "locale");
        String type = locale.getUnicodeLocaleType("ca");
        if (type == null || "iso".equals(type) || "iso8601".equals(type)) {
            return IsoChronology.INSTANCE;
        }
        // Not pre-defined; lookup by the type
        do {
            Chronology chrono = CHRONOS_BY_TYPE.get(type);
            if (chrono != null) {
                return chrono;
            }
            // If not found, do the initialization (once) and repeat the lookup
        } while (initCache());

        // Look for a Chronology using ServiceLoader of the Thread's ContextClassLoader
        // Application provided Chronologies must not be cached
        @SuppressWarnings("rawtypes")
        ServiceLoader<Chronology> loader = ServiceLoader.load(Chronology.class);
        for (Chronology chrono : loader) {
            if (type.equals(chrono.getCalendarType())) {
                return chrono;
            }
        }
        throw new DateTimeException("Unknown calendar system: " + type);
    }

    //-----------------------------------------------------------------------
    /**
     * Obtains an instance of {@code Chronology} from a chronology ID or
     * calendar system type.
     * <p>
     * This returns a chronology based on either the ID or the type.
     * The {@link #getId() chronology ID} uniquely identifies the chronology.
     * The {@link #getCalendarType() calendar system type} is defined by the
     * CLDR specification.
     * <p>
     * The chronology may be a system chronology or a chronology
     * provided by the application via ServiceLoader configuration.
     * <p>
     * Since some calendars can be customized, the ID or type typically refers
     * to the default customization. For example, the Gregorian calendar can have multiple
     * cutover dates from the Julian, but the lookup only provides the default cutover date.
     *
     * @param id  the chronology ID or calendar system type, not null
     * @return the chronology with the identifier requested, not null
     * @throws DateTimeException if the chronology cannot be found
     */
    public static Chronology of(String id) {
        Objects.requireNonNull(id, "id");
        do {
            Chronology chrono = of0(id);
            if (chrono != null) {
                return chrono;
            }
            // If not found, do the initialization (once) and repeat the lookup
        } while (initCache());

        // Look for a Chronology using ServiceLoader of the Thread's ContextClassLoader
        // Application provided Chronologies must not be cached
        @SuppressWarnings("rawtypes")
        ServiceLoader<Chronology> loader = ServiceLoader.load(Chronology.class);
        for (Chronology chrono : loader) {
            if (id.equals(chrono.getId()) || id.equals(chrono.getCalendarType())) {
                return chrono;
            }
        }
        throw new DateTimeException("Unknown chronology: " + id);
    }

    /**
     * Obtains an instance of {@code Chronology} from a chronology ID or
     * calendar system type.
     *
     * @param id  the chronology ID or calendar system type, not null
     * @return the chronology with the identifier requested, or {@code null} if not found
     */
    private static Chronology of0(String id) {
        Chronology chrono = CHRONOS_BY_ID.get(id);
        if (chrono == null) {
            chrono = CHRONOS_BY_TYPE.get(id);
        }
        return chrono;
    }

    /**
     * Returns the available chronologies.
     * <p>
     * Each returned {@code Chronology} is available for use in the system.
     * The set of chronologies includes the system chronologies and
     * any chronologies provided by the application via ServiceLoader
     * configuration.
     *
     * @return the independent, modifiable set of the available chronology IDs, not null
     */
    public static Set<Chronology> getAvailableChronologies() {
        initCache();       // force initialization
        HashSet<Chronology> chronos = new HashSet<>(CHRONOS_BY_ID.values());

        /// Add in Chronologies from the ServiceLoader configuration
        @SuppressWarnings("rawtypes")
        ServiceLoader<Chronology> loader = ServiceLoader.load(Chronology.class);
        for (Chronology chrono : loader) {
            chronos.add(chrono);
        }
        return chronos;
    }

    //-----------------------------------------------------------------------
    /**
     * Creates an instance.
     */
    protected Chronology() {
    }

    //-----------------------------------------------------------------------
    /**
     * Gets the ID of the chronology.
     * <p>
     * The ID uniquely identifies the {@code Chronology}.
     * It can be used to lookup the {@code Chronology} using {@link #of(String)}.
     *
     * @return the chronology ID, not null
     * @see #getCalendarType()
     */
    public abstract String getId();

    /**
     * Gets the calendar type of the calendar system.
     * <p>
     * The calendar type is an identifier defined by the CLDR and
     * <em>Unicode Locale Data Markup Language (LDML)</em> specifications
     * to uniquely identification a calendar.
     * The {@code getCalendarType} is the concatenation of the CLDR calendar type
     * and the variant, if applicable, is appended separated by "-".
     * The calendar type is used to lookup the {@code Chronology} using {@link #of(String)}.
     *
     * @return the calendar system type, null if the calendar is not defined by CLDR/LDML
     * @see #getId()
     */
    public abstract String getCalendarType();

    //-----------------------------------------------------------------------
    /**
     * Obtains a local date in this chronology from the era, year-of-era,
     * month-of-year and day-of-month fields.
     *
     * @param era  the era of the correct type for the chronology, not null
     * @param yearOfEra  the chronology year-of-era
     * @param month  the chronology month-of-year
     * @param dayOfMonth  the chronology day-of-month
     * @return the local date in this chronology, not null
     * @throws DateTimeException if unable to create the date
     * @throws ClassCastException if the {@code era} is not of the correct type for the chronology
     */
    public ChronoLocalDate date(Era era, int yearOfEra, int month, int dayOfMonth) {
        return date(prolepticYear(era, yearOfEra), month, dayOfMonth);
    }

    /**
     * Obtains a local date in this chronology from the proleptic-year,
     * month-of-year and day-of-month fields.
     *
     * @param prolepticYear  the chronology proleptic-year
     * @param month  the chronology month-of-year
     * @param dayOfMonth  the chronology day-of-month
     * @return the local date in this chronology, not null
     * @throws DateTimeException if unable to create the date
     */
    public abstract ChronoLocalDate date(int prolepticYear, int month, int dayOfMonth);

    /**
     * Obtains a local date in this chronology from the era, year-of-era and
     * day-of-year fields.
     *
     * @param era  the era of the correct type for the chronology, not null
     * @param yearOfEra  the chronology year-of-era
     * @param dayOfYear  the chronology day-of-year
     * @return the local date in this chronology, not null
     * @throws DateTimeException if unable to create the date
     * @throws ClassCastException if the {@code era} is not of the correct type for the chronology
     */
    public ChronoLocalDate dateYearDay(Era era, int yearOfEra, int dayOfYear) {
        return dateYearDay(prolepticYear(era, yearOfEra), dayOfYear);
    }

    /**
     * Obtains a local date in this chronology from the proleptic-year and
     * day-of-year fields.
     *
     * @param prolepticYear  the chronology proleptic-year
     * @param dayOfYear  the chronology day-of-year
     * @return the local date in this chronology, not null
     * @throws DateTimeException if unable to create the date
     */
    public abstract ChronoLocalDate dateYearDay(int prolepticYear, int dayOfYear);

    /**
     * Obtains a local date in this chronology from the epoch-day.
     * <p>
     * The definition of {@link ChronoField#EPOCH_DAY EPOCH_DAY} is the same
     * for all calendar systems, thus it can be used for conversion.
     *
     * @param epochDay  the epoch day
     * @return the local date in this chronology, not null
     * @throws DateTimeException if unable to create the date
     */
    public abstract ChronoLocalDate dateEpochDay(long epochDay);

    //-----------------------------------------------------------------------
    /**
     * Obtains the current local date in this chronology 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.
     * <p>
     * This implementation uses {@link #dateNow(Clock)}.
     *
     * @return the current local date using the system clock and default time-zone, not null
     * @throws DateTimeException if unable to create the date
     */
    public ChronoLocalDate dateNow() {
        return dateNow(Clock.systemDefaultZone());
    }

    /**
     * Obtains the current local date in this chronology 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 local date using the system clock, not null
     * @throws DateTimeException if unable to create the date
     */
    public ChronoLocalDate dateNow(ZoneId zone) {
        return dateNow(Clock.system(zone));
    }

    /**
     * Obtains the current local date in this chronology 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 local date, not null
     * @throws DateTimeException if unable to create the date
     */
    public ChronoLocalDate dateNow(Clock clock) {
        Objects.requireNonNull(clock, "clock");
        return date(LocalDate.now(clock));
    }

    //-----------------------------------------------------------------------
    /**
     * Obtains a local date in this chronology from another temporal object.
     * <p>
     * This obtains a date in this chronology 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 ChronoLocalDate}.
     * <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 aChronology::date}.
     *
     * @param temporal  the temporal object to convert, not null
     * @return the local date in this chronology, not null
     * @throws DateTimeException if unable to create the date
     * @see ChronoLocalDate#from(TemporalAccessor)
     */
    public abstract ChronoLocalDate date(TemporalAccessor temporal);

    /**
     * Obtains a local date-time in this chronology from another temporal object.
     * <p>
     * This obtains a date-time in this chronology 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 ChronoLocalDateTime}.
     * <p>
     * The conversion extracts and combines the {@code ChronoLocalDate} and the
     * {@code LocalTime} from the temporal object.
     * Implementations are permitted to perform optimizations such as accessing
     * those fields that are equivalent to the relevant objects.
     * The result uses this chronology.
     * <p>
     * This method matches the signature of the functional interface {@link TemporalQuery}
     * allowing it to be used as a query via method reference, {@code aChronology::localDateTime}.
     *
     * @param temporal  the temporal object to convert, not null
     * @return the local date-time in this chronology, not null
     * @throws DateTimeException if unable to create the date-time
     * @see ChronoLocalDateTime#from(TemporalAccessor)
     */
    public ChronoLocalDateTime<? extends ChronoLocalDate> localDateTime(TemporalAccessor temporal) {
        try {
            return date(temporal).atTime(LocalTime.from(temporal));
        } catch (DateTimeException ex) {
            throw new DateTimeException("Unable to obtain ChronoLocalDateTime from TemporalAccessor: " + temporal.getClass(), ex);
        }
    }

    /**
     * Obtains a {@code ChronoZonedDateTime} in this chronology from another temporal object.
     * <p>
     * This obtains a zoned date-time in this chronology 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 ChronoZonedDateTime}.
     * <p>
     * The conversion will first obtain a {@code ZoneId} from the temporal object,
     * falling back to a {@code ZoneOffset} if necessary. It will then try to obtain
     * an {@code Instant}, falling back to a {@code ChronoLocalDateTime} if necessary.
     * The result will be either the combination of {@code ZoneId} or {@code ZoneOffset}
     * with {@code Instant} or {@code ChronoLocalDateTime}.
     * Implementations are permitted to perform optimizations such as accessing
     * those fields that are equivalent to the relevant objects.
     * The result uses this chronology.
     * <p>
     * This method matches the signature of the functional interface {@link TemporalQuery}
     * allowing it to be used as a query via method reference, {@code aChronology::zonedDateTime}.
     *
     * @param temporal  the temporal object to convert, not null
     * @return the zoned date-time in this chronology, not null
     * @throws DateTimeException if unable to create the date-time
     * @see ChronoZonedDateTime#from(TemporalAccessor)
     */
    public ChronoZonedDateTime<? extends ChronoLocalDate> zonedDateTime(TemporalAccessor temporal) {
        try {
            ZoneId zone = ZoneId.from(temporal);
            try {
                Instant instant = Instant.from(temporal);
                return zonedDateTime(instant, zone);

            } catch (DateTimeException ex1) {
                ChronoLocalDateTimeImpl<?> cldt = ChronoLocalDateTimeImpl.ensureValid(this, localDateTime(temporal));
                return ChronoZonedDateTimeImpl.ofBest(cldt, zone, null);
            }
        } catch (DateTimeException ex) {
            throw new DateTimeException("Unable to obtain ChronoZonedDateTime from TemporalAccessor: " + temporal.getClass(), ex);
        }
    }

    /**
     * Obtains a {@code ChronoZonedDateTime} in this chronology from an {@code Instant}.
     * <p>
     * This obtains a zoned date-time with the same instant as that specified.
     *
     * @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
     */
    public ChronoZonedDateTime<? extends ChronoLocalDate> zonedDateTime(Instant instant, ZoneId zone) {
        return ChronoZonedDateTimeImpl.ofInstant(this, instant, zone);
    }

    //-----------------------------------------------------------------------
    /**
     * Checks if the specified year is a leap year.
     * <p>
     * A leap-year is a year of a longer length than normal.
     * The exact meaning is determined by the chronology according to the following constraints.
     * <p><ul>
     * <li>a leap-year must imply a year-length longer than a non leap-year.
     * <li>a chronology that does not support the concept of a year must return false.
     * </ul><p>
     *
     * @param prolepticYear  the proleptic-year to check, not validated for range
     * @return true if the year is a leap year
     */
    public abstract boolean isLeapYear(long prolepticYear);

    /**
     * Calculates the proleptic-year given the era and year-of-era.
     * <p>
     * This combines the era and year-of-era into the single proleptic-year field.
     * <p>
     * If the chronology makes active use of eras, such as {@code JapaneseChronology}
     * then the year-of-era will be validated against the era.
     * For other chronologies, validation is optional.
     *
     * @param era  the era of the correct type for the chronology, not null
     * @param yearOfEra  the chronology year-of-era
     * @return the proleptic-year
     * @throws DateTimeException if unable to convert to a proleptic-year,
     *  such as if the year is invalid for the era
     * @throws ClassCastException if the {@code era} is not of the correct type for the chronology
     */
    public abstract int prolepticYear(Era era, int yearOfEra);

    /**
     * Creates the chronology era object from the numeric value.
     * <p>
     * The era is, conceptually, the largest division of the time-line.
     * Most calendar systems have a single epoch dividing the time-line into two eras.
     * However, some have multiple eras, such as one for the reign of each leader.
     * The exact meaning is determined by the chronology according to the following constraints.
     * <p>
     * The era in use at 1970-01-01 must have the value 1.
     * Later eras must have sequentially higher values.
     * Earlier eras must have sequentially lower values.
     * Each chronology must refer to an enum or similar singleton to provide the era values.
     * <p>
     * This method returns the singleton era of the correct type for the specified era value.
     *
     * @param eraValue  the era value
     * @return the calendar system era, not null
     * @throws DateTimeException if unable to create the era
     */
    public abstract Era eraOf(int eraValue);

    /**
     * Gets the list of eras for the chronology.
     * <p>
     * Most calendar systems have an era, within which the year has meaning.
     * If the calendar system does not support the concept of eras, an empty
     * list must be returned.
     *
     * @return the list of eras for the chronology, may be immutable, not null
     */
    public abstract List<Era> eras();

    //-----------------------------------------------------------------------
    /**
     * Gets the range of valid values for the specified field.
     * <p>
     * All fields can be expressed as a {@code long} integer.
     * This method returns an object that describes the valid range for that value.
     * <p>
     * Note that the result only describes the minimum and maximum valid values
     * and it is important not to read too much into them. For example, there
     * could be values within the range that are invalid for the field.
     * <p>
     * This method will return a result whether or not the chronology supports the field.
     *
     * @param field  the field to get 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
     */
    public abstract ValueRange range(ChronoField field);

    //-----------------------------------------------------------------------
    /**
     * Gets the textual representation of this chronology.
     * <p>
     * This returns the textual name used to identify the chronology,
     * suitable for presentation to the user.
     * The parameters control the style of the returned text and the locale.
     *
     * @param style  the style of the text required, not null
     * @param locale  the locale to use, not null
     * @return the text value of the chronology, not null
     */
    public String getDisplayName(TextStyle style, Locale locale) {
        return new DateTimeFormatterBuilder().appendChronologyText(style).toFormatter(locale).format(toTemporal());
    }

    /**
     * Converts this chronology to a {@code TemporalAccessor}.
     * <p>
     * A {@code Chronology} can be fully represented as a {@code TemporalAccessor}.
     * However, the interface is not implemented by this class as most of the
     * methods on the interface have no meaning to {@code Chronology}.
     * <p>
     * The returned temporal has no supported fields, with the query method
     * supporting the return of the chronology using {@link TemporalQuery#chronology()}.
     *
     * @return a temporal equivalent to this chronology, not null
     */
    private TemporalAccessor toTemporal() {
        return new TemporalAccessor() {
            @Override
            public boolean isSupported(TemporalField field) {
                return false;
            }
            @Override
            public long getLong(TemporalField field) {
                throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
            }
            @SuppressWarnings("unchecked")
            @Override
            public <R> R query(TemporalQuery<R> query) {
                if (query == TemporalQuery.chronology()) {
                    return (R) Chronology.this;
                }
                return TemporalAccessor.super.query(query);
            }
        };
    }

    //-----------------------------------------------------------------------
    /**
     * 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 are resolved by this method, which may
     * be overridden in subclasses.
     * <ul>
     * <li>{@code EPOCH_DAY} - If present, this is converted to a date 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 last available era
     *  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 date.
     *  In all three modes, the {@code YEAR} is validated.
     *  If the mode is smart or strict, then the month and day are validated.
     *  If the mode is lenient, then the date is combined in a manner equivalent to
     *  creating a date on the first day of the first month 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 date.
     *  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 day of 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 date.
     *  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 day of the first month 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 date. 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 date.
     *  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 day of 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 date.
     *  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>
     * <p>
     * The default implementation is suitable for most calendar systems.
     * If {@link ChronoField#YEAR_OF_ERA} is found without an {@link ChronoField#ERA}
     * then the last era in {@link #eras()} is used.
     * The implementation assumes a 7 day week, that the first day-of-month
     * has the value 1, that first day-of-year has the value 1, and that the
     * first of the month and year always exists.
     *
     * @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
     */
    public ChronoLocalDate resolveDate(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
        // check epoch-day before inventing era
        if (fieldValues.containsKey(EPOCH_DAY)) {
            return dateEpochDay(fieldValues.remove(EPOCH_DAY));
        }

        // fix proleptic month before inventing era
        resolveProlepticMonth(fieldValues, resolverStyle);

        // invent era if necessary to resolve year-of-era
        ChronoLocalDate resolved = resolveYearOfEra(fieldValues, resolverStyle);
        if (resolved != null) {
            return resolved;
        }

        // build date
        if (fieldValues.containsKey(YEAR)) {
            if (fieldValues.containsKey(MONTH_OF_YEAR)) {
                if (fieldValues.containsKey(DAY_OF_MONTH)) {
                    return resolveYMD(fieldValues, resolverStyle);
                }
                if (fieldValues.containsKey(ALIGNED_WEEK_OF_MONTH)) {
                    if (fieldValues.containsKey(ALIGNED_DAY_OF_WEEK_IN_MONTH)) {
                        return resolveYMAA(fieldValues, resolverStyle);
                    }
                    if (fieldValues.containsKey(DAY_OF_WEEK)) {
                        return resolveYMAD(fieldValues, resolverStyle);
                    }
                }
            }
            if (fieldValues.containsKey(DAY_OF_YEAR)) {
                return resolveYD(fieldValues, resolverStyle);
            }
            if (fieldValues.containsKey(ALIGNED_WEEK_OF_YEAR)) {
                if (fieldValues.containsKey(ALIGNED_DAY_OF_WEEK_IN_YEAR)) {
                    return resolveYAA(fieldValues, resolverStyle);
                }
                if (fieldValues.containsKey(DAY_OF_WEEK)) {
                    return resolveYAD(fieldValues, resolverStyle);
                }
            }
        }
        return null;
    }

    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);
            }
            // first day-of-month is likely to be safest for setting proleptic-month
            // cannot add to year zero, as not all chronologies have a year zero
            ChronoLocalDate chronoDate = dateNow()
                    .with(DAY_OF_MONTH, 1).with(PROLEPTIC_MONTH, pMonth);
            addFieldValue(fieldValues, MONTH_OF_YEAR, chronoDate.get(MONTH_OF_YEAR));
            addFieldValue(fieldValues, YEAR, chronoDate.get(YEAR));
        }
    }

    ChronoLocalDate resolveYearOfEra(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
        Long yoeLong = fieldValues.remove(YEAR_OF_ERA);
        if (yoeLong != null) {
            Long eraLong = fieldValues.remove(ERA);
            int yoe;
            if (resolverStyle != ResolverStyle.LENIENT) {
                yoe = range(YEAR_OF_ERA).checkValidIntValue(yoeLong, YEAR_OF_ERA);
            } else {
                yoe = Math.toIntExact(yoeLong);
            }
            if (eraLong != null) {
                Era eraObj = eraOf(range(ERA).checkValidIntValue(eraLong, ERA));
                addFieldValue(fieldValues, YEAR, prolepticYear(eraObj, yoe));
            } else {
                if (fieldValues.containsKey(YEAR)) {
                    int year = range(YEAR).checkValidIntValue(fieldValues.get(YEAR), YEAR);
                    ChronoLocalDate chronoDate = dateYearDay(year, 1);
                    addFieldValue(fieldValues, YEAR, prolepticYear(chronoDate.getEra(), yoe));
                } else if (resolverStyle == ResolverStyle.STRICT) {
                    // do not invent era if strict
                    // reinstate the field removed earlier, no cross-check issues
                    fieldValues.put(YEAR_OF_ERA, yoeLong);
                } else {
                    List<Era> eras = eras();
                    if (eras.isEmpty()) {
                        addFieldValue(fieldValues, YEAR, yoe);
                    } else {
                        Era eraObj = eras.get(eras.size() - 1);
                        addFieldValue(fieldValues, YEAR, prolepticYear(eraObj, yoe));
                    }
                }
            }
        } else if (fieldValues.containsKey(ERA)) {
            range(ERA).checkValidValue(fieldValues.get(ERA), ERA);  // always validated
        }
        return null;
    }

    ChronoLocalDate resolveYMD(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
        int y = range(YEAR).checkValidIntValue(fieldValues.remove(YEAR), 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 date(y, 1, 1).plus(months, MONTHS).plus(days, DAYS);
        }
        int moy = range(MONTH_OF_YEAR).checkValidIntValue(fieldValues.remove(MONTH_OF_YEAR), MONTH_OF_YEAR);
        ValueRange domRange = range(DAY_OF_MONTH);
        int dom = domRange.checkValidIntValue(fieldValues.remove(DAY_OF_MONTH), DAY_OF_MONTH);
        if (resolverStyle == ResolverStyle.SMART) {  // previous valid
            try {
                return date(y, moy, dom);
            } catch (DateTimeException ex) {
                return date(y, moy, 1).with(TemporalAdjuster.lastDayOfMonth());
            }
        }
        return date(y, moy, dom);
    }

    ChronoLocalDate resolveYD(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
        int y = range(YEAR).checkValidIntValue(fieldValues.remove(YEAR), YEAR);
        if (resolverStyle == ResolverStyle.LENIENT) {
            long days = Math.subtractExact(fieldValues.remove(DAY_OF_YEAR), 1);
            return dateYearDay(y, 1).plus(days, DAYS);
        }
        int doy = range(DAY_OF_YEAR).checkValidIntValue(fieldValues.remove(DAY_OF_YEAR), DAY_OF_YEAR);
        return dateYearDay(y, doy);  // smart is same as strict
    }

    ChronoLocalDate resolveYMAA(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
        int y = range(YEAR).checkValidIntValue(fieldValues.remove(YEAR), YEAR);
        if (resolverStyle == ResolverStyle.LENIENT) {
            long months = Math.subtractExact(fieldValues.remove(MONTH_OF_YEAR), 1);
            long weeks = Math.subtractExact(fieldValues.remove(ALIGNED_WEEK_OF_MONTH), 1);
            long days = Math.subtractExact(fieldValues.remove(ALIGNED_DAY_OF_WEEK_IN_MONTH), 1);
            return date(y, 1, 1).plus(months, MONTHS).plus(weeks, WEEKS).plus(days, DAYS);
        }
        int moy = range(MONTH_OF_YEAR).checkValidIntValue(fieldValues.remove(MONTH_OF_YEAR), MONTH_OF_YEAR);
        int aw = range(ALIGNED_WEEK_OF_MONTH).checkValidIntValue(fieldValues.remove(ALIGNED_WEEK_OF_MONTH), ALIGNED_WEEK_OF_MONTH);
        int ad = range(ALIGNED_DAY_OF_WEEK_IN_MONTH).checkValidIntValue(fieldValues.remove(ALIGNED_DAY_OF_WEEK_IN_MONTH), ALIGNED_DAY_OF_WEEK_IN_MONTH);
        ChronoLocalDate date = date(y, moy, 1).plus((aw - 1) * 7 + (ad - 1), DAYS);
        if (resolverStyle == ResolverStyle.STRICT && date.get(MONTH_OF_YEAR) != moy) {
            throw new DateTimeException("Strict mode rejected resolved date as it is in a different month");
        }
        return date;
    }

    ChronoLocalDate resolveYMAD(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
        int y = range(YEAR).checkValidIntValue(fieldValues.remove(YEAR), YEAR);
        if (resolverStyle == ResolverStyle.LENIENT) {
            long months = Math.subtractExact(fieldValues.remove(MONTH_OF_YEAR), 1);
            long weeks = Math.subtractExact(fieldValues.remove(ALIGNED_WEEK_OF_MONTH), 1);
            long dow = Math.subtractExact(fieldValues.remove(DAY_OF_WEEK), 1);
            return resolveAligned(date(y, 1, 1), months, weeks, dow);
        }
        int moy = range(MONTH_OF_YEAR).checkValidIntValue(fieldValues.remove(MONTH_OF_YEAR), MONTH_OF_YEAR);
        int aw = range(ALIGNED_WEEK_OF_MONTH).checkValidIntValue(fieldValues.remove(ALIGNED_WEEK_OF_MONTH), ALIGNED_WEEK_OF_MONTH);
        int dow = range(DAY_OF_WEEK).checkValidIntValue(fieldValues.remove(DAY_OF_WEEK), DAY_OF_WEEK);
        ChronoLocalDate date = date(y, moy, 1).plus((aw - 1) * 7, DAYS).with(nextOrSame(DayOfWeek.of(dow)));
        if (resolverStyle == ResolverStyle.STRICT && date.get(MONTH_OF_YEAR) != moy) {
            throw new DateTimeException("Strict mode rejected resolved date as it is in a different month");
        }
        return date;
    }

    ChronoLocalDate resolveYAA(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
        int y = range(YEAR).checkValidIntValue(fieldValues.remove(YEAR), YEAR);
        if (resolverStyle == ResolverStyle.LENIENT) {
            long weeks = Math.subtractExact(fieldValues.remove(ALIGNED_WEEK_OF_YEAR), 1);
            long days = Math.subtractExact(fieldValues.remove(ALIGNED_DAY_OF_WEEK_IN_YEAR), 1);
            return dateYearDay(y, 1).plus(weeks, WEEKS).plus(days, DAYS);
        }
        int aw = range(ALIGNED_WEEK_OF_YEAR).checkValidIntValue(fieldValues.remove(ALIGNED_WEEK_OF_YEAR), ALIGNED_WEEK_OF_YEAR);
        int ad = range(ALIGNED_DAY_OF_WEEK_IN_YEAR).checkValidIntValue(fieldValues.remove(ALIGNED_DAY_OF_WEEK_IN_YEAR), ALIGNED_DAY_OF_WEEK_IN_YEAR);
        ChronoLocalDate date = dateYearDay(y, 1).plus((aw - 1) * 7 + (ad - 1), DAYS);
        if (resolverStyle == ResolverStyle.STRICT && date.get(YEAR) != y) {
            throw new DateTimeException("Strict mode rejected resolved date as it is in a different year");
        }
        return date;
    }

    ChronoLocalDate resolveYAD(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
        int y = range(YEAR).checkValidIntValue(fieldValues.remove(YEAR), YEAR);
        if (resolverStyle == ResolverStyle.LENIENT) {
            long weeks = Math.subtractExact(fieldValues.remove(ALIGNED_WEEK_OF_YEAR), 1);
            long dow = Math.subtractExact(fieldValues.remove(DAY_OF_WEEK), 1);
            return resolveAligned(dateYearDay(y, 1), 0, weeks, dow);
        }
        int aw = range(ALIGNED_WEEK_OF_YEAR).checkValidIntValue(fieldValues.remove(ALIGNED_WEEK_OF_YEAR), ALIGNED_WEEK_OF_YEAR);
        int dow = range(DAY_OF_WEEK).checkValidIntValue(fieldValues.remove(DAY_OF_WEEK), DAY_OF_WEEK);
        ChronoLocalDate date = dateYearDay(y, 1).plus((aw - 1) * 7, DAYS).with(nextOrSame(DayOfWeek.of(dow)));
        if (resolverStyle == ResolverStyle.STRICT && date.get(YEAR) != y) {
            throw new DateTimeException("Strict mode rejected resolved date as it is in a different year");
        }
        return date;
    }

    ChronoLocalDate resolveAligned(ChronoLocalDate base, long months, long weeks, long dow) {
        ChronoLocalDate date = base.plus(months, MONTHS).plus(weeks, WEEKS);
        if (dow > 7) {
            date = date.plus((dow - 1) / 7, WEEKS);
            dow = ((dow - 1) % 7) + 1;
        } else if (dow < 1) {
            date = date.plus(Math.subtractExact(dow,  7) / 7, WEEKS);
            dow = ((dow + 6) % 7) + 1;
        }
        return date.with(nextOrSame(DayOfWeek.of((int) dow)));
    }

    /**
     * Adds a field-value pair to the map, checking for conflicts.
     * <p>
     * If the field is not already present, then the field-value pair is added to the map.
     * If the field is already present and it has the same value as that specified, no action occurs.
     * If the field is already present and it has a different value to that specified, then
     * an exception is thrown.
     *
     * @param field  the field to add, not null
     * @param value  the value to add, not null
     * @throws DateTimeException if the field is already present with a different value
     */
    void addFieldValue(Map<TemporalField, Long> fieldValues, ChronoField field, long value) {
        Long old = fieldValues.get(field);  // check first for better error message
        if (old != null && old.longValue() != value) {
            throw new DateTimeException("Conflict found: " + field + " " + old + " differs from " + field + " " + value);
        }
        fieldValues.put(field, value);
    }

    //-----------------------------------------------------------------------
    /**
     * Compares this chronology to another chronology.
     * <p>
     * The comparison order first by the chronology ID string, then by any
     * additional information specific to the subclass.
     * It is "consistent with equals", as defined by {@link Comparable}.
     * <p>
     * The default implementation compares the chronology ID.
     * Subclasses must compare any additional state that they store.
     *
     * @param other  the other chronology to compare to, not null
     * @return the comparator value, negative if less, positive if greater
     */
    @Override
    public int compareTo(Chronology other) {
        return getId().compareTo(other.getId());
    }

    /**
     * Checks if this chronology is equal to another chronology.
     * <p>
     * The comparison is based on the entire state of the object.
     * <p>
     * The default implementation checks the type and calls {@link #compareTo(Chronology)}.
     *
     * @param obj  the object to check, null returns false
     * @return true if this is equal to the other chronology
     */
    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
           return true;
        }
        if (obj instanceof Chronology) {
            return compareTo((Chronology) obj) == 0;
        }
        return false;
    }

    /**
     * A hash code for this chronology.
     * <p>
     * The default implementation is based on the ID and class.
     * Subclasses should add any additional state that they store.
     *
     * @return a suitable hash code
     */
    @Override
    public int hashCode() {
        return getClass().hashCode() ^ getId().hashCode();
    }

    //-----------------------------------------------------------------------
    /**
     * Outputs this chronology as a {@code String}, using the ID.
     *
     * @return a string representation of this chronology, not null
     */
    @Override
    public String toString() {
        return getId();
    }

    //-----------------------------------------------------------------------
    /**
     * 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
     */
    Object writeReplace() {
        return new Ser(Ser.CHRONO_TYPE, this);
    }

    /**
     * Defend against malicious streams.
     * @return never
     * @throws InvalidObjectException always
     */
    private Object readResolve() throws InvalidObjectException {
        throw new InvalidObjectException("Deserialization via serialization delegate");
    }

    /**
     * Write the Chronology id to the stream.
     * @param out the output stream
     * @throws IOException on any error during the write
     */
    void writeExternal(DataOutput out) throws IOException {
        out.writeUTF(getId());
    }

    /**
     * Reads the Chronology id and creates the Chronology.
     * @param in  the input stream
     * @return  the Chronology
     * @throws IOException  on errors during the read
     * @throws DateTimeException if the Chronology cannot be returned
     */
    static Chronology readExternal(DataInput in) throws IOException {
        String id = in.readUTF();
        return Chronology.of(id);
    }

}