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/*
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 * Copyright (c) 2007-2012, Stephen Colebourne & Michael Nascimento Santos
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
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 * * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
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package java.time;

import static java.time.temporal.ChronoField.ERA;
import static java.time.temporal.ChronoField.YEAR;
import static java.time.temporal.ChronoField.YEAR_OF_ERA;
import static java.time.temporal.ChronoUnit.CENTURIES;
import static java.time.temporal.ChronoUnit.DECADES;
import static java.time.temporal.ChronoUnit.ERAS;
import static java.time.temporal.ChronoUnit.MILLENNIA;
import static java.time.temporal.ChronoUnit.YEARS;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.time.chrono.Chronology;
import java.time.chrono.IsoChronology;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeFormatterBuilder;
import java.time.format.DateTimeParseException;
import java.time.format.SignStyle;
import java.time.temporal.ChronoField;
import java.time.temporal.ChronoUnit;
import java.time.temporal.Temporal;
import java.time.temporal.TemporalAccessor;
import java.time.temporal.TemporalAdjuster;
import java.time.temporal.TemporalAmount;
import java.time.temporal.TemporalField;
import java.time.temporal.TemporalQueries;
import java.time.temporal.TemporalQuery;
import java.time.temporal.TemporalUnit;
import java.time.temporal.UnsupportedTemporalTypeException;
import java.time.temporal.ValueRange;
import java.util.Objects;

/**
 * A year in the ISO-8601 calendar system, such as {@code 2007}.
 * <p>
 * {@code Year} is an immutable date-time object that represents a year.
 * Any field that can be derived from a year can be obtained.
 * <p>
 * <b>Note that years in the ISO chronology only align with years in the
 * Gregorian-Julian system for modern years. Parts of Russia did not switch to the
 * modern Gregorian/ISO rules until 1920.
 * As such, historical years must be treated with caution.</b>
 * <p>
 * This class does not store or represent a month, day, time or time-zone.
 * For example, the value "2007" can be stored in a {@code Year}.
 * <p>
 * Years represented by this class follow the ISO-8601 standard and use
 * the proleptic numbering system. Year 1 is preceded by year 0, then by year -1.
 * <p>
 * The ISO-8601 calendar system is the modern civil calendar system used today
 * in most of the world. It is equivalent to the proleptic Gregorian calendar
 * system, in which today's rules for leap years are applied for all time.
 * For most applications written today, the ISO-8601 rules are entirely suitable.
 * However, any application that makes use of historical dates, and requires them
 * to be accurate will find the ISO-8601 approach unsuitable.
 *
 * <p>
 * This is a <a href="{@docRoot}/java/lang/doc-files/ValueBased.html">value-based</a>
 * class; use of identity-sensitive operations (including reference equality
 * ({@code ==}), identity hash code, or synchronization) on instances of
 * {@code Year} may have unpredictable results and should be avoided.
 * The {@code equals} method should be used for comparisons.
 *
 * @implSpec
 * This class is immutable and thread-safe.
 *
 * @since 1.8
 */
public final class Year
 implements Temporal, TemporalAdjuster, Comparable<Year>, Serializable {

 /**
 * The minimum supported year, '-999,999,999'.
 */
 public static final int MIN_VALUE = -999_999_999;
 /**
 * The maximum supported year, '+999,999,999'.
 */
 public static final int MAX_VALUE = 999_999_999;

 /**
 * Serialization version.
 */
 private static final long serialVersionUID = -23038383694477807L;
 /**
 * Parser.
 */
 private static final DateTimeFormatter PARSER = new DateTimeFormatterBuilder()
 .appendValue(YEAR, 4, 10, SignStyle.EXCEEDS_PAD)
 .toFormatter();

 /**
 * The year being represented.
 */
 private final int year;

 //-----------------------------------------------------------------------
 /**
 * Obtains the current year 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 year.
 * <p>
 * Using this method will prevent the ability to use an alternate clock for testing
 * because the clock is hard-coded.
 *
 * @return the current year using the system clock and default time-zone, not null
 */
 public static Year now() {
 return now(Clock.systemDefaultZone());
 }

 /**
 * Obtains the current year from the system clock in the specified time-zone.
 * <p>
 * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current year.
 * 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 year using the system clock, not null
 */
 public static Year now(ZoneId zone) {
 return now(Clock.system(zone));
 }

 /**
 * Obtains the current year from the specified clock.
 * <p>
 * This will query the specified clock to obtain the current year.
 * 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 year, not null
 */
 public static Year now(Clock clock) {
 final LocalDate now = LocalDate.now(clock); // called once
 return Year.of(now.getYear());
 }

 //-----------------------------------------------------------------------
 /**
 * Obtains an instance of {@code Year}.
 * <p>
 * This method accepts a year value from the proleptic ISO calendar system.
 * <p>
 * The year 2AD/CE is represented by 2.<br>
 * The year 1AD/CE is represented by 1.<br>
 * The year 1BC/BCE is represented by 0.<br>
 * The year 2BC/BCE is represented by -1.<br>
 *
 * @param isoYear the ISO proleptic year to represent, from {@code MIN_VALUE} to {@code MAX_VALUE}
 * @return the year, not null
 * @throws DateTimeException if the field is invalid
 */
 public static Year of(int isoYear) {
 YEAR.checkValidValue(isoYear);
 return new Year(isoYear);
 }

 //-----------------------------------------------------------------------
 /**
 * Obtains an instance of {@code Year} from a temporal object.
 * <p>
 * This obtains a year 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 Year}.
 * <p>
 * The conversion extracts the {@link ChronoField#YEAR year} field.
 * The extraction is only permitted if the temporal object has an ISO
 * chronology, or can be converted to a {@code LocalDate}.
 * <p>
 * This method matches the signature of the functional interface {@link TemporalQuery}
 * allowing it to be used as a query via method reference, {@code Year::from}.
 *
 * @param temporal the temporal object to convert, not null
 * @return the year, not null
 * @throws DateTimeException if unable to convert to a {@code Year}
 */
 public static Year from(TemporalAccessor temporal) {
 if (temporal instanceof Year) {
 return (Year) temporal;
 }
 Objects.requireNonNull(temporal, "temporal");
 try {
 if (IsoChronology.INSTANCE.equals(Chronology.from(temporal)) == false) {
 temporal = LocalDate.from(temporal);
 }
 return of(temporal.get(YEAR));
 } catch (DateTimeException ex) {
 throw new DateTimeException("Unable to obtain Year from TemporalAccessor: " +
 temporal + " of type " + temporal.getClass().getName(), ex);
 }
 }

 //-----------------------------------------------------------------------
 /**
 * Obtains an instance of {@code Year} from a text string such as {@code 2007}.
 * <p>
 * The string must represent a valid year.
 * Years outside the range 0000 to 9999 must be prefixed by the plus or minus symbol.
 *
 * @param text the text to parse such as "2007", not null
 * @return the parsed year, not null
 * @throws DateTimeParseException if the text cannot be parsed
 */
 public static Year parse(CharSequence text) {
 return parse(text, PARSER);
 }

 /**
 * Obtains an instance of {@code Year} from a text string using a specific formatter.
 * <p>
 * The text is parsed using the formatter, returning a year.
 *
 * @param text the text to parse, not null
 * @param formatter the formatter to use, not null
 * @return the parsed year, not null
 * @throws DateTimeParseException if the text cannot be parsed
 */
 public static Year parse(CharSequence text, DateTimeFormatter formatter) {
 Objects.requireNonNull(formatter, "formatter");
 return formatter.parse(text, Year::from);
 }

 //-------------------------------------------------------------------------
 /**
 * 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 year the year to check
 * @return true if the year is leap, false otherwise
 */
 public static boolean isLeap(long year) {
 return ((year & 3) == 0) && ((year % 100) != 0 || (year % 400) == 0);
 }

 //-----------------------------------------------------------------------
 /**
 * Constructor.
 *
 * @param year the year to represent
 */
 private Year(int year) {
 this.year = year;
 }

 //-----------------------------------------------------------------------
 /**
 * Gets the year value.
 * <p>
 * The year returned by this method is proleptic as per {@code get(YEAR)}.
 *
 * @return the year, {@code MIN_VALUE} to {@code MAX_VALUE}
 */
 public int getValue() {
 return year;
 }

 //-----------------------------------------------------------------------
 /**
 * Checks if the specified field is supported.
 * <p>
 * This checks if this year can be queried for the specified field.
 * If false, then calling the {@link #range(TemporalField) range},
 * {@link #get(TemporalField) get} and {@link #with(TemporalField, long)}
 * methods will throw an exception.
 * <p>
 * If the field is a {@link ChronoField} then the query is implemented here.
 * The supported fields are:
 * <ul>
 * <li>{@code YEAR_OF_ERA}
 * <li>{@code YEAR}
 * <li>{@code ERA}
 * </ul>
 * All other {@code ChronoField} instances will return false.
 * <p>
 * If the field is not a {@code ChronoField}, then the result of this method
 * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)}
 * passing {@code this} as the argument.
 * Whether the field is supported is determined by the field.
 *
 * @param field the field to check, null returns false
 * @return true if the field is supported on this year, false if not
 */
 @Override
 public boolean isSupported(TemporalField field) {
 if (field instanceof ChronoField) {
 return field == YEAR || field == YEAR_OF_ERA || field == ERA;
 }
 return field != null && field.isSupportedBy(this);
 }

 /**
 * Checks if the specified unit is supported.
 * <p>
 * This checks if the specified unit can be added to, or subtracted from, this year.
 * If false, then calling the {@link #plus(long, TemporalUnit)} and
 * {@link #minus(long, TemporalUnit) minus} methods will throw an exception.
 * <p>
 * If the unit is a {@link ChronoUnit} then the query is implemented here.
 * The supported units are:
 * <ul>
 * <li>{@code YEARS}
 * <li>{@code DECADES}
 * <li>{@code CENTURIES}
 * <li>{@code MILLENNIA}
 * <li>{@code ERAS}
 * </ul>
 * All other {@code ChronoUnit} instances will return false.
 * <p>
 * If the unit is not a {@code ChronoUnit}, then the result of this method
 * is obtained by invoking {@code TemporalUnit.isSupportedBy(Temporal)}
 * passing {@code this} as the argument.
 * Whether the unit is supported is determined by the unit.
 *
 * @param unit the unit to check, null returns false
 * @return true if the unit can be added/subtracted, false if not
 */
 @Override
 public boolean isSupported(TemporalUnit unit) {
 if (unit instanceof ChronoUnit) {
 return unit == YEARS || unit == DECADES || unit == CENTURIES || unit == MILLENNIA || unit == ERAS;
 }
 return unit != null && unit.isSupportedBy(this);
 }

 //-----------------------------------------------------------------------
 /**
 * Gets the range of valid values for the specified field.
 * <p>
 * The range object expresses the minimum and maximum valid values for a field.
 * This year is used to enhance the accuracy of the returned range.
 * If it is not possible to return the range, because the field is not supported
 * or for some other reason, an exception is thrown.
 * <p>
 * If the field is a {@link ChronoField} then the query is implemented here.
 * The {@link #isSupported(TemporalField) supported fields} will return
 * appropriate range instances.
 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
 * <p>
 * If the field is not a {@code ChronoField}, then the result of this method
 * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)}
 * passing {@code this} as the argument.
 * Whether the range can be obtained is determined by the field.
 *
 * @param field the field to query the range for, not null
 * @return the range of valid values for the field, not null
 * @throws DateTimeException if the range for the field cannot be obtained
 * @throws UnsupportedTemporalTypeException if the field is not supported
 */
 @Override
 public ValueRange range(TemporalField field) {
 if (field == YEAR_OF_ERA) {
 return (year <= 0 ? ValueRange.of(1, MAX_VALUE + 1) : ValueRange.of(1, MAX_VALUE));
 }
 return Temporal.super.range(field);
 }

 /**
 * Gets the value of the specified field from this year as an {@code int}.
 * <p>
 * This queries this year for the value of the specified field.
 * The returned value will always be within the valid range of values for the field.
 * If it is not possible to return the value, because the field is not supported
 * or for some other reason, an exception is thrown.
 * <p>
 * If the field is a {@link ChronoField} then the query is implemented here.
 * The {@link #isSupported(TemporalField) supported fields} will return valid
 * values based on this year.
 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
 * <p>
 * If the field is not a {@code ChronoField}, then the result of this method
 * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
 * passing {@code this} as the argument. Whether the value can be obtained,
 * and what the value represents, is determined by the field.
 *
 * @param field the field to get, not null
 * @return the value for the field
 * @throws DateTimeException if a value for the field cannot be obtained or
 * the value is outside the range of valid values for the field
 * @throws UnsupportedTemporalTypeException if the field is not supported or
 * the range of values exceeds an {@code int}
 * @throws ArithmeticException if numeric overflow occurs
 */
 @Override // override for Javadoc
 public int get(TemporalField field) {
 return range(field).checkValidIntValue(getLong(field), field);
 }

 /**
 * Gets the value of the specified field from this year as a {@code long}.
 * <p>
 * This queries this year for the value of the specified field.
 * If it is not possible to return the value, because the field is not supported
 * or for some other reason, an exception is thrown.
 * <p>
 * If the field is a {@link ChronoField} then the query is implemented here.
 * The {@link #isSupported(TemporalField) supported fields} will return valid
 * values based on this year.
 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
 * <p>
 * If the field is not a {@code ChronoField}, then the result of this method
 * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
 * passing {@code this} as the argument. Whether the value can be obtained,
 * and what the value represents, is determined by the field.
 *
 * @param field the field to get, not null
 * @return the value for the field
 * @throws DateTimeException if a value for the field cannot be obtained
 * @throws UnsupportedTemporalTypeException if the field is not supported
 * @throws ArithmeticException if numeric overflow occurs
 */
 @Override
 public long getLong(TemporalField field) {
 if (field instanceof ChronoField) {
 switch ((ChronoField) field) {
 case YEAR_OF_ERA: return (year < 1 ? 1 - year : year);
 case YEAR: return year;
 case ERA: return (year < 1 ? 0 : 1);
 }
 throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
 }
 return field.getFrom(this);
 }

 //-----------------------------------------------------------------------
 /**
 * Checks if the year is a leap year, according to the ISO proleptic
 * calendar system rules.
 * <p>
 * This method applies the current rules for leap years across the whole time-line.
 * In general, a year is a leap year if it is divisible by four without
 * remainder. However, years divisible by 100, are not leap years, with
 * the exception of years divisible by 400 which are.
 * <p>
 * For example, 1904 is a leap year it is divisible by 4.
 * 1900 was not a leap year as it is divisible by 100, however 2000 was a
 * leap year as it is divisible by 400.
 * <p>
 * The calculation is proleptic - applying the same rules into the far future and far past.
 * This is historically inaccurate, but is correct for the ISO-8601 standard.
 *
 * @return true if the year is leap, false otherwise
 */
 public boolean isLeap() {
 return Year.isLeap(year);
 }

 /**
 * Checks if the month-day is valid for this year.
 * <p>
 * This method checks whether this year and the input month and day form
 * a valid date.
 *
 * @param monthDay the month-day to validate, null returns false
 * @return true if the month and day are valid for this year
 */
 public boolean isValidMonthDay(MonthDay monthDay) {
 return monthDay != null && monthDay.isValidYear(year);
 }

 /**
 * Gets the length of this year in days.
 *
 * @return the length of this year in days, 365 or 366
 */
 public int length() {
 return isLeap() ? 366 : 365;
 }

 //-----------------------------------------------------------------------
 /**
 * Returns an adjusted copy of this year.
 * <p>
 * This returns a {@code Year}, based on this one, with the year adjusted.
 * The adjustment takes place using the specified adjuster strategy object.
 * Read the documentation of the adjuster to understand what adjustment will be made.
 * <p>
 * The result of this method is obtained by invoking the
 * {@link TemporalAdjuster#adjustInto(Temporal)} method on the
 * specified adjuster passing {@code this} as the argument.
 * <p>
 * This instance is immutable and unaffected by this method call.
 *
 * @param adjuster the adjuster to use, not null
 * @return a {@code Year} based on {@code this} with the adjustment made, not null
 * @throws DateTimeException if the adjustment cannot be made
 * @throws ArithmeticException if numeric overflow occurs
 */
 @Override
 public Year with(TemporalAdjuster adjuster) {
 return (Year) adjuster.adjustInto(this);
 }

 /**
 * Returns a copy of this year with the specified field set to a new value.
 * <p>
 * This returns a {@code Year}, based on this one, with the value
 * for the specified field changed.
 * If it is not possible to set the value, because the field is not supported or for
 * some other reason, an exception is thrown.
 * <p>
 * If the field is a {@link ChronoField} then the adjustment is implemented here.
 * The supported fields behave as follows:
 * <ul>
 * <li>{@code YEAR_OF_ERA} -
 * Returns a {@code Year} with the specified year-of-era
 * The era will be unchanged.
 * <li>{@code YEAR} -
 * Returns a {@code Year} with the specified year.
 * This completely replaces the date and is equivalent to {@link #of(int)}.
 * <li>{@code ERA} -
 * Returns a {@code Year} with the specified era.
 * The year-of-era will be unchanged.
 * </ul>
 * <p>
 * In all cases, if the new value is outside the valid range of values for the field
 * then a {@code DateTimeException} will be thrown.
 * <p>
 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
 * <p>
 * If the field is not a {@code ChronoField}, then the result of this method
 * is obtained by invoking {@code TemporalField.adjustInto(Temporal, long)}
 * passing {@code this} as the argument. In this case, the field determines
 * whether and how to adjust the instant.
 * <p>
 * This instance is immutable and unaffected by this method call.
 *
 * @param field the field to set in the result, not null
 * @param newValue the new value of the field in the result
 * @return a {@code Year} based on {@code this} with the specified field set, not null
 * @throws DateTimeException if the field cannot be set
 * @throws UnsupportedTemporalTypeException if the field is not supported
 * @throws ArithmeticException if numeric overflow occurs
 */
 @Override
 public Year with(TemporalField field, long newValue) {
 if (field instanceof ChronoField) {
 ChronoField f = (ChronoField) field;
 f.checkValidValue(newValue);
 switch (f) {
 case YEAR_OF_ERA: return Year.of((int) (year < 1 ? 1 - newValue : newValue));
 case YEAR: return Year.of((int) newValue);
 case ERA: return (getLong(ERA) == newValue ? this : Year.of(1 - year));
 }
 throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
 }
 return field.adjustInto(this, newValue);
 }

 //-----------------------------------------------------------------------
 /**
 * Returns a copy of this year with the specified amount added.
 * <p>
 * This returns a {@code Year}, based on this one, with the specified amount added.
 * The amount is typically {@link Period} but may be any other type implementing
 * the {@link TemporalAmount} interface.
 * <p>
 * The calculation is delegated to the amount object by calling
 * {@link TemporalAmount#addTo(Temporal)}. The amount implementation is free
 * to implement the addition in any way it wishes, however it typically
 * calls back to {@link #plus(long, TemporalUnit)}. Consult the documentation
 * of the amount implementation to determine if it can be successfully added.
 * <p>
 * This instance is immutable and unaffected by this method call.
 *
 * @param amountToAdd the amount to add, not null
 * @return a {@code Year} based on this year with the addition made, not null
 * @throws DateTimeException if the addition cannot be made
 * @throws ArithmeticException if numeric overflow occurs
 */
 @Override
 public Year plus(TemporalAmount amountToAdd) {
 return (Year) amountToAdd.addTo(this);
 }

 /**
 * Returns a copy of this year with the specified amount added.
 * <p>
 * This returns a {@code Year}, based on this one, with the amount
 * in terms of the unit added. If it is not possible to add the amount, because the
 * unit is not supported or for some other reason, an exception is thrown.
 * <p>
 * If the field is a {@link ChronoUnit} then the addition is implemented here.
 * The supported fields behave as follows:
 * <ul>
 * <li>{@code YEARS} -
 * Returns a {@code Year} with the specified number of years added.
 * This is equivalent to {@link #plusYears(long)}.
 * <li>{@code DECADES} -
 * Returns a {@code Year} with the specified number of decades added.
 * This is equivalent to calling {@link #plusYears(long)} with the amount
 * multiplied by 10.
 * <li>{@code CENTURIES} -
 * Returns a {@code Year} with the specified number of centuries added.
 * This is equivalent to calling {@link #plusYears(long)} with the amount
 * multiplied by 100.
 * <li>{@code MILLENNIA} -
 * Returns a {@code Year} with the specified number of millennia added.
 * This is equivalent to calling {@link #plusYears(long)} with the amount
 * multiplied by 1,000.
 * <li>{@code ERAS} -
 * Returns a {@code Year} with the specified number of eras added.
 * Only two eras are supported so the amount must be one, zero or minus one.
 * If the amount is non-zero then the year is changed such that the year-of-era
 * is unchanged.
 * </ul>
 * <p>
 * All other {@code ChronoUnit} instances will throw an {@code UnsupportedTemporalTypeException}.
 * <p>
 * If the field is not a {@code ChronoUnit}, then the result of this method
 * is obtained by invoking {@code TemporalUnit.addTo(Temporal, long)}
 * passing {@code this} as the argument. In this case, the unit determines
 * whether and how to perform the addition.
 * <p>
 * This instance is immutable and unaffected by this method call.
 *
 * @param amountToAdd the amount of the unit to add to the result, may be negative
 * @param unit the unit of the amount to add, not null
 * @return a {@code Year} based on this year with the specified amount added, not null
 * @throws DateTimeException if the addition cannot be made
 * @throws UnsupportedTemporalTypeException if the unit is not supported
 * @throws ArithmeticException if numeric overflow occurs
 */
 @Override
 public Year plus(long amountToAdd, TemporalUnit unit) {
 if (unit instanceof ChronoUnit) {
 switch ((ChronoUnit) unit) {
 case YEARS: return plusYears(amountToAdd);
 case DECADES: return plusYears(Math.multiplyExact(amountToAdd, 10));
 case CENTURIES: return plusYears(Math.multiplyExact(amountToAdd, 100));
 case MILLENNIA: return plusYears(Math.multiplyExact(amountToAdd, 1000));
 case ERAS: return with(ERA, Math.addExact(getLong(ERA), amountToAdd));
 }
 throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit);
 }
 return unit.addTo(this, amountToAdd);
 }

 /**
 * Returns a copy of this {@code Year} with the specified number of years added.
 * <p>
 * This instance is immutable and unaffected by this method call.
 *
 * @param yearsToAdd the years to add, may be negative
 * @return a {@code Year} based on this year with the years added, not null
 * @throws DateTimeException if the result exceeds the supported range
 */
 public Year plusYears(long yearsToAdd) {
 if (yearsToAdd == 0) {
 return this;
 }
 return of(YEAR.checkValidIntValue(year + yearsToAdd)); // overflow safe
 }

 //-----------------------------------------------------------------------
 /**
 * Returns a copy of this year with the specified amount subtracted.
 * <p>
 * This returns a {@code Year}, based on this one, with the specified amount subtracted.
 * The amount is typically {@link Period} but may be any other type implementing
 * the {@link TemporalAmount} interface.
 * <p>
 * The calculation is delegated to the amount object by calling
 * {@link TemporalAmount#subtractFrom(Temporal)}. The amount implementation is free
 * to implement the subtraction in any way it wishes, however it typically
 * calls back to {@link #minus(long, TemporalUnit)}. Consult the documentation
 * of the amount implementation to determine if it can be successfully subtracted.
 * <p>
 * This instance is immutable and unaffected by this method call.
 *
 * @param amountToSubtract the amount to subtract, not null
 * @return a {@code Year} based on this year with the subtraction made, not null
 * @throws DateTimeException if the subtraction cannot be made
 * @throws ArithmeticException if numeric overflow occurs
 */
 @Override
 public Year minus(TemporalAmount amountToSubtract) {
 return (Year) amountToSubtract.subtractFrom(this);
 }

 /**
 * Returns a copy of this year with the specified amount subtracted.
 * <p>
 * This returns a {@code Year}, based on this one, with the amount
 * in terms of the unit subtracted. If it is not possible to subtract the amount,
 * because the unit is not supported or for some other reason, an exception is thrown.
 * <p>
 * This method is equivalent to {@link #plus(long, TemporalUnit)} with the amount negated.
 * See that method for a full description of how addition, and thus subtraction, works.
 * <p>
 * This instance is immutable and unaffected by this method call.
 *
 * @param amountToSubtract the amount of the unit to subtract from the result, may be negative
 * @param unit the unit of the amount to subtract, not null
 * @return a {@code Year} based on this year with the specified amount subtracted, not null
 * @throws DateTimeException if the subtraction cannot be made
 * @throws UnsupportedTemporalTypeException if the unit is not supported
 * @throws ArithmeticException if numeric overflow occurs
 */
 @Override
 public Year minus(long amountToSubtract, TemporalUnit unit) {
 return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit));
 }

 /**
 * Returns a copy of this {@code Year} with the specified number of years subtracted.
 * <p>
 * This instance is immutable and unaffected by this method call.
 *
 * @param yearsToSubtract the years to subtract, may be negative
 * @return a {@code Year} based on this year with the year subtracted, not null
 * @throws DateTimeException if the result exceeds the supported range
 */
 public Year minusYears(long yearsToSubtract) {
 return (yearsToSubtract == Long.MIN_VALUE ? plusYears(Long.MAX_VALUE).plusYears(1) : plusYears(-yearsToSubtract));
 }

 //-----------------------------------------------------------------------
 /**
 * Queries this year using the specified query.
 * <p>
 * This queries this year using the specified query strategy object.
 * The {@code TemporalQuery} object defines the logic to be used to
 * obtain the result. Read the documentation of the query to understand
 * what the result of this method will be.
 * <p>
 * The result of this method is obtained by invoking the
 * {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the
 * specified query passing {@code this} as the argument.
 *
 * @param <R> the type of the result
 * @param query the query to invoke, not null
 * @return the query result, null may be returned (defined by the query)
 * @throws DateTimeException if unable to query (defined by the query)
 * @throws ArithmeticException if numeric overflow occurs (defined by the query)
 */
 @SuppressWarnings("unchecked")
 @Override
 public <R> R query(TemporalQuery<R> query) {
 if (query == TemporalQueries.chronology()) {
 return (R) IsoChronology.INSTANCE;
 } else if (query == TemporalQueries.precision()) {
 return (R) YEARS;
 }
 return Temporal.super.query(query);
 }

 /**
 * Adjusts the specified temporal object to have this year.
 * <p>
 * This returns a temporal object of the same observable type as the input
 * with the year changed to be the same as this.
 * <p>
 * The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)}
 * passing {@link ChronoField#YEAR} as the field.
 * If the specified temporal object does not use the ISO calendar system then
 * a {@code DateTimeException} is thrown.
 * <p>
 * In most cases, it is clearer to reverse the calling pattern by using
 * {@link Temporal#with(TemporalAdjuster)}:
 * <pre>
 * // these two lines are equivalent, but the second approach is recommended
 * temporal = thisYear.adjustInto(temporal);
 * temporal = temporal.with(thisYear);
 * </pre>
 * <p>
 * This instance is immutable and unaffected by this method call.
 *
 * @param temporal the target object to be adjusted, not null
 * @return the adjusted object, not null
 * @throws DateTimeException if unable to make the adjustment
 * @throws ArithmeticException if numeric overflow occurs
 */
 @Override
 public Temporal adjustInto(Temporal temporal) {
 if (Chronology.from(temporal).equals(IsoChronology.INSTANCE) == false) {
 throw new DateTimeException("Adjustment only supported on ISO date-time");
 }
 return temporal.with(YEAR, year);
 }

 /**
 * Calculates the amount of time until another year in terms of the specified unit.
 * <p>
 * This calculates the amount of time between two {@code Year}
 * objects in terms of a single {@code TemporalUnit}.
 * The start and end points are {@code this} and the specified year.
 * The result will be negative if the end is before the start.
 * The {@code Temporal} passed to this method is converted to a
 * {@code Year} using {@link #from(TemporalAccessor)}.
 * For example, the amount in decades between two year can be calculated
 * using {@code startYear.until(endYear, DECADES)}.
 * <p>
 * The calculation returns a whole number, representing the number of
 * complete units between the two years.
 * For example, the amount in decades between 2012 and 2031
 * will only be one decade as it is one year short of two decades.
 * <p>
 * There are two equivalent ways of using this method.
 * The first is to invoke this method.
 * The second is to use {@link TemporalUnit#between(Temporal, Temporal)}:
 * <pre>
 * // these two lines are equivalent
 * amount = start.until(end, YEARS);
 * amount = YEARS.between(start, end);
 * </pre>
 * The choice should be made based on which makes the code more readable.
 * <p>
 * The calculation is implemented in this method for {@link ChronoUnit}.
 * The units {@code YEARS}, {@code DECADES}, {@code CENTURIES},
 * {@code MILLENNIA} and {@code ERAS} are supported.
 * Other {@code ChronoUnit} values will throw an exception.
 * <p>
 * If the unit is not a {@code ChronoUnit}, then the result of this method
 * is obtained by invoking {@code TemporalUnit.between(Temporal, Temporal)}
 * passing {@code this} as the first argument and the converted input temporal
 * as the second argument.
 * <p>
 * This instance is immutable and unaffected by this method call.
 *
 * @param endExclusive the end date, exclusive, which is converted to a {@code Year}, not null
 * @param unit the unit to measure the amount in, not null
 * @return the amount of time between this year and the end year
 * @throws DateTimeException if the amount cannot be calculated, or the end
 * temporal cannot be converted to a {@code Year}
 * @throws UnsupportedTemporalTypeException if the unit is not supported
 * @throws ArithmeticException if numeric overflow occurs
 */
 @Override
 public long until(Temporal endExclusive, TemporalUnit unit) {
 Year end = Year.from(endExclusive);
 if (unit instanceof ChronoUnit) {
 long yearsUntil = ((long) end.year) - year; // no overflow
 switch ((ChronoUnit) unit) {
 case YEARS: return yearsUntil;
 case DECADES: return yearsUntil / 10;
 case CENTURIES: return yearsUntil / 100;
 case MILLENNIA: return yearsUntil / 1000;
 case ERAS: return end.getLong(ERA) - getLong(ERA);
 }
 throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit);
 }
 return unit.between(this, end);
 }

 /**
 * Formats this year using the specified formatter.
 * <p>
 * This year will be passed to the formatter to produce a string.
 *
 * @param formatter the formatter to use, not null
 * @return the formatted year string, not null
 * @throws DateTimeException if an error occurs during printing
 */
 public String format(DateTimeFormatter formatter) {
 Objects.requireNonNull(formatter, "formatter");
 return formatter.format(this);
 }

 //-----------------------------------------------------------------------
 /**
 * Combines this year with a day-of-year to create a {@code LocalDate}.
 * <p>
 * This returns a {@code LocalDate} formed from this year and the specified day-of-year.
 * <p>
 * The day-of-year value 366 is only valid in a leap year.
 *
 * @param dayOfYear the day-of-year to use, from 1 to 365-366
 * @return the local date formed from this year and the specified date of year, not null
 * @throws DateTimeException if the day of year is zero or less, 366 or greater or equal
 * to 366 and this is not a leap year
 */
 public LocalDate atDay(int dayOfYear) {
 return LocalDate.ofYearDay(year, dayOfYear);
 }

 /**
 * Combines this year with a month to create a {@code YearMonth}.
 * <p>
 * This returns a {@code YearMonth} formed from this year and the specified month.
 * All possible combinations of year and month are valid.
 * <p>
 * This method can be used as part of a chain to produce a date:
 * <pre>
 * LocalDate date = year.atMonth(month).atDay(day);
 * </pre>
 *
 * @param month the month-of-year to use, not null
 * @return the year-month formed from this year and the specified month, not null
 */
 public YearMonth atMonth(Month month) {
 return YearMonth.of(year, month);
 }

 /**
 * Combines this year with a month to create a {@code YearMonth}.
 * <p>
 * This returns a {@code YearMonth} formed from this year and the specified month.
 * All possible combinations of year and month are valid.
 * <p>
 * This method can be used as part of a chain to produce a date:
 * <pre>
 * LocalDate date = year.atMonth(month).atDay(day);
 * </pre>
 *
 * @param month the month-of-year to use, from 1 (January) to 12 (December)
 * @return the year-month formed from this year and the specified month, not null
 * @throws DateTimeException if the month is invalid
 */
 public YearMonth atMonth(int month) {
 return YearMonth.of(year, month);
 }

 /**
 * Combines this year with a month-day to create a {@code LocalDate}.
 * <p>
 * This returns a {@code LocalDate} formed from this year and the specified month-day.
 * <p>
 * A month-day of February 29th will be adjusted to February 28th in the resulting
 * date if the year is not a leap year.
 *
 * @param monthDay the month-day to use, not null
 * @return the local date formed from this year and the specified month-day, not null
 */
 public LocalDate atMonthDay(MonthDay monthDay) {
 return monthDay.atYear(year);
 }

 //-----------------------------------------------------------------------
 /**
 * Compares this year to another year.
 * <p>
 * The comparison is based on the value of the year.
 * It is "consistent with equals", as defined by {@link Comparable}.
 *
 * @param other the other year to compare to, not null
 * @return the comparator value, negative if less, positive if greater
 */
 @Override
 public int compareTo(Year other) {
 return year - other.year;
 }

 /**
 * Checks if this year is after the specified year.
 *
 * @param other the other year to compare to, not null
 * @return true if this is after the specified year
 */
 public boolean isAfter(Year other) {
 return year > other.year;
 }

 /**
 * Checks if this year is before the specified year.
 *
 * @param other the other year to compare to, not null
 * @return true if this point is before the specified year
 */
 public boolean isBefore(Year other) {
 return year < other.year;
 }

 //-----------------------------------------------------------------------
 /**
 * Checks if this year is equal to another year.
 * <p>
 * The comparison is based on the time-line position of the years.
 *
 * @param obj the object to check, null returns false
 * @return true if this is equal to the other year
 */
 @Override
 public boolean equals(Object obj) {
 if (this == obj) {
 return true;
 }
 if (obj instanceof Year) {
 return year == ((Year) obj).year;
 }
 return false;
 }

 /**
 * A hash code for this year.
 *
 * @return a suitable hash code
 */
 @Override
 public int hashCode() {
 return year;
 }

 //-----------------------------------------------------------------------
 /**
 * Outputs this year as a {@code String}.
 *
 * @return a string representation of this year, not null
 */
 @Override
 public String toString() {
 return Integer.toString(year);
 }

 //-----------------------------------------------------------------------
 /**
 * Writes the object using a
 * <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>.
 * @serialData
 * <pre>
 * out.writeByte(11); // identifies a Year
 * out.writeInt(year);
 * </pre>
 *
 * @return the instance of {@code Ser}, not null
 */
 private Object writeReplace() {
 return new Ser(Ser.YEAR_TYPE, this);
 }

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

 void writeExternal(DataOutput out) throws IOException {
 out.writeInt(year);
 }

 static Year readExternal(DataInput in) throws IOException {
 return Year.of(in.readInt());
 }

}