* {@code Year} is an immutable date-time object that represents a year. * Any field that can be derived from a year can be obtained. *
* 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. *
* 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}. *
* 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. *
* 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. * *
* This is a value-based
* 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
* This will query the {@link Clock#systemDefaultZone() system clock} in the default
* time-zone to obtain the current year.
*
* 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.
*
* 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.
*
* 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.
*
* 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}.
*
* This method accepts a year value from the proleptic ISO calendar system.
*
* The year 2AD/CE is represented by 2.
* 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}.
*
* 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}.
*
* 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}.
*
* 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.
*
* 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.
*
* This method applies the current rules for leap years across the whole time-line.
* In general, a year is a leap year if it is divisible by four without
* remainder. However, years divisible by 100, are not leap years, with
* the exception of years divisible by 400 which are.
*
* For example, 1904 is a leap year it is divisible by 4.
* 1900 was not a leap year as it is divisible by 100, however 2000 was a
* leap year as it is divisible by 400.
*
* The calculation is proleptic - applying the same rules into the far future and far past.
* This is historically inaccurate, but is correct for the ISO-8601 standard.
*
* @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.
*
* 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.
*
* 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.
*
* If the field is a {@link ChronoField} then the query is implemented here.
* The supported fields are:
*
* 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.
*
* 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.
*
* If the unit is a {@link ChronoUnit} then the query is implemented here.
* The supported units are:
*
* 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.
*
* 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.
*
* 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}.
*
* 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}.
*
* 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.
*
* 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}.
*
* 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}.
*
* 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.
*
* 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}.
*
* 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.
*
* This method applies the current rules for leap years across the whole time-line.
* In general, a year is a leap year if it is divisible by four without
* remainder. However, years divisible by 100, are not leap years, with
* the exception of years divisible by 400 which are.
*
* For example, 1904 is a leap year it is divisible by 4.
* 1900 was not a leap year as it is divisible by 100, however 2000 was a
* leap year as it is divisible by 400.
*
* The calculation is proleptic - applying the same rules into the far future and far past.
* This is historically inaccurate, but is correct for the ISO-8601 standard.
*
* @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.
*
* 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.
*
* 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.
*
* 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.
*
* 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.
*
* 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.
*
* If the field is a {@link ChronoField} then the adjustment is implemented here.
* The supported fields behave as follows:
*
* In all cases, if the new value is outside the valid range of values for the field
* then a {@code DateTimeException} will be thrown.
*
* All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
*
* 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.
*
* 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.
*
* 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.
*
* 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.
*
* 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.
*
* 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.
*
* If the field is a {@link ChronoUnit} then the addition is implemented here.
* The supported fields behave as follows:
*
* All other {@code ChronoUnit} instances will throw an {@code UnsupportedTemporalTypeException}.
*
* 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.
*
* 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.
*
* 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.
*
* 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.
*
* 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.
*
* 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.
*
* 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.
*
* 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.
*
* 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.
*
* 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.
*
* 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.
*
* 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
* This returns a temporal object of the same observable type as the input
* with the year changed to be the same as this.
*
* 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.
*
* In most cases, it is clearer to reverse the calling pattern by using
* {@link Temporal#with(TemporalAdjuster)}:
*
* 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.
*
* 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)}.
*
* 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.
*
* 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)}:
*
* 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.
*
* 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.
*
* 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.
*
* 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}.
*
* This returns a {@code LocalDate} formed from this year and the specified day-of-year.
*
* 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}.
*
* This returns a {@code YearMonth} formed from this year and the specified month.
* All possible combinations of year and month are valid.
*
* This method can be used as part of a chain to produce a date:
*
* This returns a {@code YearMonth} formed from this year and the specified month.
* All possible combinations of year and month are valid.
*
* This method can be used as part of a chain to produce a date:
*
* This returns a {@code LocalDate} formed from this year and the specified month-day.
*
* 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.
*
* 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.
*
* 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
* dedicated serialized form.
* @serialData
*
* The year 1AD/CE is represented by 1.
* The year 1BC/BCE is represented by 0.
* The year 2BC/BCE is represented by -1.
*
* @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.
*
*
* All other {@code ChronoField} instances will return false.
*
*
* All other {@code ChronoUnit} instances will return false.
*
*
*
*
*
* // these two lines are equivalent, but the second approach is recommended
* temporal = thisYear.adjustInto(temporal);
* temporal = temporal.with(thisYear);
*
*
* // these two lines are equivalent
* amount = start.until(end, YEARS);
* amount = YEARS.between(start, end);
*
* The choice should be made based on which makes the code more readable.
*
* LocalDate date = year.atMonth(month).atDay(day);
*
*
* @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}.
*
* LocalDate date = year.atMonth(month).atDay(day);
*
*
* @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}.
*
* out.writeByte(11); // identifies a Year
* out.writeInt(year);
*
*
* @return the instance of {@code Ser}, not null
*/
@java.io.Serial
private Object writeReplace() {
return new Ser(Ser.YEAR_TYPE, this);
}
/**
* Defend against malicious streams.
*
* @param s the stream to read
* @throws InvalidObjectException always
*/
@java.io.Serial
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());
}
}