Year

public final class Year extends Object
implements Temporal TemporalAdjuster Comparable<Year> Serializable

A year in the ISO-8601 calendar system, such as 2007.

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 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.

Constant Summary

int MAX_VALUE The maximum supported year, '+999,999,999'.
int MIN_VALUE The minimum supported year, '-999,999,999'.

Public Method Summary

Temporal
adjustInto(Temporal temporal)
Adjusts the specified temporal object to have this year.
LocalDate
atDay(int dayOfYear)
Combines this year with a day-of-year to create a LocalDate.
YearMonth
atMonth(int month)
Combines this year with a month to create a YearMonth.
YearMonth
atMonth(Month month)
Combines this year with a month to create a YearMonth.
LocalDate
atMonthDay(MonthDay monthDay)
Combines this year with a month-day to create a LocalDate.
int
compareTo(Year other)
Compares this year to another year.
boolean
equals(Object obj)
Checks if this year is equal to another year.
String
format(DateTimeFormatter formatter)
Formats this year using the specified formatter.
static Year
from(TemporalAccessor temporal)
Obtains an instance of Year from a temporal object.
int
get(TemporalField field)
Gets the value of the specified field from this year as an int.
long
getLong(TemporalField field)
Gets the value of the specified field from this year as a long.
int
getValue()
Gets the year value.
int
hashCode()
A hash code for this year.
boolean
isAfter(Year other)
Checks if this year is after the specified year.
boolean
isBefore(Year other)
Checks if this year is before the specified year.
boolean
isLeap()
Checks if the year is a leap year, according to the ISO proleptic calendar system rules.
static boolean
isLeap(long year)
Checks if the year is a leap year, according to the ISO proleptic calendar system rules.
boolean
isSupported(TemporalUnit unit)
Checks if the specified unit is supported.
boolean
isSupported(TemporalField field)
Checks if the specified field is supported.
boolean
isValidMonthDay(MonthDay monthDay)
Checks if the month-day is valid for this year.
int
length()
Gets the length of this year in days.
Year
minus(TemporalAmount amountToSubtract)
Returns a copy of this year with the specified amount subtracted.
Year
minus(long amountToSubtract, TemporalUnit unit)
Returns a copy of this year with the specified amount subtracted.
Year
minusYears(long yearsToSubtract)
Returns a copy of this Year with the specified number of years subtracted.
static Year
now(ZoneId zone)
Obtains the current year from the system clock in the specified time-zone.
static Year
now()
Obtains the current year from the system clock in the default time-zone.
static Year
now(Clock clock)
Obtains the current year from the specified clock.
static Year
of(int isoYear)
Obtains an instance of Year.
static Year
parse(CharSequence text, DateTimeFormatter formatter)
Obtains an instance of Year from a text string using a specific formatter.
static Year
parse(CharSequence text)
Obtains an instance of Year from a text string such as 2007.
Year
plus(TemporalAmount amountToAdd)
Returns a copy of this year with the specified amount added.
Year
plus(long amountToAdd, TemporalUnit unit)
Returns a copy of this year with the specified amount added.
Year
plusYears(long yearsToAdd)
Returns a copy of this Year with the specified number of years added.
<R> R
query(TemporalQuery<R> query)
Queries this year using the specified query.
ValueRange
range(TemporalField field)
Gets the range of valid values for the specified field.
String
toString()
Outputs this year as a String.
long
until(Temporal endExclusive, TemporalUnit unit)
Calculates the amount of time until another year in terms of the specified unit.
Year
with(TemporalField field, long newValue)
Returns a copy of this year with the specified field set to a new value.
Year
with(TemporalAdjuster adjuster)
Returns an adjusted copy of this year.

Inherited Method Summary

Constants

public static final int MAX_VALUE

The maximum supported year, '+999,999,999'.

Constant Value: 999999999

public static final int MIN_VALUE

The minimum supported year, '-999,999,999'.

Constant Value: -999999999

Public Methods

public Temporal adjustInto (Temporal temporal)

Adjusts the specified temporal object to have this year.

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 with(TemporalField, long) passing YEAR as the field. If the specified temporal object does not use the ISO calendar system then a DateTimeException is thrown.

In most cases, it is clearer to reverse the calling pattern by using with(TemporalAdjuster):

   // these two lines are equivalent, but the second approach is recommended
   temporal = thisYear.adjustInto(temporal);
   temporal = temporal.with(thisYear);
 

This instance is immutable and unaffected by this method call.

Parameters
temporal the target object to be adjusted, not null
Returns
  • the adjusted object, not null
Throws
DateTimeException if unable to make the adjustment
ArithmeticException if numeric overflow occurs

public LocalDate atDay (int dayOfYear)

Combines this year with a day-of-year to create a LocalDate.

This returns a LocalDate formed from this year and the specified day-of-year.

The day-of-year value 366 is only valid in a leap year.

Parameters
dayOfYear the day-of-year to use, from 1 to 365-366
Returns
  • 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 YearMonth atMonth (int month)

Combines this year with a month to create a YearMonth.

This returns a 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:

  LocalDate date = year.atMonth(month).atDay(day);
 

Parameters
month the month-of-year to use, from 1 (January) to 12 (December)
Returns
  • the year-month formed from this year and the specified month, not null
Throws
DateTimeException if the month is invalid

public YearMonth atMonth (Month month)

Combines this year with a month to create a YearMonth.

This returns a 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:

  LocalDate date = year.atMonth(month).atDay(day);
 

Parameters
month the month-of-year to use, not null
Returns
  • the year-month formed from this year and the specified month, not null

public LocalDate atMonthDay (MonthDay monthDay)

Combines this year with a month-day to create a LocalDate.

This returns a 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.

Parameters
monthDay the month-day to use, not null
Returns
  • the local date formed from this year and the specified month-day, not null

public int compareTo (Year other)

Compares this year to another year.

The comparison is based on the value of the year. It is "consistent with equals", as defined by Comparable.

Parameters
other the other year to compare to, not null
Returns
  • the comparator value, negative if less, positive if greater

public boolean equals (Object obj)

Checks if this year is equal to another year.

The comparison is based on the time-line position of the years.

Parameters
obj the object to check, null returns false
Returns
  • true if this is equal to the other year

public String format (DateTimeFormatter formatter)

Formats this year using the specified formatter.

This year will be passed to the formatter to produce a string.

Parameters
formatter the formatter to use, not null
Returns
  • the formatted year string, not null
Throws
DateTimeException if an error occurs during printing

public static Year from (TemporalAccessor temporal)

Obtains an instance of Year from a temporal object.

This obtains a year based on the specified temporal. A TemporalAccessor represents an arbitrary set of date and time information, which this factory converts to an instance of Year.

The conversion extracts the year field. The extraction is only permitted if the temporal object has an ISO chronology, or can be converted to a LocalDate.

This method matches the signature of the functional interface TemporalQuery allowing it to be used as a query via method reference, Year::from.

Parameters
temporal the temporal object to convert, not null
Returns
  • the year, not null
Throws
DateTimeException if unable to convert to a Year

public int get (TemporalField field)

Gets the value of the specified field from this year as an 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 ChronoField then the query is implemented here. The supported fields will return valid values based on this year. All other ChronoField instances will throw an UnsupportedTemporalTypeException.

If the field is not a ChronoField, then the result of this method is obtained by invoking TemporalField.getFrom(TemporalAccessor) passing this as the argument. Whether the value can be obtained, and what the value represents, is determined by the field.

Parameters
field the field to get, not null
Returns
  • 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
UnsupportedTemporalTypeException if the field is not supported or the range of values exceeds an int
ArithmeticException if numeric overflow occurs

public long getLong (TemporalField field)

Gets the value of the specified field from this year as a 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 ChronoField then the query is implemented here. The supported fields will return valid values based on this year. All other ChronoField instances will throw an UnsupportedTemporalTypeException.

If the field is not a ChronoField, then the result of this method is obtained by invoking TemporalField.getFrom(TemporalAccessor) passing this as the argument. Whether the value can be obtained, and what the value represents, is determined by the field.

Parameters
field the field to get, not null
Returns
  • the value for the field
Throws
DateTimeException if a value for the field cannot be obtained
UnsupportedTemporalTypeException if the field is not supported
ArithmeticException if numeric overflow occurs

public int getValue ()

Gets the year value.

The year returned by this method is proleptic as per get(YEAR).

Returns
  • the year, MIN_VALUE to MAX_VALUE

public int hashCode ()

A hash code for this year.

Returns
  • a suitable hash code

public boolean isAfter (Year other)

Checks if this year is after the specified year.

Parameters
other the other year to compare to, not null
Returns
  • true if this is after the specified year

public boolean isBefore (Year other)

Checks if this year is before the specified year.

Parameters
other the other year to compare to, not null
Returns
  • true if this point is before the specified year

public boolean isLeap ()

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.

Returns
  • true if the year is leap, false otherwise

public static boolean isLeap (long year)

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.

Parameters
year the year to check
Returns
  • true if the year is leap, false otherwise

public boolean isSupported (TemporalUnit unit)

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 plus(long, TemporalUnit) and minus methods will throw an exception.

If the unit is a ChronoUnit then the query is implemented here. The supported units are:

  • YEARS
  • DECADES
  • CENTURIES
  • MILLENNIA
  • ERAS
All other ChronoUnit instances will return false.

If the unit is not a ChronoUnit, then the result of this method is obtained by invoking TemporalUnit.isSupportedBy(Temporal) passing this as the argument. Whether the unit is supported is determined by the unit.

Parameters
unit the unit to check, null returns false
Returns
  • true if the unit can be added/subtracted, false if not

public boolean isSupported (TemporalField field)

Checks if the specified field is supported.

This checks if this year can be queried for the specified field. If false, then calling the range, get and with(TemporalField, long) methods will throw an exception.

If the field is a ChronoField then the query is implemented here. The supported fields are:

  • YEAR_OF_ERA
  • YEAR
  • ERA
All other ChronoField instances will return false.

If the field is not a ChronoField, then the result of this method is obtained by invoking TemporalField.isSupportedBy(TemporalAccessor) passing this as the argument. Whether the field is supported is determined by the field.

Parameters
field the field to check, null returns false
Returns
  • true if the field is supported on this year, false if not

public boolean isValidMonthDay (MonthDay monthDay)

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.

Parameters
monthDay the month-day to validate, null returns false
Returns
  • true if the month and day are valid for this year

public int length ()

Gets the length of this year in days.

Returns
  • the length of this year in days, 365 or 366

public Year minus (TemporalAmount amountToSubtract)

Returns a copy of this year with the specified amount subtracted.

This returns a Year, based on this one, with the specified amount subtracted. The amount is typically Period but may be any other type implementing the TemporalAmount interface.

The calculation is delegated to the amount object by calling subtractFrom(Temporal). The amount implementation is free to implement the subtraction in any way it wishes, however it typically calls back to 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.

Parameters
amountToSubtract the amount to subtract, not null
Returns
  • a Year based on this year with the subtraction made, not null
Throws
DateTimeException if the subtraction cannot be made
ArithmeticException if numeric overflow occurs

public Year minus (long amountToSubtract, TemporalUnit unit)

Returns a copy of this year with the specified amount subtracted.

This returns a 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 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.

Parameters
amountToSubtract the amount of the unit to subtract from the result, may be negative
unit the unit of the amount to subtract, not null
Returns
  • a Year based on this year with the specified amount subtracted, not null
Throws
DateTimeException if the subtraction cannot be made
UnsupportedTemporalTypeException if the unit is not supported
ArithmeticException if numeric overflow occurs

public Year minusYears (long yearsToSubtract)

Returns a copy of this Year with the specified number of years subtracted.

This instance is immutable and unaffected by this method call.

Parameters
yearsToSubtract the years to subtract, may be negative
Returns
  • a Year based on this year with the year subtracted, not null
Throws
DateTimeException if the result exceeds the supported range

public static Year now (ZoneId zone)

Obtains the current year from the system clock in the specified time-zone.

This will query the 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.

Parameters
zone the zone ID to use, not null
Returns
  • the current year using the system clock, not null

public static Year now ()

Obtains the current year from the system clock in the default time-zone.

This will query the 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.

Returns
  • the current year using the system clock and default time-zone, not null

public static Year now (Clock clock)

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 dependency injection.

Parameters
clock the clock to use, not null
Returns
  • the current year, not null

public static Year of (int isoYear)

Obtains an instance of Year.

This method accepts a year value from the proleptic ISO calendar system.

The year 2AD/CE is represented by 2.
The year 1AD/CE is represented by 1.
The year 1BC/BCE is represented by 0.
The year 2BC/BCE is represented by -1.

Parameters
isoYear the ISO proleptic year to represent, from MIN_VALUE to MAX_VALUE
Returns
  • the year, not null
Throws
DateTimeException if the field is invalid

public static Year parse (CharSequence text, DateTimeFormatter formatter)

Obtains an instance of Year from a text string using a specific formatter.

The text is parsed using the formatter, returning a year.

Parameters
text the text to parse, not null
formatter the formatter to use, not null
Returns
  • the parsed year, not null
Throws
DateTimeParseException if the text cannot be parsed

public static Year parse (CharSequence text)

Obtains an instance of Year from a text string such as 2007.

The string must represent a valid year. Years outside the range 0000 to 9999 must be prefixed by the plus or minus symbol.

Parameters
text the text to parse such as "2007", not null
Returns
  • the parsed year, not null
Throws
DateTimeParseException if the text cannot be parsed

public Year plus (TemporalAmount amountToAdd)

Returns a copy of this year with the specified amount added.

This returns a Year, based on this one, with the specified amount added. The amount is typically Period but may be any other type implementing the TemporalAmount interface.

The calculation is delegated to the amount object by calling addTo(Temporal). The amount implementation is free to implement the addition in any way it wishes, however it typically calls back to 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.

Parameters
amountToAdd the amount to add, not null
Returns
  • a Year based on this year with the addition made, not null
Throws
DateTimeException if the addition cannot be made
ArithmeticException if numeric overflow occurs

public Year plus (long amountToAdd, TemporalUnit unit)

Returns a copy of this year with the specified amount added.

This returns a 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 ChronoUnit then the addition is implemented here. The supported fields behave as follows:

  • YEARS - Returns a Year with the specified number of years added. This is equivalent to plusYears(long).
  • DECADES - Returns a Year with the specified number of decades added. This is equivalent to calling plusYears(long) with the amount multiplied by 10.
  • CENTURIES - Returns a Year with the specified number of centuries added. This is equivalent to calling plusYears(long) with the amount multiplied by 100.
  • MILLENNIA - Returns a Year with the specified number of millennia added. This is equivalent to calling plusYears(long) with the amount multiplied by 1,000.
  • ERAS - Returns a 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.

All other ChronoUnit instances will throw an UnsupportedTemporalTypeException.

If the field is not a ChronoUnit, then the result of this method is obtained by invoking TemporalUnit.addTo(Temporal, long) passing 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.

Parameters
amountToAdd the amount of the unit to add to the result, may be negative
unit the unit of the amount to add, not null
Returns
  • a Year based on this year with the specified amount added, not null
Throws
DateTimeException if the addition cannot be made
UnsupportedTemporalTypeException if the unit is not supported
ArithmeticException if numeric overflow occurs

public Year plusYears (long yearsToAdd)

Returns a copy of this Year with the specified number of years added.

This instance is immutable and unaffected by this method call.

Parameters
yearsToAdd the years to add, may be negative
Returns
  • a Year based on this year with the years added, not null
Throws
DateTimeException if the result exceeds the supported range

public R query (TemporalQuery<R> query)

Queries this year using the specified query.

This queries this year using the specified query strategy object. The 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 queryFrom(TemporalAccessor) method on the specified query passing this as the argument.

Parameters
query the query to invoke, not null
Returns
  • the query result, null may be returned (defined by the query)
Throws
DateTimeException if unable to query (defined by the query)
ArithmeticException if numeric overflow occurs (defined by the query)

public ValueRange range (TemporalField field)

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 ChronoField then the query is implemented here. The supported fields will return appropriate range instances. All other ChronoField instances will throw an UnsupportedTemporalTypeException.

If the field is not a ChronoField, then the result of this method is obtained by invoking TemporalField.rangeRefinedBy(TemporalAccessor) passing this as the argument. Whether the range can be obtained is determined by the field.

Parameters
field the field to query the range for, not null
Returns
  • the range of valid values for the field, not null
Throws
DateTimeException if the range for the field cannot be obtained
UnsupportedTemporalTypeException if the field is not supported

public String toString ()

Outputs this year as a String.

Returns
  • a string representation of this year, not null

public long until (Temporal endExclusive, TemporalUnit unit)

Calculates the amount of time until another year in terms of the specified unit.

This calculates the amount of time between two Year objects in terms of a single TemporalUnit. The start and end points are this and the specified year. The result will be negative if the end is before the start. The Temporal passed to this method is converted to a Year using from(TemporalAccessor). For example, the amount in decades between two year can be calculated using 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 between(Temporal, Temporal):

   // 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.

The calculation is implemented in this method for ChronoUnit. The units YEARS, DECADES, CENTURIES, MILLENNIA and ERAS are supported. Other ChronoUnit values will throw an exception.

If the unit is not a ChronoUnit, then the result of this method is obtained by invoking TemporalUnit.between(Temporal, Temporal) passing this as the first argument and the converted input temporal as the second argument.

This instance is immutable and unaffected by this method call.

Parameters
endExclusive the end date, exclusive, which is converted to a Year, not null
unit the unit to measure the amount in, not null
Returns
  • 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 Year
UnsupportedTemporalTypeException if the unit is not supported
ArithmeticException if numeric overflow occurs

public Year with (TemporalField field, long newValue)

Returns a copy of this year with the specified field set to a new value.

This returns a 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 ChronoField then the adjustment is implemented here. The supported fields behave as follows:

  • YEAR_OF_ERA - Returns a Year with the specified year-of-era The era will be unchanged.
  • YEAR - Returns a Year with the specified year. This completely replaces the date and is equivalent to of(int).
  • ERA - Returns a Year with the specified era. The year-of-era will be unchanged.

In all cases, if the new value is outside the valid range of values for the field then a DateTimeException will be thrown.

All other ChronoField instances will throw an UnsupportedTemporalTypeException.

If the field is not a ChronoField, then the result of this method is obtained by invoking TemporalField.adjustInto(Temporal, long) passing 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.

Parameters
field the field to set in the result, not null
newValue the new value of the field in the result
Returns
  • a Year based on this with the specified field set, not null
Throws
DateTimeException if the field cannot be set
UnsupportedTemporalTypeException if the field is not supported
ArithmeticException if numeric overflow occurs

public Year with (TemporalAdjuster adjuster)

Returns an adjusted copy of this year.

This returns a 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 adjustInto(Temporal) method on the specified adjuster passing this as the argument.

This instance is immutable and unaffected by this method call.

Parameters
adjuster the adjuster to use, not null
Returns
  • a Year based on this with the adjustment made, not null
Throws
DateTimeException if the adjustment cannot be made
ArithmeticException if numeric overflow occurs