Class Year
- All Implemented Interfaces:
Serializable
,Comparable<Year>
,Temporal
,TemporalAccessor
,TemporalAdjuster
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.
Specification for implementors
This class is immutable and thread-safe.- See Also:
- Serialized Form
-
Field Summary
Fields -
Method Summary
Modifier and TypeMethodDescriptionadjustInto(Temporal temporal)
Adjusts the specified temporal object to have this year.atDay(int dayOfYear)
Combines this year with a day-of-year to create aLocalDate
.atMonth(int month)
Combines this year with a month to create aYearMonth
.Combines this year with a month to create aYearMonth
.atMonthDay(MonthDay monthDay)
Combines this year with a month-day to create aLocalDate
.int
Compares this year to another year.boolean
Checks if this year is equal to another year.format(DateTimeFormatter formatter)
Outputs this year as aString
using the formatter.static Year
from(TemporalAccessor temporal)
Obtains an instance ofYear
from a temporal object.int
get(TemporalField field)
Gets the value of the specified field from this year as anint
.long
getLong(TemporalField field)
Gets the value of the specified field from this year as along
.int
getValue()
Gets the year value.int
hashCode()
A hash code for this year.boolean
Is this year after the specified year.boolean
Is this year 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(TemporalField field)
Checks if the specified field is supported.boolean
isSupported(TemporalUnit unit)
Checks if the specified unit 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.minus(long amountToSubtract, TemporalUnit unit)
Returns an object of the same type as this object with the specified period subtracted.minus(TemporalAmount amount)
Returns a copy of this year with the specified period subtracted.minusYears(long yearsToSubtract)
Returns a copy of this year with the specified number of years subtracted.static Year
now()
Obtains the current year from the system clock in the default time-zone.static Year
Obtains the current year from the specified clock.static Year
Obtains the current year from the system clock in the specified time-zone.static Year
of(int isoYear)
Obtains an instance ofYear
.static Year
parse(CharSequence text)
Obtains an instance ofYear
from a text string such as2007
.static Year
parse(CharSequence text, DateTimeFormatter formatter)
Obtains an instance ofYear
from a text string using a specific formatter.plus(long amountToAdd, TemporalUnit unit)
Returns an object of the same type as this object with the specified period added.plus(TemporalAmount amount)
Returns a copy of this year with the specified period added.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.range(TemporalField field)
Gets the range of valid values for the specified field.toString()
Outputs this year as aString
.long
until(Temporal endExclusive, TemporalUnit unit)
Calculates the period between this year and another year in terms of the specified unit.with(TemporalAdjuster adjuster)
Returns an adjusted copy of this year.with(TemporalField field, long newValue)
Returns a copy of this year with the specified field set to a new value.
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Field Details
-
MIN_VALUE
public static final int MIN_VALUEThe minimum supported year, '-999,999,999'.- See Also:
- Constant Field Values
-
MAX_VALUE
public static final int MAX_VALUEThe maximum supported year, '+999,999,999'.- See Also:
- Constant Field Values
-
-
Method Details
-
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
-
now
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
-
now
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
-
of
Obtains an instance ofYear
.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, fromMIN_VALUE
toMAX_VALUE
- Returns:
- the year, not null
- Throws:
DateTimeException
- if the field is invalid
-
from
Obtains an instance ofYear
from a temporal object.A
TemporalAccessor
represents some form of date and time information. This factory converts the arbitrary temporal object to an instance ofYear
.The conversion extracts the
year
field. The extraction is only permitted if the temporal object has an ISO chronology, or can be converted to aLocalDate
.This method matches the signature of the functional interface
TemporalQuery
allowing it to be used in queries 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 aYear
-
parse
Obtains an instance ofYear
from a text string such as2007
.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
-
parse
Obtains an instance ofYear
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 nullformatter
- the formatter to use, not null- Returns:
- the parsed year, not null
- Throws:
DateTimeParseException
- if the text cannot be parsed
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isLeap
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
-
getValue
public int getValue()Gets the year value.The year returned by this method is proleptic as per
get(YEAR)
.- Returns:
- the year,
MIN_VALUE
toMAX_VALUE
-
isSupported
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
andget
methods will throw an exception.If the field is a
ChronoField
then the query is implemented here. Thesupported fields
will return valid values based on this date-time. The supported fields are:YEAR_OF_ERA
YEAR
ERA
ChronoField
instances will return false.If the field is not a
ChronoField
, then the result of this method is obtained by invokingTemporalField.isSupportedBy(TemporalAccessor)
passingthis
as the argument. Whether the field is supported is determined by the field.- Specified by:
isSupported
in interfaceTemporalAccessor
- Parameters:
field
- the field to check, null returns false- Returns:
- true if the field is supported on this year, false if not
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isSupported
Description copied from interface:Temporal
Checks if the specified unit is supported.This checks if the date-time can be queried for the specified unit. If false, then calling the
plus
andminus
methods will throw an exception.Specification for implementors
Implementations must check and handle all fields defined inChronoUnit
. If the field is supported, then true is returned, otherwise falseIf the field is not a
ChronoUnit
, then the result of this method is obtained by invokingTemporalUnit.isSupportedBy(Temporal)
passingthis
as the argument.Implementations must not alter this object.
- Specified by:
isSupported
in interfaceTemporal
- Parameters:
unit
- the unit to check, null returns false- Returns:
- true if this date-time can be queried for the unit, false if not
-
range
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. Thesupported fields
will return appropriate range instances. All otherChronoField
instances will throw aDateTimeException
.If the field is not a
ChronoField
, then the result of this method is obtained by invokingTemporalField.rangeRefinedBy(TemporalAccessor)
passingthis
as the argument. Whether the range can be obtained is determined by the field.- Specified by:
range
in interfaceTemporalAccessor
- 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
-
get
Gets the value of the specified field from this year as anint
.This queries this year for the value for 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. Thesupported fields
will return valid values based on this year. All otherChronoField
instances will throw aDateTimeException
.If the field is not a
ChronoField
, then the result of this method is obtained by invokingTemporalField.getFrom(TemporalAccessor)
passingthis
as the argument. Whether the value can be obtained, and what the value represents, is determined by the field.- Specified by:
get
in interfaceTemporalAccessor
- Parameters:
field
- the field to get, not null- Returns:
- the value for the field
- Throws:
DateTimeException
- if a value for the field cannot be obtainedArithmeticException
- if numeric overflow occurs
-
getLong
Gets the value of the specified field from this year as along
.This queries this year for the value for 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. Thesupported fields
will return valid values based on this year. All otherChronoField
instances will throw aDateTimeException
.If the field is not a
ChronoField
, then the result of this method is obtained by invokingTemporalField.getFrom(TemporalAccessor)
passingthis
as the argument. Whether the value can be obtained, and what the value represents, is determined by the field.- Specified by:
getLong
in interfaceTemporalAccessor
- Parameters:
field
- the field to get, not null- Returns:
- the value for the field
- Throws:
DateTimeException
- if a value for the field cannot be obtainedArithmeticException
- if numeric overflow occurs
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isLeap
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
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isValidMonthDay
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
-
length
public int length()Gets the length of this year in days.- Returns:
- the length of this year in days, 365 or 366
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with
Returns an adjusted copy of this year.This returns a new
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
TemporalAdjuster.adjustInto(Temporal)
method on the specified adjuster passingthis
as the argument.This instance is immutable and unaffected by this method call.
- Specified by:
with
in interfaceTemporal
- Parameters:
adjuster
- the adjuster to use, not null- Returns:
- a
Year
based onthis
with the adjustment made, not null - Throws:
DateTimeException
- if the adjustment cannot be madeArithmeticException
- if numeric overflow occurs
-
with
Returns a copy of this year with the specified field set to a new value.This returns a new
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 aYear
with the specified year-of-era The era will be unchanged.YEAR
- Returns aYear
with the specified year. This completely replaces the date and is equivalent toof(int)
.ERA
- Returns aYear
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 aDateTimeException
.If the field is not a
ChronoField
, then the result of this method is obtained by invokingTemporalField.adjustInto(Temporal, long)
passingthis
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.
- Specified by:
with
in interfaceTemporal
- Parameters:
field
- the field to set in the result, not nullnewValue
- the new value of the field in the result- Returns:
- a
Year
based onthis
with the specified field set, not null - Throws:
DateTimeException
- if the field cannot be setArithmeticException
- if numeric overflow occurs
-
plus
Returns a copy of this year with the specified period added.This method returns a new year based on this year with the specified period added. The adder is typically
Period
but may be any other type implementing theTemporalAmount
interface. The calculation is delegated to the specified adjuster, which typically calls back toplus(long, TemporalUnit)
.This instance is immutable and unaffected by this method call.
- Specified by:
plus
in interfaceTemporal
- Parameters:
amount
- 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 madeArithmeticException
- if numeric overflow occurs
-
plus
Returns an object of the same type as this object with the specified period added.This method returns a new object based on this one with the specified period added. For example, on a
LocalDate
, this could be used to add a number of years, months or days. The returned object will have the same observable type as this object.In some cases, changing a field is not fully defined. For example, if the target object is a date representing the 31st January, then adding one month would be unclear. In cases like this, the field is responsible for resolving the result. Typically it will choose the previous valid date, which would be the last valid day of February in this example.
If the implementation represents a date-time that has boundaries, such as
LocalTime
, then the permitted units must include the boundary unit, but no multiples of the boundary unit. For example,LocalTime
must acceptDAYS
but notWEEKS
orMONTHS
.Specification for implementors
Implementations must check and handle all units defined inChronoUnit
. If the unit is supported, then the addition must be performed. If unsupported, then aDateTimeException
must be thrown.If the unit is not a
ChronoUnit
, then the result of this method is obtained by invokingTemporalUnit.addTo(Temporal, long)
passingthis
as the first argument.Implementations must not alter either this object or the specified temporal object. Instead, an adjusted copy of the original must be returned. This provides equivalent, safe behavior for immutable and mutable implementations.
- Specified by:
plus
in interfaceTemporal
- Parameters:
amountToAdd
- the amount of the specified unit to add, may be negativeunit
- the unit of the period to add, not null- Returns:
- an object of the same type with the specified period added, not null
- Throws:
DateTimeException
- if the unit cannot be addedArithmeticException
- if numeric overflow occurs
-
plusYears
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 period added, not null - Throws:
DateTimeException
- if the result exceeds the supported year range
-
minus
Returns a copy of this year with the specified period subtracted.This method returns a new year based on this year with the specified period subtracted. The subtractor is typically
Period
but may be any other type implementing theTemporalAmount
interface. The calculation is delegated to the specified adjuster, which typically calls back tominus(long, TemporalUnit)
.This instance is immutable and unaffected by this method call.
- Specified by:
minus
in interfaceTemporal
- Parameters:
amount
- 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 madeArithmeticException
- if numeric overflow occurs
-
minus
Returns an object of the same type as this object with the specified period subtracted.This method returns a new object based on this one with the specified period subtracted. For example, on a
LocalDate
, this could be used to subtract a number of years, months or days. The returned object will have the same observable type as this object.In some cases, changing a field is not fully defined. For example, if the target object is a date representing the 31st March, then subtracting one month would be unclear. In cases like this, the field is responsible for resolving the result. Typically it will choose the previous valid date, which would be the last valid day of February in this example.
If the implementation represents a date-time that has boundaries, such as
LocalTime
, then the permitted units must include the boundary unit, but no multiples of the boundary unit. For example,LocalTime
must acceptDAYS
but notWEEKS
orMONTHS
.Specification for implementors
Implementations must behave in a manor equivalent to the default method behavior.Implementations must not alter either this object or the specified temporal object. Instead, an adjusted copy of the original must be returned. This provides equivalent, safe behavior for immutable and mutable implementations.
- Specified by:
minus
in interfaceTemporal
- Parameters:
amountToSubtract
- the amount of the specified unit to subtract, may be negativeunit
- the unit of the period to subtract, not null- Returns:
- an object of the same type with the specified period subtracted, not null
- Throws:
DateTimeException
- if the unit cannot be subtractedArithmeticException
- if numeric overflow occurs
-
minusYears
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 period subtracted, not null - Throws:
DateTimeException
- if the result exceeds the supported year range
-
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
TemporalQuery.queryFrom(TemporalAccessor)
method on the specified query passingthis
as the argument.- Specified by:
query
in interfaceTemporalAccessor
- Type Parameters:
R
- the type of the result- 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)
-
adjustInto
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
Temporal.with(TemporalField, long)
passingChronoField.YEAR
as the field. If the specified temporal object does not use the ISO calendar system then aDateTimeException
is thrown.In most cases, it is clearer to reverse the calling pattern by using
Temporal.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.
- Specified by:
adjustInto
in interfaceTemporalAdjuster
- Parameters:
temporal
- the target object to be adjusted, not null- Returns:
- the adjusted object, not null
- Throws:
DateTimeException
- if unable to make the adjustmentArithmeticException
- if numeric overflow occurs
-
until
Calculates the period between this year and another year in terms of the specified unit.This calculates the period between two years in terms of a single unit. The start and end points are
this
and the specified year. The result will be negative if the end is before the start. TheTemporal
passed to this method must be aYear
. For example, the period in decades between two year can be calculated usingstartYear.until(endYear, DECADES)
.The calculation returns a whole number, representing the number of complete units between the two years. For example, the period in decades between 2012 and 2031 will only be one decade as it is one year short of two decades.
This method operates in association with
TemporalUnit.between(org.threeten.bp.temporal.Temporal, org.threeten.bp.temporal.Temporal)
. The result of this method is along
representing the amount of the specified unit. By contrast, the result ofbetween
is an object that can be used directly in addition/subtraction:long period = start.until(end, YEARS); // this method dateTime.plus(YEARS.between(start, end)); // use in plus/minus
The calculation is implemented in this method for
ChronoUnit
. The unitsYEARS
,DECADES
,CENTURIES
,MILLENNIA
andERAS
are supported. OtherChronoUnit
values will throw an exception.If the unit is not a
ChronoUnit
, then the result of this method is obtained by invokingTemporalUnit.between(Temporal, Temporal)
passingthis
as the first argument and the input temporal as the second argument.This instance is immutable and unaffected by this method call.
- Specified by:
until
in interfaceTemporal
- Parameters:
endExclusive
- the end year, which is converted to aYear
, not nullunit
- the unit to measure the period in, not null- Returns:
- the amount of the period between this year and the end year
- Throws:
DateTimeException
- if the period cannot be calculatedArithmeticException
- if numeric overflow occurs
-
atDay
Combines this year with a day-of-year to create aLocalDate
.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, not null- 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
-
atMonth
Combines this year with a month to create aYearMonth
.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
-
atMonth
Combines this year with a month to create aYearMonth
.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
-
atMonthDay
Combines this year with a month-day to create aLocalDate
.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
-
compareTo
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
.- Specified by:
compareTo
in interfaceComparable<Year>
- Parameters:
other
- the other year to compare to, not null- Returns:
- the comparator value, negative if less, positive if greater
-
isAfter
Is this year after the specified year.- Parameters:
other
- the other year to compare to, not null- Returns:
- true if this is after the specified year
-
isBefore
Is this year before the specified year.- Parameters:
other
- the other year to compare to, not null- Returns:
- true if this point is before the specified year
-
equals
Checks if this year is equal to another year.The comparison is based on the time-line position of the years.
-
hashCode
public int hashCode()A hash code for this year. -
toString
Outputs this year as aString
. -
format
Outputs this year as aString
using the formatter.This year will be passed to the formatter
print method
.- Parameters:
formatter
- the formatter to use, not null- Returns:
- the formatted year string, not null
- Throws:
DateTimeException
- if an error occurs during printing
-