Serializable
, Comparable<Year>
, Temporal
, TemporalAccessor
, TemporalAdjuster
public final class Year extends Object implements Temporal, TemporalAdjuster, Comparable<Year>, Serializable
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.
This is a value-based
class; use of identity-sensitive operations (including reference equality
(==
), identity hash code, or synchronization) on instances of
Year
may have unpredictable results and should be avoided.
The equals
method should be used for comparisons.
Modifier and Type | Field | Description |
---|---|---|
static int |
MAX_VALUE |
The maximum supported year, '+999,999,999'.
|
static int |
MIN_VALUE |
The minimum supported year, '-999,999,999'.
|
Modifier and Type | Method | Description |
---|---|---|
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(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.
|
Year |
minus(long amountToSubtract,
TemporalUnit unit) |
Returns a copy of this year with the specified amount subtracted.
|
Year |
minus(TemporalAmount amountToSubtract) |
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() |
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 |
now(ZoneId zone) |
Obtains the current year from the system clock in the specified time-zone.
|
static Year |
of(int isoYear) |
Obtains an instance of
Year . |
static Year |
parse(CharSequence text) |
Obtains an instance of
Year from a text string such as 2007 . |
static Year |
parse(CharSequence text,
DateTimeFormatter formatter) |
Obtains an instance of
Year from a text string using a specific formatter. |
Year |
plus(long amountToAdd,
TemporalUnit unit) |
Returns a copy of this year with the specified amount added.
|
Year |
plus(TemporalAmount amountToAdd) |
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(TemporalAdjuster adjuster) |
Returns an adjusted copy of this year.
|
Year |
with(TemporalField field,
long newValue) |
Returns a copy of this year with the specified field set to a new value.
|
public static final int MIN_VALUE
public static final int MAX_VALUE
public static Year now()
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.
public static Year now(ZoneId 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.
zone
- the zone ID to use, not nullpublic static Year now(Clock 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
.
clock
- the clock to use, not nullpublic static Year of(int isoYear)
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.
isoYear
- the ISO proleptic year to represent, from MIN_VALUE
to MAX_VALUE
DateTimeException
- if the field is invalidpublic static Year from(TemporalAccessor temporal)
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
.
temporal
- the temporal object to convert, not nullDateTimeException
- if unable to convert to a Year
public static Year parse(CharSequence text)
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.
text
- the text to parse such as "2007", not nullDateTimeParseException
- if the text cannot be parsedpublic static Year parse(CharSequence text, DateTimeFormatter formatter)
Year
from a text string using a specific formatter.
The text is parsed using the formatter, returning a year.
text
- the text to parse, not nullformatter
- the formatter to use, not nullDateTimeParseException
- if the text cannot be parsedpublic static boolean isLeap(long year)
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.
year
- the year to checkpublic int getValue()
The year returned by this method is proleptic as per get(YEAR)
.
MIN_VALUE
to MAX_VALUE
public boolean isSupported(TemporalField field)
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
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.
isSupported
in interface TemporalAccessor
field
- the field to check, null returns falsepublic boolean isSupported(TemporalUnit unit)
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
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.
isSupported
in interface Temporal
unit
- the unit to check, null returns falsepublic ValueRange range(TemporalField 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.
range
in interface TemporalAccessor
field
- the field to query the range for, not nullDateTimeException
- if the range for the field cannot be obtainedUnsupportedTemporalTypeException
- if the field is not supportedpublic int get(TemporalField field)
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.
get
in interface TemporalAccessor
field
- the field to get, not nullDateTimeException
- if a value for the field cannot be obtained or
the value is outside the range of valid values for the fieldUnsupportedTemporalTypeException
- if the field is not supported or
the range of values exceeds an int
ArithmeticException
- if numeric overflow occurspublic long getLong(TemporalField field)
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.
getLong
in interface TemporalAccessor
field
- the field to get, not nullDateTimeException
- if a value for the field cannot be obtainedUnsupportedTemporalTypeException
- if the field is not supportedArithmeticException
- if numeric overflow occurspublic boolean isLeap()
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.
public boolean isValidMonthDay(MonthDay monthDay)
This method checks whether this year and the input month and day form a valid date.
monthDay
- the month-day to validate, null returns falsepublic int length()
public Year with(TemporalAdjuster adjuster)
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
TemporalAdjuster.adjustInto(Temporal)
method on the
specified adjuster passing this
as the argument.
This instance is immutable and unaffected by this method call.
with
in interface Temporal
adjuster
- the adjuster to use, not nullYear
based on this
with the adjustment made, not nullDateTimeException
- if the adjustment cannot be madeArithmeticException
- if numeric overflow occurspublic Year with(TemporalField field, long newValue)
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.
with
in interface Temporal
field
- the field to set in the result, not nullnewValue
- the new value of the field in the resultYear
based on this
with the specified field set, not nullDateTimeException
- if the field cannot be setUnsupportedTemporalTypeException
- if the field is not supportedArithmeticException
- if numeric overflow occurspublic Year plus(TemporalAmount amountToAdd)
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
TemporalAmount.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.
plus
in interface Temporal
amountToAdd
- the amount to add, not nullYear
based on this year with the addition made, not nullDateTimeException
- if the addition cannot be madeArithmeticException
- if numeric overflow occurspublic Year plus(long amountToAdd, TemporalUnit unit)
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.
plus
in interface Temporal
amountToAdd
- the amount of the unit to add to the result, may be negativeunit
- the unit of the amount to add, not nullYear
based on this year with the specified amount added, not nullDateTimeException
- if the addition cannot be madeUnsupportedTemporalTypeException
- if the unit is not supportedArithmeticException
- if numeric overflow occurspublic Year plusYears(long yearsToAdd)
Year
with the specified number of years added.
This instance is immutable and unaffected by this method call.
yearsToAdd
- the years to add, may be negativeYear
based on this year with the years added, not nullDateTimeException
- if the result exceeds the supported rangepublic Year minus(TemporalAmount amountToSubtract)
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
TemporalAmount.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.
minus
in interface Temporal
amountToSubtract
- the amount to subtract, not nullYear
based on this year with the subtraction made, not nullDateTimeException
- if the subtraction cannot be madeArithmeticException
- if numeric overflow occurspublic Year minus(long amountToSubtract, TemporalUnit unit)
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.
minus
in interface Temporal
amountToSubtract
- the amount of the unit to subtract from the result, may be negativeunit
- the unit of the amount to subtract, not nullYear
based on this year with the specified amount subtracted, not nullDateTimeException
- if the subtraction cannot be madeUnsupportedTemporalTypeException
- if the unit is not supportedArithmeticException
- if numeric overflow occurspublic Year minusYears(long yearsToSubtract)
Year
with the specified number of years subtracted.
This instance is immutable and unaffected by this method call.
yearsToSubtract
- the years to subtract, may be negativeYear
based on this year with the year subtracted, not nullDateTimeException
- if the result exceeds the supported rangepublic <R> R query(TemporalQuery<R> 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 passing this
as the argument.
query
in interface TemporalAccessor
R
- the type of the resultquery
- the query to invoke, not nullDateTimeException
- if unable to query (defined by the query)ArithmeticException
- if numeric overflow occurs (defined by the query)public Temporal adjustInto(Temporal temporal)
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)
passing ChronoField.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
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.
adjustInto
in interface TemporalAdjuster
temporal
- the target object to be adjusted, not nullDateTimeException
- if unable to make the adjustmentArithmeticException
- if numeric overflow occurspublic long until(Temporal endExclusive, TemporalUnit 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 TemporalUnit.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.
until
in interface Temporal
endExclusive
- the end date, exclusive, which is converted to a Year
, not nullunit
- the unit to measure the amount in, not nullDateTimeException
- if the amount cannot be calculated, or the end
temporal cannot be converted to a Year
UnsupportedTemporalTypeException
- if the unit is not supportedArithmeticException
- if numeric overflow occurspublic String format(DateTimeFormatter formatter)
This year will be passed to the formatter to produce a string.
formatter
- the formatter to use, not nullDateTimeException
- if an error occurs during printingpublic LocalDate atDay(int dayOfYear)
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.
dayOfYear
- the day-of-year to use, from 1 to 365-366DateTimeException
- if the day of year is zero or less, 366 or greater or equal
to 366 and this is not a leap yearpublic YearMonth atMonth(Month month)
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);
month
- the month-of-year to use, not nullpublic YearMonth atMonth(int month)
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);
month
- the month-of-year to use, from 1 (January) to 12 (December)DateTimeException
- if the month is invalidpublic LocalDate atMonthDay(MonthDay monthDay)
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.
monthDay
- the month-day to use, not nullpublic int compareTo(Year other)
The comparison is based on the value of the year.
It is "consistent with equals", as defined by Comparable
.
compareTo
in interface Comparable<Year>
other
- the other year to compare to, not nullpublic boolean isAfter(Year other)
other
- the other year to compare to, not nullpublic boolean isBefore(Year other)
other
- the other year to compare to, not nullpublic boolean equals(Object obj)
The comparison is based on the time-line position of the years.
equals
in class Object
obj
- the object to check, null returns falseObject.hashCode()
,
HashMap
public int hashCode()
hashCode
in class Object
Object.equals(java.lang.Object)
,
System.identityHashCode(java.lang.Object)
Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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