public final class Year extends java.lang.Object implements Temporal, TemporalAdjuster, java.lang.Comparable<Year>, java.io.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.
Modifier and Type | Field and 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 and Description |
---|---|
Temporal |
adjustInto(Temporal temporal)
Adjusts the specified temporal object to have this year.
|
LocalDate |
atDay(int dayOfYear)
Returns a date formed from this year at the specified day-of-year.
|
YearMonth |
atMonth(int month)
Returns a year-month formed from this year at the specified month.
|
YearMonth |
atMonth(Month month)
Returns a year-month formed from this year at the specified month.
|
LocalDate |
atMonthDay(MonthDay monthDay)
Returns a date formed from this year at the specified month-day.
|
int |
compareTo(Year other)
Compares this year to another year.
|
boolean |
equals(java.lang.Object obj)
Checks if this year is equal to another year.
|
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)
Is this year after the specified year.
|
boolean |
isBefore(Year other)
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 |
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 an object of the same type as this object with the specified period subtracted.
|
Year |
minus(TemporalSubtractor subtractor)
Returns a copy of this year with the specified period 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(java.lang.CharSequence text)
Obtains an instance of
Year from a text string such as 2007 . |
static Year |
parse(java.lang.CharSequence text,
DateTimeFormatter formatter)
Obtains an instance of
Year from a text string using a specific formatter. |
long |
periodUntil(Temporal endYear,
TemporalUnit unit)
Calculates the period between this year and another year in
terms of the specified unit.
|
Year |
plus(long amountToAdd,
TemporalUnit unit)
Returns an object of the same type as this object with the specified period added.
|
Year |
plus(TemporalAdder adder)
Returns a copy of this year with the specified period 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.
|
java.lang.String |
toString()
Outputs this year as a
String . |
java.lang.String |
toString(DateTimeFormatter formatter)
Outputs this year as a
String using the formatter. |
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.
A TemporalAccessor
represents some form of date and time information.
This factory converts the arbitrary temporal object 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 in queries via method reference, Year::from
.
temporal
- the temporal object to convert, not nullDateTimeException
- if unable to convert to a Year
public static Year parse(java.lang.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(java.lang.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
and
get
methods will throw an exception.
If the field is a ChronoField
then the query is implemented here.
The supported 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 invoking TemporalField.doIsSupported(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 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 a DateTimeException
.
If the field is not a ChronoField
, then the result of this method
is obtained by invoking TemporalField.doRange(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 obtainedpublic int get(TemporalField field)
int
.
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.
The supported fields
will return valid
values based on this year.
All other ChronoField
instances will throw a DateTimeException
.
If the field is not a ChronoField
, then the result of this method
is obtained by invoking TemporalField.doGet(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 obtainedjava.lang.ArithmeticException
- if numeric overflow occurspublic long getLong(TemporalField field)
long
.
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.
The supported fields
will return valid
values based on this year.
All other ChronoField
instances will throw a DateTimeException
.
If the field is not a ChronoField
, then the result of this method
is obtained by invoking TemporalField.doGet(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 obtainedjava.lang.ArithmeticException
- 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 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 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 madejava.lang.ArithmeticException
- if numeric overflow occurspublic Year with(TemporalField field, long newValue)
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 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 a DateTimeException
.
If the field is not a ChronoField
, then the result of this method
is obtained by invoking TemporalField.doWith(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 setjava.lang.ArithmeticException
- if numeric overflow occurspublic Year plus(TemporalAdder adder)
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
the TemporalAdder
interface.
The calculation is delegated to the specified adjuster, which typically calls
back to plus(long, TemporalUnit)
.
This instance is immutable and unaffected by this method call.
plus
in interface Temporal
adder
- the adder to use, not nullYear
based on this year with the addition made, not nullDateTimeException
- if the addition cannot be madejava.lang.ArithmeticException
- if numeric overflow occurspublic Year plus(long amountToAdd, TemporalUnit unit)
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 accept DAYS
but not WEEKS
or MONTHS
.
ChronoUnit
.
If the unit is supported, then the addition must be performed.
If unsupported, then a DateTimeException
must be thrown.
If the unit is not a ChronoUnit
, then the result of this method
is obtained by invoking TemporalUnit.doPlus(Temporal, long)
passing this
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.
plus
in interface Temporal
amountToAdd
- the amount of the specified unit to add, may be negativeunit
- the unit of the period to add, not nullDateTimeException
- if the unit cannot be addedjava.lang.ArithmeticException
- if numeric overflow occurspublic Year plusYears(long yearsToAdd)
This instance is immutable and unaffected by this method call.
yearsToAdd
- the years to add, may be negativeYear
based on this year with the period added, not nullDateTimeException
- if the result exceeds the supported year rangepublic Year minus(TemporalSubtractor subtractor)
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
the TemporalSubtractor
interface.
The calculation is delegated to the specified adjuster, which typically calls
back to minus(long, TemporalUnit)
.
This instance is immutable and unaffected by this method call.
minus
in interface Temporal
subtractor
- the subtractor to use, not nullYear
based on this year with the subtraction made, not nullDateTimeException
- if the subtraction cannot be madejava.lang.ArithmeticException
- if numeric overflow occurspublic Year minus(long amountToSubtract, TemporalUnit unit)
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 accept DAYS
but not WEEKS
or MONTHS
.
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.
The default implementation must behave equivalent to this code:
return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit));
minus
in interface Temporal
amountToSubtract
- the amount of the specified unit to subtract, may be negativeunit
- the unit of the period to subtract, not nullDateTimeException
- if the unit cannot be subtractedjava.lang.ArithmeticException
- if numeric overflow occurspublic Year minusYears(long yearsToSubtract)
This instance is immutable and unaffected by this method call.
yearsToSubtract
- the years to subtract, may be negativeYear
based on this year with the period subtracted, not nullDateTimeException
- if the result exceeds the supported year 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)java.lang.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 adjustmentjava.lang.ArithmeticException
- if numeric overflow occurspublic long periodUntil(Temporal endYear, TemporalUnit 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.
The Temporal
passed to this method must be a Year
.
For example, the period in decades between two year can be calculated
using startYear.periodUntil(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(R, R)
.
The result of this method is a long
representing the amount of
the specified unit. By contrast, the result of between
is an
object that can be used directly in addition/subtraction:
long period = start.periodUntil(end, YEARS); // this method dateTime.plus(YEARS.between(start, end)); // use in plus/minus
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 input temporal as
the second argument.
This instance is immutable and unaffected by this method call.
periodUntil
in interface Temporal
endYear
- the end year, which must be a Year
, not nullunit
- the unit to measure the period in, not nullDateTimeException
- if the period cannot be calculatedjava.lang.ArithmeticException
- if numeric overflow occurspublic LocalDate atDay(int dayOfYear)
This combines this year and the specified day-of-year to form a LocalDate
.
The day-of-year value 366 is only valid in a leap year.
This instance is immutable and unaffected by this method call.
dayOfYear
- the day-of-year to use, not nullDateTimeException
- if the day of year is 366 and this is not a leap yearpublic YearMonth atMonth(Month month)
This combines this year and the specified month to form a YearMonth
.
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);
This instance is immutable and unaffected by this method call.
month
- the month-of-year to use, not nullpublic YearMonth atMonth(int month)
This combines this year and the specified month to form a YearMonth
.
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);
This instance is immutable and unaffected by this method call.
month
- the month-of-year to use, from 1 (January) to 12 (December)public LocalDate atMonthDay(MonthDay monthDay)
This combines this year and the specified month-day to form a LocalDate
.
The month-day value of February 29th is only valid in a leap year.
This instance is immutable and unaffected by this method call.
monthDay
- the month-day to use, not nullDateTimeException
- if the month-day is February 29th and this is not a leap yearpublic 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 java.lang.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(java.lang.Object obj)
The comparison is based on the time-line position of the years.
equals
in class java.lang.Object
obj
- the object to check, null returns falseObject.hashCode()
,
HashMap
public int hashCode()
hashCode
in class java.lang.Object
Object.equals(java.lang.Object)
,
System.identityHashCode(java.lang.Object)
public java.lang.String toString()
String
.toString
in class java.lang.Object
public java.lang.String toString(DateTimeFormatter formatter)
String
using the formatter.
This year will be passed to the formatter
print method
.
formatter
- the formatter to use, not nullDateTimeException
- if an error occurs during printing