JapaneseDate
public
final
class
JapaneseDate
extends Object
implements
ChronoLocalDate,
Temporal,
TemporalAdjuster,
Serializable
java.lang.Object | |
↳ | java.time.chrono.JapaneseDate |
A date in the Japanese Imperial calendar system.
This date operates using the Japanese Imperial calendar. This calendar system is primarily used in Japan.
The Japanese Imperial calendar system is the same as the ISO calendar system apart from the era-based year numbering. The proleptic-year is defined to be equal to the ISO proleptic-year.
Japan introduced the Gregorian calendar starting with Meiji 6. Only Meiji and later eras are supported; dates before Meiji 6, January 1 are not supported.
For example, the Japanese year "Heisei 24" corresponds to ISO year "2012".
Calling japaneseDate.get(YEAR_OF_ERA)
will return 24.
Calling japaneseDate.get(YEAR)
will return 2012.
Calling japaneseDate.get(ERA)
will return 2, corresponding to
JapaneseChronology.ERA_HEISEI
.
Summary
Public methods | |
---|---|
ChronoLocalDateTime<JapaneseDate>
|
atTime(LocalTime localTime)
Combines this date with a time to create a |
boolean
|
equals(Object obj)
Compares this date to another date, including the chronology. |
static
JapaneseDate
|
from(TemporalAccessor temporal)
Obtains a |
JapaneseChronology
|
getChronology()
Gets the chronology of this date, which is the Japanese calendar system. |
JapaneseEra
|
getEra()
Gets the era applicable at this date. |
long
|
getLong(TemporalField field)
Gets the value of the specified field as a |
int
|
hashCode()
A hash code for this date. |
boolean
|
isSupported(TemporalField field)
Checks if the specified field is supported. |
int
|
lengthOfMonth()
Returns the length of the month represented by this date. |
int
|
lengthOfYear()
Returns the length of the year represented by this date, as defined by the calendar system. |
JapaneseDate
|
minus(TemporalAmount amount)
Returns an object of the same type as this object with an amount subtracted. |
JapaneseDate
|
minus(long amountToAdd, TemporalUnit unit)
Returns an object of the same type as this object with the specified period subtracted. |
static
JapaneseDate
|
now(ZoneId zone)
Obtains the current |
static
JapaneseDate
|
now()
Obtains the current |
static
JapaneseDate
|
now(Clock clock)
Obtains the current |
static
JapaneseDate
|
of(JapaneseEra era, int yearOfEra, int month, int dayOfMonth)
Obtains a |
static
JapaneseDate
|
of(int prolepticYear, int month, int dayOfMonth)
Obtains a |
JapaneseDate
|
plus(TemporalAmount amount)
Returns an object of the same type as this object with an amount added. |
JapaneseDate
|
plus(long amountToAdd, TemporalUnit unit)
Returns an object of the same type as this object with the specified period added. |
ValueRange
|
range(TemporalField field)
Gets the range of valid values for the specified field. |
long
|
toEpochDay()
Converts this date to the Epoch Day. |
String
|
toString()
Returns a string representation of the object. |
long
|
until(Temporal endExclusive, TemporalUnit unit)
Calculates the amount of time until another date in terms of the specified unit. |
ChronoPeriod
|
until(ChronoLocalDate endDate)
Calculates the period between this date and another date as a |
JapaneseDate
|
with(TemporalField field, long newValue)
Returns an object of the same type as this object with the specified field altered. |
JapaneseDate
|
with(TemporalAdjuster adjuster)
Returns an adjusted object of the same type as this object with the adjustment made. |
Inherited methods | |
---|---|
Public methods
atTime
public ChronoLocalDateTime<JapaneseDate> atTime (LocalTime localTime)
Combines this date with a time to create a ChronoLocalDateTime
.
This returns a ChronoLocalDateTime
formed from this date at the specified time.
All possible combinations of date and time are valid.
Parameters | |
---|---|
localTime |
LocalTime : the local time to use, not null |
Returns | |
---|---|
ChronoLocalDateTime<JapaneseDate> |
the local date-time formed from this date and the specified time, not null |
equals
public boolean equals (Object obj)
Compares this date to another date, including the chronology.
Compares this JapaneseDate
with another ensuring that the date is the same.
Only objects of type JapaneseDate
are compared, other types return false.
To compare the dates of two TemporalAccessor
instances, including dates
in two different chronologies, use ChronoField#EPOCH_DAY
as a comparator.
Parameters | |
---|---|
obj |
Object : the object to check, null returns false |
Returns | |
---|---|
boolean |
true if this is equal to the other date |
from
public static JapaneseDate from (TemporalAccessor temporal)
Obtains a JapaneseDate
from a temporal object.
This obtains a date in the Japanese calendar system based on the specified temporal.
A TemporalAccessor
represents an arbitrary set of date and time information,
which this factory converts to an instance of JapaneseDate
.
The conversion typically uses the EPOCH_DAY
field, which is standardized across calendar systems.
This method matches the signature of the functional interface TemporalQuery
allowing it to be used as a query via method reference, JapaneseDate::from
.
Parameters | |
---|---|
temporal |
TemporalAccessor : the temporal object to convert, not null |
Returns | |
---|---|
JapaneseDate |
the date in Japanese calendar system, not null |
Throws | |
---|---|
DateTimeException |
if unable to convert to a JapaneseDate |
getChronology
public JapaneseChronology getChronology ()
Gets the chronology of this date, which is the Japanese calendar system.
The Chronology
represents the calendar system in use.
The era and other fields in ChronoField
are defined by the chronology.
Returns | |
---|---|
JapaneseChronology |
the Japanese chronology, not null |
getEra
public JapaneseEra getEra ()
Gets the era applicable at this date.
The Japanese calendar system has multiple eras defined by JapaneseEra
.
Returns | |
---|---|
JapaneseEra |
the era applicable at this date, not null |
getLong
public long getLong (TemporalField field)
Gets the value of the specified field as a long
.
This queries the date-time for the value of the specified field. The returned value may be outside the valid range of values for the field. If the date-time cannot return the value, because the field is unsupported or for some other reason, an exception will be thrown.
Parameters | |
---|---|
field |
TemporalField : the field to get, not null |
Returns | |
---|---|
long |
the value for the field |
hashCode
public int hashCode ()
A hash code for this date.
Returns | |
---|---|
int |
a suitable hash code based only on the Chronology and the date |
isSupported
public boolean isSupported (TemporalField field)
Checks if the specified field is supported.
This checks if this date 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 are:
DAY_OF_WEEK
DAY_OF_MONTH
DAY_OF_YEAR
EPOCH_DAY
MONTH_OF_YEAR
PROLEPTIC_MONTH
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.
Parameters | |
---|---|
field |
TemporalField : the field to check, null returns false |
Returns | |
---|---|
boolean |
true if the field is supported on this date, false if not |
lengthOfMonth
public int lengthOfMonth ()
Returns the length of the month represented by this date.
This returns the length of the month in days. Month lengths match those of the ISO calendar system.
Returns | |
---|---|
int |
the length of the month in days |
lengthOfYear
public int lengthOfYear ()
Returns the length of the year represented by this date, as defined by the calendar system.
This returns the length of the year in days.
The default implementation uses isLeapYear()
and returns 365 or 366.
Returns | |
---|---|
int |
the length of the year in days |
minus
public JapaneseDate minus (TemporalAmount amount)
Returns an object of the same type as this object with an amount subtracted.
This adjusts this temporal, subtracting according to the rules of the specified amount.
The amount is typically a Period
but may be any other type implementing
the TemporalAmount
interface, such as Duration
.
Some example code indicating how and why this method is used:
date = date.minus(period); // subtract a Period instance date = date.minus(duration); // subtract a Duration instance date = date.minus(workingDays(6)); // example user-written workingDays method
Note that calling plus
followed by minus
is not guaranteed to
return the same date-time.
Parameters | |
---|---|
amount |
TemporalAmount : the amount to subtract, not null |
Returns | |
---|---|
JapaneseDate |
an object of the same type with the specified adjustment made, not null |
Throws | |
---|---|
DateTimeException |
|
ArithmeticException |
minus
public JapaneseDate minus (long amountToAdd, TemporalUnit unit)
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.
Parameters | |
---|---|
amountToAdd |
long : the amount of the specified unit to subtract, may be negative |
unit |
TemporalUnit : the unit of the amount to subtract, not null |
Returns | |
---|---|
JapaneseDate |
an object of the same type with the specified period subtracted, not null |
now
public static JapaneseDate now (ZoneId zone)
Obtains the current JapaneseDate
from the system clock in the specified time-zone.
This will query the system clock
to obtain the current date.
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 |
ZoneId : the zone ID to use, not null |
Returns | |
---|---|
JapaneseDate |
the current date using the system clock, not null |
now
public static JapaneseDate now ()
Obtains the current JapaneseDate
from the system clock in the default time-zone.
This will query the system clock
in the default
time-zone to obtain the current date.
Using this method will prevent the ability to use an alternate clock for testing because the clock is hard-coded.
Returns | |
---|---|
JapaneseDate |
the current date using the system clock and default time-zone, not null |
now
public static JapaneseDate now (Clock clock)
Obtains the current JapaneseDate
from the specified clock.
This will query the specified clock to obtain the current date - today. Using this method allows the use of an alternate clock for testing. The alternate clock may be introduced using dependency injection.
Parameters | |
---|---|
clock |
Clock : the clock to use, not null |
Returns | |
---|---|
JapaneseDate |
the current date, not null |
Throws | |
---|---|
DateTimeException |
if the current date cannot be obtained |
of
public static JapaneseDate of (JapaneseEra era, int yearOfEra, int month, int dayOfMonth)
Obtains a JapaneseDate
representing a date in the Japanese calendar
system from the era, year-of-era, month-of-year and day-of-month fields.
This returns a JapaneseDate
with the specified fields.
The day must be valid for the year and month, otherwise an exception will be thrown.
The Japanese month and day-of-month are the same as those in the ISO calendar system. They are not reset when the era changes. For example:
6th Jan Showa 64 = ISO 1989-01-06 7th Jan Showa 64 = ISO 1989-01-07 8th Jan Heisei 1 = ISO 1989-01-08 9th Jan Heisei 1 = ISO 1989-01-09
Parameters | |
---|---|
era |
JapaneseEra : the Japanese era, not null |
yearOfEra |
int : the Japanese year-of-era |
month |
int : the Japanese month-of-year, from 1 to 12 |
dayOfMonth |
int : the Japanese day-of-month, from 1 to 31 |
Returns | |
---|---|
JapaneseDate |
the date in Japanese calendar system, not null |
Throws | |
---|---|
DateTimeException |
if the value of any field is out of range, or if the day-of-month is invalid for the month-year, or if the date is not a Japanese era |
of
public static JapaneseDate of (int prolepticYear, int month, int dayOfMonth)
Obtains a JapaneseDate
representing a date in the Japanese calendar
system from the proleptic-year, month-of-year and day-of-month fields.
This returns a JapaneseDate
with the specified fields.
The day must be valid for the year and month, otherwise an exception will be thrown.
The Japanese proleptic year, month and day-of-month are the same as those in the ISO calendar system. They are not reset when the era changes.
Parameters | |
---|---|
prolepticYear |
int : the Japanese proleptic-year |
month |
int : the Japanese month-of-year, from 1 to 12 |
dayOfMonth |
int : the Japanese day-of-month, from 1 to 31 |
Returns | |
---|---|
JapaneseDate |
the date in Japanese calendar system, not null |
Throws | |
---|---|
DateTimeException |
if the value of any field is out of range, or if the day-of-month is invalid for the month-year |
plus
public JapaneseDate plus (TemporalAmount amount)
Returns an object of the same type as this object with an amount added.
This adjusts this temporal, adding according to the rules of the specified amount.
The amount is typically a Period
but may be any other type implementing
the TemporalAmount
interface, such as Duration
.
Some example code indicating how and why this method is used:
date = date.plus(period); // add a Period instance date = date.plus(duration); // add a Duration instance date = date.plus(workingDays(6)); // example user-written workingDays method
Note that calling plus
followed by minus
is not guaranteed to
return the same date-time.
Parameters | |
---|---|
amount |
TemporalAmount : the amount to add, not null |
Returns | |
---|---|
JapaneseDate |
an object of the same type with the specified adjustment made, not null |
Throws | |
---|---|
DateTimeException |
|
ArithmeticException |
plus
public JapaneseDate plus (long amountToAdd, TemporalUnit unit)
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.
Parameters | |
---|---|
amountToAdd |
long : the amount of the specified unit to add, may be negative |
unit |
TemporalUnit : the unit of the amount to add, not null |
Returns | |
---|---|
JapaneseDate |
an object of the same type with the specified period added, not null |
range
public ValueRange range (TemporalField field)
Gets the range of valid values for the specified field.
All fields can be expressed as a long
integer.
This method returns an object that describes the valid range for that value.
The value of this temporal object is used to enhance the accuracy of the returned range.
If the date-time cannot return the range, because the field is unsupported or for
some other reason, an exception will be thrown.
Note that the result only describes the minimum and maximum valid values and it is important not to read too much into them. For example, there could be values within the range that are invalid for the field.
Parameters | |
---|---|
field |
TemporalField : the field to query the range for, not null |
Returns | |
---|---|
ValueRange |
the range of valid values for the field, not null |
toEpochDay
public long toEpochDay ()
Converts this date to the Epoch Day.
The Epoch Day count
is a simple
incrementing count of days where day 0 is 1970-01-01 (ISO).
This definition is the same for all chronologies, enabling conversion.
This default implementation queries the EPOCH_DAY
field.
Returns | |
---|---|
long |
the Epoch Day equivalent to this date |
toString
public String toString ()
Returns a string representation of the object.
Returns | |
---|---|
String |
a string representation of the object. |
until
public long until (Temporal endExclusive, TemporalUnit unit)
Calculates the amount of time until another date in terms of the specified unit.
This calculates the amount of time between two ChronoLocalDate
objects in terms of a single TemporalUnit
.
The start and end points are this
and the specified date.
The result will be negative if the end is before the start.
The Temporal
passed to this method is converted to a
ChronoLocalDate
using Chronology#date(TemporalAccessor)
.
The calculation returns a whole number, representing the number of
complete units between the two dates.
For example, the amount in days between two dates can be calculated
using startDate.until(endDate, DAYS)
.
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, MONTHS); amount = MONTHS.between(start, end);
The calculation is implemented in this method for ChronoUnit
.
The units DAYS
, WEEKS
, MONTHS
, YEARS
,
DECADES
, CENTURIES
, MILLENNIA
and ERAS
should be supported by all implementations.
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 |
Temporal : the end date, exclusive, which is converted to a
ChronoLocalDate in the same chronology, not null |
unit |
TemporalUnit : the unit to measure the amount in, not null |
Returns | |
---|---|
long |
the amount of time between this date and the end date |
until
public ChronoPeriod until (ChronoLocalDate endDate)
Calculates the period between this date and another date as a ChronoPeriod
.
This calculates the period between two dates. All supplied chronologies
calculate the period using years, months and days, however the
ChronoPeriod
API allows the period to be represented using other units.
The start and end points are this
and the specified date.
The result will be negative if the end is before the start.
The negative sign will be the same in each of year, month and day.
The calculation is performed using the chronology of this date. If necessary, the input date will be converted to match.
This instance is immutable and unaffected by this method call.
Parameters | |
---|---|
endDate |
ChronoLocalDate : the end date, exclusive, which may be in any chronology, not null |
Returns | |
---|---|
ChronoPeriod |
the period between this date and the end date, not null |
with
public JapaneseDate with (TemporalField field, long newValue)
Returns an object of the same type as this object with the specified field altered.
This returns a new object based on this one with the value for the specified field changed.
For example, on a LocalDate
, this could be used to set the year, month or day-of-month.
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 changing the month to February 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.
Parameters | |
---|---|
field |
TemporalField : the field to set in the result, not null |
newValue |
long : the new value of the field in the result |
Returns | |
---|---|
JapaneseDate |
an object of the same type with the specified field set, not null |
with
public JapaneseDate with (TemporalAdjuster adjuster)
Returns an adjusted object of the same type as this object with the adjustment made.
This adjusts this date-time according to the rules of the specified adjuster.
A simple adjuster might simply set the one of the fields, such as the year field.
A more complex adjuster might set the date to the last day of the month.
A selection of common adjustments is provided in
TemporalAdjusters
.
These include finding the "last day of the month" and "next Wednesday".
The adjuster is responsible for handling special cases, such as the varying
lengths of month and leap years.
Some example code indicating how and why this method is used:
date = date.with(Month.JULY); // most key classes implement TemporalAdjuster date = date.with(lastDayOfMonth()); // static import from Adjusters date = date.with(next(WEDNESDAY)); // static import from Adjusters and DayOfWeek
Parameters | |
---|---|
adjuster |
TemporalAdjuster : the adjuster to use, not null |
Returns | |
---|---|
JapaneseDate |
an object of the same type with the specified adjustment made, not null |
Throws | |
---|---|
DateTimeException |
|
ArithmeticException |