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added in API level 26

JapaneseDate

public final class JapaneseDate
extends Object implements ChronoLocalDate, Temporal, TemporalAdjuster, Serializable, ChronoLocalDate, 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 ChronoLocalDateTime.

boolean equals(Object obj)

Compares this date to another date, including the chronology.

static JapaneseDate from(TemporalAccessor temporal)

Obtains a JapaneseDate from a temporal object.

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 long.

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 JapaneseDate from the system clock in the specified time-zone.

static JapaneseDate now()

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

static JapaneseDate now(Clock clock)

Obtains the current JapaneseDate from the specified clock.

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.

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.

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 ChronoPeriod.

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

added in API level 26
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

added in API level 26
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

added in API level 26
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

added in API level 26
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

added in API level 26
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

added in API level 26
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

added in API level 26
public int hashCode ()

A hash code for this date.

Returns
int a suitable hash code based only on the Chronology and the date

isSupported

added in API level 26
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
All other ChronoField instances will return false.

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

Parameters
field TemporalField: the field to check, null returns false

Returns
boolean true if the field is supported on this date, false if not

lengthOfMonth

added in API level 26
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

added in API level 26
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

added in API level 27
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

added in API level 27
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

added in API level 26
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

added in API level 26
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

added in API level 26
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

added in API level 26
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

added in API level 26
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

added in API level 27
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

added in API level 27
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

added in API level 26
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

added in API level 26
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

added in API level 26
public String toString ()

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())
 

Returns
String a string representation of the object.

until

added in API level 26
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 choice should be made based on which makes the code more readable.

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

added in API level 26
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

added in API level 27
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

added in API level 27
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