- java.lang.Object
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- java.time.chrono.JapaneseDate
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- All Implemented Interfaces:
Serializable,Comparable<ChronoLocalDate>,ChronoLocalDate,Temporal,TemporalAccessor,TemporalAdjuster
public final class JapaneseDate extends Object implements ChronoLocalDate, Serializable
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".
CallingjapaneseDate.get(YEAR_OF_ERA)will return 24.
CallingjapaneseDate.get(YEAR)will return 2012.
CallingjapaneseDate.get(ERA)will return 2, corresponding toJapaneseChronology.ERA_HEISEI.
This is a value-based class; use of identity-sensitive operations (including reference equality (
==), identity hash code, or synchronization) on instances ofJapaneseDatemay have unpredictable results and should be avoided. Theequalsmethod should be used for comparisons.- Implementation Requirements:
- This class is immutable and thread-safe.
- Since:
- 1.8
- See Also:
- Serialized Form
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description booleanequals(Object obj)Compares this date to another date, including the chronology.static JapaneseDatefrom(TemporalAccessor temporal)Obtains aJapaneseDatefrom a temporal object.JapaneseChronologygetChronology()Gets the chronology of this date, which is the Japanese calendar system.JapaneseEragetEra()Gets the era applicable at this date.inthashCode()A hash code for this date.booleanisSupported(TemporalField field)Checks if the specified field is supported.intlengthOfMonth()Returns the length of the month represented by this date.JapaneseDateminus(TemporalAmount amount)Returns an object of the same type as this object with an amount subtracted.static JapaneseDatenow()Obtains the currentJapaneseDatefrom the system clock in the default time-zone.static JapaneseDatenow(Clock clock)Obtains the currentJapaneseDatefrom the specified clock.static JapaneseDatenow(ZoneId zone)Obtains the currentJapaneseDatefrom the system clock in the specified time-zone.static JapaneseDateof(int prolepticYear, int month, int dayOfMonth)Obtains aJapaneseDaterepresenting a date in the Japanese calendar system from the proleptic-year, month-of-year and day-of-month fields.static JapaneseDateof(JapaneseEra era, int yearOfEra, int month, int dayOfMonth)Obtains aJapaneseDaterepresenting a date in the Japanese calendar system from the era, year-of-era, month-of-year and day-of-month fields.JapaneseDateplus(TemporalAmount amount)Returns an object of the same type as this object with an amount added.StringtoString()Answers a string containing a concise, human-readable description of the receiver.longuntil(Temporal endExclusive, TemporalUnit unit)Calculates the amount of time until another date in terms of the specified unit.JapaneseDatewith(TemporalAdjuster adjuster)Returns an adjusted object of the same type as this object with the adjustment made.-
Methods declared in class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
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Methods declared in interface java.time.chrono.ChronoLocalDate
adjustInto, atTime, compareTo, format, isAfter, isBefore, isEqual, isLeapYear, isSupported, lengthOfYear, minus, plus, query, toEpochDay, toString, until, until, with
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Methods declared in interface java.time.temporal.TemporalAccessor
get, getLong, range
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Method Detail
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now
public static JapaneseDate now()
Obtains the currentJapaneseDatefrom the system clock in the default time-zone.This will query the
system clockin 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:
- the current date using the system clock and default time-zone, not null
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now
public static JapaneseDate now(ZoneId zone)
Obtains the currentJapaneseDatefrom the system clock in the specified time-zone.This will query the
system clockto 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- the zone ID to use, not null- Returns:
- the current date using the system clock, not null
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now
public static JapaneseDate now(Clock clock)
Obtains the currentJapaneseDatefrom 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- the clock to use, not null- Returns:
- the current date, not null
- Throws:
DateTimeException- if the current date cannot be obtained
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of
public static JapaneseDate of(JapaneseEra era, int yearOfEra, int month, int dayOfMonth)
Obtains aJapaneseDaterepresenting a date in the Japanese calendar system from the era, year-of-era, month-of-year and day-of-month fields.This returns a
JapaneseDatewith 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- the Japanese era, not nullyearOfEra- the Japanese year-of-eramonth- the Japanese month-of-year, from 1 to 12dayOfMonth- the Japanese day-of-month, from 1 to 31- Returns:
- 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
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of
public static JapaneseDate of(int prolepticYear, int month, int dayOfMonth)
Obtains aJapaneseDaterepresenting a date in the Japanese calendar system from the proleptic-year, month-of-year and day-of-month fields.This returns a
JapaneseDatewith 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- the Japanese proleptic-yearmonth- the Japanese month-of-year, from 1 to 12dayOfMonth- the Japanese day-of-month, from 1 to 31- Returns:
- 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
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from
public static JapaneseDate from(TemporalAccessor temporal)
Obtains aJapaneseDatefrom a temporal object.This obtains a date in the Japanese calendar system based on the specified temporal. A
TemporalAccessorrepresents an arbitrary set of date and time information, which this factory converts to an instance ofJapaneseDate.The conversion typically uses the
EPOCH_DAYfield, which is standardized across calendar systems.This method matches the signature of the functional interface
TemporalQueryallowing it to be used as a query via method reference,JapaneseDate::from.- Parameters:
temporal- the temporal object to convert, not null- Returns:
- the date in Japanese calendar system, not null
- Throws:
DateTimeException- if unable to convert to aJapaneseDate- See Also:
Chronology.date(TemporalAccessor)
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getChronology
public JapaneseChronology getChronology()
Gets the chronology of this date, which is the Japanese calendar system.The
Chronologyrepresents the calendar system in use. The era and other fields inChronoFieldare defined by the chronology.- Specified by:
getChronologyin interfaceChronoLocalDate- Returns:
- the Japanese chronology, not null
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getEra
public JapaneseEra getEra()
Gets the era applicable at this date.The Japanese calendar system has multiple eras defined by
JapaneseEra.- Specified by:
getErain interfaceChronoLocalDate- Returns:
- the era applicable at this date, not null
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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.
- Specified by:
lengthOfMonthin interfaceChronoLocalDate- Returns:
- the length of the month in days
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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
rangeandgetmethods will throw an exception.If the field is a
ChronoFieldthen the query is implemented here. The supported fields are:DAY_OF_WEEKDAY_OF_MONTHDAY_OF_YEAREPOCH_DAYMONTH_OF_YEARPROLEPTIC_MONTHYEAR_OF_ERAYEARERA
ChronoFieldinstances will return false.If the field is not a
ChronoField, then the result of this method is obtained by invokingTemporalField.isSupportedBy(TemporalAccessor)passingthisas the argument. Whether the field is supported is determined by the field.- Specified by:
isSupportedin interfaceChronoLocalDate- Specified by:
isSupportedin interfaceTemporalAccessor- Parameters:
field- the field to check, null returns false- Returns:
- true if the field is supported on this date, false if not
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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
- Specified by:
within interfaceChronoLocalDate- Specified by:
within interfaceTemporal- Parameters:
adjuster- the adjuster to use, not null- Returns:
- an object of the same type with the specified adjustment made, not null
- Throws:
DateTimeException- if unable to make the adjustmentArithmeticException- if numeric overflow occurs
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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
Periodbut may be any other type implementing theTemporalAmountinterface, such asDuration.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
plusfollowed byminusis not guaranteed to return the same date-time.- Specified by:
plusin interfaceChronoLocalDate- Specified by:
plusin interfaceTemporal- Parameters:
amount- the amount to add, not null- Returns:
- an object of the same type with the specified adjustment made, not null
- Throws:
DateTimeException- if the addition cannot be madeArithmeticException- if numeric overflow occurs
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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
Periodbut may be any other type implementing theTemporalAmountinterface, such asDuration.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
plusfollowed byminusis not guaranteed to return the same date-time.- Specified by:
minusin interfaceChronoLocalDate- Specified by:
minusin interfaceTemporal- Parameters:
amount- the amount to subtract, not null- Returns:
- an object of the same type with the specified adjustment made, not null
- Throws:
DateTimeException- if the subtraction cannot be madeArithmeticException- if numeric overflow occurs
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equals
public boolean equals(Object obj)
Compares this date to another date, including the chronology.Compares this
JapaneseDatewith another ensuring that the date is the same.Only objects of type
JapaneseDateare compared, other types return false. To compare the dates of twoTemporalAccessorinstances, including dates in two different chronologies, useChronoField.EPOCH_DAYas a comparator.- Specified by:
equalsin interfaceChronoLocalDate- Parameters:
obj- the object to check, null returns false- Returns:
- true if this is equal to the other date
- See Also:
Object.hashCode()
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hashCode
public int hashCode()
A hash code for this date.- Specified by:
hashCodein interfaceChronoLocalDate- Returns:
- a suitable hash code based only on the Chronology and the date
- See Also:
Object.equals(java.lang.Object)
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until
public long until(Temporal endExclusive, TemporalUnit unit)
Description copied from interface:ChronoLocalDateCalculates the amount of time until another date in terms of the specified unit.This calculates the amount of time between two
ChronoLocalDateobjects in terms of a singleTemporalUnit. The start and end points arethisand the specified date. The result will be negative if the end is before the start. TheTemporalpassed to this method is converted to aChronoLocalDateusingChronology.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 usingstartDate.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 unitsDAYS,WEEKS,MONTHS,YEARS,DECADES,CENTURIES,MILLENNIAandERASshould be supported by all implementations. OtherChronoUnitvalues will throw an exception.If the unit is not a
ChronoUnit, then the result of this method is obtained by invokingTemporalUnit.between(Temporal, Temporal)passingthisas the first argument and the converted input temporal as the second argument.This instance is immutable and unaffected by this method call.
- Specified by:
untilin interfaceChronoLocalDate- Specified by:
untilin interfaceTemporal- Parameters:
endExclusive- the end date, exclusive, which is converted to aChronoLocalDatein the same chronology, not nullunit- the unit to measure the amount in, not null- Returns:
- the amount of time between this date and the end date
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toString
public String toString()
Description copied from class:ObjectAnswers a string containing a concise, human-readable description of the receiver.- Specified by:
toStringin interfaceChronoLocalDate- Overrides:
toStringin classObject- Returns:
- String a printable representation for the receiver.
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