Added in API level 26

IsoChronology

class IsoChronology : AbstractChronology, Serializable
kotlin.Any
   ↳ java.time.chrono.AbstractChronology
   ↳ java.time.chrono.IsoChronology

The ISO calendar system.

This chronology defines the rules of the ISO calendar system. This calendar system is based on the ISO-8601 standard, which is the de facto world calendar.

The fields are defined as follows:

  • era - There are two eras, 'Current Era' (CE) and 'Before Current Era' (BCE).
  • year-of-era - The year-of-era is the same as the proleptic-year for the current CE era. For the BCE era before the ISO epoch the year increases from 1 upwards as time goes backwards.
  • proleptic-year - The proleptic year is the same as the year-of-era for the current era. For the previous era, years have zero, then negative values.
  • month-of-year - There are 12 months in an ISO year, numbered from 1 to 12.
  • day-of-month - There are between 28 and 31 days in each of the ISO month, numbered from 1 to 31. Months 4, 6, 9 and 11 have 30 days, Months 1, 3, 5, 7, 8, 10 and 12 have 31 days. Month 2 has 28 days, or 29 in a leap year.
  • day-of-year - There are 365 days in a standard ISO year and 366 in a leap year. The days are numbered from 1 to 365 or 1 to 366.
  • leap-year - Leap years occur every 4 years, except where the year is divisble by 100 and not divisble by 400.

Summary

Public methods
LocalDate!
date(era: Era!, yearOfEra: Int, month: Int, dayOfMonth: Int)

Obtains an ISO local date from the era, year-of-era, month-of-year and day-of-month fields.

LocalDate!
date(prolepticYear: Int, month: Int, dayOfMonth: Int)

Obtains an ISO local date from the proleptic-year, month-of-year and day-of-month fields.

LocalDate!
date(temporal: TemporalAccessor!)

Obtains an ISO local date from another date-time object.

LocalDate!
dateEpochDay(epochDay: Long)

Obtains an ISO local date from the epoch-day.

LocalDate!

Obtains the current ISO local date from the system clock in the default time-zone.

LocalDate!
dateNow(zone: ZoneId!)

Obtains the current ISO local date from the system clock in the specified time-zone.

LocalDate!
dateNow(clock: Clock!)

Obtains the current ISO local date from the specified clock.

LocalDate!
dateYearDay(era: Era!, yearOfEra: Int, dayOfYear: Int)

Obtains an ISO local date from the era, year-of-era and day-of-year fields.

LocalDate!
dateYearDay(prolepticYear: Int, dayOfYear: Int)

Obtains an ISO local date from the proleptic-year and day-of-year fields.

Long
epochSecond(prolepticYear: Int, month: Int, dayOfMonth: Int, hour: Int, minute: Int, second: Int, zoneOffset: ZoneOffset!)

Gets the number of seconds from the epoch of 1970-01-01T00:00:00Z.

IsoEra!
eraOf(eraValue: Int)

MutableList<Era!>!

String!

Gets the calendar type of the underlying calendar system - 'iso8601'.

String!

Gets the ID of the chronology - 'ISO'.

Boolean
isLeapYear(prolepticYear: Long)

Checks if the year is a leap year, according to the ISO proleptic calendar system rules.

LocalDateTime!

Obtains an ISO local date-time from another date-time object.

Period!
period(years: Int, months: Int, days: Int)

Obtains a period for this chronology based on years, months and days.

Int
prolepticYear(era: Era!, yearOfEra: Int)

ValueRange!
range(field: ChronoField!)

LocalDate!
resolveDate(fieldValues: MutableMap<TemporalField!, Long!>!, resolverStyle: ResolverStyle!)

Resolves parsed ChronoField values into a date during parsing.

ZonedDateTime!

Obtains an ISO zoned date-time from another date-time object.

ZonedDateTime!
zonedDateTime(instant: Instant!, zone: ZoneId!)

Obtains an ISO zoned date-time in this chronology from an Instant.

Inherited functions
Properties
static IsoChronology!

Singleton instance of the ISO chronology.

Public methods

date

Added in API level 26
fun date(
    era: Era!,
    yearOfEra: Int,
    month: Int,
    dayOfMonth: Int
): LocalDate!

Obtains an ISO local date from the era, year-of-era, month-of-year and day-of-month fields.

Parameters
era Era!: the ISO era, not null
yearOfEra Int: the ISO year-of-era
month Int: the ISO month-of-year
dayOfMonth Int: the ISO day-of-month
Return
LocalDate! the ISO local date, not null
Exceptions
java.time.DateTimeException if unable to create the date
java.lang.ClassCastException if the type of era is not IsoEra

date

Added in API level 26
fun date(
    prolepticYear: Int,
    month: Int,
    dayOfMonth: Int
): LocalDate!

Obtains an ISO local date from the proleptic-year, month-of-year and day-of-month fields.

This is equivalent to LocalDate#of(int, int, int).

Parameters
prolepticYear Int: the ISO proleptic-year
month Int: the ISO month-of-year
dayOfMonth Int: the ISO day-of-month
Return
LocalDate! the ISO local date, not null
Exceptions
java.time.DateTimeException if unable to create the date

date

Added in API level 26
fun date(temporal: TemporalAccessor!): LocalDate!

Obtains an ISO local date from another date-time object.

This is equivalent to java.time.LocalDate#from(java.time.temporal.TemporalAccessor).

Parameters
temporal TemporalAccessor!: the date-time object to convert, not null
Return
LocalDate! the ISO local date, not null
Exceptions
java.time.DateTimeException if unable to create the date

dateEpochDay

Added in API level 26
fun dateEpochDay(epochDay: Long): LocalDate!

Obtains an ISO local date from the epoch-day.

This is equivalent to LocalDate#ofEpochDay(long).

Parameters
epochDay Long: the epoch day
Return
LocalDate! the ISO local date, not null
Exceptions
java.time.DateTimeException if unable to create the date

dateNow

Added in API level 26
fun dateNow(): LocalDate!

Obtains the current ISO local date 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.

Return
LocalDate! the current ISO local date using the system clock and default time-zone, not null
Exceptions
java.time.DateTimeException if unable to create the date

dateNow

Added in API level 26
fun dateNow(zone: ZoneId!): LocalDate!

Obtains the current ISO local date 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
Return
LocalDate! the current ISO local date using the system clock, not null
Exceptions
java.time.DateTimeException if unable to create the date

dateNow

Added in API level 26
fun dateNow(clock: Clock!): LocalDate!

Obtains the current ISO local date 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
Return
LocalDate! the current ISO local date, not null
Exceptions
java.time.DateTimeException if unable to create the date

dateYearDay

Added in API level 26
fun dateYearDay(
    era: Era!,
    yearOfEra: Int,
    dayOfYear: Int
): LocalDate!

Obtains an ISO local date from the era, year-of-era and day-of-year fields.

Parameters
era Era!: the ISO era, not null
yearOfEra Int: the ISO year-of-era
dayOfYear Int: the ISO day-of-year
Return
LocalDate! the ISO local date, not null
Exceptions
java.time.DateTimeException if unable to create the date
java.lang.ClassCastException if the era is not of the correct type for the chronology

dateYearDay

Added in API level 26
fun dateYearDay(
    prolepticYear: Int,
    dayOfYear: Int
): LocalDate!

Obtains an ISO local date from the proleptic-year and day-of-year fields.

This is equivalent to LocalDate#ofYearDay(int, int).

Parameters
prolepticYear Int: the ISO proleptic-year
dayOfYear Int: the ISO day-of-year
Return
LocalDate! the ISO local date, not null
Exceptions
java.time.DateTimeException if unable to create the date

epochSecond

Added in API level 34
fun epochSecond(
    prolepticYear: Int,
    month: Int,
    dayOfMonth: Int,
    hour: Int,
    minute: Int,
    second: Int,
    zoneOffset: ZoneOffset!
): Long

Gets the number of seconds from the epoch of 1970-01-01T00:00:00Z.

The number of seconds is calculated using the year, month, day-of-month, hour, minute, second, and zoneOffset.

Parameters
prolepticYear Int: the year, from MIN_YEAR to MAX_YEAR
month Int: the month-of-year, from 1 to 12
dayOfMonth Int: the day-of-month, from 1 to 31
hour Int: the hour-of-day, from 0 to 23
minute Int: the minute-of-hour, from 0 to 59
second Int: the second-of-minute, from 0 to 59
zoneOffset ZoneOffset!: the zone offset, not null
Return
Long the number of seconds relative to 1970-01-01T00:00:00Z, may be negative
Exceptions
java.time.DateTimeException if the value of any argument is out of range, or if the day-of-month is invalid for the month-of-year

eraOf

Added in API level 26
fun eraOf(eraValue: Int): IsoEra!
Parameters
eraValue Int: the era value
Return
IsoEra! the calendar system era, not null
Exceptions
java.time.DateTimeException if unable to create the era

eras

Added in API level 26
fun eras(): MutableList<Era!>!
Return
MutableList<Era!>! the list of eras for the chronology, may be immutable, not null

getCalendarType

Added in API level 26
fun getCalendarType(): String!

Gets the calendar type of the underlying calendar system - 'iso8601'.

The calendar type is an identifier defined by the Unicode Locale Data Markup Language (LDML) specification. It can be used to lookup the Chronology using Chronology#of(String). It can also be used as part of a locale, accessible via Locale#getUnicodeLocaleType(String) with the key 'ca'.

Return
String! the calendar system type - 'iso8601'

See Also

getId

Added in API level 26
fun getId(): String!

Gets the ID of the chronology - 'ISO'.

The ID uniquely identifies the Chronology. It can be used to lookup the Chronology using Chronology#of(String).

Return
String! the chronology ID - 'ISO'

isLeapYear

Added in API level 26
fun isLeapYear(prolepticYear: Long): Boolean

Checks if the year is a leap year, according to the ISO proleptic calendar system rules.

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.

Parameters
prolepticYear Long: the ISO proleptic year to check
Return
Boolean true if the year is leap, false otherwise

localDateTime

Added in API level 26
fun localDateTime(temporal: TemporalAccessor!): LocalDateTime!

Obtains an ISO local date-time from another date-time object.

This is equivalent to java.time.LocalDateTime#from(java.time.temporal.TemporalAccessor).

Parameters
temporal TemporalAccessor!: the date-time object to convert, not null
Return
LocalDateTime! the ISO local date-time, not null
Exceptions
java.time.DateTimeException if unable to create the date-time

period

Added in API level 26
fun period(
    years: Int,
    months: Int,
    days: Int
): Period!

Obtains a period for this chronology based on years, months and days.

This returns a period tied to the ISO chronology using the specified years, months and days. See Period for further details.

Parameters
years Int: the number of years, may be negative
months Int: the number of years, may be negative
days Int: the number of years, may be negative
Return
Period! the ISO period, not null

prolepticYear

Added in API level 26
fun prolepticYear(
    era: Era!,
    yearOfEra: Int
): Int
Parameters
era Era!: the era of the correct type for the chronology, not null
yearOfEra Int: the chronology year-of-era
Return
Int the proleptic-year
Exceptions
java.time.DateTimeException if unable to convert to a proleptic-year, such as if the year is invalid for the era
java.lang.ClassCastException if the era is not of the correct type for the chronology

range

Added in API level 26
fun range(field: ChronoField!): ValueRange!
Parameters
field ChronoField!: the field to get the range for, not null
Return
ValueRange! the range of valid values for the field, not null
Exceptions
java.time.DateTimeException if the range for the field cannot be obtained

resolveDate

Added in API level 26
fun resolveDate(
    fieldValues: MutableMap<TemporalField!, Long!>!,
    resolverStyle: ResolverStyle!
): LocalDate!

Resolves parsed ChronoField values into a date during parsing.

Most TemporalField implementations are resolved using the resolve method on the field. By contrast, the ChronoField class defines fields that only have meaning relative to the chronology. As such, ChronoField date fields are resolved here in the context of a specific chronology.

ChronoField instances on the ISO calendar system are resolved as follows.

  • EPOCH_DAY - If present, this is converted to a LocalDate and all other date fields are then cross-checked against the date.
  • PROLEPTIC_MONTH - If present, then it is split into the YEAR and MONTH_OF_YEAR. If the mode is strict or smart then the field is validated.
  • YEAR_OF_ERA and ERA - If both are present, then they are combined to form a YEAR. In lenient mode, the YEAR_OF_ERA range is not validated, in smart and strict mode it is. The ERA is validated for range in all three modes. If only the YEAR_OF_ERA is present, and the mode is smart or lenient, then the current era (CE/AD) is assumed. In strict mode, no era is assumed and the YEAR_OF_ERA is left untouched. If only the ERA is present, then it is left untouched.
  • YEAR, MONTH_OF_YEAR and DAY_OF_MONTH - If all three are present, then they are combined to form a LocalDate. In all three modes, the YEAR is validated. If the mode is smart or strict, then the month and day are validated, with the day validated from 1 to 31. If the mode is lenient, then the date is combined in a manner equivalent to creating a date on the first of January in the requested year, then adding the difference in months, then the difference in days. If the mode is smart, and the day-of-month is greater than the maximum for the year-month, then the day-of-month is adjusted to the last day-of-month. If the mode is strict, then the three fields must form a valid date.
  • YEAR and DAY_OF_YEAR - If both are present, then they are combined to form a LocalDate. In all three modes, the YEAR is validated. If the mode is lenient, then the date is combined in a manner equivalent to creating a date on the first of January in the requested year, then adding the difference in days. If the mode is smart or strict, then the two fields must form a valid date.
  • YEAR, MONTH_OF_YEAR, ALIGNED_WEEK_OF_MONTH and ALIGNED_DAY_OF_WEEK_IN_MONTH - If all four are present, then they are combined to form a LocalDate. In all three modes, the YEAR is validated. If the mode is lenient, then the date is combined in a manner equivalent to creating a date on the first of January in the requested year, then adding the difference in months, then the difference in weeks, then in days. If the mode is smart or strict, then the all four fields are validated to their outer ranges. The date is then combined in a manner equivalent to creating a date on the first day of the requested year and month, then adding the amount in weeks and days to reach their values. If the mode is strict, the date is additionally validated to check that the day and week adjustment did not change the month.
  • YEAR, MONTH_OF_YEAR, ALIGNED_WEEK_OF_MONTH and DAY_OF_WEEK - If all four are present, then they are combined to form a LocalDate. The approach is the same as described above for years, months and weeks in ALIGNED_DAY_OF_WEEK_IN_MONTH. The day-of-week is adjusted as the next or same matching day-of-week once the years, months and weeks have been handled.
  • YEAR, ALIGNED_WEEK_OF_YEAR and ALIGNED_DAY_OF_WEEK_IN_YEAR - If all three are present, then they are combined to form a LocalDate. In all three modes, the YEAR is validated. If the mode is lenient, then the date is combined in a manner equivalent to creating a date on the first of January in the requested year, then adding the difference in weeks, then in days. If the mode is smart or strict, then the all three fields are validated to their outer ranges. The date is then combined in a manner equivalent to creating a date on the first day of the requested year, then adding the amount in weeks and days to reach their values. If the mode is strict, the date is additionally validated to check that the day and week adjustment did not change the year.
  • YEAR, ALIGNED_WEEK_OF_YEAR and DAY_OF_WEEK - If all three are present, then they are combined to form a LocalDate. The approach is the same as described above for years and weeks in ALIGNED_DAY_OF_WEEK_IN_YEAR. The day-of-week is adjusted as the next or same matching day-of-week once the years and weeks have been handled.
Parameters
fieldValues MutableMap<TemporalField!, Long!>!: the map of fields to values, which can be updated, not null
resolverStyle ResolverStyle!: the requested type of resolve, not null
Return
LocalDate! the resolved date, null if insufficient information to create a date
Exceptions
java.time.DateTimeException if the date cannot be resolved, typically because of a conflict in the input data

zonedDateTime

Added in API level 26
fun zonedDateTime(temporal: TemporalAccessor!): ZonedDateTime!

Obtains an ISO zoned date-time from another date-time object.

This is equivalent to java.time.ZonedDateTime#from(java.time.temporal.TemporalAccessor).

Parameters
temporal TemporalAccessor!: the date-time object to convert, not null
Return
ZonedDateTime! the ISO zoned date-time, not null
Exceptions
java.time.DateTimeException if unable to create the date-time

zonedDateTime

Added in API level 26
fun zonedDateTime(
    instant: Instant!,
    zone: ZoneId!
): ZonedDateTime!

Obtains an ISO zoned date-time in this chronology from an Instant.

This is equivalent to ZonedDateTime#ofInstant(Instant, ZoneId).

Parameters
instant Instant!: the instant to create the date-time from, not null
zone ZoneId!: the time-zone, not null
Return
ZonedDateTime! the zoned date-time, not null
Exceptions
java.time.DateTimeException if the result exceeds the supported range

Properties

INSTANCE

Added in API level 26
static val INSTANCE: IsoChronology!

Singleton instance of the ISO chronology.