Chronology

compareTo

abstract fun compareTo(other: Chronology!): Int

Compares this chronology to another chronology.

The comparison order first by the chronology ID string, then by any additional information specific to the subclass. It is "consistent with equals", as defined by Comparable.

date

open fun date(
    era: Era!, 
    yearOfEra: Int, 
    month: Int, 
    dayOfMonth: Int
): ChronoLocalDate!

Obtains a local date in this chronology from the era, year-of-era, month-of-year and day-of-month fields.

date

abstract fun date(
    prolepticYear: Int, 
    month: Int, 
    dayOfMonth: Int
): ChronoLocalDate!

Obtains a local date in this chronology from the proleptic-year, month-of-year and day-of-month fields.

date

abstract fun date(temporal: TemporalAccessor!): ChronoLocalDate!

Obtains a local date in this chronology from another temporal object.

This obtains a date in this chronology based on the specified temporal. A TemporalAccessor represents an arbitrary set of date and time information, which this factory converts to an instance of ChronoLocalDate.

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, aChronology::date.

dateEpochDay

abstract fun dateEpochDay(epochDay: Long): ChronoLocalDate!

Obtains a local date in this chronology from the epoch-day.

The definition of EPOCH_DAY is the same for all calendar systems, thus it can be used for conversion.

dateNow

open fun dateNow(): ChronoLocalDate!

Obtains the current local date in this chronology 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.

dateNow

open fun dateNow(zone: ZoneId!): ChronoLocalDate!

Obtains the current local date in this chronology 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.

dateNow

open fun dateNow(clock: Clock!): ChronoLocalDate!

Obtains the current local date in this chronology 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.

dateYearDay

open fun dateYearDay(
    era: Era!, 
    yearOfEra: Int, 
    dayOfYear: Int
): ChronoLocalDate!

Obtains a local date in this chronology from the era, year-of-era and day-of-year fields.

dateYearDay

abstract fun dateYearDay(
    prolepticYear: Int, 
    dayOfYear: Int
): ChronoLocalDate!

Obtains a local date in this chronology from the proleptic-year and day-of-year fields.

epochSecond

open 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 proleptic-year, month, day-of-month, hour, minute, second, and zoneOffset.

epochSecond

open fun epochSecond(
    era: Era!, 
    yearOfEra: 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 era, year-of-era, month, day-of-month, hour, minute, second, and zoneOffset.

eraOf

abstract fun eraOf(eraValue: Int): Era!

Creates the chronology era object from the numeric value.

The era is, conceptually, the largest division of the time-line. Most calendar systems have a single epoch dividing the time-line into two eras. However, some have multiple eras, such as one for the reign of each leader. The exact meaning is determined by the chronology according to the following constraints.

The era in use at 1970-01-01 must have the value 1. Later eras must have sequentially higher values. Earlier eras must have sequentially lower values. Each chronology must refer to an enum or similar singleton to provide the era values.

This method returns the singleton era of the correct type for the specified era value.

eras

abstract fun eras(): MutableList<Era!>!

Gets the list of eras for the chronology.

Most calendar systems have an era, within which the year has meaning. If the calendar system does not support the concept of eras, an empty list must be returned.

from

open static fun from(temporal: TemporalAccessor!): Chronology!

Obtains an instance of Chronology from a temporal object.

This obtains a chronology based on the specified temporal. A TemporalAccessor represents an arbitrary set of date and time information, which this factory converts to an instance of Chronology.

The conversion will obtain the chronology using TemporalQueries#chronology(). If the specified temporal object does not have a chronology, IsoChronology is returned.

This method matches the signature of the functional interface TemporalQuery allowing it to be used as a query via method reference, Chronology::from.

getAvailableChronologies

open static fun getAvailableChronologies(): MutableSet<Chronology!>!

Returns the available chronologies.

Each returned Chronology is available for use in the system. The set of chronologies includes the system chronologies and any chronologies provided by the application via ServiceLoader configuration.

getCalendarType

abstract fun getCalendarType(): String!

Gets the calendar type of the calendar system.

The calendar type is an identifier defined by the CLDR and Unicode Locale Data Markup Language (LDML) specifications to uniquely identify a calendar. The getCalendarType is the concatenation of the CLDR calendar type and the variant, if applicable, is appended separated by "-". The calendar type is used to lookup the Chronology using of(java.lang.String).

getDisplayName

open fun getDisplayName(
    style: TextStyle!, 
    locale: Locale!
): String!

Gets the textual representation of this chronology.

This returns the textual name used to identify the chronology, suitable for presentation to the user. The parameters control the style of the returned text and the locale.

getId

abstract fun getId(): String!

Gets the ID of the chronology.

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

isLeapYear

abstract fun isLeapYear(prolepticYear: Long): Boolean

Checks if the specified year is a leap year.

A leap-year is a year of a longer length than normal. The exact meaning is determined by the chronology according to the following constraints.

• a leap-year must imply a year-length longer than a non leap-year.
• a chronology that does not support the concept of a year must return false.
• the correct result must be returned for all years within the valid range of years for the chronology.

Outside the range of valid years an implementation is free to return either a best guess or false. An implementation must not throw an exception, even if the year is outside the range of valid years.

localDateTime

open fun localDateTime(temporal: TemporalAccessor!): ChronoLocalDateTime<out ChronoLocalDate!>!

Obtains a local date-time in this chronology from another temporal object.

This obtains a date-time in this chronology based on the specified temporal. A TemporalAccessor represents an arbitrary set of date and time information, which this factory converts to an instance of ChronoLocalDateTime.

The conversion extracts and combines the ChronoLocalDate and the LocalTime from the temporal object. Implementations are permitted to perform optimizations such as accessing those fields that are equivalent to the relevant objects. The result uses this chronology.

This method matches the signature of the functional interface TemporalQuery allowing it to be used as a query via method reference, aChronology::localDateTime.

of

open static fun of(id: String!): Chronology!

Obtains an instance of Chronology from a chronology ID or calendar system type.

This returns a chronology based on either the ID or the type. The chronology ID uniquely identifies the chronology. The calendar system type is defined by the CLDR specification.

The chronology may be a system chronology or a chronology provided by the application via ServiceLoader configuration.

Since some calendars can be customized, the ID or type typically refers to the default customization. For example, the Gregorian calendar can have multiple cutover dates from the Julian, but the lookup only provides the default cutover date.

ofLocale

open static fun ofLocale(locale: Locale!): Chronology!

Obtains an instance of Chronology from a locale.

This returns a Chronology based on the specified locale, typically returning IsoChronology. Other calendar systems are only returned if they are explicitly selected within the locale.

The Locale class provide access to a range of information useful for localizing an application. This includes the language and region, such as "en-GB" for English as used in Great Britain.

The Locale class also supports an extension mechanism that can be used to identify a calendar system. The mechanism is a form of key-value pairs, where the calendar system has the key "ca". For example, the locale "en-JP-u-ca-japanese" represents the English language as used in Japan with the Japanese calendar system.

This method finds the desired calendar system in a manner equivalent to passing "ca" to Locale#getUnicodeLocaleType(String). If the "ca" key is not present, then IsoChronology is returned.

Note that the behavior of this method differs from the older java.util.Calendar#getInstance(Locale) method. If that method receives a locale of "th_TH" it will return BuddhistCalendar. By contrast, this method will return IsoChronology. Passing the locale "th-TH-u-ca-buddhist" into either method will result in the Thai Buddhist calendar system and is therefore the recommended approach going forward for Thai calendar system localization.

A similar, but simpler, situation occurs for the Japanese calendar system. The locale "jp_JP_JP" has previously been used to access the calendar. However, unlike the Thai locale, "ja_JP_JP" is automatically converted by Locale to the modern and recommended form of "ja-JP-u-ca-japanese". Thus, there is no difference in behavior between this method and Calendar#getInstance(Locale).

period

open fun period(
    years: Int, 
    months: Int, 
    days: Int
): ChronoPeriod!

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

This returns a period tied to this chronology using the specified years, months and days. All supplied chronologies use periods based on years, months and days, however the ChronoPeriod API allows the period to be represented using other units.

prolepticYear

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

Calculates the proleptic-year given the era and year-of-era.

This combines the era and year-of-era into the single proleptic-year field.

If the chronology makes active use of eras, such as JapaneseChronology then the year-of-era will be validated against the era. For other chronologies, validation is optional.

range

abstract fun range(field: ChronoField!): ValueRange!

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.

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.

This method will return a result whether or not the chronology supports the field.

resolveDate

abstract fun resolveDate(
    fieldValues: MutableMap<TemporalField!, Long!>!, 
    resolverStyle: ResolverStyle!
): ChronoLocalDate!

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.

The default implementation, which explains typical resolve behaviour, is provided in AbstractChronology.

zonedDateTime

open fun zonedDateTime(temporal: TemporalAccessor!): ChronoZonedDateTime<out ChronoLocalDate!>!

Obtains a ChronoZonedDateTime in this chronology from another temporal object.

This obtains a zoned date-time in this chronology based on the specified temporal. A TemporalAccessor represents an arbitrary set of date and time information, which this factory converts to an instance of ChronoZonedDateTime.

The conversion will first obtain a ZoneId from the temporal object, falling back to a ZoneOffset if necessary. It will then try to obtain an Instant, falling back to a ChronoLocalDateTime if necessary. The result will be either the combination of ZoneId or ZoneOffset with Instant or ChronoLocalDateTime. Implementations are permitted to perform optimizations such as accessing those fields that are equivalent to the relevant objects. The result uses this chronology.

This method matches the signature of the functional interface TemporalQuery allowing it to be used as a query via method reference, aChronology::zonedDateTime.

zonedDateTime

open fun zonedDateTime(
    instant: Instant!, 
    zone: ZoneId!
): ChronoZonedDateTime<out ChronoLocalDate!>!

Obtains a ChronoZonedDateTime in this chronology from an Instant.

This obtains a zoned date-time with the same instant as that specified.