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.
Field Summary
public static final IsoChronology | INSTANCE | Singleton instance of the ISO chronology. |
Public Method Summary
LocalDate |
date(int prolepticYear, int month, int dayOfMonth)
Obtains an ISO local date from the proleptic-year, month-of-year
and day-of-month fields.
|
LocalDate | |
LocalDate | |
LocalDate |
dateEpochDay(long epochDay)
Obtains an ISO local date from the epoch-day.
|
LocalDate | |
LocalDate |
dateNow()
Obtains the current ISO local date from the system clock in the default time-zone.
|
LocalDate | |
LocalDate |
dateYearDay(Era era, int yearOfEra, int dayOfYear)
Obtains an ISO local date from the era, year-of-era and day-of-year fields.
|
LocalDate |
dateYearDay(int prolepticYear, int dayOfYear)
Obtains an ISO local date from the proleptic-year and day-of-year fields.
|
IsoEra |
eraOf(int eraValue)
|
List<Era> |
eras()
|
String |
getCalendarType()
Gets the calendar type of the underlying calendar system - 'iso8601'.
|
String |
getId()
Gets the ID of the chronology - 'ISO'.
|
boolean |
isLeapYear(long prolepticYear)
Checks if the year is a leap year, according to the ISO proleptic
calendar system rules.
|
LocalDateTime |
localDateTime(TemporalAccessor temporal)
Obtains an ISO local date-time from another date-time object.
|
Period |
period(int years, int months, int days)
Obtains a period for this chronology based on years, months and days.
|
int |
prolepticYear(Era era, int yearOfEra)
|
ValueRange |
range(ChronoField field)
|
LocalDate |
resolveDate(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle)
Resolves parsed
ChronoField values into a date during parsing. |
ZonedDateTime |
zonedDateTime(TemporalAccessor temporal)
Obtains an ISO zoned date-time from another date-time object.
|
ZonedDateTime |
zonedDateTime(Instant instant, ZoneId zone)
Obtains an ISO zoned date-time in this chronology from an
Instant . |
Inherited Method Summary
Fields
public static final IsoChronology INSTANCE
Singleton instance of the ISO chronology.
Public Methods
public LocalDate date (int prolepticYear, int month, int dayOfMonth)
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 | the ISO proleptic-year |
---|---|
month | the ISO month-of-year |
dayOfMonth | the ISO day-of-month |
Returns
- the ISO local date, not null
Throws
DateTimeException | if unable to create the date |
---|
public LocalDate date (Era era, int yearOfEra, int month, int dayOfMonth)
Obtains an ISO local date from the era, year-of-era, month-of-year and day-of-month fields.
Parameters
era | the ISO era, not null |
---|---|
yearOfEra | the ISO year-of-era |
month | the ISO month-of-year |
dayOfMonth | the ISO day-of-month |
Returns
- the ISO local date, not null
Throws
DateTimeException | if unable to create the date |
---|---|
ClassCastException | if the type of era is not IsoEra
|
public LocalDate date (TemporalAccessor temporal)
Obtains an ISO local date from another date-time object.
This is equivalent to LocalDate.from(TemporalAccessor)
.
Parameters
temporal | the date-time object to convert, not null |
---|
Returns
- the ISO local date, not null
Throws
DateTimeException | if unable to create the date |
---|
public LocalDate dateEpochDay (long epochDay)
Obtains an ISO local date from the epoch-day.
This is equivalent to LocalDate.ofEpochDay(long)
.
Parameters
epochDay | the epoch day |
---|
Returns
- the ISO local date, not null
Throws
DateTimeException | if unable to create the date |
---|
public LocalDate dateNow (ZoneId zone)
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 |
---|
Returns
- the current ISO local date using the system clock, not null
Throws
DateTimeException | if unable to create the date |
---|
public LocalDate dateNow ()
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.
Returns
- the current ISO local date using the system clock and default time-zone, not null
Throws
DateTimeException | if unable to create the date |
---|
public LocalDate dateNow (Clock clock)
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 | the clock to use, not null |
---|
Returns
- the current ISO local date, not null
Throws
DateTimeException | if unable to create the date |
---|
public LocalDate dateYearDay (Era era, int yearOfEra, int dayOfYear)
Obtains an ISO local date from the era, year-of-era and day-of-year fields.
Parameters
era | the ISO era, not null |
---|---|
yearOfEra | the ISO year-of-era |
dayOfYear | the ISO day-of-year |
Returns
- the ISO local date, not null
Throws
DateTimeException | if unable to create the date |
---|
public LocalDate dateYearDay (int prolepticYear, int dayOfYear)
Obtains an ISO local date from the proleptic-year and day-of-year fields.
This is equivalent to LocalDate.ofYearDay(int, int)
.
Parameters
prolepticYear | the ISO proleptic-year |
---|---|
dayOfYear | the ISO day-of-year |
Returns
- the ISO local date, not null
Throws
DateTimeException | if unable to create the date |
---|
public String getCalendarType ()
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'.
Returns
- the calendar system type - 'iso8601'
See Also
public String getId ()
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)
.
Returns
- the chronology ID - 'ISO'
See Also
public boolean isLeapYear (long prolepticYear)
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 | the ISO proleptic year to check |
---|
Returns
- true if the year is leap, false otherwise
public LocalDateTime localDateTime (TemporalAccessor temporal)
Obtains an ISO local date-time from another date-time object.
This is equivalent to LocalDateTime.from(TemporalAccessor)
.
Parameters
temporal | the date-time object to convert, not null |
---|
Returns
- the ISO local date-time, not null
Throws
DateTimeException | if unable to create the date-time |
---|
public Period period (int years, int months, int days)
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 | the number of years, may be negative |
---|---|
months | the number of years, may be negative |
days | the number of years, may be negative |
Returns
- the period in terms of this chronology, not nullthe ISO period, not null
public LocalDate resolveDate (Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle)
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 aLocalDate
and all other date fields are then cross-checked against the date.PROLEPTIC_MONTH
- If present, then it is split into theYEAR
andMONTH_OF_YEAR
. If the mode is strict or smart then the field is validated.YEAR_OF_ERA
andERA
- If both are present, then they are combined to form aYEAR
. In lenient mode, theYEAR_OF_ERA
range is not validated, in smart and strict mode it is. TheERA
is validated for range in all three modes. If only theYEAR_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 theYEAR_OF_ERA
is left untouched. If only theERA
is present, then it is left untouched.YEAR
,MONTH_OF_YEAR
andDAY_OF_MONTH
- If all three are present, then they are combined to form aLocalDate
. In all three modes, theYEAR
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
andDAY_OF_YEAR
- If both are present, then they are combined to form aLocalDate
. In all three modes, theYEAR
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
andALIGNED_DAY_OF_WEEK_IN_MONTH
- If all four are present, then they are combined to form aLocalDate
. In all three modes, theYEAR
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
andDAY_OF_WEEK
- If all four are present, then they are combined to form aLocalDate
. The approach is the same as described above for years, months and weeks inALIGNED_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
andALIGNED_DAY_OF_WEEK_IN_YEAR
- If all three are present, then they are combined to form aLocalDate
. In all three modes, theYEAR
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
andDAY_OF_WEEK
- If all three are present, then they are combined to form aLocalDate
. The approach is the same as described above for years and weeks inALIGNED_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 | the map of fields to values, which can be updated, not null |
---|---|
resolverStyle | the requested type of resolve, not null |
Returns
- the resolved date, null if insufficient information to create a date
Throws
DateTimeException | if the date cannot be resolved, typically because of a conflict in the input data |
---|
public ZonedDateTime zonedDateTime (TemporalAccessor temporal)
Obtains an ISO zoned date-time from another date-time object.
This is equivalent to ZonedDateTime.from(TemporalAccessor)
.
Parameters
temporal | the date-time object to convert, not null |
---|
Returns
- the ISO zoned date-time, not null
Throws
DateTimeException | if unable to create the date-time |
---|
public ZonedDateTime zonedDateTime (Instant instant, ZoneId zone)
Obtains an ISO zoned date-time in this chronology from an Instant
.
This is equivalent to ZonedDateTime.ofInstant(Instant, ZoneId)
.
Parameters
instant | the instant to create the date-time from, not null |
---|---|
zone | the time-zone, not null |
Returns
- the zoned date-time, not null
Throws
DateTimeException | if the result exceeds the supported range |
---|