Package org.threeten.extra.chrono

Class JulianChronology

java.lang.Object
java.time.chrono.AbstractChronology
org.threeten.extra.chrono.JulianChronology
All Implemented Interfaces:
Serializable, Comparable<Chronology>, Chronology
public final class JulianChronology extends AbstractChronology implements Serializable
The Julian calendar system.

This chronology defines the rules of the proleptic Julian calendar system. This calendar system is the forerunner to the modern Gregorian and ISO calendars. The Julian differs from the Gregorian only in terms of the leap year rule. Dates are aligned such that 0001-01-01 (Julian) is 0000-12-30 (ISO).

This class is proleptic. It implements Julian rules to the entire time-line.

This class implements a calendar where January 1st is the start of the year. The history of the start of the year is complex and using the current standard is the most consistent.

The fields are defined as follows:

  • era - There are two eras, the current 'Anno Domini' (AD) and the previous era 'Before Christ' (BC).
  • year-of-era - The year-of-era for the current era increases uniformly from the epoch at year one. For the previous era the year increases from one 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 a Julian year, numbered from 1 to 12.
  • day-of-month - There are between 28 and 31 days in each Julian 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 Julian 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.

Implementation Requirements

This class is immutable and thread-safe.
See Also:

  • Field Details

    • INSTANCE

      public static final JulianChronology INSTANCE
      Singleton instance for the Julian chronology.

  • Constructor Details

    • JulianChronology

      @Deprecated public JulianChronology()
      Deprecated.
      Use the singleton INSTANCE instead.
      Private constructor, that is public to satisfy the ServiceLoader.

  • Method Details

    • getId

      public String getId()
      Gets the ID of the chronology - 'Julian'.

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

      Specified by:
      getId in interface Chronology
      Returns:
      the chronology ID - 'Julian'
      See Also:

    • getCalendarType

      public String getCalendarType()
      Gets the calendar type of the underlying calendar system - 'julian'.

      The Unicode Locale Data Markup Language (LDML) specification does not define an identifier for the Julian calendar, but were it to do so, 'julian' is highly likely to be chosen.

      Specified by:
      getCalendarType in interface Chronology
      Returns:
      the calendar system type - 'julian'
      See Also:

    • date

      public JulianDate date(Era era, int yearOfEra, int month, int dayOfMonth)
      Obtains a local date in Julian calendar system from the era, year-of-era, month-of-year and day-of-month fields.
      Specified by:
      date in interface Chronology
      Parameters:
      era - the Julian era, not null
      yearOfEra - the year-of-era
      month - the month-of-year
      dayOfMonth - the day-of-month
      Returns:
      the Julian local date, not null
      Throws:
      DateTimeException - if unable to create the date
      ClassCastException - if the era is not a JulianEra

    • date

      public JulianDate date(int prolepticYear, int month, int dayOfMonth)
      Obtains a local date in Julian calendar system from the proleptic-year, month-of-year and day-of-month fields.
      Specified by:
      date in interface Chronology
      Parameters:
      prolepticYear - the proleptic-year
      month - the month-of-year
      dayOfMonth - the day-of-month
      Returns:
      the Julian local date, not null
      Throws:
      DateTimeException - if unable to create the date

    • dateYearDay

      public JulianDate dateYearDay(Era era, int yearOfEra, int dayOfYear)
      Obtains a local date in Julian calendar system from the era, year-of-era and day-of-year fields.
      Specified by:
      dateYearDay in interface Chronology
      Parameters:
      era - the Julian era, not null
      yearOfEra - the year-of-era
      dayOfYear - the day-of-year
      Returns:
      the Julian local date, not null
      Throws:
      DateTimeException - if unable to create the date
      ClassCastException - if the era is not a JulianEra

    • dateYearDay

      public JulianDate dateYearDay(int prolepticYear, int dayOfYear)
      Obtains a local date in Julian calendar system from the proleptic-year and day-of-year fields.
      Specified by:
      dateYearDay in interface Chronology
      Parameters:
      prolepticYear - the proleptic-year
      dayOfYear - the day-of-year
      Returns:
      the Julian local date, not null
      Throws:
      DateTimeException - if unable to create the date

    • dateEpochDay

      public JulianDate dateEpochDay(long epochDay)
      Obtains a local date in the Julian calendar system from the epoch-day.
      Specified by:
      dateEpochDay in interface Chronology
      Parameters:
      epochDay - the epoch day
      Returns:
      the Julian local date, not null
      Throws:
      DateTimeException - if unable to create the date

    • dateNow

      public JulianDate dateNow()
      Obtains the current Julian 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.

      Specified by:
      dateNow in interface Chronology
      Returns:
      the current Julian local date using the system clock and default time-zone, not null
      Throws:
      DateTimeException - if unable to create the date

    • dateNow

      public JulianDate dateNow(ZoneId zone)
      Obtains the current Julian 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.

      Specified by:
      dateNow in interface Chronology
      Parameters:
      zone - the zone ID to use, not null
      Returns:
      the current Julian local date using the system clock, not null
      Throws:
      DateTimeException - if unable to create the date

    • dateNow

      public JulianDate dateNow(Clock clock)
      Obtains the current Julian 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.

      Specified by:
      dateNow in interface Chronology
      Parameters:
      clock - the clock to use, not null
      Returns:
      the current Julian local date, not null
      Throws:
      DateTimeException - if unable to create the date

    • date

      public JulianDate date(TemporalAccessor temporal)
      Obtains a Julian local date from another date-time object.
      Specified by:
      date in interface Chronology
      Parameters:
      temporal - the date-time object to convert, not null
      Returns:
      the Julian local date, not null
      Throws:
      DateTimeException - if unable to create the date

    • localDateTime

      public ChronoLocalDateTime<JulianDate> localDateTime(TemporalAccessor temporal)
      Obtains a Julian local date-time from another date-time object.
      Specified by:
      localDateTime in interface Chronology
      Parameters:
      temporal - the date-time object to convert, not null
      Returns:
      the Julian local date-time, not null
      Throws:
      DateTimeException - if unable to create the date-time

    • zonedDateTime

      public ChronoZonedDateTime<JulianDate> zonedDateTime(TemporalAccessor temporal)
      Obtains a Julian zoned date-time from another date-time object.
      Specified by:
      zonedDateTime in interface Chronology
      Parameters:
      temporal - the date-time object to convert, not null
      Returns:
      the Julian zoned date-time, not null
      Throws:
      DateTimeException - if unable to create the date-time

    • zonedDateTime

      public ChronoZonedDateTime<JulianDate> zonedDateTime(Instant instant, ZoneId zone)
      Obtains a Julian zoned date-time in this chronology from an Instant.
      Specified by:
      zonedDateTime in interface Chronology
      Parameters:
      instant - the instant to create the date-time from, not null
      zone - the time-zone, not null
      Returns:
      the Julian zoned date-time, not null
      Throws:
      DateTimeException - if the result exceeds the supported range

    • isLeapYear

      public boolean isLeapYear(long prolepticYear)
      Checks if the specified year is a leap year.

      A Julian proleptic-year is leap if the remainder after division by four equals zero. This method does not validate the year passed in, and only has a well-defined result for years in the supported range.

      Specified by:
      isLeapYear in interface Chronology
      Parameters:
      prolepticYear - the proleptic-year to check, not validated for range
      Returns:
      true if the year is a leap year

    • prolepticYear

      public int prolepticYear(Era era, int yearOfEra)
      Specified by:
      prolepticYear in interface Chronology

    • eraOf

      public JulianEra eraOf(int eraValue)
      Specified by:
      eraOf in interface Chronology

    • eras

      public List<Era> eras()
      Specified by:
      eras in interface Chronology

    • range

      public ValueRange range(ChronoField field)
      Specified by:
      range in interface Chronology

    • resolveDate

      public @Nullable JulianDate resolveDate(Map<TemporalField,Long> fieldValues, ResolverStyle resolverStyle)
      Specified by:
      resolveDate in interface Chronology
      Overrides:
      resolveDate in class AbstractChronology