Module org.threeten.extra
Package org.threeten.extra.chrono

Class 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:
    Serialized Form

    • Field Detail

      • INSTANCE

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

    • Constructor Detail

      • JulianChronology

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

    • Method Detail

      • 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()

      • 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:
        getId()

      • 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

      • 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