Class DiscordianDate

  • All Implemented Interfaces:
    Serializable, Comparable<ChronoLocalDate>, ChronoLocalDate, Temporal, TemporalAccessor, TemporalAdjuster

    public final class DiscordianDate
    extends Object
    implements ChronoLocalDate, Serializable
    A date in the Discordian calendar system.

    This date operates using the Discordian calendar. This calendar system is used by some adherents to Discordianism. The Discordian differs from the Gregorian in terms of the length of the week and month, and uses an offset year. Dates are aligned such that 0001-01-01 (Discordian) is -1165-01-01 (ISO).

    Implementation Requirements

    This class is immutable and thread-safe.

    This class must be treated as a value type. Do not synchronize, rely on the identity hash code or use the distinction between equals() and ==.

    See Also:
    Serialized Form
    • Method Detail

      • now

        public static DiscordianDate now()
        Obtains the current DiscordianDate 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 date using the system clock and default time-zone, not null
      • now

        public static DiscordianDate now​(ZoneId zone)
        Obtains the current DiscordianDate 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 - the zone ID to use, not null
        Returns:
        the current date using the system clock, not null
      • now

        public static DiscordianDate now​(Clock clock)
        Obtains the current DiscordianDate 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 date, not null
        Throws:
        DateTimeException - if the current date cannot be obtained
      • of

        public static DiscordianDate of​(int prolepticYear,
                                        int month,
                                        int dayOfMonth)
        Obtains a DiscordianDate representing a date in the Discordian calendar system from the proleptic-year, month-of-year and day-of-month fields.

        This returns a DiscordianDate with the specified fields. The day must be valid for the year and month, otherwise an exception will be thrown.

        St. Tib's Day is indicated by specifying 0 for both month and day-of-month.

        Parameters:
        prolepticYear - the Discordian proleptic-year
        month - the Discordian month-of-year, from 1 to 5
        dayOfMonth - the Discordian day-of-month, from 1 to 73
        Returns:
        the date in Discordian calendar system, not null
        Throws:
        DateTimeException - if the value of any field is out of range, or if the day-of-month is invalid for the month-year
      • from

        public static DiscordianDate from​(TemporalAccessor temporal)
        Obtains a DiscordianDate from a temporal object.

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

        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, DiscordianDate::from.

        Parameters:
        temporal - the temporal object to convert, not null
        Returns:
        the date in Discordian calendar system, not null
        Throws:
        DateTimeException - if unable to convert to a DiscordianDate
      • getChronology

        public DiscordianChronology getChronology()
        Gets the chronology of this date, which is the Discordian calendar system.

        The Chronology represents the calendar system in use. The era and other fields in ChronoField are defined by the chronology.

        Specified by:
        getChronology in interface ChronoLocalDate
        Returns:
        the Discordian chronology, not null
      • getEra

        public DiscordianEra getEra()
        Gets the era applicable at this date.

        The Discordian calendar system has one era, 'YOLD', defined by DiscordianEra.

        Specified by:
        getEra in interface ChronoLocalDate
        Returns:
        the era YOLD, not null
      • equals

        public boolean equals​(Object obj)
        Compares this date to another date, including the chronology.

        Compares this date with another ensuring that the date is the same.

        Only objects of this concrete type are compared, other types return false. To compare the dates of two TemporalAccessor instances, including dates in two different chronologies, use ChronoField.EPOCH_DAY as a comparator.

        Specified by:
        equals in interface ChronoLocalDate
        Overrides:
        equals in class Object
        Parameters:
        obj - the object to check, null returns false
        Returns:
        true if this is equal to the other date
      • hashCode

        public int hashCode()
        A hash code for this date.
        Specified by:
        hashCode in interface ChronoLocalDate
        Overrides:
        hashCode in class Object
        Returns:
        a suitable hash code based only on the Chronology and the date