Class GJChronology

All Implemented Interfaces:
Serializable

public final class GJChronology extends AssembledChronology
Implements the Gregorian/Julian calendar system which is the calendar system used in most of the world. Wherever possible, it is recommended to use the ISOChronology instead.

The Gregorian calendar replaced the Julian calendar, and the point in time when this chronology switches can be controlled using the second parameter of the getInstance method. By default this cutover is set to the date the Gregorian calendar was first instituted, October 15, 1582.

Before this date, this chronology uses the proleptic Julian calendar (proleptic means extending indefinitely). The Julian calendar has leap years every four years, whereas the Gregorian has special rules for 100 and 400 years. A meaningful result will thus be obtained for all input values. However before 8 CE, Julian leap years were irregular, and before 45 BCE there was no Julian calendar.

This chronology differs from GregorianCalendar in that years in BCE are returned correctly. Thus year 1 BCE is returned as -1 instead of 1. The yearOfEra field produces results compatible with GregorianCalendar.

The Julian calendar does not have a year zero, and so year -1 is followed by year 1. If the Gregorian cutover date is specified at or before year -1 (Julian), year zero is defined. In other words, the proleptic Gregorian chronology used by this class has a year zero.

To create a pure proleptic Julian chronology, use JulianChronology, and to create a pure proleptic Gregorian chronology, use GregorianChronology.

GJChronology is thread-safe and immutable.

Since:
1.0
Author:
Brian S O'Neill, Stephen Colebourne
See Also:
  • Method Details

    • getInstanceUTC

      public static GJChronology getInstanceUTC()
      Factory method returns instances of the default GJ cutover chronology. This uses a cutover date of October 15, 1582 (Gregorian) 00:00:00 UTC. For this value, October 4, 1582 (Julian) is followed by October 15, 1582 (Gregorian).

      The first day of the week is designated to be Monday, and the minimum days in the first week of the year is 4.

      The time zone of the returned instance is UTC.

    • getInstance

      public static GJChronology getInstance()
      Factory method returns instances of the default GJ cutover chronology. This uses a cutover date of October 15, 1582 (Gregorian) 00:00:00 UTC. For this value, October 4, 1582 (Julian) is followed by October 15, 1582 (Gregorian).

      The first day of the week is designated to be Monday, and the minimum days in the first week of the year is 4.

      The returned chronology is in the default time zone.

    • getInstance

      public static GJChronology getInstance(DateTimeZone zone)
      Factory method returns instances of the GJ cutover chronology. This uses a cutover date of October 15, 1582 (Gregorian) 00:00:00 UTC. For this value, October 4, 1582 (Julian) is followed by October 15, 1582 (Gregorian).

      The first day of the week is designated to be Monday, and the minimum days in the first week of the year is 4.

      Parameters:
      zone - the time zone to use, null is default
    • getInstance

      public static GJChronology getInstance(DateTimeZone zone, ReadableInstant gregorianCutover)
      Factory method returns instances of the GJ cutover chronology. Any cutover date may be specified.

      The first day of the week is designated to be Monday, and the minimum days in the first week of the year is 4.

      Parameters:
      zone - the time zone to use, null is default
      gregorianCutover - the cutover to use, null means default
    • getInstance

      public static GJChronology getInstance(DateTimeZone zone, ReadableInstant gregorianCutover, int minDaysInFirstWeek)
      Factory method returns instances of the GJ cutover chronology. Any cutover date may be specified.
      Parameters:
      zone - the time zone to use, null is default
      gregorianCutover - the cutover to use, null means default
      minDaysInFirstWeek - minimum number of days in first week of the year; default is 4
    • getInstance

      public static GJChronology getInstance(DateTimeZone zone, long gregorianCutover, int minDaysInFirstWeek)
      Factory method returns instances of the GJ cutover chronology. Any cutover date may be specified.
      Parameters:
      zone - the time zone to use, null is default
      gregorianCutover - the cutover to use
      minDaysInFirstWeek - minimum number of days in first week of the year; default is 4
    • getZone

      public DateTimeZone getZone()
      Description copied from class: BaseChronology
      Returns the DateTimeZone that this Chronology operates in, or null if unspecified.
      Overrides:
      getZone in class AssembledChronology
      Returns:
      DateTimeZone null if unspecified
    • withUTC

      public Chronology withUTC()
      Gets the Chronology in the UTC time zone.
      Specified by:
      withUTC in class BaseChronology
      Returns:
      the chronology in UTC
    • withZone

      public Chronology withZone(DateTimeZone zone)
      Gets the Chronology in a specific time zone.
      Specified by:
      withZone in class BaseChronology
      Parameters:
      zone - the zone to get the chronology in, null is default
      Returns:
      the chronology
      See Also:
    • getDateTimeMillis

      public long getDateTimeMillis(int year, int monthOfYear, int dayOfMonth, int millisOfDay) throws IllegalArgumentException
      Description copied from class: BaseChronology
      Returns a datetime millisecond instant, formed from the given year, month, day, and millisecond values. The set of given values must refer to a valid datetime, or else an IllegalArgumentException is thrown.

      The default implementation calls upon separate DateTimeFields to determine the result. Subclasses are encouraged to provide a more efficient implementation.

      Overrides:
      getDateTimeMillis in class AssembledChronology
      Parameters:
      year - year to use
      monthOfYear - month to use
      dayOfMonth - day of month to use
      millisOfDay - millisecond to use
      Returns:
      millisecond instant from 1970-01-01T00:00:00Z
      Throws:
      IllegalArgumentException - if the values are invalid
    • getDateTimeMillis

      public long getDateTimeMillis(int year, int monthOfYear, int dayOfMonth, int hourOfDay, int minuteOfHour, int secondOfMinute, int millisOfSecond) throws IllegalArgumentException
      Description copied from class: BaseChronology
      Returns a datetime millisecond instant, formed from the given year, month, day, hour, minute, second, and millisecond values. The set of given values must refer to a valid datetime, or else an IllegalArgumentException is thrown.

      The default implementation calls upon separate DateTimeFields to determine the result. Subclasses are encouraged to provide a more efficient implementation.

      Overrides:
      getDateTimeMillis in class AssembledChronology
      Parameters:
      year - year to use
      monthOfYear - month to use
      dayOfMonth - day of month to use
      hourOfDay - hour to use
      minuteOfHour - minute to use
      secondOfMinute - second to use
      millisOfSecond - millisecond to use
      Returns:
      millisecond instant from 1970-01-01T00:00:00Z
      Throws:
      IllegalArgumentException - if the values are invalid
    • getGregorianCutover

      public Instant getGregorianCutover()
      Gets the cutover instant between Gregorian and Julian chronologies.
      Returns:
      the cutover instant
    • getMinimumDaysInFirstWeek

      public int getMinimumDaysInFirstWeek()
      Gets the minimum days needed for a week to be the first week in a year.
      Returns:
      the minimum days
    • equals

      public boolean equals(Object obj)
      Checks if this chronology instance equals another.
      Overrides:
      equals in class Object
      Parameters:
      obj - the object to compare to
      Returns:
      true if equal
      Since:
      1.6
    • hashCode

      public int hashCode()
      A suitable hash code for the chronology.
      Overrides:
      hashCode in class Object
      Returns:
      the hash code
      Since:
      1.6
    • toString

      public String toString()
      Gets a debugging toString.
      Specified by:
      toString in class BaseChronology
      Returns:
      a debugging string
    • assemble

      protected void assemble(AssembledChronology.Fields fields)
      Description copied from class: AssembledChronology
      Invoked by the constructor and after deserialization to allow subclasses to define all of its supported fields. All unset fields default to unsupported instances.
      Specified by:
      assemble in class AssembledChronology
      Parameters:
      fields - container of fields