Package org.joda.time.chrono

Class IslamicChronology

  • All Implemented Interfaces:
    java.io.Serializable
    public final class IslamicChronology
extends AssembledChronology
    Implements the Islamic, or Hijri, calendar system using arithmetic rules.

    This calendar is a lunar calendar with a shorter year than ISO. Year 1 in the Islamic calendar began on July 16, 622 CE (Julian), thus Islamic years do not begin at the same time as Julian years. This chronology is not proleptic, as it does not allow dates before the first Islamic year.

    There are two basic forms of the Islamic calendar, the tabular and the observed. The observed form cannot easily be used by computers as it relies on human observation of the new moon. The tabular calendar, implemented here, is an arithmetical approximation of the observed form that follows relatively simple rules.

    The tabular form of the calendar defines 12 months of alternately 30 and 29 days. The last month is extended to 30 days in a leap year. Leap years occur according to a 30 year cycle. There are four recognised patterns of leap years in the 30 year cycle: 

     Years 2, 5, 7, 10, 13, 15, 18, 21, 24, 26 & 29 - 15-based, used by Microsoft
 Years 2, 5, 7, 10, 13, 16, 18, 21, 24, 26 & 29 - 16-based, most commonly used
 Years 2, 5, 8, 10, 13, 16, 19, 21, 24, 27 & 29 - Indian
 Years 2, 5, 8, 11, 13, 16, 19, 21, 24, 27 & 30 - Habash al-Hasib
    You can select which pattern to use via the factory methods, or use the default (16-based).

    This implementation defines a day as midnight to midnight exactly as per the ISO chronology. This correct start of day is at sunset on the previous day, however this cannot readily be modelled and has been ignored.

    IslamicChronology is thread-safe and immutable.

    Since:
    1.2
    See Also:
    Wikipedia, Serialized Form

    • Method Detail

      • getInstanceUTC

        public static IslamicChronology getInstanceUTC()
        Gets an instance of the IslamicChronology. The time zone of the returned instance is UTC.
        Returns:
        a singleton UTC instance of the chronology

      • getInstance

        public static IslamicChronology getInstance()
        Gets an instance of the IslamicChronology in the default time zone.
        Returns:
        a chronology in the default time zone

      • getInstance

        public static IslamicChronology getInstance​(DateTimeZone zone)
        Gets an instance of the IslamicChronology in the given time zone.
        Parameters:
        zone - the time zone to get the chronology in, null is default
        Returns:
        a chronology in the specified time zone

      • getInstance

        public static IslamicChronology getInstance​(DateTimeZone zone,
                                            IslamicChronology.LeapYearPatternType leapYears)
        Gets an instance of the IslamicChronology in the given time zone.
        Parameters:
        zone - the time zone to get the chronology in, null is default
        leapYears - the type defining the leap year pattern
        Returns:
        a chronology in the specified time zone

      • withUTC

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

      • equals

        public boolean equals​(java.lang.Object obj)
        Checks if this chronology instance equals another.
        Parameters:
        obj - the object to compare to
        Returns:
        true if equal
        Since:
        2.3

      • hashCode

        public int hashCode()
        A suitable hash code for the chronology.
        Returns:
        the hash code
        Since:
        1.6

      • 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

      • getDateTimeMillis

        public long getDateTimeMillis​(int year,
                              int monthOfYear,
                              int dayOfMonth,
                              int millisOfDay)
                       throws java.lang.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:
        java.lang.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 java.lang.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:
        java.lang.IllegalArgumentException - if the values are invalid

      • getMinimumDaysInFirstWeek

        public int getMinimumDaysInFirstWeek()

      • toString

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