Package org.joda.time.chrono

Class IslamicChronology

java.lang.Object
org.joda.time.Chronology
org.joda.time.chrono.BaseChronology
org.joda.time.chrono.AssembledChronology
org.joda.time.chrono.IslamicChronology
All Implemented Interfaces:
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 invalid input: '&' 29 - 15-based, used by Microsoft
 Years 2, 5, 7, 10, 13, 16, 18, 21, 24, 26 invalid input: '&' 29 - 16-based, most commonly used
 Years 2, 5, 8, 10, 13, 16, 19, 21, 24, 27 invalid input: '&' 29 - Indian
 Years 2, 5, 8, 11, 13, 16, 19, 21, 24, 27 invalid input: '&' 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:

  • Field Details

  • Method Details

    • 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

    • getLeapYearPatternType

      public IslamicChronology.LeapYearPatternType getLeapYearPatternType()
      Gets the leap year pattern type.
      Returns:
      the pattern type

    • 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:

    • equals

      public boolean equals(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 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

    • getMinimumDaysInFirstWeek

      public int getMinimumDaysInFirstWeek()

    • toString

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