org.joda.time.chrono
Class IslamicChronology

java.lang.Object
  extended by org.joda.time.Chronology
      extended by org.joda.time.chrono.BaseChronology
          extended by org.joda.time.chrono.AssembledChronology
              extended by 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 & 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
Author:
Stephen Colebourne
See Also:
Wikipedia, Serialized Form

Nested Class Summary
static class IslamicChronology.LeapYearPatternType
          Opaque object describing a leap year pattern for the Islamic Chronology.
 
Nested classes/interfaces inherited from class org.joda.time.chrono.AssembledChronology
AssembledChronology.Fields
 
Field Summary
static int AH
          Constant value for 'Anno Hegirae', equivalent to the value returned for AD/CE.
static IslamicChronology.LeapYearPatternType LEAP_YEAR_15_BASED
          Leap year 15-based pattern.
static IslamicChronology.LeapYearPatternType LEAP_YEAR_16_BASED
          Leap year 16-based pattern.
static IslamicChronology.LeapYearPatternType LEAP_YEAR_HABASH_AL_HASIB
          Leap year Habash al-Hasib pattern.
static IslamicChronology.LeapYearPatternType LEAP_YEAR_INDIAN
          Leap year Indian pattern.
 
Method Summary
protected  void assemble(AssembledChronology.Fields fields)
          Invoked by the constructor and after deserialization to allow subclasses to define all of its supported fields.
 boolean equals(Object obj)
          Checks if this chronology instance equals another.
 long getDateTimeMillis(int year, int monthOfYear, int dayOfMonth, int millisOfDay)
          Returns a datetime millisecond instant, formed from the given year, month, day, and millisecond values.
 long getDateTimeMillis(int year, int monthOfYear, int dayOfMonth, int hourOfDay, int minuteOfHour, int secondOfMinute, int millisOfSecond)
          Returns a datetime millisecond instant, formed from the given year, month, day, hour, minute, second, and millisecond values.
static IslamicChronology getInstance()
          Gets an instance of the IslamicChronology in the default time zone.
static IslamicChronology getInstance(DateTimeZone zone)
          Gets an instance of the IslamicChronology in the given time zone.
static IslamicChronology getInstance(DateTimeZone zone, IslamicChronology.LeapYearPatternType leapYears)
          Gets an instance of the IslamicChronology in the given time zone.
static IslamicChronology getInstanceUTC()
          Gets an instance of the IslamicChronology.
 IslamicChronology.LeapYearPatternType getLeapYearPatternType()
          Gets the leap year pattern type.
 int getMinimumDaysInFirstWeek()
           
 DateTimeZone getZone()
          Returns the DateTimeZone that this Chronology operates in, or null if unspecified.
 int hashCode()
          A suitable hash code for the chronology.
 String toString()
          Gets a debugging toString.
 Chronology withUTC()
          Gets the Chronology in the UTC time zone.
 Chronology withZone(DateTimeZone zone)
          Gets the Chronology in a specific time zone.
 
Methods inherited from class org.joda.time.chrono.AssembledChronology
centuries, centuryOfEra, clockhourOfDay, clockhourOfHalfday, dayOfMonth, dayOfWeek, dayOfYear, days, era, eras, getBase, getDateTimeMillis, getParam, halfdayOfDay, halfdays, hourOfDay, hourOfHalfday, hours, millis, millisOfDay, millisOfSecond, minuteOfDay, minuteOfHour, minutes, monthOfYear, months, secondOfDay, secondOfMinute, seconds, weekOfWeekyear, weeks, weekyear, weekyearOfCentury, weekyears, year, yearOfCentury, yearOfEra, years
 
Methods inherited from class org.joda.time.chrono.BaseChronology
add, add, get, get, get, set, validate
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

AH

public static final int AH
Constant value for 'Anno Hegirae', equivalent to the value returned for AD/CE.

See Also:
Constant Field Values

LEAP_YEAR_15_BASED

public static final IslamicChronology.LeapYearPatternType LEAP_YEAR_15_BASED
Leap year 15-based pattern.


LEAP_YEAR_16_BASED

public static final IslamicChronology.LeapYearPatternType LEAP_YEAR_16_BASED
Leap year 16-based pattern.


LEAP_YEAR_INDIAN

public static final IslamicChronology.LeapYearPatternType LEAP_YEAR_INDIAN
Leap year Indian pattern.


LEAP_YEAR_HABASH_AL_HASIB

public static final IslamicChronology.LeapYearPatternType LEAP_YEAR_HABASH_AL_HASIB
Leap year Habash al-Hasib pattern.

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

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:
ZonedChronology

hashCode

public int hashCode()
A suitable hash code for the chronology.

Returns:
the hash code
Since:
1.6

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.

Parameters:
fields - container of fields

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()

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

toString

public String toString()
Gets a debugging toString.

Specified by:
toString in class BaseChronology
Returns:
a debugging string


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