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 & 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