javahijritime4j

year number convert from gregorian to hijri java time4j

I take a year number from user. How can convert it to hijri year number? Better using not jodatime but time4j or java 8.

Example: I need from 2016 to have hijri year number.

I have found this post, Is there any library or algorithm for Persian (Shamsi or Jalali) calendar in Android? 

System.out.println(jalali.transform(PlainDate.class)); // 2015-03-25

But method transform doesn't work.

Also I have found this post to convert hijri to gregorian: Get a gregorian date from Hijri date strings

But I need from gregorian to hijri.

Solution

  • The sentence "But method transform doesn't work." should probably be read "does not compile".

    Reason is that the HijriCalendar represents a family of different variants (for example Umalqura). Technical background: This class inherits from CalendarVariant instead of Calendrical. Therefore the compiler forces you to use a transform()-method with TWO arguments. The second argument specifies the variant of HijriCalendar. Example:

    PlainDate today = SystemClock.inLocalView().today();

HijriCalendar umalqura = 
  today.transform(HijriCalendar.class, HijriCalendar.VARIANT_UMALQURA);
HijriCalendar westIslamicCivil = 
  today.transform(HijriCalendar.class, HijriAlgorithm.WEST_ISLAMIC_CIVIL);

System.out.println(umalqura); // AH-1437-07-23[islamic-umalqura]
System.out.println(westIslamicCivil); // AH-1437-07-22[islamic-civil]

    This example also demonstrates why it is important to specify the variant. You see a difference of one day (for the same gregorian date)! Actually Time4J supports 11 variants. The umalquara-variant is the official calendar of Saudi-Arabia while the 8 algorithmic variants should rather be interpreted as approximations and have a wider validity range.

    Once you have an instance of HijriCalendar you can easily get the hijri year:

    int hijriYear = umalqura.getYear();
System.out.println("Year (hirji-umalqura): " + hijriYear); // 1437