Class HebrewCalendar

java.lang.Object
com.ibm.icu.util.Calendar
com.ibm.icu.util.HebrewCalendar
All Implemented Interfaces:
Serializable, Cloneable, Comparable<Calendar>

public class HebrewCalendar extends Calendar
HebrewCalendar is a subclass of Calendar that that implements the traditional Hebrew calendar. This is the civil calendar in Israel and the liturgical calendar of the Jewish faith worldwide.

The Hebrew calendar is lunisolar and thus has a number of interesting properties that distinguish it from the Gregorian. Months start on the day of (an arithmetic approximation of) each new moon. Since the solar year (approximately 365.24 days) is not an even multiple of the lunar month (approximately 29.53 days) an extra "leap month" is inserted in 7 out of every 19 years. To make matters even more interesting, the start of a year can be delayed by up to three days in order to prevent certain holidays from falling on the Sabbath and to prevent certain illegal year lengths. Finally, the lengths of certain months can vary depending on the number of days in the year.

The leap month is known as "Adar 1" and is inserted between the months of Shevat and Adar in leap years. Since the leap month does not come at the end of the year, calculations involving month numbers are particularly complex. Users of this class should make sure to use the roll and add methods rather than attempting to perform date arithmetic by manipulating the fields directly.

Note: In the traditional Hebrew calendar, days start at sunset. However, in order to keep the time fields in this class synchronized with those of the other calendars and with local clock time, we treat days and months as beginning at midnight, roughly 6 hours after the corresponding sunset.

If you are interested in more information on the rules behind the Hebrew calendar, see one of the following references:

This class should not be subclassed.

HebrewCalendar usually should be instantiated using Calendar.getInstance(ULocale) passing in a ULocale with the tag "@calendar=hebrew".

Author:
Laura Werner, Alan Liu
See Also:
  • Field Details

    • TISHRI

      public static final int TISHRI
      Constant for Tishri, the 1st month of the Hebrew year.
      See Also:
    • HESHVAN

      public static final int HESHVAN
      Constant for Heshvan, the 2nd month of the Hebrew year.
      See Also:
    • KISLEV

      public static final int KISLEV
      Constant for Kislev, the 3rd month of the Hebrew year.
      See Also:
    • TEVET

      public static final int TEVET
      Constant for Tevet, the 4th month of the Hebrew year.
      See Also:
    • SHEVAT

      public static final int SHEVAT
      Constant for Shevat, the 5th month of the Hebrew year.
      See Also:
    • ADAR_1

      public static final int ADAR_1
      Constant for Adar I, the 6th month of the Hebrew year (present in leap years only). In non-leap years, the calendar jumps from Shevat (5th month) to Adar (7th month).
      See Also:
    • ADAR

      public static final int ADAR
      Constant for the Adar, the 7th month of the Hebrew year.
      See Also:
    • NISAN

      public static final int NISAN
      Constant for Nisan, the 8th month of the Hebrew year.
      See Also:
    • IYAR

      public static final int IYAR
      Constant for Iyar, the 9th month of the Hebrew year.
      See Also:
    • SIVAN

      public static final int SIVAN
      Constant for Sivan, the 10th month of the Hebrew year.
      See Also:
    • TAMUZ

      public static final int TAMUZ
      Constant for Tammuz, the 11th month of the Hebrew year.
      See Also:
    • AV

      public static final int AV
      Constant for Av, the 12th month of the Hebrew year.
      See Also:
    • ELUL

      public static final int ELUL
      Constant for Elul, the 13th month of the Hebrew year.
      See Also:
  • Constructor Details

    • HebrewCalendar

      public HebrewCalendar()
      Constructs a default HebrewCalendar using the current time in the default time zone with the default FORMAT locale.
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    • HebrewCalendar

      public HebrewCalendar(TimeZone zone)
      Constructs a HebrewCalendar based on the current time in the given time zone with the default FORMAT locale.
      Parameters:
      zone - The time zone for the new calendar.
      See Also:
    • HebrewCalendar

      public HebrewCalendar(Locale aLocale)
      Constructs a HebrewCalendar based on the current time in the default time zone with the given locale.
      Parameters:
      aLocale - The locale for the new calendar.
    • HebrewCalendar

      public HebrewCalendar(ULocale locale)
      Constructs a HebrewCalendar based on the current time in the default time zone with the given locale.
      Parameters:
      locale - The locale for the new calendar.
    • HebrewCalendar

      public HebrewCalendar(TimeZone zone, Locale aLocale)
      Constructs a HebrewCalendar based on the current time in the given time zone with the given locale.
      Parameters:
      zone - The time zone for the new calendar.
      aLocale - The locale for the new calendar.
    • HebrewCalendar

      public HebrewCalendar(TimeZone zone, ULocale locale)
      Constructs a HebrewCalendar based on the current time in the given time zone with the given locale.
      Parameters:
      zone - The time zone for the new calendar.
      locale - The locale for the new calendar.
    • HebrewCalendar

      public HebrewCalendar(int year, int month, int date)
      Constructs a HebrewCalendar with the given date set in the default time zone with the default FORMAT locale.
      Parameters:
      year - The value used to set the calendar's YEAR time field.
      month - The value used to set the calendar's MONTH time field. The value is 0-based. e.g., 0 for Tishri.
      date - The value used to set the calendar's DATE time field.
      See Also:
    • HebrewCalendar

      public HebrewCalendar(Date date)
      Constructs a HebrewCalendar with the given date set in the default time zone with the default FORMAT locale.
      Parameters:
      date - The date to which the new calendar is set.
      See Also:
    • HebrewCalendar

      public HebrewCalendar(int year, int month, int date, int hour, int minute, int second)
      Constructs a HebrewCalendar with the given date and time set for the default time zone with the default FORMAT locale.
      Parameters:
      year - The value used to set the calendar's YEAR time field.
      month - The value used to set the calendar's MONTH time field. The value is 0-based. e.g., 0 for Tishri.
      date - The value used to set the calendar's DATE time field.
      hour - The value used to set the calendar's HOUR_OF_DAY time field.
      minute - The value used to set the calendar's MINUTE time field.
      second - The value used to set the calendar's SECOND time field.
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  • Method Details

    • add

      public void add(int field, int amount)
      Add a signed amount to a specified field, using this calendar's rules. For example, to add three days to the current date, you can call add(Calendar.DATE, 3).

      When adding to certain fields, the values of other fields may conflict and need to be changed. For example, when adding one to the MONTH field for the date "30 Av 5758", the DAY_OF_MONTH field must be adjusted so that the result is "29 Elul 5758" rather than the invalid "30 Elul 5758".

      This method is able to add to all fields except for ERA, DST_OFFSET, and ZONE_OFFSET.

      Note: You should always use roll and add rather than attempting to perform arithmetic operations directly on the fields of a HebrewCalendar. Since the MONTH field behaves discontinuously in non-leap years, simple arithmetic can give invalid results.

      Overrides:
      add in class Calendar
      Parameters:
      field - the time field.
      amount - the amount to add to the field.
      Throws:
      IllegalArgumentException - if the field is invalid or refers to a field that cannot be handled by this method.
      See Also:
    • roll

      public void roll(int field, int amount)
      Rolls (up/down) a specified amount time on the given field. For example, to roll the current date up by three days, you can call roll(Calendar.DATE, 3). If the field is rolled past its maximum allowable value, it will "wrap" back to its minimum and continue rolling. For example, calling roll(Calendar.DATE, 10) on a Hebrew calendar set to "25 Av 5758" will result in the date "5 Av 5758".

      When rolling certain fields, the values of other fields may conflict and need to be changed. For example, when rolling the MONTH field upward by one for the date "30 Av 5758", the DAY_OF_MONTH field must be adjusted so that the result is "29 Elul 5758" rather than the invalid "30 Elul".

      This method is able to roll all fields except for ERA, DST_OFFSET, and ZONE_OFFSET. Subclasses may, of course, add support for additional fields in their overrides of roll.

      Note: You should always use roll and add rather than attempting to perform arithmetic operations directly on the fields of a HebrewCalendar. Since the MONTH field behaves discontinuously in non-leap years, simple arithmetic can give invalid results.

      Overrides:
      roll in class Calendar
      Parameters:
      field - the time field.
      amount - the amount by which the field should be rolled.
      Throws:
      IllegalArgumentException - if the field is invalid or refers to a field that cannot be handled by this method.
      See Also:
    • isLeapYear

      @Deprecated public static boolean isLeapYear(int year)
      Deprecated.
      This API is ICU internal only.
      Determine whether a given Hebrew year is a leap year The rule here is that if (year % 19) == 0, 3, 6, 8, 11, 14, or 17. The formula below performs the same test, believe it or not.
    • handleGetLimit

      protected int handleGetLimit(int field, int limitType)
      Description copied from class: Calendar
      Subclass API for defining limits of different types. Subclasses must implement this method to return limits for the following fields:
      ERA
       YEAR
       MONTH
       WEEK_OF_YEAR
       WEEK_OF_MONTH
       DAY_OF_MONTH
       DAY_OF_YEAR
       DAY_OF_WEEK_IN_MONTH
       YEAR_WOY
       EXTENDED_YEAR
      Specified by:
      handleGetLimit in class Calendar
      Parameters:
      field - one of the above field numbers
      limitType - one of MINIMUM, GREATEST_MINIMUM, LEAST_MAXIMUM, or MAXIMUM
    • handleGetMonthLength

      protected int handleGetMonthLength(int extendedYear, int month)
      Returns the length of the given month in the given year
      Overrides:
      handleGetMonthLength in class Calendar
    • handleGetYearLength

      protected int handleGetYearLength(int eyear)
      Returns the number of days in the given Hebrew year
      Overrides:
      handleGetYearLength in class Calendar
    • validateField

      @Deprecated protected void validateField(int field)
      Deprecated.
      This API is ICU internal only.
      Validate a single field of this calendar. Subclasses should override this method to validate any calendar-specific fields. Generic fields can be handled by Calendar.validateField().

      Overrides Calendar.validateField(int) to provide special handling for month validation for Hebrew calendar.

      Overrides:
      validateField in class Calendar
      See Also:
    • handleComputeFields

      protected void handleComputeFields(int julianDay)
      Subclasses may override this method to compute several fields specific to each calendar system. These are:
      • ERA
      • YEAR
      • MONTH
      • DAY_OF_MONTH
      • DAY_OF_YEAR
      • EXTENDED_YEAR
      Subclasses can refer to the DAY_OF_WEEK and DOW_LOCAL fields, which will be set when this method is called. Subclasses can also call the getGregorianXxx() methods to obtain Gregorian calendar equivalents for the given Julian day.

      In addition, subclasses should compute any subclass-specific fields, that is, fields from BASE_FIELD_COUNT to getFieldCount() - 1.

      Overrides:
      handleComputeFields in class Calendar
    • handleGetExtendedYear

      protected int handleGetExtendedYear()
      Description copied from class: Calendar
      Returns the extended year defined by the current fields. This will use the EXTENDED_YEAR field or the YEAR and supra-year fields (such as ERA) specific to the calendar system, depending on which set of fields is newer.
      Specified by:
      handleGetExtendedYear in class Calendar
      Returns:
      the extended year
    • handleComputeMonthStart

      protected int handleComputeMonthStart(int eyear, int month, boolean useMonth)
      Return JD of start of given month/year.
      Specified by:
      handleComputeMonthStart in class Calendar
      Parameters:
      eyear - the extended year
      month - the zero-based month, or 0 if useMonth is false
      useMonth - if false, compute the day before the first day of the given year, otherwise, compute the day before the first day of the given month
      Returns:
      the Julian day number of the day before the first day of the given month and year
    • getType

      public String getType()
      Returns the calendar type name string for this Calendar object. The returned string is the legacy ICU calendar attribute value, for example, "gregorian" or "japanese".

      See type="old type name" for the calendar attribute of locale IDs at http://www.unicode.org/reports/tr35/#Key_Type_Definitions

      Overrides:
      getType in class Calendar
      Returns:
      legacy calendar type name string