HebrewCalendar

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 getInstance(ULocale) passing in a ULocale with the tag "@calendar=hebrew".

Constant Summary

int ADAR Constant for the Adar, the 7th month of the Hebrew year.
int ADAR_1 Constant for Adar I, the 6th month of the Hebrew year (present in leap years only).
int AV Constant for Av, the 12th month of the Hebrew year.
int ELUL Constant for Elul, the 13th month of the Hebrew year.
int HESHVAN Constant for Heshvan, the 2nd month of the Hebrew year.
int IYAR Constant for Iyar, the 9th month of the Hebrew year.
int KISLEV Constant for Kislev, the 3rd month of the Hebrew year.
int NISAN Constant for Nisan, the 8th month of the Hebrew year.
int SHEVAT Constant for Shevat, the 5th month of the Hebrew year.
int SIVAN Constant for Sivan, the 10th month of the Hebrew year.
int TAMUZ Constant for Tammuz, the 11th month of the Hebrew year.
int TEVET Constant for Tevet, the 4th month of the Hebrew year.
int TISHRI Constant for Tishri, the 1st month of the Hebrew year.

Inherited Constant Summary

Inherited Field Summary

Public Constructor Summary

HebrewCalendar()
Constructs a default HebrewCalendar using the current time in the default time zone with the default FORMAT locale.
HebrewCalendar(TimeZone zone)
Constructs a HebrewCalendar based on the current time in the given time zone with the default FORMAT locale.
HebrewCalendar(Locale aLocale)
Constructs a HebrewCalendar based on the current time in the default time zone with the given locale.
HebrewCalendar(ULocale locale)
Constructs a HebrewCalendar based on the current time in the default time zone with the given locale.
HebrewCalendar(TimeZone zone, Locale aLocale)
Constructs a HebrewCalendar based on the current time in the given time zone with the given locale.
HebrewCalendar(TimeZone zone, ULocale locale)
Constructs a HebrewCalendar based on the current time in the given time zone with the given locale.
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.
HebrewCalendar(Date date)
Constructs a HebrewCalendar with the given date set in the default time zone with the default FORMAT locale.
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.

Public Method Summary

void
add(int field, int amount)
Add a signed amount to a specified field, using this calendar's rules.
String
getType()
[icu] Returns the calendar type name string for this Calendar object.
void
roll(int field, int amount)
Rolls (up/down) a specified amount time on the given field.

Protected Method Summary

void
handleComputeFields(int julianDay)
Subclasses may override this method to compute several fields specific to each calendar system.
int
handleComputeMonthStart(int eyear, int month, boolean useMonth)
Return JD of start of given month/year.
int
handleGetExtendedYear()
Returns the extended year defined by the current fields.
int
handleGetLimit(int field, int limitType)
Subclass API for defining limits of different types.
int
handleGetMonthLength(int extendedYear, int month)
Returns the length of the given month in the given year
int
handleGetYearLength(int eyear)
Returns the number of days in the given Hebrew year

Inherited Method Summary

Constants

public static final int ADAR

Constant for the Adar, the 7th month of the Hebrew year.

Constant Value: 6

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).

Constant Value: 5

public static final int AV

Constant for Av, the 12th month of the Hebrew year.

Constant Value: 11

public static final int ELUL

Constant for Elul, the 13th month of the Hebrew year.

Constant Value: 12

public static final int HESHVAN

Constant for Heshvan, the 2nd month of the Hebrew year.

Constant Value: 1

public static final int IYAR

Constant for Iyar, the 9th month of the Hebrew year.

Constant Value: 8

public static final int KISLEV

Constant for Kislev, the 3rd month of the Hebrew year.

Constant Value: 2

public static final int NISAN

Constant for Nisan, the 8th month of the Hebrew year.

Constant Value: 7

public static final int SHEVAT

Constant for Shevat, the 5th month of the Hebrew year.

Constant Value: 4

public static final int SIVAN

Constant for Sivan, the 10th month of the Hebrew year.

Constant Value: 9

public static final int TAMUZ

Constant for Tammuz, the 11th month of the Hebrew year.

Constant Value: 10

public static final int TEVET

Constant for Tevet, the 4th month of the Hebrew year.

Constant Value: 3

public static final int TISHRI

Constant for Tishri, the 1st month of the Hebrew year.

Constant Value: 0

Public Constructors

public HebrewCalendar ()

Constructs a default HebrewCalendar using the current time in the default time zone with the default FORMAT locale.

See Also

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

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.

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.

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.

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.

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

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

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.
See Also

Public Methods

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.

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.

public String getType ()

[icu] 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

Returns
  • legacy calendar type name string

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.

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.

Protected Methods

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.

Parameters
julianDay

protected int handleComputeMonthStart (int eyear, int month, boolean useMonth)

Return JD of start of given month/year.

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

protected int handleGetExtendedYear ()

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.

Returns
  • the extended year

protected int handleGetLimit (int field, int limitType)

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

Parameters
field one of the above field numbers
limitType one of MINIMUM, GREATEST_MINIMUM, LEAST_MAXIMUM, or MAXIMUM

protected int handleGetMonthLength (int extendedYear, int month)

Returns the length of the given month in the given year

Parameters
extendedYear
month

protected int handleGetYearLength (int eyear)

Returns the number of days in the given Hebrew year

Parameters
eyear