com.ibm.icu.util

Class HebrewCalendar

Implemented Interfaces:
Cloneable, Comparable, Serializable

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".

Authors:
Laura Werner
Alan Liu
See Also:
GregorianCalendar, Calendar

Field Summary

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

Fields inherited from class com.ibm.icu.util.Calendar

AM, AM_PM, APRIL, AUGUST, BASE_FIELD_COUNT, DATE, DAY_OF_MONTH, DAY_OF_WEEK, DAY_OF_WEEK_IN_MONTH, DAY_OF_YEAR, DECEMBER, DOW_LOCAL, DST_OFFSET, EPOCH_JULIAN_DAY, ERA, EXTENDED_YEAR, FEBRUARY, FRIDAY, GREATEST_MINIMUM, HOUR, HOUR_OF_DAY, INTERNALLY_SET, JANUARY, JAN_1_1_JULIAN_DAY, JULIAN_DAY, JULY, JUNE, LEAST_MAXIMUM, MARCH, MAXIMUM, MAX_DATE, MAX_FIELD_COUNT, MAX_JULIAN, MAX_MILLIS, MAY, MILLISECOND, MILLISECONDS_IN_DAY, MINIMUM, MINIMUM_USER_STAMP, MINUTE, MIN_DATE, MIN_JULIAN, MIN_MILLIS, MONDAY, MONTH, NOVEMBER, OCTOBER, ONE_DAY, ONE_HOUR, ONE_MINUTE, ONE_SECOND, ONE_WEEK, PM, RESOLVE_REMAP, SATURDAY, SECOND, SEPTEMBER, SUNDAY, THURSDAY, TUESDAY, UNDECIMBER, UNSET, WEDNESDAY, WEEKDAY, WEEKEND, WEEKEND_CEASE, WEEKEND_ONSET, WEEK_OF_MONTH, WEEK_OF_YEAR, YEAR, YEAR_WOY, ZONE_OFFSET

Constructor Summary

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

Method Summary

void
add(int field, int amount)
Add a signed amount to a specified field, using this calendar's rules.
String
getType()
Return the current Calendar type.
protected void
handleComputeFields(int julianDay)
Subclasses may override this method to compute several fields specific to each calendar system.
protected int
handleComputeMonthStart(int eyear, int month, boolean useMonth)
Return JD of start of given month/year.
protected int
handleGetExtendedYear()
protected int
handleGetLimit(int field, int limitType)
protected int
handleGetMonthLength(int extendedYear, int month)
Returns the length of the given month in the given year
protected int
handleGetYearLength(int eyear)
Returns the number of days in the given Hebrew year
void
roll(int field, int amount)
Rolls (up/down) a specified amount time on the given field.

Methods inherited from class com.ibm.icu.util.Calendar

add, after, before, clear, clear, clone, compareTo, compareTo, complete, computeFields, computeGregorianFields, computeGregorianMonthStart, computeJulianDay, computeMillisInDay, computeTime, computeZoneOffset, equals, fieldDifference, fieldName, floorDivide, floorDivide, floorDivide, floorDivide, get, getActualMaximum, getActualMinimum, getAvailableLocales, getAvailableULocales, getDateTimeFormat, getDateTimeFormat, getDayOfWeekType, getDisplayName, getDisplayName, getFieldCount, getFieldResolutionTable, getFirstDayOfWeek, getGreatestMinimum, getGregorianDayOfMonth, getGregorianDayOfYear, getGregorianMonth, getGregorianYear, getInstance, getInstance, getInstance, getInstance, getInstance, getInstance, getLeastMaximum, getLimit, getLocale, getMaximum, getMinimalDaysInFirstWeek, getMinimum, getStamp, getTime, getTimeInMillis, getTimeZone, getType, getWeekendTransition, gregorianMonthLength, gregorianPreviousMonthLength, handleComputeFields, handleComputeJulianDay, handleComputeMonthStart, handleCreateFields, handleGetDateFormat, handleGetDateFormat, handleGetExtendedYear, handleGetLimit, handleGetMonthLength, handleGetYearLength, hashCode, internalGet, internalGet, internalGetTimeInMillis, internalSet, isEquivalentTo, isGregorianLeapYear, isLenient, isSet, isWeekend, isWeekend, julianDayToDayOfWeek, julianDayToMillis, millisToJulianDay, newerField, newestStamp, pinField, prepareGetActual, resolveFields, roll, roll, set, set, set, set, setFirstDayOfWeek, setLenient, setMinimalDaysInFirstWeek, setTime, setTimeInMillis, setTimeZone, toString, validateField, validateField, validateFields, weekNumber, weekNumber

Field Details

ADAR

public static final int ADAR
Constant for the Adar, the 7th month of the Hebrew year.
Field Value:
6

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).
Field Value:
5

AV

public static final int AV
Constant for Av, the 12th month of the Hebrew year.
Field Value:
11

ELUL

public static final int ELUL
Constant for Elul, the 13th month of the Hebrew year.
Field Value:
12

HESHVAN

public static final int HESHVAN
Constant for Heshvan, the 2nd month of the Hebrew year.
Field Value:
1

IYAR

public static final int IYAR
Constant for Iyar, the 9th month of the Hebrew year.
Field Value:
8

KISLEV

public static final int KISLEV
Constant for Kislev, the 3rd month of the Hebrew year.
Field Value:
2

NISAN

public static final int NISAN
Constant for Nisan, the 8th month of the Hebrew year.
Field Value:
7

SHEVAT

public static final int SHEVAT
Constant for Shevat, the 5th month of the Hebrew year.
Field Value:
4

SIVAN

public static final int SIVAN
Constant for Sivan, the 10th month of the Hebrew year.
Field Value:
9

TAMUZ

public static final int TAMUZ
Constant for Tammuz, the 11th month of the Hebrew year.
Field Value:
10

TEVET

public static final int TEVET
Constant for Tevet, the 4th month of the Hebrew year.
Field Value:
3

TISHRI

public static final int TISHRI
Constant for Tishri, the 1st month of the Hebrew year.
Field Value:
0

Constructor Details

HebrewCalendar

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

HebrewCalendar

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

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(TimeZone zone)
Constructs a HebrewCalendar based on the current time in the given time zone with the default locale.
Parameters:
zone - The time zone 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(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(int year,
                      int month,
                      int date)
Constructs a HebrewCalendar with the given date set in the default time zone with the default 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.

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 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.

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 interface Calendar
Parameters:
field - the time field.
amount - the amount to add to the field.

getType

public String getType()
Return the current Calendar type.
Overrides:
getType in interface Calendar
Returns:
type of calendar (gregorian, etc.)

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 interface Calendar

handleComputeMonthStart

protected int handleComputeMonthStart(int eyear,
                                      int month,
                                      boolean useMonth)
Return JD of start of given month/year.
Overrides:
handleComputeMonthStart in interface Calendar

handleGetExtendedYear

protected int handleGetExtendedYear()
Overrides:
handleGetExtendedYear in interface Calendar

handleGetLimit

protected int handleGetLimit(int field,
                             int limitType)
Overrides:
handleGetLimit in interface Calendar

handleGetMonthLength

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

handleGetYearLength

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

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 interface Calendar
Parameters:
field - the time field.
amount - the amount by which the field should be rolled.

Copyright (c) 2006 IBM Corporation and others.