com.ibm.icu.util
public class ChineseCalendar extends Calendar
ChineseCalendar
is a concrete subclass of Calendar
that implements a traditional Chinese calendar. The traditional Chinese
calendar is a lunisolar calendar: Each month starts on a new moon, and
the months are numbered according to solar events, specifically, to
guarantee that month 11 always contains the winter solstice. In order
to accomplish this, leap months are inserted in certain years. Leap
months are numbered the same as the month they follow. The decision of
which month is a leap month depends on the relative movements of the sun
and moon.
This class defines one addition field beyond those defined by
Calendar
: The IS_LEAP_MONTH
field takes the
value of 0 for normal months, or 1 for leap months.
All astronomical computations are performed with respect to a time zone of GMT+8:00 and a longitude of 120 degrees east. Although some calendars implement a historically more accurate convention of using Beijing's local longitude (116 degrees 25 minutes east) and time zone (GMT+7:45:40) for dates before 1929, we do not implement this here.
Years are counted in two different ways in the Chinese calendar. The
first method is by sequential numbering from the 61st year of the reign
of Huang Di, 2637 BCE, which is designated year 1 on the Chinese
calendar. The second method uses 60-year cycles from the same starting
point, which is designated year 1 of cycle 1. In this class, the
EXTENDED_YEAR
field contains the sequential year count.
The ERA
field contains the cycle number, and the
YEAR
field contains the year of the cycle, a value between
1 and 60.
There is some variation in what is considered the starting point of the calendar, with some sources starting in the first year of the reign of Huang Di, rather than the 61st. This gives continuous year numbers 60 years greater and cycle numbers one greater than what this class implements.
Because ChineseCalendar
defines an additional field and
redefines the way the ERA
field is used, it requires a new
format class, ChineseDateFormat
. As always, use the
methods DateFormat.getXxxInstance(Calendar cal,...)
to
obtain a formatter for this calendar.
References:
This class should not be subclassed.
ChineseCalendar usually should be instantiated using
getInstance passing in a ULocale
with the tag "@calendar=chinese"
.
See Also: ChineseDateFormat Calendar
UNKNOWN: ICU 2.8
Field Summary | |
---|---|
static int | IS_LEAP_MONTH
Field indicating whether or not the current month is a leap month.
|
Constructor Summary | |
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ChineseCalendar()
Construct a Chinese calendar with the default time zone and locale. | |
ChineseCalendar(TimeZone zone, Locale locale)
Construct a Chinese calendar with the given time zone and locale. | |
ChineseCalendar(TimeZone zone, ULocale locale)
Construct a Chinese calendar with the given time zone and locale. |
Method Summary | |
---|---|
void | add(int field, int amount)
Override Calendar to handle leap months properly. |
protected int[][][] | getFieldResolutionTable()
Override Calendar to add IS_LEAP_MONTH to the field resolution
table. |
String | getType()
Return the current Calendar type. |
protected void | handleComputeFields(int julianDay)
Override Calendar to compute several fields specific to the Chinese
calendar system. |
protected int | handleComputeMonthStart(int eyear, int month, boolean useMonth)
Return the Julian day number of day before the first day of the
given month in the given extended year.
|
protected int[] | handleCreateFields()
Override Calendar to allocate our additional field. |
protected DateFormat | handleGetDateFormat(String pattern, ULocale locale)
Framework method to create a calendar-specific DateFormat object
using the the given pattern. |
protected int | handleGetExtendedYear()
Implement abstract Calendar method to return the extended year
defined by the current fields. |
protected int | handleGetLimit(int field, int limitType)
Override Calendar to return the limit value for the given field. |
protected int | handleGetMonthLength(int extendedYear, int month)
Override Calendar method to return the number of days in the given
extended year and month.
|
void | roll(int field, int amount)
Override Calendar to handle leap months properly. |
UNKNOWN: ICU 2.8
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Parameters: zone time zone for this calendar locale locale for this calendar
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Parameters: zone time zone for this calendar locale ulocale for this calendar
UNKNOWN: ICU 3.2 This API might change or be removed in a future release.
UNKNOWN: ICU 2.8
UNKNOWN: ICU 2.8
Deprecated: This API is ICU internal only.
Return the current Calendar type.Returns: type of calendar (gregorian, etc.)
UNKNOWN: ICU 3.0
Compute the ChineseCalendar-specific field IS_LEAP_MONTH.
UNKNOWN: ICU 2.8
Note: This method reads the IS_LEAP_MONTH field to determine whether the given month is a leap month.
Parameters: eyear the extended year month the zero-based month. The month is also determined by reading the IS_LEAP_MONTH field.
Returns: the Julian day number of the day before the first day of the given month and year
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Note: This method also reads the IS_LEAP_MONTH field to determine whether or not the given month is a leap month.
UNKNOWN: ICU 2.8
UNKNOWN: ICU 2.8