Class ChineseCalendar

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Cloneable, java.lang.Comparable<Calendar>
    Direct Known Subclasses:
    DangiCalendar

    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.

    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:

    • Dershowitz and Reingold, Calendrical Calculations, Cambridge University Press, 1997
    • The Calendar FAQ

    This class should not be subclassed.

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

    See Also:
    Calendar, Serialized Form
    • Field Detail

      • epochYear

        private int epochYear
        The start year of this Chinese calendar instance.
      • zoneAstro

        private TimeZone zoneAstro
        The zone used for the astronomical calculation of this Chinese calendar instance.
      • winterSolsticeCache

        private transient CalendarCache winterSolsticeCache
        Cache that maps Gregorian year to local days of winter solstice.
        See Also:
        winterSolstice(int)
      • newYearCache

        private transient CalendarCache newYearCache
        Cache that maps Gregorian year to local days of Chinese new year.
        See Also:
        newYear(int)
      • hasLeapMonthBetweenWinterSolstices

        private transient boolean hasLeapMonthBetweenWinterSolstices
        True if there is a leap month between the Winter Solstice before and after the current date.This is different from leap year because in some year, such as 1813 and 2033, the leap month is after the Winter Solstice of that year. So this value could be false for a date prior to the Winter Solstice of that year but that year still has a leap month and therefor is a leap year.
        See Also:
        computeChineseFields(int, int, int, boolean)
      • LIMITS

        private static final int[][] LIMITS
        Array defining the limits of field values for this class. Field limits which are invariant with respect to calendar system and defined by Calendar are left blank. Notes: ERA 5000000 / 60 = 83333. MONTH There are 12 or 13 lunar months in a year. However, we always number them 0..11, with an intercalated, identically numbered leap month, when necessary. DAY_OF_YEAR In a non-leap year there are 353, 354, or 355 days. In a leap year there are 383, 384, or 385 days. WEEK_OF_YEAR The least maximum occurs if there are 353 days in the year, and the first 6 are the last week of the previous year. Then we have 49 full weeks and 4 days in the last week: 6 + 49*7 + 4 = 353. So the least maximum is 50. The maximum occurs if there are 385 days in the year, and WOY 1 extends 6 days into the prior year. Then there are 54 full weeks, and 6 days in the last week: 1 + 54*7 + 6 = 385. The 6 days of the last week will fall into WOY 1 of the next year. Maximum is 55. WEEK_OF_MONTH In a 29 day month, if the first 7 days make up week 1 that leaves 3 full weeks and 1 day at the end. The least maximum is thus 5. In a 30 days month, if the previous 6 days belong WOM 1 of this month, we have 4 full weeks and 1 days at the end (which technically will be WOM 1 of the next month, but will be reported by time->fields and hence by getActualMaximum as WOM 6 of this month). Maximum is 6. DAY_OF_WEEK_IN_MONTH In a 29 or 30 day month, there are 4 full weeks plus 1 or 2 days at the end, so the maximum is always 5.
      • CHINESE_DATE_PRECEDENCE

        static final int[][][] CHINESE_DATE_PRECEDENCE
        Field resolution table that incorporates IS_LEAP_MONTH.
      • CHINESE_EPOCH_YEAR

        private static final int CHINESE_EPOCH_YEAR
        The start year of the Chinese calendar, the 61st year of the reign of Huang Di. Some sources use the first year of his reign, resulting in EXTENDED_YEAR values 60 years greater and ERA (cycle) values one greater.
        See Also:
        Constant Field Values
      • CHINA_ZONE

        private static final TimeZone CHINA_ZONE
        The time zone used for performing astronomical computations. Some sources use a different historically accurate offset of GMT+7:45:40 for years before 1929; we do not do this.
      • SYNODIC_GAP

        private static final int SYNODIC_GAP
        Value to be added or subtracted from the local days of a new moon to get close to the next or prior new moon, but not cross it. Must be >= 1 and < CalendarAstronomer.SYNODIC_MONTH.
        See Also:
        Constant Field Values
      • gTemporalLeapMonthCodes

        private static java.lang.String[] gTemporalLeapMonthCodes
    • Constructor Detail

      • ChineseCalendar

        public ChineseCalendar()
        Construct a ChineseCalendar with the default time zone and locale.
      • ChineseCalendar

        public ChineseCalendar​(java.util.Date date)
        Construct a ChineseCalendar with the give date set in the default time zone with the default locale.
        Parameters:
        date - The date to which the new calendar is set.
      • ChineseCalendar

        public ChineseCalendar​(int year,
                               int month,
                               int isLeapMonth,
                               int date)
        Constructs a ChineseCalendar 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 January.
        isLeapMonth - The value used to set the Chinese calendar's Calendar.IS_LEAP_MONTH time field.
        date - The value used to set the calendar's DATE time field.
        See Also:
        ULocale.Category.FORMAT
      • ChineseCalendar

        public ChineseCalendar​(int year,
                               int month,
                               int isLeapMonth,
                               int date,
                               int hour,
                               int minute,
                               int second)
        Constructs a ChineseCalendar 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 YEAR time field in the calendar.
        month - the value used to set the MONTH time field in the calendar. Note that the month value is 0-based. e.g., 0 for January.
        isLeapMonth - the value used to set the Calendar.IS_LEAP_MONTH time field in the calendar.
        date - the value used to set the DATE time field in the calendar.
        hour - the value used to set the HOUR_OF_DAY time field in the calendar.
        minute - the value used to set the MINUTE time field in the calendar.
        second - the value used to set the SECOND time field in the calendar.
        See Also:
        ULocale.Category.FORMAT
      • ChineseCalendar

        public ChineseCalendar​(int era,
                               int year,
                               int month,
                               int isLeapMonth,
                               int date)
        Constructs a ChineseCalendar with the given date set in the default time zone with the default FORMAT locale.
        Parameters:
        era - The value used to set the calendar's ERA time field.
        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 January.
        isLeapMonth - The value used to set the Chinese calendar's Calendar.IS_LEAP_MONTH time field.
        date - The value used to set the calendar's DATE time field.
        See Also:
        ULocale.Category.FORMAT
      • ChineseCalendar

        public ChineseCalendar​(int era,
                               int year,
                               int month,
                               int isLeapMonth,
                               int date,
                               int hour,
                               int minute,
                               int second)
        Constructs a ChineseCalendar with the given date and time set for the default time zone with the default FORMAT locale.
        Parameters:
        era - the value used to set the calendar's ERA time field.
        year - the value used to set the YEAR time field in the calendar.
        month - the value used to set the MONTH time field in the calendar. Note that the month value is 0-based. e.g., 0 for January.
        isLeapMonth - the value used to set the Calendar.IS_LEAP_MONTH time field in the calendar.
        date - the value used to set the DATE time field in the calendar.
        hour - the value used to set the HOUR_OF_DAY time field in the calendar.
        minute - the value used to set the MINUTE time field in the calendar.
        second - the value used to set the SECOND time field in the calendar.
        See Also:
        ULocale.Category.FORMAT
      • ChineseCalendar

        public ChineseCalendar​(java.util.Locale aLocale)
        Constructs a ChineseCalendar based on the current time in the default time zone with the given locale.
        Parameters:
        aLocale - The given locale
      • ChineseCalendar

        public ChineseCalendar​(TimeZone zone)
        Construct a ChineseCalendar based on the current time in the given time zone with the default FORMAT locale.
        Parameters:
        zone - the given time zone
        See Also:
        ULocale.Category.FORMAT
      • ChineseCalendar

        public ChineseCalendar​(TimeZone zone,
                               java.util.Locale aLocale)
        Construct a ChineseCalendar based on the current time in the given time zone with the given locale.
        Parameters:
        zone - the given time zone
        aLocale - the given locale
      • ChineseCalendar

        public ChineseCalendar​(ULocale locale)
        Constructs a ChineseCalendar based on the current time in the default time zone with the given locale.
        Parameters:
        locale - the given ulocale
      • ChineseCalendar

        public ChineseCalendar​(TimeZone zone,
                               ULocale locale)
        Construct a ChineseCalendar based on the current time with the given time zone with the given locale.
        Parameters:
        zone - the given time zone
        locale - the given ulocale
      • ChineseCalendar

        @Deprecated
        protected ChineseCalendar​(TimeZone zone,
                                  ULocale locale,
                                  int epochYear,
                                  TimeZone zoneAstroCalc)
        Deprecated.
        This API is ICU internal only.
        Construct a ChineseCalenar based on the current time with the given time zone, the locale, the epoch year and the time zone used for astronomical calculation.
    • Method Detail

      • handleGetLimit

        protected int handleGetLimit​(int field,
                                     int limitType)
        Override Calendar to return the limit value for the given field.
        Specified by:
        handleGetLimit in class Calendar
        Parameters:
        field - one of the above field numbers
        limitType - one of MINIMUM, GREATEST_MINIMUM, LEAST_MAXIMUM, or MAXIMUM
      • handleGetExtendedYear

        protected int handleGetExtendedYear()
        Implement abstract Calendar method to return the extended year defined by the current fields. This will use either the ERA and YEAR field as the cycle and year-of-cycle, or the EXTENDED_YEAR field as the continuous year count, depending on which is newer.
        Specified by:
        handleGetExtendedYear in class Calendar
        Returns:
        the extended year
      • handleGetMonthLength

        protected int handleGetMonthLength​(int extendedYear,
                                           int month)
        Override Calendar method to return the number of days in the given extended year and month.

        Note: This method also reads the IS_LEAP_MONTH field to determine whether or not the given month is a leap month.

        Overrides:
        handleGetMonthLength in class Calendar
      • handleGetDateFormat

        protected DateFormat handleGetDateFormat​(java.lang.String pattern,
                                                 java.lang.String override,
                                                 ULocale locale)
        Creates a DateFormat appropriate to this calendar. This is a framework method for subclasses to override. This method is responsible for creating the calendar-specific DateFormat and DateFormatSymbols objects as needed.
        Overrides:
        handleGetDateFormat in class Calendar
        Parameters:
        pattern - the pattern, specific to the DateFormat subclass
        locale - the locale for which the symbols should be drawn
        Returns:
        a DateFormat appropriate to this calendar
      • offsetMonth

        private void offsetMonth​(int newMoon,
                                 int dom,
                                 int delta)
        Adjust this calendar to be delta months before or after a given start position, pinning the day of month if necessary. The start position is given as a local days number for the start of the month and a day-of-month. Used by add() and roll().
        Parameters:
        newMoon - the local days of the first day of the month of the start position (days after January 1, 1970 0:00 Asia/Shanghai)
        dom - the 1-based day-of-month of the start position
        delta - the number of months to move forward or backward from the start position
      • add

        public void add​(int field,
                        int amount)
        Override Calendar to handle leap months properly.
        Overrides:
        add in class Calendar
        Parameters:
        field - the time field.
        amount - the amount to add to the field.
        See Also:
        Calendar.roll(int, int)
      • roll

        public void roll​(int field,
                         int amount)
        Override Calendar to handle leap months properly.
        Overrides:
        roll in class Calendar
        Parameters:
        field - the calendar field to roll.
        amount - the amount by which the field should be rolled.
        See Also:
        Calendar.roll(int, boolean), Calendar.add(int, int)
      • daysToMillis

        private final long daysToMillis​(int days)
        Convert local days to UTC epoch milliseconds. This is not an accurate conversion in terms that getTimezoneOffset takes the milliseconds in GMT (not local time). In theory, more accurate algorithm can be implemented but practically we do not need to go through that complication as long as the historically timezone changes did not happen around the 'tricky' new moon (new moon around the midnight).
        Parameters:
        days - days after January 1, 1970 0:00 in the astronomical base zone
        Returns:
        milliseconds after January 1, 1970 0:00 GMT
      • millisToDays

        private final int millisToDays​(long millis)
        Convert UTC epoch milliseconds to local days.
        Parameters:
        millis - milliseconds after January 1, 1970 0:00 GMT
        Returns:
        days days after January 1, 1970 0:00 in the astronomical base zone
      • winterSolstice

        private int winterSolstice​(int gyear)
        Return the major solar term on or after December 15 of the given Gregorian year, that is, the winter solstice of the given year. Computations are relative to Asia/Shanghai time zone.
        Parameters:
        gyear - a Gregorian year
        Returns:
        days after January 1, 1970 0:00 Asia/Shanghai of the winter solstice of the given year
      • newMoonNear

        private int newMoonNear​(int days,
                                boolean after)
        Return the closest new moon to the given date, searching either forward or backward in time.
        Parameters:
        days - days after January 1, 1970 0:00 Asia/Shanghai
        after - if true, search for a new moon on or after the given date; otherwise, search for a new moon before it
        Returns:
        days after January 1, 1970 0:00 Asia/Shanghai of the nearest new moon after or before days
      • synodicMonthsBetween

        private int synodicMonthsBetween​(int day1,
                                         int day2)
        Return the nearest integer number of synodic months between two dates.
        Parameters:
        day1 - days after January 1, 1970 0:00 Asia/Shanghai
        day2 - days after January 1, 1970 0:00 Asia/Shanghai
        Returns:
        the nearest integer number of months between day1 and day2
      • majorSolarTerm

        private int majorSolarTerm​(int days)
        Return the major solar term on or before a given date. This will be an integer from 1..12, with 1 corresponding to 330 degrees, 2 to 0 degrees, 3 to 30 degrees,..., and 12 to 300 degrees.
        Parameters:
        days - days after January 1, 1970 0:00 Asia/Shanghai
      • hasNoMajorSolarTerm

        private boolean hasNoMajorSolarTerm​(int newMoon)
        Return true if the given month lacks a major solar term.
        Parameters:
        newMoon - days after January 1, 1970 0:00 Asia/Shanghai of a new moon
      • isLeapMonthBetween

        private boolean isLeapMonthBetween​(int newMoon1,
                                           int newMoon2)
        Return true if there is a leap month on or after month newMoon1 and at or before month newMoon2.
        Parameters:
        newMoon1 - days after January 1, 1970 0:00 astronomical base zone of a new moon
        newMoon2 - days after January 1, 1970 0:00 astronomical base zone of a new moon
      • handleComputeFields

        protected void handleComputeFields​(int julianDay)
        Override Calendar to compute several fields specific to the Chinese calendar system. These are:
        • ERA
        • YEAR
        • MONTH
        • DAY_OF_MONTH
        • DAY_OF_YEAR
        • EXTENDED_YEAR
        The DAY_OF_WEEK and DOW_LOCAL fields are already set when this method is called. The getGregorianXxx() methods return Gregorian calendar equivalents for the given Julian day.

        Compute the ChineseCalendar-specific field IS_LEAP_MONTH.

        Overrides:
        handleComputeFields in class Calendar
      • computeChineseFields

        private void computeChineseFields​(int days,
                                          int gyear,
                                          int gmonth,
                                          boolean setAllFields)
        Compute fields for the Chinese calendar system. This method can either set all relevant fields, as required by handleComputeFields(), or it can just set the MONTH and IS_LEAP_MONTH fields, as required by handleComputeMonthStart().

        As a side effect, this method sets hasLeapMonthBetweenWinterSolstices.

        Parameters:
        days - days after January 1, 1970 0:00 astronomical base zone of the date to compute fields for
        gyear - the Gregorian year of the given date
        gmonth - the Gregorian month of the given date
        setAllFields - if true, set the EXTENDED_YEAR, ERA, YEAR, DAY_OF_MONTH, and DAY_OF_YEAR fields. In either case set the MONTH and IS_LEAP_MONTH fields.
      • newYear

        private int newYear​(int gyear)
        Return the Chinese new year of the given Gregorian year.
        Parameters:
        gyear - a Gregorian year
        Returns:
        days after January 1, 1970 0:00 astronomical base zone of the Chinese new year of the given year (this will be a new moon)
      • handleComputeMonthStart

        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.

        Note: This method reads the IS_LEAP_MONTH field to determine whether the given month is a leap month.

        Specified by:
        handleComputeMonthStart in class Calendar
        Parameters:
        eyear - the extended year
        month - the zero-based month. The month is also determined by reading the IS_LEAP_MONTH field.
        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 java.lang.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
      • haveDefaultCentury

        @Deprecated
        public boolean haveDefaultCentury()
        Deprecated.
        This API is ICU internal only.
        Returns if two digit representation of year in this calendar type customarily implies a default century (i.e. 03 -> 2003). The default implementation returns true. A subclass may return false if such practice is not applicable (for example, Chinese calendar and Japanese calendar).
        Overrides:
        haveDefaultCentury in class Calendar
        Returns:
        true if this calendar has a default century.
      • readObject

        private void readObject​(java.io.ObjectInputStream stream)
                         throws java.io.IOException,
                                java.lang.ClassNotFoundException
        Override readObject.
        Throws:
        java.io.IOException
        java.lang.ClassNotFoundException
      • inTemporalLeapYear

        public boolean inTemporalLeapYear()
        Returns true if the date is in a leap year. Recalculate the current time field values if the time value has been changed by a call to setTime(). This method is semantically const, but may alter the object in memory. A "leap year" is a year that contains more days than other years (for solar or lunar calendars) or more months than other years (for lunisolar calendars like Hebrew or Chinese), as defined in the ECMAScript Temporal proposal.
        Overrides:
        inTemporalLeapYear in class Calendar
        Returns:
        true if the date in the fields is in a Temporal proposal defined leap year. False otherwise.
      • getTemporalMonthCode

        public java.lang.String getTemporalMonthCode()
        Gets The Temporal monthCode value corresponding to the month for the date. The value is a string identifier that starts with the literal grapheme "M" followed by two graphemes representing the zero-padded month number of the current month in a normal (non-leap) year and suffixed by an optional literal grapheme "L" if this is a leap month in a lunisolar calendar. For the Chinese calendar, the values are "M01" .. "M12" for non-leap year and * in leap year with another monthCode in "M01L" .. "M12L".
        Overrides:
        getTemporalMonthCode in class Calendar
        Returns:
        One of 24 possible strings in {"M01".."M12", "M01L".."M12L"}.
      • setTemporalMonthCode

        public void setTemporalMonthCode​(java.lang.String temporalMonth)
        Sets The Temporal monthCode which is a string identifier that starts with the literal grapheme "M" followed by two graphemes representing the zero-padded month number of the current month in a normal (non-leap) year and suffixed by an optional literal grapheme "L" if this is a leap month in a lunisolar calendar. For the Chinese calendar, the values are "M01" .. "M12" for non-leap year and in leap year with another monthCode in "M01L" .. "M12L".
        Overrides:
        setTemporalMonthCode in class Calendar
        Parameters:
        temporalMonth - One of 25 possible strings in {"M01".. "M12", "M13", "M01L", "M12L"}.
      • internalGetMonth

        @Deprecated
        protected int internalGetMonth()
        Deprecated.
        This API is ICU internal only.
        Use this function instead of internalGet(MONTH). The implementation check the timestamp of MONTH and ORDINAL_MONTH and use the one set later. The subclass should override it to conver the value of ORDINAL_MONTH to MONTH correctly if ORDINAL_MONTH has higher priority.
        Overrides:
        internalGetMonth in class Calendar
        Returns:
        the value for the given time field.
      • internalGetMonth

        @Deprecated
        protected int internalGetMonth​(int defaultValue)
        Deprecated.
        This API is ICU internal only.
        Use this function instead of internalGet(MONTH, defaultValue). The implementation check the timestamp of MONTH and ORDINAL_MONTH and use the one set later. The subclass should override it to conver the value of ORDINAL_MONTH to MONTH correctly if ORDINAL_MONTH has higher priority.
        Overrides:
        internalGetMonth in class Calendar
        Parameters:
        defaultValue - a default value used if the MONTH and ORDINAL_MONTH are both unset.
        Returns:
        the value for the MONTH.