icuSources/i18n/japancal.h

   1 // © 2016 and later: Unicode, Inc. and others.
   2 // License & terms of use: http://www.unicode.org/copyright.html
   3 /*
   4  ********************************************************************************
   5  * Copyright (C) 2003-2008, International Business Machines Corporation
   6  * and others. All Rights Reserved.
   7  ********************************************************************************
   8  *
   9  * File JAPANCAL.H
  10  *
  11  * Modification History:
  12  *
  13  *   Date        Name        Description
  14  *   05/13/2003  srl         copied from gregocal.h
  15  ********************************************************************************
  16  */
  17
  18 #ifndef JAPANCAL_H
  19 #define JAPANCAL_H
  20
  21 #include "unicode/utypes.h"
  22
  23 #if !UCONFIG_NO_FORMATTING
  24
  25 #include "unicode/calendar.h"
  26 #include "unicode/gregocal.h"
  27
  28 U_NAMESPACE_BEGIN
  29
  30 /**
  31  * Concrete class which provides the Japanese calendar.
  32  * <P>
  33  * <code>JapaneseCalendar</code> is a subclass of <code>GregorianCalendar</code>
  34  * that numbers years and eras based on the reigns of the Japanese emperors.
  35  * The Japanese calendar is identical to the Gregorian calendar in all respects
  36  * except for the year and era.  The ascension of each  emperor to the throne
  37  * begins a new era, and the years of that era are numbered starting with the
  38  * year of ascension as year 1.
  39  * <p>
  40  * Note that in the year of an imperial ascension, there are two possible sets
  41  * of year and era values: that for the old era and for the new.  For example, a
  42  * new era began on January 7, 1989 AD.  Strictly speaking, the first six days
  43  * of that year were in the Showa era, e.g. "January 6, 64 Showa", while the rest
  44  * of the year was in the Heisei era, e.g. "January 7, 1 Heisei".  This class
  45  * handles this distinction correctly when computing dates.  However, in lenient
  46  * mode either form of date is acceptable as input.
  47  * <p>
  48  * In modern times, eras have started on January 8, 1868 AD, Gregorian (Meiji),
  49  * July 30, 1912 (Taisho), December 25, 1926 (Showa), and January 7, 1989 (Heisei).  Constants
  50  * for these eras, suitable for use in the <code>UCAL_ERA</code> field, are provided
  51  * in this class.  Note that the <em>number</em> used for each era is more or
  52  * less arbitrary.  Currently, the era starting in 1053 AD is era #0; however this
  53  * may change in the future as we add more historical data.  Use the predefined
  54  * constants rather than using actual, absolute numbers.
  55  * <p>
  56  * @internal
  57  */
  58 class JapaneseCalendar : public GregorianCalendar {
  59 public:
  60
  61     /**
  62      * Useful constants for JapaneseCalendar.
  63      * @internal
  64      */
  65     U_I18N_API static uint32_t U_EXPORT2 getCurrentEra(void); // the current era
  66
  67     /**
  68      * Constructs a JapaneseCalendar based on the current time in the default time zone
  69      * with the given locale.
  70      *
  71      * @param aLocale  The given locale.
  72      * @param success  Indicates the status of JapaneseCalendar object construction.
  73      *                 Returns U_ZERO_ERROR if constructed successfully.
  74      * @stable ICU 2.0
  75      */
  76     JapaneseCalendar(const Locale& aLocale, UErrorCode& success);
  77
  78
  79     /**
  80      * Destructor
  81      * @internal
  82      */
  83     virtual ~JapaneseCalendar();
  84
  85     /**
  86      * Copy constructor
  87      * @param source    the object to be copied.
  88      * @internal
  89      */
  90     JapaneseCalendar(const JapaneseCalendar& source);
  91
  92     /**
  93      * Default assignment operator
  94      * @param right    the object to be copied.
  95      * @internal
  96      */
  97     JapaneseCalendar& operator=(const JapaneseCalendar& right);
  98
  99     /**
 100      * Create and return a polymorphic copy of this calendar.
 101      * @return    return a polymorphic copy of this calendar.
 102      * @internal
 103      */
 104     virtual Calendar* clone(void) const;
 105
 106     /**
 107      * Return the extended year defined by the current fields.  In the
 108      * Japanese calendar case, this is equal to the equivalent extended Gregorian year.
 109      * @internal
 110      */
 111     virtual int32_t handleGetExtendedYear();
 112
 113     /**
 114      * Return the maximum value that this field could have, given the current date.
 115      * @internal
 116      */
 117     virtual int32_t getActualMaximum(UCalendarDateFields field, UErrorCode& status) const;
 118
 119
 120 public:
 121     /**
 122      * Override Calendar Returns a unique class ID POLYMORPHICALLY. Pure virtual
 123      * override. This method is to implement a simple version of RTTI, since not all C++
 124      * compilers support genuine RTTI. Polymorphic operator==() and clone() methods call
 125      * this method.
 126      *
 127      * @return   The class ID for this object. All objects of a given class have the
 128      *           same class ID. Objects of other classes have different class IDs.
 129      * @internal
 130      */
 131     virtual UClassID getDynamicClassID(void) const;
 132
 133     /**
 134      * Return the class ID for this class. This is useful only for comparing to a return
 135      * value from getDynamicClassID(). For example:
 136      *
 137      *      Base* polymorphic_pointer = createPolymorphicObject();
 138      *      if (polymorphic_pointer->getDynamicClassID() ==
 139      *          Derived::getStaticClassID()) ...
 140      *
 141      * @return   The class ID for all objects of this class.
 142      * @internal
 143      */
 144     U_I18N_API static UClassID U_EXPORT2 getStaticClassID(void);
 145
 146     /**
 147      * return the calendar type, "japanese".
 148      *
 149      * @return calendar type
 150      * @internal
 151      */
 152     virtual const char * getType() const;
 153
 154     /**
 155      * @return FALSE - no default century in Japanese
 156      * @internal
 157      */
 158     virtual UBool haveDefaultCentury() const;
 159
 160     /**
 161      * Not used - no default century.
 162      * @internal
 163      */
 164     virtual UDate defaultCenturyStart() const;
 165     /**
 166      * Not used - no default century.
 167      * @internal
 168      */
 169     virtual int32_t defaultCenturyStartYear() const;
 170
 171 private:
 172     JapaneseCalendar(); // default constructor not implemented
 173
 174 protected:
 175     /**
 176      * Calculate the era for internal computation
 177      * @internal
 178      */
 179     virtual int32_t internalGetEra() const;
 180
 181     /**
 182      * Compute fields from the JD
 183      * @internal
 184      */
 185     virtual void handleComputeFields(int32_t julianDay, UErrorCode& status);
 186
 187     /**
 188      * Calculate the limit for a specified type of limit and field
 189      * @internal
 190      */
 191     virtual int32_t handleGetLimit(UCalendarDateFields field, ELimitType limitType) const;
 192
 193     /***
 194      * Called by computeJulianDay.  Returns the default month (0-based) for the year,
 195      * taking year and era into account.  Will return the first month of the given era, if
 196      * the current year is an ascension year.
 197      * @param eyear the extended year
 198      * @internal
 199      */
 200     virtual int32_t getDefaultMonthInYear(int32_t eyear);
 201
 202     /***
 203      * Called by computeJulianDay.  Returns the default day (1-based) for the month,
 204      * taking currently-set year and era into account.  Will return the first day of the given
 205      * era, if the current month is an ascension year and month.
 206      * @param eyear the extended year
 207      * @param mon the month in the year
 208      * @internal
 209      */
 210     virtual int32_t getDefaultDayInMonth(int32_t eyear, int32_t month);
 211 };
 212
 213 U_NAMESPACE_END
 214
 215 #endif /* #if !UCONFIG_NO_FORMATTING */
 216
 217 #endif
 218 //eof
 219