* Clients are encouraged to create a date-time formatter using DateFormat::getInstance(), * getDateInstance(), getDateInstance(), or getDateTimeInstance() rather than * explicitly constructing an instance of SimpleDateFormat. This way, the client * is guaranteed to get an appropriate formatting pattern for whatever locale the * program is running in. However, if the client needs something more unusual than * the default patterns in the locales, he can construct a SimpleDateFormat directly * and give it an appropriate pattern (or use one of the factory methods on DateFormat * and modify the pattern after the fact with toPattern() and applyPattern(). * *
Date and Time Patterns:
Date and time formats are specified by date and time pattern strings. * Within date and time pattern strings, all unquoted ASCII letters [A-Za-z] are reserved * as pattern letters representing calendar fields. SimpleDateFormat supports * the date and time formatting algorithm and pattern letters defined by * UTS#35 * Unicode Locale Data Markup Language (LDML) and further documented for ICU in the * ICU * User Guide. The following pattern letters are currently available (note that the actual * values depend on CLDR and may change from the examples shown here):
SimpleDateFormat
* Any characters in the pattern that are not in the ranges of ['a'..'z'] and * ['A'..'Z'] will be treated as quoted text. For instance, characters * like ':', '.', ' ', '#' and '@' will appear in the resulting time text * even they are not embraced within single quotes. *
* A pattern containing any invalid pattern letter will result in a failing * UErrorCode result during formatting or parsing. *
* Examples using the US locale: *
* \code * Format Pattern Result * -------------- ------- * "yyyy.MM.dd G 'at' HH:mm:ss vvvv" ->> 1996.07.10 AD at 15:08:56 Pacific Time * "EEE, MMM d, ''yy" ->> Wed, July 10, '96 * "h:mm a" ->> 12:08 PM * "hh 'o''clock' a, zzzz" ->> 12 o'clock PM, Pacific Daylight Time * "K:mm a, vvv" ->> 0:00 PM, PT * "yyyyy.MMMMM.dd GGG hh:mm aaa" ->> 1996.July.10 AD 12:08 PM * \endcode *
* \code * UErrorCode success = U_ZERO_ERROR; * SimpleTimeZone* pdt = new SimpleTimeZone(-8 * 60 * 60 * 1000, "PST"); * pdt->setStartRule( Calendar::APRIL, 1, Calendar::SUNDAY, 2*60*60*1000); * pdt->setEndRule( Calendar::OCTOBER, -1, Calendar::SUNDAY, 2*60*60*1000); * * // Format the current time. * SimpleDateFormat* formatter * = new SimpleDateFormat ("yyyy.MM.dd G 'at' hh:mm:ss a zzz", success ); * GregorianCalendar cal(success); * UDate currentTime_1 = cal.getTime(success); * FieldPosition fp(FieldPosition::DONT_CARE); * UnicodeString dateString; * formatter->format( currentTime_1, dateString, fp ); * cout << "result: " << dateString << endl; * * // Parse the previous string back into a Date. * ParsePosition pp(0); * UDate currentTime_2 = formatter->parse(dateString, pp ); * \endcode *
* When parsing a date string using the abbreviated year pattern ("y" or "yy"), * SimpleDateFormat must interpret the abbreviated year * relative to some century. It does this by adjusting dates to be * within 80 years before and 20 years after the time the SimpleDateFormat * instance is created. For example, using a pattern of "MM/dd/yy" and a * SimpleDateFormat instance created on Jan 1, 1997, the string * "01/11/12" would be interpreted as Jan 11, 2012 while the string "05/04/64" * would be interpreted as May 4, 1964. * During parsing, only strings consisting of exactly two digits, as defined by * Unicode::isDigit(), will be parsed into the default century. * Any other numeric string, such as a one digit string, a three or more digit * string, or a two digit string that isn't all digits (for example, "-1"), is * interpreted literally. So "01/02/3" or "01/02/003" are parsed (for the * Gregorian calendar), using the same pattern, as Jan 2, 3 AD. Likewise (but * only in lenient parse mode, the default) "01/02/-3" is parsed as Jan 2, 4 BC. * *
Unicode::isDigit()
* If the year pattern has more than two 'y' characters, the year is * interpreted literally, regardless of the number of digits. So using the * pattern "MM/dd/yyyy", "01/11/12" parses to Jan 11, 12 A.D. * *
* When numeric fields abut one another directly, with no intervening delimiter * characters, they constitute a run of abutting numeric fields. Such runs are * parsed specially. For example, the format "HHmmss" parses the input text * "123456" to 12:34:56, parses the input text "12345" to 1:23:45, and fails to * parse "1234". In other words, the leftmost field of the run is flexible, * while the others keep a fixed width. If the parse fails anywhere in the run, * then the leftmost field is shortened by one character, and the entire run is * parsed again. This is repeated until either the parse succeeds or the * leftmost field is one character in length. If the parse still fails at that * point, the parse of the run fails. * *
* For time zones that have no names, SimpleDateFormat uses strings GMT+hours:minutes or * GMT-hours:minutes. *
* The calendar defines what is the first day of the week, the first week of the * year, whether hours are zero based or not (0 vs 12 or 24), and the timezone. * There is one common number format to handle all the numbers; the digit count * is handled programmatically according to the pattern. * *
User subclasses are not supported. While clients may write * subclasses, such code will not necessarily work and will not be * guaranteed to work stably from release to release. */ class U_I18N_API SimpleDateFormat: public DateFormat { public: /** * Construct a SimpleDateFormat using the default pattern for the default * locale. *
* [Note:] Not all locales support SimpleDateFormat; for full generality, * use the factory methods in the DateFormat class. * @param status Output param set to success/failure code. * @stable ICU 2.0 */ SimpleDateFormat(UErrorCode& status); /** * Construct a SimpleDateFormat using the given pattern and the default locale. * The locale is used to obtain the symbols used in formatting (e.g., the * names of the months), but not to provide the pattern. *
* [Note:] Not all locales support SimpleDateFormat; for full generality, * use the factory methods in the DateFormat class. * @param pattern the pattern for the format. * @param status Output param set to success/failure code. * @stable ICU 2.0 */ SimpleDateFormat(const UnicodeString& pattern, UErrorCode& status); /** * Construct a SimpleDateFormat using the given pattern, numbering system override, and the default locale. * The locale is used to obtain the symbols used in formatting (e.g., the * names of the months), but not to provide the pattern. *
* A numbering system override is a string containing either the name of a known numbering system, * or a set of field and numbering system pairs that specify which fields are to be formattied with * the alternate numbering system. For example, to specify that all numeric fields in the specified * date or time pattern are to be rendered using Thai digits, simply specify the numbering system override * as "thai". To specify that just the year portion of the date be formatted using Hebrew numbering, * use the override string "y=hebrew". Numbering system overrides can be combined using a semi-colon * character in the override string, such as "d=decimal;M=arabic;y=hebrew", etc. * *
* [Note:] Not all locales support SimpleDateFormat; for full generality, * use the factory methods in the DateFormat class. * @param pattern the pattern for the format. * @param override the override string. * @param status Output param set to success/failure code. * @stable ICU 4.2 */ SimpleDateFormat(const UnicodeString& pattern, const UnicodeString& override, UErrorCode& status); /** * Construct a SimpleDateFormat using the given pattern and locale. * The locale is used to obtain the symbols used in formatting (e.g., the * names of the months), but not to provide the pattern. *
* [Note:] Not all locales support SimpleDateFormat; for full generality, * use the factory methods in the DateFormat class. * @param pattern the pattern for the format. * @param locale the given locale. * @param status Output param set to success/failure code. * @stable ICU 2.0 */ SimpleDateFormat(const UnicodeString& pattern, const Locale& locale, UErrorCode& status); /** * Construct a SimpleDateFormat using the given pattern, numbering system override, and locale. * The locale is used to obtain the symbols used in formatting (e.g., the * names of the months), but not to provide the pattern. *
* A numbering system override is a string containing either the name of a known numbering system, * or a set of field and numbering system pairs that specify which fields are to be formattied with * the alternate numbering system. For example, to specify that all numeric fields in the specified * date or time pattern are to be rendered using Thai digits, simply specify the numbering system override * as "thai". To specify that just the year portion of the date be formatted using Hebrew numbering, * use the override string "y=hebrew". Numbering system overrides can be combined using a semi-colon * character in the override string, such as "d=decimal;M=arabic;y=hebrew", etc. *
* [Note:] Not all locales support SimpleDateFormat; for full generality, * use the factory methods in the DateFormat class. * @param pattern the pattern for the format. * @param override the numbering system override. * @param locale the given locale. * @param status Output param set to success/failure code. * @stable ICU 4.2 */ SimpleDateFormat(const UnicodeString& pattern, const UnicodeString& override, const Locale& locale, UErrorCode& status); /** * Construct a SimpleDateFormat using the given pattern and locale-specific * symbol data. The formatter takes ownership of the DateFormatSymbols object; * the caller is no longer responsible for deleting it. * @param pattern the given pattern for the format. * @param formatDataToAdopt the symbols to be adopted. * @param status Output param set to success/faulure code. * @stable ICU 2.0 */ SimpleDateFormat(const UnicodeString& pattern, DateFormatSymbols* formatDataToAdopt, UErrorCode& status); /** * Construct a SimpleDateFormat using the given pattern and locale-specific * symbol data. The DateFormatSymbols object is NOT adopted; the caller * remains responsible for deleting it. * @param pattern the given pattern for the format. * @param formatData the formatting symbols to be use. * @param status Output param set to success/faulure code. * @stable ICU 2.0 */ SimpleDateFormat(const UnicodeString& pattern, const DateFormatSymbols& formatData, UErrorCode& status); /** * Copy constructor. * @stable ICU 2.0 */ SimpleDateFormat(const SimpleDateFormat&); /** * Assignment operator. * @stable ICU 2.0 */ SimpleDateFormat& operator=(const SimpleDateFormat&); /** * Destructor. * @stable ICU 2.0 */ virtual ~SimpleDateFormat(); /** * Clone this Format object polymorphically. The caller owns the result and * should delete it when done. * @return A copy of the object. * @stable ICU 2.0 */ virtual SimpleDateFormat* clone() const; /** * Return true if the given Format objects are semantically equal. Objects * of different subclasses are considered unequal. * @param other the object to be compared with. * @return true if the given Format objects are semantically equal. * @stable ICU 2.0 */ virtual UBool operator==(const Format& other) const; using DateFormat::format; /** * Format a date or time, which is the standard millis since 24:00 GMT, Jan * 1, 1970. Overrides DateFormat pure virtual method. *
* Example: using the US locale: "yyyy.MM.dd e 'at' HH:mm:ss zzz" ->> * 1996.07.10 AD at 15:08:56 PDT * * @param cal Calendar set to the date and time to be formatted * into a date/time string. * @param appendTo Output parameter to receive result. * Result is appended to existing contents. * @param pos The formatting position. On input: an alignment field, * if desired. On output: the offsets of the alignment field. * @return Reference to 'appendTo' parameter. * @stable ICU 2.1 */ virtual UnicodeString& format( Calendar& cal, UnicodeString& appendTo, FieldPosition& pos) const; /** * Format a date or time, which is the standard millis since 24:00 GMT, Jan * 1, 1970. Overrides DateFormat pure virtual method. *
* Example: using the US locale: "yyyy.MM.dd e 'at' HH:mm:ss zzz" ->> * 1996.07.10 AD at 15:08:56 PDT * * @param cal Calendar set to the date and time to be formatted * into a date/time string. * @param appendTo Output parameter to receive result. * Result is appended to existing contents. * @param posIter On return, can be used to iterate over positions * of fields generated by this format call. Field values * are defined in UDateFormatField. * @param status Input/output param set to success/failure code. * @return Reference to 'appendTo' parameter. * @stable ICU 4.4 */ virtual UnicodeString& format( Calendar& cal, UnicodeString& appendTo, FieldPositionIterator* posIter, UErrorCode& status) const; using DateFormat::parse; /** * Parse a date/time string beginning at the given parse position. For * example, a time text "07/10/96 4:5 PM, PDT" will be parsed into a Date * that is equivalent to Date(837039928046). *
* By default, parsing is lenient: If the input is not in the form used by * this object's format method but can still be parsed as a date, then the * parse succeeds. Clients may insist on strict adherence to the format by * calling setLenient(false). * @see DateFormat::setLenient(boolean) * * @param text The date/time string to be parsed * @param cal A Calendar set on input to the date and time to be used for * missing values in the date/time string being parsed, and set * on output to the parsed date/time. When the calendar type is * different from the internal calendar held by this SimpleDateFormat * instance, the internal calendar will be cloned to a work * calendar set to the same milliseconds and time zone as the * cal parameter, field values will be parsed based on the work * calendar, then the result (milliseconds and time zone) will * be set in this calendar. * @param pos On input, the position at which to start parsing; on * output, the position at which parsing terminated, or the * start position if the parse failed. * @stable ICU 2.1 */ virtual void parse( const UnicodeString& text, Calendar& cal, ParsePosition& pos) const; /** * Set the start UDate used to interpret two-digit year strings. * When dates are parsed having 2-digit year strings, they are placed within * a assumed range of 100 years starting on the two digit start date. For * example, the string "24-Jan-17" may be in the year 1817, 1917, 2017, or * some other year. SimpleDateFormat chooses a year so that the resultant * date is on or after the two digit start date and within 100 years of the * two digit start date. *
* By default, the two digit start date is set to 80 years before the current * time at which a SimpleDateFormat object is created. * @param d start UDate used to interpret two-digit year strings. * @param status Filled in with U_ZERO_ERROR if the parse was successful, and with * an error value if there was a parse error. * @stable ICU 2.0 */ virtual void set2DigitYearStart(UDate d, UErrorCode& status); /** * Get the start UDate used to interpret two-digit year strings. * When dates are parsed having 2-digit year strings, they are placed within * a assumed range of 100 years starting on the two digit start date. For * example, the string "24-Jan-17" may be in the year 1817, 1917, 2017, or * some other year. SimpleDateFormat chooses a year so that the resultant * date is on or after the two digit start date and within 100 years of the * two digit start date. *
* By default, the two digit start date is set to 80 years before the current * time at which a SimpleDateFormat object is created. * @param status Filled in with U_ZERO_ERROR if the parse was successful, and with * an error value if there was a parse error. * @stable ICU 2.0 */ UDate get2DigitYearStart(UErrorCode& status) const; /** * Return a pattern string describing this date format. * @param result Output param to receive the pattern. * @return A reference to 'result'. * @stable ICU 2.0 */ virtual UnicodeString& toPattern(UnicodeString& result) const; /** * Return a localized pattern string describing this date format. * In most cases, this will return the same thing as toPattern(), * but a locale can specify characters to use in pattern descriptions * in place of the ones described in this class's class documentation. * (Presumably, letters that would be more mnemonic in that locale's * language.) This function would produce a pattern using those * letters. *
* Note: This implementation depends on DateFormatSymbols::getLocalPatternChars() * to get localized format pattern characters. ICU does not include * localized pattern character data, therefore, unless user sets localized * pattern characters manually, this method returns the same result as * toPattern(). * * @param result Receives the localized pattern. * @param status Output param set to success/failure code on * exit. If the pattern is invalid, this will be * set to a failure result. * @return A reference to 'result'. * @stable ICU 2.0 */ virtual UnicodeString& toLocalizedPattern(UnicodeString& result, UErrorCode& status) const; /** * Apply the given unlocalized pattern string to this date format. * (i.e., after this call, this formatter will format dates according to * the new pattern) * * @param pattern The pattern to be applied. * @stable ICU 2.0 */ virtual void applyPattern(const UnicodeString& pattern); /** * Apply the given localized pattern string to this date format. * (see toLocalizedPattern() for more information on localized patterns.) * * @param pattern The localized pattern to be applied. * @param status Output param set to success/failure code on * exit. If the pattern is invalid, this will be * set to a failure result. * @stable ICU 2.0 */ virtual void applyLocalizedPattern(const UnicodeString& pattern, UErrorCode& status); /** * Gets the date/time formatting symbols (this is an object carrying * the various strings and other symbols used in formatting: e.g., month * names and abbreviations, time zone names, AM/PM strings, etc.) * @return a copy of the date-time formatting data associated * with this date-time formatter. * @stable ICU 2.0 */ virtual const DateFormatSymbols* getDateFormatSymbols(void) const; /** * Set the date/time formatting symbols. The caller no longer owns the * DateFormatSymbols object and should not delete it after making this call. * @param newFormatSymbols the given date-time formatting symbols to copy. * @stable ICU 2.0 */ virtual void adoptDateFormatSymbols(DateFormatSymbols* newFormatSymbols); /** * Set the date/time formatting data. * @param newFormatSymbols the given date-time formatting symbols to copy. * @stable ICU 2.0 */ virtual void setDateFormatSymbols(const DateFormatSymbols& newFormatSymbols); /** * Return the class ID for this class. This is useful only for comparing to * a return value from getDynamicClassID(). For example: *
* . Base* polymorphic_pointer = createPolymorphicObject(); * . if (polymorphic_pointer->getDynamicClassID() == * . erived::getStaticClassID()) ... *
TRUE
FALSE