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SimpleDateFormat Class Reference

SimpleDateFormat is a concrete class for formatting and parsing dates in a language-independent manner. More...

#include <smpdtfmt.h>

Class diagram for SimpleDateFormat:

DateFormat Format

List of all members.


Public Members

 SimpleDateFormat (UErrorCode& status)
Construct a SimpleDateFormat using the default pattern for the default locale. More...

 SimpleDateFormat (const UnicodeString& pattern, UErrorCode& status)
Construct a SimpleDateFormat using the given pattern and the default locale. More...

 SimpleDateFormat (const UnicodeString& pattern, const Locale& locale, UErrorCode& status)
Construct a SimpleDateFormat using the given pattern and locale. More...

 SimpleDateFormat (const UnicodeString& pattern, DateFormatSymbols* formatDataToAdopt, UErrorCode& status)
Construct a SimpleDateFormat using the given pattern and locale-specific symbol data. More...

 SimpleDateFormat (const UnicodeString& pattern, const DateFormatSymbols& formatData, UErrorCode& status)
Construct a SimpleDateFormat using the given pattern and locale-specific symbol data. More...

 SimpleDateFormat (const SimpleDateFormat&)
Copy constructor. More...

SimpleDateFormat& operator= (const SimpleDateFormat&)
Assignment operator. More...

virtual ~SimpleDateFormat ()
Destructor. More...

virtual Formatclone (void) const
Clone this Format object polymorphically. More...

virtual UBool operator== (const Format& other) const
Return true if the given Format objects are semantically equal. More...

virtual UnicodeStringformat ( UDate date, UnicodeString& toAppendTo, FieldPosition& pos) const
Format a date or time, which is the standard millis since 24:00 GMT, Jan 1, 1970. More...

virtual UnicodeStringformat ( const Formattable& obj, UnicodeString& toAppendTo, FieldPosition& pos, UErrorCode& status) const
Format a date or time, which is the standard millis since 24:00 GMT, Jan 1, 1970. More...

UnicodeStringformat (const Formattable& obj, UnicodeString& result, UErrorCode& status) const
Redeclared DateFormat method. More...

UnicodeStringformat (UDate date, UnicodeString& result) const
Redeclared DateFormat method. More...

virtual UDate parse ( const UnicodeString& text, ParsePosition& pos) const
Parse a date/time string starting at the given parse position. More...

virtual UDate parse ( const UnicodeString& text, UErrorCode& status) const
Parse a date/time string. More...

virtual void set2DigitYearStart (UDate d, UErrorCode& status)
Set the start UDate used to interpret two-digit year strings. More...

UDate get2DigitYearStart (UErrorCode& status) const
Get the start UDate used to interpret two-digit year strings. More...

virtual UnicodeStringtoPattern (UnicodeString& result) const
Return a pattern string describing this date format. More...

virtual UnicodeStringtoLocalizedPattern (UnicodeString& result, UErrorCode& status) const
Return a localized pattern string describing this date format. More...

virtual void applyPattern (const UnicodeString& pattern)
Apply the given unlocalized pattern string to this date format. More...

virtual void applyLocalizedPattern (const UnicodeString& pattern, UErrorCode& status)
Apply the given localized pattern string to this date format. More...

virtual const DateFormatSymbolsgetDateFormatSymbols (void) const
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.). More...

virtual void adoptDateFormatSymbols (DateFormatSymbols* newFormatSymbols)
Set the date/time formatting symbols. More...

virtual void setDateFormatSymbols (const DateFormatSymbols& newFormatSymbols)
Set the date/time formatting data. More...

virtual UClassID getDynamicClassID (void) const
Returns a unique class ID POLYMORPHICALLY. More...


Static Public Members

UClassID getStaticClassID (void)
Return the class ID for this class. More...

const char* fgErasTag
Resource bundle file suffix and tag names used by this class.

const char* fgMonthNamesTag
const char* fgMonthAbbreviationsTag
const char* fgDayNamesTag
const char* fgDayAbbreviationsTag
const char* fgAmPmMarkersTag
const char* fgDateTimePatternsTag
const char* fgZoneStringsTag
const char* fgLocalPatternCharsTag
const UnicodeString fgDefaultPattern
const UDate fgSystemDefaultCentury
If a start date is set to this value, that indicates that the system default start is in effect for this instance.


Friends

class  DateFormat

Detailed Description

SimpleDateFormat is a concrete class for formatting and parsing dates in a language-independent manner.

It allows for formatting (millis -> text), parsing (text -> millis), and normalization. Formats/Parses a date or time, which is the standard milliseconds since 24:00 GMT, Jan 1, 1970.

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/Time format syntax:

The date/time format is specified by means of a string time pattern. In this pattern, all ASCII letters are reserved as pattern letters, which are defined as the following:

 .   Symbol   Meaning                 Presentation       Example
 .   ------   -------                 ------------       -------
 .   G        era designator          (Text)             AD
 .   y        year                    (Number)           1996
 .   Y        year/week of year       (Number)           1996
 .   M        month in year           (Text & Number)    July & 07
 .   d        day in month            (Number)           10
 .   h        hour in am/pm (1~12)    (Number)           12
 .   H        hour in day (0~23)      (Number)           0
 .   m        minute in hour          (Number)           30
 .   s        second in minute        (Number)           55
 .   S        millisecond             (Number)           978
 .   E        day of week             (Text)             Tuesday
 .   e        day of week/local (1~7) (Number)           2
 .   D        day of year             (Number)           189
 .   F        day of week in month    (Number)           2 (2nd Wed in July)
 .   w        week in year            (Number)           27
 .   W        week in month           (Number)           2
 .   a        am/pm marker            (Text)             PM
 .   k        hour in day (1~24)      (Number)           24
 .   K        hour in am/pm (0~11)    (Number)           0
 .   z        time zone               (Text)             Pacific Standard Time
 .   '        escape for text
 .   ''       single quote                               '
 
The count of pattern letters determine the format.

(Text): 4 or more, use full form, <4, use short or abbreviated form if it exists. (e.g., "EEEE" produces "Monday", "EEE" produces "Mon")

(Number): the minimum number of digits. Shorter numbers are zero-padded to this amount (e.g. if "m" produces "6", "mm" produces "06"). Year is handled specially; that is, if the count of 'y' is 2, the Year will be truncated to 2 digits. (e.g., if "yyyy" produces "1997", "yy" produces "97".)

(Text & Number): 3 or over, use text, otherwise use number. (e.g., "M" produces "1", "MM" produces "01", "MMM" produces "Jan", and "MMMM" produces "January".)

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:

 .   Format Pattern                         Result
 .   --------------                         -------
 .   "yyyy.MM.dd G 'at' HH:mm:ss z"    ->>  1996.07.10 AD at 15:08:56 PDT
 .   "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, z"                       ->>  0:00 PM, PST
 .   "yyyyy.MMMMM.dd GGG hh:mm aaa"    ->>  1996.July.10 AD 12:08 PM
 
Code Sample:
 .    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(0);
 .    UnicodeString dateString;
 .    formatter->format( currentTime_1, dateString, fp );
 .    cout &lt;&lt; "result: " &lt;&lt; dateString &lt;&lt; endl;
 .    
 .    // Parse the previous string back into a Date.
 .    ParsePosition pp(0);
 .    UDate currentTime_2 = formatter->parse(dateString, pp );
 
In the above example, the time value "currentTime_2" obtained from parsing will be equal to currentTime_1. However, they may not be equal if the am/pm marker 'a' is left out from the format pattern while the "hour in am/pm" pattern symbol is used. This information loss can happen when formatting the time in PM.

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, using the same pattern, as Jan 2, 3 AD. Likewise, "01/02/-3" is parsed as Jan 2, 4 BC.

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.

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.

Definition at line 166 of file smpdtfmt.h.


Member Function Documentation

SimpleDateFormat::SimpleDateFormat (UErrorCode & status)

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.

Stable:

SimpleDateFormat::SimpleDateFormat (const UnicodeString & pattern, 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.

Stable:

SimpleDateFormat::SimpleDateFormat (const UnicodeString & pattern, const Locale & locale, 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.

Stable:

SimpleDateFormat::SimpleDateFormat (const UnicodeString & pattern, DateFormatSymbols * formatDataToAdopt, 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.

Stable:

SimpleDateFormat::SimpleDateFormat (const UnicodeString & pattern, const DateFormatSymbols & formatData, 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.

Stable:

SimpleDateFormat::SimpleDateFormat (const SimpleDateFormat &)

Copy constructor.

Stable:

SimpleDateFormat & SimpleDateFormat::operator= (const SimpleDateFormat &)

Assignment operator.

Stable:

virtual SimpleDateFormat::~SimpleDateFormat () [virtual]

Destructor.

Stable:

virtual Format * SimpleDateFormat::clone (void) const [virtual]

Clone this Format object polymorphically.

The caller owns the result and should delete it when done.

Stable:

Reimplemented from Format.

virtual UBool SimpleDateFormat::operator== (const Format & other) const [virtual]

Return true if the given Format objects are semantically equal.

Objects of different subclasses are considered unequal.

Stable:

Reimplemented from Format.

virtual UnicodeString & SimpleDateFormat::format (UDate date, UnicodeString & toAppendTo, FieldPosition & pos) const [virtual]

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

Parameters:
date   The date-time value to be formatted into a date-time string.
toAppendTo   The result of the formatting operation is appended to this string.
pos   The formatting position. On input: an alignment field, if desired. On output: the offsets of the alignment field.
Returns:
A reference to 'toAppendTo'.
Stable:

Reimplemented from DateFormat.

virtual UnicodeString & SimpleDateFormat::format (const Formattable & obj, UnicodeString & toAppendTo, FieldPosition & pos, UErrorCode & status) const [virtual]

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

Parameters:
obj   A Formattable containing the date-time value to be formatted into a date-time string. If the type of the Formattable is a numeric type, it is treated as if it were an instance of Date.
toAppendTo   The result of the formatting operation is appended to this string.
pos   The formatting position. On input: an alignment field, if desired. On output: the offsets of the alignment field.
Returns:
A reference to 'toAppendTo'.
Stable:

Reimplemented from Format.

UnicodeString & SimpleDateFormat::format (const Formattable & obj, UnicodeString & result, UErrorCode & status) const [inline]

Redeclared DateFormat method.

Stable:

Reimplemented from Format.

Definition at line 748 of file smpdtfmt.h.

UnicodeString & SimpleDateFormat::format (UDate date, UnicodeString & result) const [inline]

Redeclared DateFormat method.

Stable:

Reimplemented from DateFormat.

Definition at line 757 of file smpdtfmt.h.

virtual UDate SimpleDateFormat::parse (const UnicodeString & text, ParsePosition & pos) const [virtual]

Parse a date/time string starting 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 also:
DateFormat::setLenient(boolean)

Parameters:
text   The date/time string to be parsed
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.
Returns:
A valid UDate if the input could be parsed.
Stable:

Reimplemented from DateFormat.

virtual UDate SimpleDateFormat::parse (const UnicodeString & text, UErrorCode & status) const [virtual]

Parse a date/time string.

For example, a time text "07/10/96 4:5 PM, PDT" will be parsed into a UDate that is equivalent to Date(837039928046). Parsing begins at the beginning of the string and proceeds as far as possible. Assuming no parse errors were encountered, this function doesn't return any information about how much of the string was consumed by the parsing. If you need that information, use the version of parse() that takes a ParsePosition.

Parameters:
text   The date/time string to be parsed
status   Filled in with U_ZERO_ERROR if the parse was successful, and with an error value if there was a parse error.
Returns:
A valid UDate if the input could be parsed.
Stable:

Reimplemented from DateFormat.

virtual void SimpleDateFormat::set2DigitYearStart (UDate d, UErrorCode & status) [virtual]

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.

Stable:

UDate SimpleDateFormat::get2DigitYearStart (UErrorCode & status) const [inline]

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.

Stable:

Definition at line 742 of file smpdtfmt.h.

virtual UnicodeString & SimpleDateFormat::toPattern (UnicodeString & result) const [virtual]

Return a pattern string describing this date format.

Stable:

virtual UnicodeString & SimpleDateFormat::toLocalizedPattern (UnicodeString & result, UErrorCode & status) const [virtual]

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.

Parameters:
result   Receives the localized pattern.
status   Output param set to success/failure code on exit. If the pattern is invalid, this will be set to a failure result.
Stable:

virtual void SimpleDateFormat::applyPattern (const UnicodeString & pattern) [virtual]

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)

Parameters:
pattern   The pattern to be applied.
Stable:

virtual void SimpleDateFormat::applyLocalizedPattern (const UnicodeString & pattern, UErrorCode & status) [virtual]

Apply the given localized pattern string to this date format.

(see toLocalizedPattern() for more information on localized patterns.)

Parameters:
pattern   The localized pattern to be applied.
status   Output param set to success/failure code on exit. If the pattern is invalid, this will be set to a failure result.
Stable:

virtual const DateFormatSymbols * SimpleDateFormat::getDateFormatSymbols (void) const [virtual]

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.).

Returns:
a copy of the date-time formatting data associated with this date-time formatter.
Stable:

virtual void SimpleDateFormat::adoptDateFormatSymbols (DateFormatSymbols * newFormatSymbols) [virtual]

Set the date/time formatting symbols.

The caller no longer owns the DateFormatSymbols object and should not delete it after making this call.

Parameters:
newFormatData   the given date-time formatting data.
Stable:

virtual void SimpleDateFormat::setDateFormatSymbols (const DateFormatSymbols & newFormatSymbols) [virtual]

Set the date/time formatting data.

Parameters:
newFormatData   the given date-time formatting data.
Stable:

virtual UClassID SimpleDateFormat::getDynamicClassID (void) const [inline, virtual]

Returns a unique class ID POLYMORPHICALLY.

Pure virtual override. This method is to implement a simple version of RTTI, since not all C++ compilers support genuine RTTI. Polymorphic operator==() and clone() methods call this method.

Returns:
The class ID for this object. All objects of a given class have the same class ID. Objects of other classes have different class IDs.
Stable:

Reimplemented from Format.

Definition at line 497 of file smpdtfmt.h.

UClassID SimpleDateFormat::getStaticClassID (void) [inline, static]

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()) ...
 
Returns:
The class ID for all objects of this class.
Stable:

Definition at line 484 of file smpdtfmt.h.


Friends And Related Function Documentation

friend class DateFormat [friend]

Definition at line 502 of file smpdtfmt.h.


Member Data Documentation

const char* SimpleDateFormat::fgErasTag [static]

Resource bundle file suffix and tag names used by this class.

Definition at line 459 of file smpdtfmt.h.

const char* SimpleDateFormat::fgMonthNamesTag [static]

Definition at line 460 of file smpdtfmt.h.

const char* SimpleDateFormat::fgMonthAbbreviationsTag [static]

Definition at line 461 of file smpdtfmt.h.

const char* SimpleDateFormat::fgDayNamesTag [static]

Definition at line 462 of file smpdtfmt.h.

const char* SimpleDateFormat::fgDayAbbreviationsTag [static]

Definition at line 463 of file smpdtfmt.h.

const char* SimpleDateFormat::fgAmPmMarkersTag [static]

Definition at line 464 of file smpdtfmt.h.

const char* SimpleDateFormat::fgDateTimePatternsTag [static]

Definition at line 465 of file smpdtfmt.h.

const char* SimpleDateFormat::fgZoneStringsTag [static]

Definition at line 467 of file smpdtfmt.h.

const char* SimpleDateFormat::fgLocalPatternCharsTag [static]

Definition at line 468 of file smpdtfmt.h.

const UnicodeString SimpleDateFormat::fgDefaultPattern [static]

Definition at line 470 of file smpdtfmt.h.

const UDate SimpleDateFormat::fgSystemDefaultCentury [static]

If a start date is set to this value, that indicates that the system default start is in effect for this instance.

Definition at line 738 of file smpdtfmt.h.


The documentation for this class was generated from the following file:
Generated at Mon Jun 5 12:53:21 2000 for ICU1.5 by doxygen 1.0.0 written by Dimitri van Heesch, © 1997-1999