DateFormat is an abstract class for a family of classes that convert dates and times from their internal representations to textual form and back again in a language-independent manner. More...

#include <datefmt.h>

Inheritance diagram for icu::DateFormat:

Public Types
enum	EStyle { kNone = -1 , kFull = 0 , kLong = 1 , kMedium = 2 , kShort = 3 , kDateOffset = kShort + 1 , kDateTime = 8 , kDateTimeOffset = kDateTime + 1 , kRelative = (1 << 7) , kFullRelative = (kFull \| kRelative) , kLongRelative = kLong \| kRelative , kMediumRelative = kMedium \| kRelative , kShortRelative = kShort \| kRelative , kDefault = kMedium , FULL = kFull , LONG = kLong , MEDIUM = kMedium , SHORT = kShort , DEFAULT = kDefault , DATE_OFFSET = kDateOffset , NONE = kNone , DATE_TIME = kDateTime }
	Constants for various style patterns. More...

enum	EField { kEraField = UDAT_ERA_FIELD , kYearField = UDAT_YEAR_FIELD , kMonthField = UDAT_MONTH_FIELD , kDateField = UDAT_DATE_FIELD , kHourOfDay1Field = UDAT_HOUR_OF_DAY1_FIELD , kHourOfDay0Field = UDAT_HOUR_OF_DAY0_FIELD , kMinuteField = UDAT_MINUTE_FIELD , kSecondField = UDAT_SECOND_FIELD , kMillisecondField = UDAT_FRACTIONAL_SECOND_FIELD , kDayOfWeekField = UDAT_DAY_OF_WEEK_FIELD , kDayOfYearField = UDAT_DAY_OF_YEAR_FIELD , kDayOfWeekInMonthField = UDAT_DAY_OF_WEEK_IN_MONTH_FIELD , kWeekOfYearField = UDAT_WEEK_OF_YEAR_FIELD , kWeekOfMonthField = UDAT_WEEK_OF_MONTH_FIELD , kAmPmField = UDAT_AM_PM_FIELD , kHour1Field = UDAT_HOUR1_FIELD , kHour0Field = UDAT_HOUR0_FIELD , kTimezoneField = UDAT_TIMEZONE_FIELD , kYearWOYField = UDAT_YEAR_WOY_FIELD , kDOWLocalField = UDAT_DOW_LOCAL_FIELD , kExtendedYearField = UDAT_EXTENDED_YEAR_FIELD , kJulianDayField = UDAT_JULIAN_DAY_FIELD , kMillisecondsInDayField = UDAT_MILLISECONDS_IN_DAY_FIELD , ERA_FIELD = UDAT_ERA_FIELD , YEAR_FIELD = UDAT_YEAR_FIELD , MONTH_FIELD = UDAT_MONTH_FIELD , DATE_FIELD = UDAT_DATE_FIELD , HOUR_OF_DAY1_FIELD = UDAT_HOUR_OF_DAY1_FIELD , HOUR_OF_DAY0_FIELD = UDAT_HOUR_OF_DAY0_FIELD , MINUTE_FIELD = UDAT_MINUTE_FIELD , SECOND_FIELD = UDAT_SECOND_FIELD , MILLISECOND_FIELD = UDAT_FRACTIONAL_SECOND_FIELD , DAY_OF_WEEK_FIELD = UDAT_DAY_OF_WEEK_FIELD , DAY_OF_YEAR_FIELD = UDAT_DAY_OF_YEAR_FIELD , DAY_OF_WEEK_IN_MONTH_FIELD = UDAT_DAY_OF_WEEK_IN_MONTH_FIELD , WEEK_OF_YEAR_FIELD = UDAT_WEEK_OF_YEAR_FIELD , WEEK_OF_MONTH_FIELD = UDAT_WEEK_OF_MONTH_FIELD , AM_PM_FIELD = UDAT_AM_PM_FIELD , HOUR1_FIELD = UDAT_HOUR1_FIELD , HOUR0_FIELD = UDAT_HOUR0_FIELD , TIMEZONE_FIELD = UDAT_TIMEZONE_FIELD }
	Field selector for FieldPosition for DateFormat fields. More...

Public Member Functions
virtual	~DateFormat ()
	Destructor. More...

virtual DateFormat *	clone () const override=0
	Clones this object polymorphically. More...

virtual bool	operator== (const Format &) const override
	Equality operator. More...

virtual UnicodeString &	format (const Formattable &obj, UnicodeString &appendTo, FieldPosition &pos, UErrorCode &status) const override
	Format an object to produce a string. More...

virtual UnicodeString &	format (const Formattable &obj, UnicodeString &appendTo, FieldPositionIterator *posIter, UErrorCode &status) const override
	Format an object to produce a string. More...

virtual UnicodeString &	format (Calendar &cal, UnicodeString &appendTo, FieldPosition &fieldPosition) const =0
	Formats a date into a date/time string. More...

virtual UnicodeString &	format (Calendar &cal, UnicodeString &appendTo, FieldPositionIterator *posIter, UErrorCode &status) const
	Formats a date into a date/time string. More...

UnicodeString &	format (UDate date, UnicodeString &appendTo, FieldPosition &fieldPosition) const
	Formats a UDate into a date/time string. More...

UnicodeString &	format (UDate date, UnicodeString &appendTo, FieldPositionIterator *posIter, UErrorCode &status) const
	Formats a UDate into a date/time string. More...

UnicodeString &	format (UDate date, UnicodeString &appendTo) const
	Formats a UDate into a date/time string. More...

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

virtual void	parse (const UnicodeString &text, Calendar &cal, ParsePosition &pos) const =0
	Parse a date/time string beginning at the given parse position. More...

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

virtual void	parseObject (const UnicodeString &source, Formattable &result, ParsePosition &parse_pos) const override
	Parse a string to produce an object. More...

virtual UBool	isLenient (void) const
	Returns whether both date/time parsing in the encapsulated Calendar object and DateFormat whitespace & numeric processing is lenient. More...

virtual void	setLenient (UBool lenient)
	Specifies whether date/time parsing is to be lenient. More...

virtual UBool	isCalendarLenient (void) const
	Returns whether date/time parsing in the encapsulated Calendar object processing is lenient. More...

virtual void	setCalendarLenient (UBool lenient)
	Specifies whether encapsulated Calendar date/time parsing is to be lenient. More...

virtual const Calendar *	getCalendar (void) const
	Gets the calendar associated with this date/time formatter. More...

virtual void	adoptCalendar (Calendar *calendarToAdopt)
	Set the calendar to be used by this date format. More...

virtual void	setCalendar (const Calendar &newCalendar)
	Set the calendar to be used by this date format. More...

virtual const NumberFormat *	getNumberFormat (void) const
	Gets the number formatter which this date/time formatter uses to format and parse the numeric portions of the pattern. More...

virtual void	adoptNumberFormat (NumberFormat *formatToAdopt)
	Allows you to set the number formatter. More...

virtual void	setNumberFormat (const NumberFormat &newNumberFormat)
	Allows you to set the number formatter. More...

virtual const TimeZone &	getTimeZone (void) const
	Returns a reference to the TimeZone used by this DateFormat's calendar. More...

virtual void	adoptTimeZone (TimeZone *zoneToAdopt)
	Sets the time zone for the calendar of this DateFormat object. More...

virtual void	setTimeZone (const TimeZone &zone)
	Sets the time zone for the calendar of this DateFormat object. More...

virtual void	setContext (UDisplayContext value, UErrorCode &status)
	Set a particular UDisplayContext value in the formatter, such as UDISPCTX_CAPITALIZATION_FOR_STANDALONE. More...

virtual UDisplayContext	getContext (UDisplayContextType type, UErrorCode &status) const
	Get the formatter's UDisplayContext value for the specified UDisplayContextType, such as UDISPCTX_TYPE_CAPITALIZATION. More...

virtual DateFormat &	setBooleanAttribute (UDateFormatBooleanAttribute attr, UBool newvalue, UErrorCode &status)
	Sets an boolean attribute on this DateFormat. More...

virtual UBool	getBooleanAttribute (UDateFormatBooleanAttribute attr, UErrorCode &status) const
	Returns a boolean from this DateFormat May return U_UNSUPPORTED_ERROR if this instance does not support the specified attribute. More...

UnicodeString &	format (const Formattable &obj, UnicodeString &appendTo, UErrorCode &status) const
	Formats an object to produce a string. More...

virtual UnicodeString &	format (const Formattable &obj, UnicodeString &appendTo, FieldPosition &pos, UErrorCode &status) const=0
	Format an object to produce a string. More...

virtual UnicodeString &	format (const Formattable &obj, UnicodeString &appendTo, FieldPositionIterator *posIter, UErrorCode &status) const
	Format an object to produce a string. More...

Public Member Functions inherited from icu::Format
virtual	~Format ()
	Destructor. More...

virtual bool	operator== (const Format &other) const =0
	Return true if the given Format objects are semantically equal. More...

bool	operator!= (const Format &other) const
	Return true if the given Format objects are not semantically equal. More...

virtual Format *	clone () const =0
	Clone this object polymorphically. More...

UnicodeString &	format (const Formattable &obj, UnicodeString &appendTo, UErrorCode &status) const
	Formats an object to produce a string. More...

virtual UnicodeString &	format (const Formattable &obj, UnicodeString &appendTo, FieldPosition &pos, UErrorCode &status) const =0
	Format an object to produce a string. More...

virtual UnicodeString &	format (const Formattable &obj, UnicodeString &appendTo, FieldPositionIterator *posIter, UErrorCode &status) const
	Format an object to produce a string. More...

virtual void	parseObject (const UnicodeString &source, Formattable &result, ParsePosition &parse_pos) const =0
	Parse a string to produce an object. More...

void	parseObject (const UnicodeString &source, Formattable &result, UErrorCode &status) const
	Parses a string to produce an object. More...

Locale	getLocale (ULocDataLocaleType type, UErrorCode &status) const
	Get the locale for this format object. More...

const char *	getLocaleID (ULocDataLocaleType type, UErrorCode &status) const
	Get the locale for this format object. More...

Public Member Functions inherited from icu::UObject
virtual	~UObject ()
	Destructor. More...

virtual UClassID	getDynamicClassID () const
	ICU4C "poor man's RTTI", returns a UClassID for the actual ICU class. More...

Static Public Member Functions
static DateFormat *	createInstance (void)
	Create a default date/time formatter that uses the SHORT style for both the date and the time. More...

static DateFormat *	createTimeInstance (EStyle style=kDefault, const Locale &aLocale=Locale::getDefault())
	Creates a time formatter with the given formatting style for the given locale. More...

static DateFormat *	createDateInstance (EStyle style=kDefault, const Locale &aLocale=Locale::getDefault())
	Creates a date formatter with the given formatting style for the given const locale. More...

static DateFormat *	createDateTimeInstance (EStyle dateStyle=kDefault, EStyle timeStyle=kDefault, const Locale &aLocale=Locale::getDefault())
	Creates a date/time formatter with the given formatting styles for the given locale. More...

static UnicodeString	getBestPattern (const Locale &locale, const UnicodeString &skeleton, UErrorCode &status)
	Returns the best pattern given a skeleton and locale. More...

static DateFormat *	createInstanceForSkeleton (const UnicodeString &skeleton, UErrorCode &status)
	Creates a date/time formatter for the given skeleton and default locale. More...

static DateFormat *	createInstanceForSkeleton (const UnicodeString &skeleton, const Locale &locale, UErrorCode &status)
	Creates a date/time formatter for the given skeleton and locale. More...

static DateFormat *	createInstanceForSkeleton (Calendar *calendarToAdopt, const UnicodeString &skeleton, const Locale &locale, UErrorCode &status)
	Creates a date/time formatter for the given skeleton and locale. More...

static const Locale *	getAvailableLocales (int32_t &count)
	Gets the set of locales for which DateFormats are installed. More...

Protected Member Functions
	DateFormat ()
	Default constructor. More...

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

DateFormat &	operator= (const DateFormat &)
	Default assignment operator. More...

Protected Member Functions inherited from icu::Format
void	setLocaleIDs (const char valid, const char actual)

	Format ()
	Default constructor for subclass use only. More...

	Format (const Format &)

Format &	operator= (const Format &)

Protected Attributes
Calendar *	fCalendar
	The calendar that DateFormat uses to produce the time field values needed to implement date/time formatting. More...

NumberFormat *	fNumberFormat
	The number formatter that DateFormat uses to format numbers in dates and times. More...

Friends
class	DateFmtKeyByStyle

Additional Inherited Members
Static Protected Member Functions inherited from icu::Format
static void	syntaxError (const UnicodeString &pattern, int32_t pos, UParseError &parseError)
	Simple function for initializing a UParseError from a UnicodeString. More...

Detailed Description

DateFormat is an abstract class for a family of classes that convert dates and times from their internal representations to textual form and back again in a language-independent manner.

Converting from the internal representation (milliseconds since midnight, January 1, 1970) to text is known as "formatting," and converting from text to millis is known as "parsing." We currently define only one concrete subclass of DateFormat: SimpleDateFormat, which can handle pretty much all normal date formatting and parsing actions.

DateFormat helps you to format and parse dates for any locale. Your code can be completely independent of the locale conventions for months, days of the week, or even the calendar format: lunar vs. solar.

To format a date for the current Locale, use one of the static factory methods:

DateFormat* dfmt = DateFormat::createDateInstance();
UDate myDate = Calendar::getNow();
UnicodeString myString;
myString = dfmt->format( myDate, myString );
icu::Calendar::getNow
static UDate getNow(void)
Returns the current UTC (GMT) time measured in milliseconds since 0:00:00 on 1/1/70 (derived from the...
icu::DateFormat
DateFormat is an abstract class for a family of classes that convert dates and times from their inter...
Definition: datefmt.h:156
icu::DateFormat::createDateInstance
static DateFormat * createDateInstance(EStyle style=kDefault, const Locale &aLocale=Locale::getDefault())
Creates a date formatter with the given formatting style for the given const locale.
icu::DateFormat::format
virtual UnicodeString & format(const Formattable &obj, UnicodeString &appendTo, FieldPosition &pos, UErrorCode &status) const override
Format an object to produce a string.
icu::UnicodeString
UnicodeString is a string class that stores Unicode characters directly and provides similar function...
Definition: unistr.h:296
UDate
double UDate
Date and Time data type.
Definition: utypes.h:203

If you are formatting multiple numbers, it is more efficient to get the format and use it multiple times so that the system doesn't have to fetch the information about the local language and country conventions multiple times.

DateFormat* df = DateFormat::createDateInstance();
UnicodeString myString;
UDate myDateArr[] = { 0.0, 100000000.0, 2000000000.0 }; // test values
for (int32_t i = 0; i < 3; ++i) {
    myString.remove();
    cout << df->format( myDateArr[i], myString ) << endl;
}
icu::UnicodeString::remove
UnicodeString & remove()
Removes all characters from the UnicodeString object and clears the bogus flag.
Definition: unistr.h:4696

To get specific fields of a date, you can use UFieldPosition to get specific fields.

DateFormat* dfmt = DateFormat::createDateInstance();
FieldPosition pos(DateFormat::YEAR_FIELD);
UnicodeString myString;
myString = dfmt->format( myDate, myString );
cout << myString << endl;
cout << pos.getBeginIndex() << "," << pos. getEndIndex() << endl;
icu::FieldPosition
FieldPosition is a simple class used by Format and its subclasses to identify fields in formatted out...
Definition: fieldpos.h:110

To format a date for a different Locale, specify it in the call to createDateInstance().

DateFormat* df =
    DateFormat::createDateInstance( DateFormat::SHORT, Locale::getFrance());
icu::Locale::getFrance
static const Locale & getFrance(void)
Useful constant for this country/region.

You can use a DateFormat to parse also.

UErrorCode status = U_ZERO_ERROR;
UDate myDate = df->parse(myString, status);
icu::DateFormat::parse
virtual UDate parse(const UnicodeString &text, UErrorCode &status) const
Parse a date/time string.
UErrorCode
UErrorCode
Standard ICU4C error code type, a substitute for exceptions.
Definition: utypes.h:415
U_ZERO_ERROR
@ U_ZERO_ERROR
No error, no warning.
Definition: utypes.h:449

Use createDateInstance() to produce the normal date format for that country. There are other static factory methods available. Use createTimeInstance() to produce the normal time format for that country. Use createDateTimeInstance() to produce a DateFormat that formats both date and time. You can pass in different options to these factory methods to control the length of the result; from SHORT to MEDIUM to LONG to FULL. The exact result depends on the locale, but generally:

SHORT is completely numeric, such as 12/13/52 or 3:30pm
MEDIUM is longer, such as Jan 12, 1952
LONG is longer, such as January 12, 1952 or 3:30:32pm
FULL is pretty completely specified, such as Tuesday, April 12, 1952 AD or 3:30:42pm PST.

You can also set the time zone on the format if you wish. If you want even more control over the format or parsing, (or want to give your users more control), you can try casting the DateFormat you get from the factory methods to a SimpleDateFormat. This will work for the majority of countries; just remember to check getDynamicClassID() before carrying out the cast.

You can also use forms of the parse and format methods with ParsePosition and FieldPosition to allow you to

Progressively parse through pieces of a string.
Align any particular field, or find out where it is for selection on the screen.

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.

Definition at line 156 of file datefmt.h.

Member Enumeration Documentation

◆ EField

enum icu::DateFormat::EField

Field selector for FieldPosition for DateFormat fields.

Obsolete:: ICU 3.4 use UDateFormatField instead, since this API will be removed in that release

Definition at line 912 of file datefmt.h.

◆ EStyle

enum icu::DateFormat::EStyle

Constants for various style patterns.

These reflect the order of items in the DateTimePatterns resource. There are 4 time patterns, 4 date patterns, the default date-time pattern, and 4 date-time patterns. Each block of 4 values in the resource occurs in the order full, long, medium, short.

Stable:: ICU 2.4

Enumerator
FULL	These constants are provided for backwards compatibility only. Please use the C++ style constants defined above.

Definition at line 166 of file datefmt.h.

Constructor & Destructor Documentation

◆ ~DateFormat()

virtual icu::DateFormat::~DateFormat ( )

virtual

Destructor.

Stable:: ICU 2.0

◆ DateFormat() [1/2]

icu::DateFormat::DateFormat ( )

protected

Default constructor.

Creates a DateFormat with no Calendar or NumberFormat associated with it. This constructor depends on the subclasses to fill in the calendar and numberFormat fields.

Stable:: ICU 2.0

◆ DateFormat() [2/2]

icu::DateFormat::DateFormat ( const DateFormat & )

protected

Copy constructor.

Stable:: ICU 2.0

Member Function Documentation

◆ adoptCalendar()

virtual void icu::DateFormat::adoptCalendar ( Calendar * calendarToAdopt )

virtual

Set the calendar to be used by this date format.

Initially, the default calendar for the specified or default locale is used. The caller should not delete the Calendar object after it is adopted by this call. Adopting a new calendar will change to the default symbols.

Parameters

calendarToAdopt Calendar object to be adopted.

Stable:: ICU 2.0

Reimplemented in icu::SimpleDateFormat.

◆ adoptNumberFormat()

virtual void icu::DateFormat::adoptNumberFormat ( NumberFormat * formatToAdopt )

virtual

Allows you to set the number formatter.

The caller should not delete the NumberFormat object after it is adopted by this call.

Parameters

formatToAdopt NumberFormat object to be adopted.

Stable:: ICU 2.0

Reimplemented in icu::SimpleDateFormat.

◆ adoptTimeZone()

virtual void icu::DateFormat::adoptTimeZone ( TimeZone * zoneToAdopt )

virtual

Sets the time zone for the calendar of this DateFormat object.

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

Parameters

zoneToAdopt the TimeZone to be adopted.

Stable:: ICU 2.0

◆ clone()

virtual DateFormat * icu::DateFormat::clone ( ) const

overridepure virtual

Clones this object polymorphically.

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

Returns: clone, or nullptr if an error occurred

Stable:: ICU 2.0

Implements icu::Format.

Implemented in icu::SimpleDateFormat.

◆ createDateInstance()

static DateFormat * icu::DateFormat::createDateInstance	(	EStyle	style = `kDefault`,
		const Locale &	aLocale = `Locale::getDefault()`
	)

static

Creates a date formatter with the given formatting style for the given const locale.

Parameters

style The given formatting style. For example, SHORT for "M/d/yy" in the US locale. As currently implemented, relative date formatting only affects a limited range of calendar days before or after the current date, based on the CLDR <field type="day">/<relative> data: For example, in English, "Yesterday", "Today", and "Tomorrow". Outside of this range, dates are formatted using the corresponding non-relative style.

aLocale The given locale.

Returns: A date formatter which the caller owns.

Stable:: ICU 2.0

◆ createDateTimeInstance()

static DateFormat * icu::DateFormat::createDateTimeInstance	(	EStyle	dateStyle = `kDefault`,
		EStyle	timeStyle = `kDefault`,
		const Locale &	aLocale = `Locale::getDefault()`
	)

static

Creates a date/time formatter with the given formatting styles for the given locale.

Parameters

dateStyle	The given formatting style for the date portion of the result. For example, SHORT for "M/d/yy" in the US locale. As currently implemented, relative date formatting only affects a limited range of calendar days before or after the current date, based on the CLDR <field type="day">/<relative> data: For example, in English, "Yesterday", "Today", and "Tomorrow". Outside of this range, dates are formatted using the corresponding non-relative style.
timeStyle	The given formatting style for the time portion of the result. For example, SHORT for "h:mm a" in the US locale. Relative time styles are not currently supported.
aLocale	The given locale.

Returns: A date/time formatter which the caller owns.

Stable:: ICU 2.0

◆ createInstance()

static DateFormat * icu::DateFormat::createInstance ( void )

static

Create a default date/time formatter that uses the SHORT style for both the date and the time.

Returns: A date/time formatter which the caller owns.

Stable:: ICU 2.0

◆ createInstanceForSkeleton() [1/3]

static DateFormat * icu::DateFormat::createInstanceForSkeleton	(	Calendar *	calendarToAdopt,
		const UnicodeString &	skeleton,
		const Locale &	locale,
		UErrorCode &	status
	)

static

Creates a date/time formatter for the given skeleton and locale.

Parameters

calendarToAdopt	the calendar returned DateFormat is to use.
skeleton	The skeleton e.g "yMMMMd." Fields in the skeleton can be in any order, and this method uses the locale to map the skeleton to a pattern that includes locale specific separators with the fields in the appropriate order for that locale.
locale	The given locale.
status	Any error returned here.

Returns: A date/time formatter which the caller owns.

Stable:: ICU 55

◆ createInstanceForSkeleton() [2/3]

static DateFormat * icu::DateFormat::createInstanceForSkeleton	(	const UnicodeString &	skeleton,
		const Locale &	locale,
		UErrorCode &	status
	)

static

Creates a date/time formatter for the given skeleton and locale.

Parameters

skeleton	The skeleton e.g "yMMMMd." Fields in the skeleton can be in any order, and this method uses the locale to map the skeleton to a pattern that includes locale specific separators with the fields in the appropriate order for that locale.
locale	The given locale.
status	Any error returned here.

Returns: A date/time formatter which the caller owns.

Stable:: ICU 55

◆ createInstanceForSkeleton() [3/3]

static DateFormat * icu::DateFormat::createInstanceForSkeleton	(	const UnicodeString &	skeleton,
		UErrorCode &	status
	)

static

Creates a date/time formatter for the given skeleton and default locale.

Parameters

skeleton	The skeleton e.g "yMMMMd." Fields in the skeleton can be in any order, and this method uses the locale to map the skeleton to a pattern that includes locale specific separators with the fields in the appropriate order for that locale.
status	Any error returned here.

Returns: A date/time formatter which the caller owns.

Stable:: ICU 55

◆ createTimeInstance()

static DateFormat * icu::DateFormat::createTimeInstance	(	EStyle	style = `kDefault`,
		const Locale &	aLocale = `Locale::getDefault()`
	)

static

Creates a time formatter with the given formatting style for the given locale.

Parameters

style	The given formatting style. For example, SHORT for "h:mm a" in the US locale. Relative time styles are not currently supported.
aLocale	The given locale.

Returns: A time formatter which the caller owns.

Stable:: ICU 2.0

◆ format() [1/10]

virtual UnicodeString & icu::DateFormat::format	(	Calendar &	cal,
		UnicodeString &	appendTo,
		FieldPosition &	fieldPosition
	)		const

pure virtual

Formats a date into a date/time string.

This is an abstract method which concrete subclasses must implement.

On input, the FieldPosition parameter may have its "field" member filled with an enum value specifying a field. On output, the FieldPosition will be filled in with the text offsets for that field.

For example, given a time text "1996.07.10 AD at 15:08:56 PDT", if the given fieldPosition.field is UDAT_YEAR_FIELD, the offsets fieldPosition.beginIndex and statfieldPositionus.getEndIndex will be set to 0 and 4, respectively.

Notice that if the same time field appears more than once in a pattern, the status will be set for the first occurrence of that time field. For instance, formatting a UDate to the time string "1 PM PDT (Pacific Daylight Time)" using the pattern "h a z (zzzz)" and the alignment field DateFormat::TIMEZONE_FIELD, the offsets fieldPosition.beginIndex and fieldPosition.getEndIndex will be set to 5 and 8, respectively, for the first occurrence of the timezone pattern character 'z'.

Parameters

cal	Calendar set to the date and time to be formatted into a date/time string. When the calendar type is different from the internal calendar held by this DateFormat instance, the date and the time zone will be inherited from the input calendar, but other calendar field values will be calculated by the internal calendar.
appendTo	Output parameter to receive result. Result is appended to existing contents.
fieldPosition	On input: an alignment field, if desired (see examples above) On output: the offsets of the alignment field (see examples above)

Returns: Reference to 'appendTo' parameter.

Stable:: ICU 2.1

Implemented in icu::SimpleDateFormat, and icu::SimpleDateFormat.

◆ format() [2/10]

virtual UnicodeString & icu::DateFormat::format	(	Calendar &	cal,
		UnicodeString &	appendTo,
		FieldPositionIterator *	posIter,
		UErrorCode &	status
	)		const

virtual

Formats a date into a date/time string.

Subclasses should implement this method.

Parameters

cal	Calendar set to the date and time to be formatted into a date/time string. When the calendar type is different from the internal calendar held by this DateFormat instance, the date and the time zone will be inherited from the input calendar, but other calendar field values will be calculated by the internal calendar.
appendTo	Output parameter to receive result. Result is appended to existing contents.
posIter	On return, can be used to iterate over positions of fields generated by this format call. Field values are defined in UDateFormatField. Can be NULL.
status	error status.

Returns: Reference to 'appendTo' parameter.

Stable:: ICU 4.4

Reimplemented in icu::SimpleDateFormat, and icu::SimpleDateFormat.

◆ format() [3/10]

virtual UnicodeString & icu::DateFormat::format	(	const Formattable &	obj,
		UnicodeString &	appendTo,
		FieldPosition &	pos,
		UErrorCode &	status
	)		const

overridevirtual

Format an object to produce a string.

This method handles Formattable objects with a UDate type. If a the Formattable object type is not a Date, then it returns a failing UErrorCode.

Parameters

obj	The object to format. Must be a Date.
appendTo	Output parameter to receive result. Result is appended to existing contents.
pos	On input: an alignment field, if desired. On output: the offsets of the alignment field.
status	Output param filled with success/failure status.

Returns: Reference to 'appendTo' parameter.

Stable:: ICU 2.0

Implements icu::Format.

Reimplemented in icu::SimpleDateFormat, and icu::SimpleDateFormat.

◆ format() [4/10]

virtual UnicodeString & icu::Format::format	(	const Formattable &	obj,
		UnicodeString &	appendTo,
		FieldPosition &	pos,
		UErrorCode &	status
	)		const

virtual

Format an object to produce a string.

This is a pure virtual method which subclasses must implement. This method allows polymorphic formatting of Formattable objects. If a subclass of Format receives a Formattable object type it doesn't handle (e.g., if a numeric Formattable is passed to a DateFormat object) then it returns a failing UErrorCode.

Parameters

obj	The object to format.
appendTo	Output parameter to receive result. Result is appended to existing contents.
pos	On input: an alignment field, if desired. On output: the offsets of the alignment field.
status	Output param filled with success/failure status.

Returns: Reference to 'appendTo' parameter.

Stable:: ICU 2.0

Implements icu::Format.

Reimplemented in icu::SimpleDateFormat, and icu::SimpleDateFormat.

◆ format() [5/10]

virtual UnicodeString & icu::Format::format	(	const Formattable &	obj,
		UnicodeString &	appendTo,
		FieldPositionIterator *	posIter,
		UErrorCode &	status
	)		const

virtual

Format an object to produce a string.

Subclasses should override this method. This method allows polymorphic formatting of Formattable objects. If a subclass of Format receives a Formattable object type it doesn't handle (e.g., if a numeric Formattable is passed to a DateFormat object) then it returns a failing UErrorCode.

Parameters

obj	The object to format.
appendTo	Output parameter to receive result. Result is appended to existing contents.
posIter	On return, can be used to iterate over positions of fields generated by this format call.
status	Output param filled with success/failure status.

Returns: Reference to 'appendTo' parameter.

Stable:: ICU 4.4

Reimplemented from icu::Format.

Reimplemented in icu::SimpleDateFormat, and icu::SimpleDateFormat.

◆ format() [6/10]

virtual UnicodeString & icu::DateFormat::format	(	const Formattable &	obj,
		UnicodeString &	appendTo,
		FieldPositionIterator *	posIter,
		UErrorCode &	status
	)		const

overridevirtual

Format an object to produce a string.

This method handles Formattable objects with a UDate type. If a the Formattable object type is not a Date, then it returns a failing UErrorCode.

Parameters

obj	The object to format. Must be a Date.
appendTo	Output parameter to receive result. Result is appended to existing contents.
posIter	On return, can be used to iterate over positions of fields generated by this format call. Field values are defined in UDateFormatField. Can be NULL.
status	Output param filled with success/failure status.

Returns: Reference to 'appendTo' parameter.

Stable:: ICU 4.4

Reimplemented from icu::Format.

Reimplemented in icu::SimpleDateFormat, and icu::SimpleDateFormat.

◆ format() [7/10]

UnicodeString & icu::Format::format	(	const Formattable &	obj,
		UnicodeString &	appendTo,
		UErrorCode &	status
	)		const

Formats an object to produce a string.

Parameters

obj	The object to format.
appendTo	Output parameter to receive result. Result is appended to existing contents.
status	Output parameter filled in with success or failure status.

Returns: Reference to 'appendTo' parameter.

Stable:: ICU 2.0

◆ format() [8/10]

UnicodeString & icu::DateFormat::format	(	UDate	date,
		UnicodeString &	appendTo
	)		const

Formats a UDate into a date/time string.

If there is a problem, you won't know, using this method. Use the overloaded format() method which takes a FieldPosition& to detect formatting problems.

Parameters

date	The UDate value to be formatted into a string.
appendTo	Output parameter to receive result. Result is appended to existing contents.

Returns: Reference to 'appendTo' parameter.

Stable:: ICU 2.0

◆ format() [9/10]

UnicodeString & icu::DateFormat::format	(	UDate	date,
		UnicodeString &	appendTo,
		FieldPosition &	fieldPosition
	)		const

Formats a UDate into a date/time string.

On input, the FieldPosition parameter may have its "field" member filled with an enum value specifying a field. On output, the FieldPosition will be filled in with the text offsets for that field.

For example, given a time text "1996.07.10 AD at 15:08:56 PDT", if the given fieldPosition.field is UDAT_YEAR_FIELD, the offsets fieldPosition.beginIndex and statfieldPositionus.getEndIndex will be set to 0 and 4, respectively.

Notice that if the same time field appears more than once in a pattern, the status will be set for the first occurrence of that time field. For instance, formatting a UDate to the time string "1 PM PDT (Pacific Daylight Time)" using the pattern "h a z (zzzz)" and the alignment field DateFormat::TIMEZONE_FIELD, the offsets fieldPosition.beginIndex and fieldPosition.getEndIndex will be set to 5 and 8, respectively, for the first occurrence of the timezone pattern character 'z'.

Parameters

date	UDate to be formatted into a date/time string.
appendTo	Output parameter to receive result. Result is appended to existing contents.
fieldPosition	On input: an alignment field, if desired (see examples above) On output: the offsets of the alignment field (see examples above)

Returns: Reference to 'appendTo' parameter.

Stable:: ICU 2.0

◆ format() [10/10]

UnicodeString & icu::DateFormat::format	(	UDate	date,
		UnicodeString &	appendTo,
		FieldPositionIterator *	posIter,
		UErrorCode &	status
	)		const

Formats a UDate into a date/time string.

Parameters

date	UDate to be formatted into a date/time string.
appendTo	Output parameter to receive result. Result is appended to existing contents.
posIter	On return, can be used to iterate over positions of fields generated by this format call. Field values are defined in UDateFormatField. Can be NULL.
status	error status.

Returns: Reference to 'appendTo' parameter.

Stable:: ICU 4.4

◆ getAvailableLocales()

static const Locale * icu::DateFormat::getAvailableLocales ( int32_t & count )

static

Gets the set of locales for which DateFormats are installed.

Parameters

count Filled in with the number of locales in the list that is returned.

Returns: the set of locales for which DateFormats are installed. The caller does NOT own this list and must not delete it.

Stable:: ICU 2.0

◆ getBestPattern()

static UnicodeString icu::DateFormat::getBestPattern	(	const Locale &	locale,
		const UnicodeString &	skeleton,
		UErrorCode &	status
	)

static

Returns the best pattern given a skeleton and locale.

Parameters

locale	the locale
skeleton	the skeleton
status	ICU error returned here

Returns: the best pattern.

Internal:: Do not use. This API is for internal use only. For ICU use only.

◆ getBooleanAttribute()

virtual UBool icu::DateFormat::getBooleanAttribute	(	UDateFormatBooleanAttribute	attr,
		UErrorCode &	status
	)		const

virtual

Returns a boolean from this DateFormat May return U_UNSUPPORTED_ERROR if this instance does not support the specified attribute.

Parameters

attr	the attribute to set
status	the error type

Returns: the attribute value. Undefined if there is an error.

Stable:: ICU 53

◆ getCalendar()

virtual const Calendar * icu::DateFormat::getCalendar ( void ) const

virtual

Gets the calendar associated with this date/time formatter.

The calendar is owned by the formatter and must not be modified. Also, the calendar does not reflect the results of a parse operation. To parse to a calendar, use parse(const UnicodeString&, Calendar& cal, ParsePosition&)

Returns: the calendar associated with this date/time formatter.

Stable:: ICU 2.0

◆ getContext()

virtual UDisplayContext icu::DateFormat::getContext	(	UDisplayContextType	type,
		UErrorCode &	status
	)		const

virtual

Get the formatter's UDisplayContext value for the specified UDisplayContextType, such as UDISPCTX_TYPE_CAPITALIZATION.

Parameters

type	The UDisplayContextType whose value to return
status	Input/output status. If at entry this indicates a failure status, the function will do nothing; otherwise this will be updated with any new status from the function.

Returns: The UDisplayContextValue for the specified type.

Stable:: ICU 53

◆ getNumberFormat()

virtual const NumberFormat * icu::DateFormat::getNumberFormat ( void ) const

virtual

Gets the number formatter which this date/time formatter uses to format and parse the numeric portions of the pattern.

Returns: the number formatter which this date/time formatter uses.

Stable:: ICU 2.0

◆ getTimeZone()

virtual const TimeZone & icu::DateFormat::getTimeZone ( void ) const

virtual

Returns a reference to the TimeZone used by this DateFormat's calendar.

Returns: the time zone associated with the calendar of DateFormat.

Stable:: ICU 2.0

◆ isCalendarLenient()

virtual UBool icu::DateFormat::isCalendarLenient ( void ) const

virtual

Returns whether date/time parsing in the encapsulated Calendar object processing is lenient.

Stable:: ICU 53

◆ isLenient()

virtual UBool icu::DateFormat::isLenient ( void ) const

virtual

Returns whether both date/time parsing in the encapsulated Calendar object and DateFormat whitespace & numeric processing is lenient.

Stable:: ICU 2.0

◆ operator=()

DateFormat & icu::DateFormat::operator= ( const DateFormat & )

protected

Default assignment operator.

Stable:: ICU 2.0

◆ operator==()

virtual bool icu::DateFormat::operator== ( const Format & ) const

overridevirtual

Equality operator.

Returns true if the two formats have the same behavior.

Stable:: ICU 2.0

Implements icu::Format.

Reimplemented in icu::SimpleDateFormat.

◆ parse() [1/3]

virtual void icu::DateFormat::parse	(	const UnicodeString &	text,
		Calendar &	cal,
		ParsePosition &	pos
	)		const

pure virtual

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 also: DateFormat::setLenient(boolean)

Parameters

text	The date/time string to be parsed.
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 DateFormat 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.
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

Implemented in icu::SimpleDateFormat, and icu::SimpleDateFormat.

◆ parse() [2/3]

UDate icu::DateFormat::parse	(	const UnicodeString &	text,
		ParsePosition &	pos
	)		const

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 also: DateFormat::setLenient(boolean)

Note that the normal date formats associated with some calendars - such as the Chinese lunar calendar - do not specify enough fields to enable dates to be parsed unambiguously. In the case of the Chinese lunar calendar, while the year within the current 60-year cycle is specified, the number of such cycles since the start date of the calendar (in the ERA field of the Calendar object) is not normally part of the format, and parsing may assume the wrong era. For cases such as this it is recommended that clients parse using the method parse(const UnicodeString&, Calendar& cal, ParsePosition&) with the Calendar passed in set to the current date, or to a date within the era/cycle that should be assumed if absent in the format.

Parameters

text	The date/time string to be parsed into a UDate value.
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:: ICU 2.0

◆ parse() [3/3]

virtual UDate icu::DateFormat::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.

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)

Note that the normal date formats associated with some calendars - such as the Chinese lunar calendar - do not specify enough fields to enable dates to be parsed unambiguously. In the case of the Chinese lunar calendar, while the year within the current 60-year cycle is specified, the number of such cycles since the start date of the calendar (in the ERA field of the Calendar object) is not normally part of the format, and parsing may assume the wrong era. For cases such as this it is recommended that clients parse using the method parse(const UnicodeString&, Calendar& cal, ParsePosition&) with the Calendar passed in set to the current date, or to a date within the era/cycle that should be assumed if absent in the format.

Parameters

text	The date/time string to be parsed into a UDate value.
status	Output param to be set to success/failure code. If 'text' cannot be parsed, it will be set to a failure code.

Returns: The parsed UDate value, if successful.

Stable:: ICU 2.0

Reimplemented in icu::SimpleDateFormat.

◆ parseObject()

virtual void icu::DateFormat::parseObject	(	const UnicodeString &	source,
		Formattable &	result,
		ParsePosition &	parse_pos
	)		const

overridevirtual

Parse a string to produce an object.

This methods handles parsing of date/time strings into Formattable objects with UDate types.

Before calling, set parse_pos.index to the offset you want to start parsing at in the source. After calling, parse_pos.index is the end of the text you parsed. If error occurs, index is unchanged.

When parsing, leading whitespace is discarded (with a successful parse), while trailing whitespace is left as is.

See Format::parseObject() for more.

Parameters

source	The string to be parsed into an object.
result	Formattable to be set to the parse result. If parse fails, return contents are undefined.
parse_pos	The position to start parsing at. Upon return this param is set to the position after the last character successfully parsed. If the source is not parsed successfully, this param will remain unchanged.

Stable:: ICU 2.0

Implements icu::Format.

◆ setBooleanAttribute()

virtual DateFormat & icu::DateFormat::setBooleanAttribute	(	UDateFormatBooleanAttribute	attr,
		UBool	newvalue,
		UErrorCode &	status
	)

virtual

Sets an boolean attribute on this DateFormat.

May return U_UNSUPPORTED_ERROR if this instance does not support the specified attribute.

Parameters

attr	the attribute to set
newvalue	new value
status	the error type

Returns: *this - for chaining (example: format.setAttribute(...).setAttribute(...) )

Stable:: ICU 53

◆ setCalendar()

virtual void icu::DateFormat::setCalendar ( const Calendar & newCalendar )

virtual

Set the calendar to be used by this date format.

Initially, the default calendar for the specified or default locale is used.

Parameters

newCalendar Calendar object to be set.

Stable:: ICU 2.0

◆ setCalendarLenient()

virtual void icu::DateFormat::setCalendarLenient ( UBool lenient )

virtual

Specifies whether encapsulated Calendar date/time parsing is to be lenient.

With lenient parsing, the parser may use heuristics to interpret inputs that do not precisely match this object's format. Without lenient parsing, inputs must match this object's format more closely.

Parameters

lenient when true, parsing is lenient

See also: com.ibm.icu.util.Calendar::setLenient

Stable:: ICU 53

◆ setContext()

virtual void icu::DateFormat::setContext	(	UDisplayContext	value,
		UErrorCode &	status
	)

virtual

Set a particular UDisplayContext value in the formatter, such as UDISPCTX_CAPITALIZATION_FOR_STANDALONE.

Parameters

value	The UDisplayContext value to set.
status	Input/output status. If at entry this indicates a failure status, the function will do nothing; otherwise this will be updated with any new status from the function.

Stable:: ICU 53

Reimplemented in icu::SimpleDateFormat.

◆ setLenient()

virtual void icu::DateFormat::setLenient ( UBool lenient )

virtual

Specifies whether date/time parsing is to be lenient.

With lenient parsing, the parser may use heuristics to interpret inputs that do not precisely match this object's format. Without lenient parsing, inputs must match this object's format more closely.

Note: ICU 53 introduced finer grained control of leniency (and added new control points) making the preferred method a combination of setCalendarLenient() & setBooleanAttribute() calls. This method supports prior functionality but may not support all future leniency control & behavior of DateFormat. For control of pre 53 leniency,
Calendar and DateFormat whitespace & numeric tolerance, this method is safe to use. However, mixing leniency control via this method and modification of the newer attributes via setBooleanAttribute() may produce undesirable results.

Parameters

lenient True specifies date/time interpretation to be lenient.

See also: Calendar::setLenient

Stable:: ICU 2.0

◆ setNumberFormat()

virtual void icu::DateFormat::setNumberFormat ( const NumberFormat & newNumberFormat )

virtual

Allows you to set the number formatter.

Parameters

newNumberFormat NumberFormat object to be set.

Stable:: ICU 2.0

◆ setTimeZone()

virtual void icu::DateFormat::setTimeZone ( const TimeZone & zone )

virtual

Sets the time zone for the calendar of this DateFormat object.

Parameters

zone	the new time zone.

Stable:: ICU 2.0

Friends And Related Function Documentation

◆ DateFmtKeyByStyle

friend class DateFmtKeyByStyle

friend

Definition at line 903 of file datefmt.h.

Field Documentation

◆ fCalendar

Calendar* icu::DateFormat::fCalendar

protected

The calendar that DateFormat uses to produce the time field values needed to implement date/time formatting.

Subclasses should generally initialize this to the default calendar for the locale associated with this DateFormat.

Stable:: ICU 2.4

Definition at line 872 of file datefmt.h.

◆ fNumberFormat

NumberFormat* icu::DateFormat::fNumberFormat

protected

The number formatter that DateFormat uses to format numbers in dates and times.

Subclasses should generally initialize this to the default number format for the locale associated with this DateFormat.

Stable:: ICU 2.4

Definition at line 880 of file datefmt.h.

The documentation for this class was generated from the following file:

datefmt.h

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Friends

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ EField

◆ EStyle

Constructor & Destructor Documentation

◆ ~DateFormat()

◆ DateFormat() [1/2]

◆ DateFormat() [2/2]

Member Function Documentation

◆ adoptCalendar()

◆ adoptNumberFormat()

◆ adoptTimeZone()

◆ clone()

◆ createDateInstance()

◆ createDateTimeInstance()

◆ createInstance()

◆ createInstanceForSkeleton() [1/3]

◆ createInstanceForSkeleton() [2/3]

◆ createInstanceForSkeleton() [3/3]

◆ createTimeInstance()

◆ format() [1/10]

◆ format() [2/10]

◆ format() [3/10]

◆ format() [4/10]

◆ format() [5/10]

◆ format() [6/10]

◆ format() [7/10]

◆ format() [8/10]

◆ format() [9/10]

◆ format() [10/10]

◆ getAvailableLocales()

◆ getBestPattern()

◆ getBooleanAttribute()

◆ getCalendar()

◆ getContext()

◆ getNumberFormat()

◆ getTimeZone()

◆ isCalendarLenient()

◆ isLenient()

◆ operator=()

◆ operator==()

◆ parse() [1/3]

◆ parse() [2/3]

◆ parse() [3/3]

◆ parseObject()

◆ setBooleanAttribute()

◆ setCalendar()

◆ setCalendarLenient()

◆ setContext()

◆ setLenient()

◆ setNumberFormat()

◆ setTimeZone()

Friends And Related Function Documentation

◆ DateFmtKeyByStyle

Field Documentation

◆ fCalendar

◆ fNumberFormat