ICU 74.1 74.1
Public Types | Public Member Functions | Static Public Member Functions | Protected Member Functions | Protected Attributes | Friends
icu::DateFormat Class Referenceabstract

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:
icu::Format icu::UObject icu::UMemory icu::SimpleDateFormat

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 DateFormatclone () const override=0
 Clones this object polymorphically. More...
 
virtual bool operator== (const Format &) const override
 Equality operator. More...
 
virtual UnicodeStringformat (const Formattable &obj, UnicodeString &appendTo, FieldPosition &pos, UErrorCode &status) const override
 Format an object to produce a string. More...
 
virtual UnicodeStringformat (const Formattable &obj, UnicodeString &appendTo, FieldPositionIterator *posIter, UErrorCode &status) const override
 Format an object to produce a string. More...
 
virtual UnicodeStringformat (Calendar &cal, UnicodeString &appendTo, FieldPosition &fieldPosition) const =0
 Formats a date into a date/time string. More...
 
virtual UnicodeStringformat (Calendar &cal, UnicodeString &appendTo, FieldPositionIterator *posIter, UErrorCode &status) const
 Formats a date into a date/time string. More...
 
UnicodeStringformat (UDate date, UnicodeString &appendTo, FieldPosition &fieldPosition) const
 Formats a UDate into a date/time string. More...
 
UnicodeStringformat (UDate date, UnicodeString &appendTo, FieldPositionIterator *posIter, UErrorCode &status) const
 Formats a UDate into a date/time string. More...
 
UnicodeStringformat (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 CalendargetCalendar (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 NumberFormatgetNumberFormat (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 TimeZonegetTimeZone (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 DateFormatsetBooleanAttribute (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...
 
UnicodeStringformat (const Formattable &obj, UnicodeString &appendTo, UErrorCode &status) const
 Formats an object to produce a string. More...
 
virtual UnicodeStringformat (const Formattable &obj, UnicodeString &appendTo, FieldPosition &pos, UErrorCode &status) const=0
 Format an object to produce a string. More...
 
virtual UnicodeStringformat (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 Formatclone () const =0
 Clone this object polymorphically. More...
 
UnicodeStringformat (const Formattable &obj, UnicodeString &appendTo, UErrorCode &status) const
 Formats an object to produce a string. More...
 
virtual UnicodeStringformat (const Formattable &obj, UnicodeString &appendTo, FieldPosition &pos, UErrorCode &status) const =0
 Format an object to produce a string. More...
 
virtual UnicodeStringformat (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 DateFormatcreateInstance (void)
 Create a default date/time formatter that uses the SHORT style for both the date and the time. More...
 
static DateFormatcreateTimeInstance (EStyle style=kDefault, const Locale &aLocale=Locale::getDefault())
 Creates a time formatter with the given formatting style for the given locale. More...
 
static DateFormatcreateDateInstance (EStyle style=kDefault, const Locale &aLocale=Locale::getDefault())
 Creates a date formatter with the given formatting style for the given const locale. More...
 
static DateFormatcreateDateTimeInstance (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 DateFormatcreateInstanceForSkeleton (const UnicodeString &skeleton, UErrorCode &status)
 Creates a date/time formatter for the given skeleton and default locale. More...
 
static DateFormatcreateInstanceForSkeleton (const UnicodeString &skeleton, const Locale &locale, UErrorCode &status)
 Creates a date/time formatter for the given skeleton and locale. More...
 
static DateFormatcreateInstanceForSkeleton (Calendar *calendarToAdopt, const UnicodeString &skeleton, const Locale &locale, UErrorCode &status)
 Creates a date/time formatter for the given skeleton and locale. More...
 
static const LocalegetAvailableLocales (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...
 
DateFormatoperator= (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 &)
 
Formatoperator= (const Format &)
 

Protected Attributes

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

UnicodeString myString;
myString = dfmt->format( myDate, myString );
static UDate getNow(void)
Returns the current UTC (GMT) time measured in milliseconds since 0:00:00 on 1/1/70 (derived from the...
DateFormat is an abstract class for a family of classes that convert dates and times from their inter...
Definition: datefmt.h:156
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.
virtual UnicodeString & format(const Formattable &obj, UnicodeString &appendTo, FieldPosition &pos, UErrorCode &status) const override
Format an object to produce a string.
UnicodeString is a string class that stores Unicode characters directly and provides similar function...
Definition: unistr.h:296
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.

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;
}
UnicodeString & remove()
Removes all characters from the UnicodeString object and clears the bogus flag.
Definition: unistr.h:4723

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

FieldPosition pos(DateFormat::YEAR_FIELD);
UnicodeString myString;
myString = dfmt->format( myDate, myString );
cout << myString << endl;
cout << pos.getBeginIndex() << "," << pos. getEndIndex() << endl;
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().

static const Locale & getFrance(void)
Useful constant for this country/region.

You can use a DateFormat to parse also.

UDate myDate = df->parse(myString, status);
virtual UDate parse(const UnicodeString &text, UErrorCode &status) const
Parse a date/time string.
UErrorCode
Standard ICU4C error code type, a substitute for exceptions.
Definition: utypes.h:415
@ 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:

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

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

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

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
calendarToAdoptCalendar 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
formatToAdoptNumberFormat 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
zoneToAdoptthe 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
styleThe 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.
aLocaleThe 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
dateStyleThe 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.
timeStyleThe 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.
aLocaleThe 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
calendarToAdoptthe calendar returned DateFormat is to use.
skeletonThe 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.
localeThe given locale.
statusAny 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
skeletonThe 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.
localeThe given locale.
statusAny 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
skeletonThe 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.
statusAny 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
styleThe given formatting style. For example, SHORT for "h:mm a" in the US locale. Relative time styles are not currently supported.
aLocaleThe 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
calCalendar 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.
appendToOutput parameter to receive result. Result is appended to existing contents.
fieldPositionOn 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
calCalendar 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.
appendToOutput parameter to receive result. Result is appended to existing contents.
posIterOn return, can be used to iterate over positions of fields generated by this format call. Field values are defined in UDateFormatField. Can be nullptr.
statuserror 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
objThe object to format. Must be a Date.
appendToOutput parameter to receive result. Result is appended to existing contents.
posOn input: an alignment field, if desired. On output: the offsets of the alignment field.
statusOutput 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
objThe object to format.
appendToOutput parameter to receive result. Result is appended to existing contents.
posOn input: an alignment field, if desired. On output: the offsets of the alignment field.
statusOutput 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
objThe object to format.
appendToOutput parameter to receive result. Result is appended to existing contents.
posIterOn return, can be used to iterate over positions of fields generated by this format call.
statusOutput 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
objThe object to format. Must be a Date.
appendToOutput parameter to receive result. Result is appended to existing contents.
posIterOn return, can be used to iterate over positions of fields generated by this format call. Field values are defined in UDateFormatField. Can be nullptr.
statusOutput 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
objThe object to format.
appendToOutput parameter to receive result. Result is appended to existing contents.
statusOutput 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
dateThe UDate value to be formatted into a string.
appendToOutput 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
dateUDate to be formatted into a date/time string.
appendToOutput parameter to receive result. Result is appended to existing contents.
fieldPositionOn 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
dateUDate to be formatted into a date/time string.
appendToOutput parameter to receive result. Result is appended to existing contents.
posIterOn return, can be used to iterate over positions of fields generated by this format call. Field values are defined in UDateFormatField. Can be nullptr.
statuserror 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
countFilled 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
localethe locale
skeletonthe skeleton
statusICU 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
attrthe attribute to set
statusthe 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
typeThe UDisplayContextType whose value to return
statusInput/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
textThe date/time string to be parsed.
calA 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.
posOn 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
textThe date/time string to be parsed into a UDate value.
posOn 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
textThe date/time string to be parsed into a UDate value.
statusOutput 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
sourceThe string to be parsed into an object.
resultFormattable to be set to the parse result. If parse fails, return contents are undefined.
parse_posThe 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
attrthe attribute to set
newvaluenew value
statusthe 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
newCalendarCalendar 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
lenientwhen 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
valueThe UDisplayContext value to set.
statusInput/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
lenientTrue 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
newNumberFormatNumberFormat 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
zonethe 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: