A value class that represents a date on the Gregorian calendar. More...

#include <Wt/WDate.h>

Public Member Functions
	WDate ()
	Construct a Null date. More...

	WDate (const std::chrono::system_clock::time_point &tp)
	Construct a date with a time_point.

	WDate (int year, int month, int day)
	Specify a date by year, month, and day. More...

void	setDate (int year, int month, int day)
	Sets the date by year, month, and day. More...

void	setTimePoint (const std::chrono::system_clock::time_point &tp)
	Sets the date from a time point.

WDate	addDays (int ndays) const
	Adds days. More...

WDate	addMonths (int nmonths) const
	Adds months. More...

WDate	addYears (int nyears) const
	Adds years. More...

bool	isNull () const
	Returns if this date is Null. More...

bool	isValid () const
	Returns if this date is valid. More...

int	year () const
	Returns the year. More...

int	month () const
	Returns the month (1-12). More...

int	day () const
	Returns the day of month (1-31). More...

int	dayOfWeek () const
	Returns the day of week (1-7). More...

int	daysTo (const WDate &date) const
	Returns the difference between two dates (in days). More...

int	toJulianDay () const
	Converts the date to a Julian day. More...

bool	operator< (const WDate &other) const
	Compares two dates.

bool	operator<= (const WDate &other) const
	Compares two dates.

bool	operator> (const WDate &other) const
	Compares two dates.

bool	operator>= (const WDate &other) const
	Compares two dates.

bool	operator== (const WDate &other) const
	Compares two dates.

bool	operator!= (const WDate &other) const
	Compares two dates.

WString	toString () const
	Formats this date to a string using a default format. More...

WString	toString (const WString &format, bool localizedString=true) const
	Formats this date to a string using a specified format. More...

Static Public Member Functions
static WDate	fromString (const WString &s)
	Parses a string to a date using a default format. More...

static WDate	fromString (const WString &s, const WString &format)
	Parses a string to a date using a specified format. More...

static WDate	fromJulianDay (int jd)
	Converts a Julian Day jd to a WDate . More...

static WDate	currentDate ()
	Reports the current client date. More...

static WDate	currentServerDate ()
	Reports the current server date. More...

static bool	isLeapYear (int year)
	Returns whether the given year is a leap year. More...

static WDate	previousWeekday (WDate &d, int weekday)
	Returns a date object representing the previous weekday. More...

static Wt::WString	shortDayName (int weekday, bool localizedString=true)
	Returns the short day name. More...

static Wt::WString	shortMonthName (int month, bool localizedString=true)
	Returns the short month name. More...

static Wt::WString	longDayName (int weekday, bool localizedString=true)
	Returns the long day name. More...

static Wt::WString	longMonthName (int month, bool localizedString=true)
	Returns the long month name. More...

Detailed Description

A value class that represents a date on the Gregorian calendar.

Class which holds a date on the gregorian calendar, specified as day/month/year.

A WDate may either specify a valid date, or be a Null date (using the default constructor WDate::WDate(), for which isNull() returns true).

A valid date may be specified by year, month, and day of month (using the WDate(year, month, day) constructor, or the setDate() method). When attempting to specify an invalid date (with an impossible combination of year/month/date), isIvalid() will return false.

The class provides a flexible way for converting between strings and dates. Use toString() to convert to strings, and fromString() for parsing strings. Both methods take a format string, and the same format syntax is supported by both methods.

Simple operations are supported to compare dates, or to calculate with dates.

i18n

If the thread using a WDate is bound to a WApplication (i.e. WApplication::instance() does not return 0), the date strings can be localized by overriding the default values for the localized string keys in the resource bundles of the WApplication:

Short day names: Wt.WDate.3.Mon through Wt.WDate.3.Sun
Long day names: Wt.WDate.Monday through Wt.WDate.Sunday
Short month names: Wt.WDate.3.Jan through Wt.WDate.3.Dec
Long month names: Wt.WDate.January through Wt.WDate.December

If the thread using a WDate is not bound to a WApplication (i.e. WApplication::instance() returns 0), english strings will be used.

Internationalization affects both WDate to string conversions and string to WDate conversion.

Constructor & Destructor Documentation

◆ WDate() [1/2]

Wt::WDate::WDate ( )

Construct a Null date.

A date for which isNull() returns true. A Null date is also invalid.

See also: isValid(), isNull()

◆ WDate() [2/2]

Wt::WDate::WDate	(	int	year,
		int	month,
		int	day
	)

Specify a date by year, month, and day.

The month has range 1-12 and the day has range 1-31. When the date is invalid, isValid() is set to false.

See also: setDate(), year(), month(), day()

Member Function Documentation

◆ addDays()

WDate Wt::WDate::addDays ( int ndays ) const

Adds days.

Returns a date that is ndays later than this date. Negative values for ndays will result in a date that is as many days earlier.

Returns a null date if the current date is invalid or the new date is out of range.

See also: addMonths(), addYears()

◆ addMonths()

WDate Wt::WDate::addMonths ( int nmonths ) const

Adds months.

Returns a date that is the same day of the month, but nmonths later than this date. Negative values for nmonths will result in a date that is as many months earlier.

If the day does not exist in the resulting month/year then the date is set to the last day of that month (e.g. 2019-05-31 + 1 month = 2019-06-30)

Returns a null date if the current date is invalid or the new date is out of range.

See also: addDays(), addYears()

◆ addYears()

WDate Wt::WDate::addYears ( int nyears ) const

Adds years.

Returns a date that is nyears later than this date. Negative values for nyears will result in a date that is as many years earlier.

If the day does not exist in the resulting month/year then the date is set to the last day of that month (e.g. 2016-02-29 + 1 year = 2017-02-28)

Returns a null date if the current date is invalid or the new date is out of range.

See also: addDays(), addMonths()

◆ currentDate()

WDate Wt::WDate::currentDate ( )

static

Reports the current client date.

This method uses browser information to retrieve the date that is configured in the client.

See also: WLocalDateTime::currentDate()

◆ currentServerDate()

WDate Wt::WDate::currentServerDate ( )

static

Reports the current server date.

This method returns the local date on the server.

See also: WDateTime::currentDateTime(), WLocalDateTime::currentServerDateTime()

◆ day()

int Wt::WDate::day ( ) const

Returns the day of month (1-31).

Returns 0 if the date is invalid.

◆ dayOfWeek()

int Wt::WDate::dayOfWeek ( ) const

Returns the day of week (1-7).

Returns the day of week, from Monday (=1) to Sunday (=7).

Returns 0 if the date is invalid.

◆ daysTo()

int Wt::WDate::daysTo ( const WDate & date ) const

Returns the difference between two dates (in days).

Returns 0 if either date is invalid.

◆ fromJulianDay()

WDate Wt::WDate::fromJulianDay ( int jd )

static

Converts a Julian Day jd to a WDate .

See also: toJulianDay() const

◆ fromString() [1/2]

WDate Wt::WDate::fromString ( const WString & s )

static

Parses a string to a date using a default format.

The default format is "ddd MMM d yyyy". For example, a date specified as:

"Wed Aug 29 2007"

will be parsed as a date that equals a date constructed as:

WDate d(2007,8,29);

Wt::WDate::WDate

WDate()

Construct a Null date.

Definition: WDate.C:31

When the date could not be parsed or is not valid, an invalid date is returned (for which isValid() returns false).

See also: fromString(const WString& s, const WString& format), isValid()

◆ fromString() [2/2]

WDate Wt::WDate::fromString	(	const WString &	s,
		const WString &	format
	)

static

Parses a string to a date using a specified format.

The format follows the same syntax as used by toString(const WString& format).

When the date could not be parsed or is not valid, an invalid date is returned (for which isValid() returns false).

See also: toString(const WString&) const

◆ isLeapYear()

bool Wt::WDate::isLeapYear ( int year )

static

Returns whether the given year is a leap year.

A leap year has 29 days in February, in case you wondered.

◆ isNull()

bool Wt::WDate::isNull ( ) const

Returns if this date is Null.

A null date is also invalid.

See also: isValid(), WDate()

◆ isValid()

bool Wt::WDate::isValid ( ) const

Returns if this date is valid.

See also: isNull(), WDate(int, int, int), setDate()

◆ longDayName()

WString Wt::WDate::longDayName	(	int	weekday,
		bool	localizedString = `true`
	)

static

Returns the long day name.

Results (for given weekDay) are (default English):
"Monday" (1),
"Tuesday" (2),
"Wednesday" (3),
"Thursday" (4),
"Friday" (5),
"Saturday" (6),
"Sunday" (7).

The result is affected by localization using the "Wt.WDate.Monday" to "Wt.WDate.Sunday" keys.

See also: shortDayName()

◆ longMonthName()

WString Wt::WDate::longMonthName	(	int	month,
		bool	localizedString = `true`
	)

static

Returns the long month name.

Results (for given month) are (default English):
"January" (1),
"February" (2),
"March" (3),
"April" (4),
"May" (5),
"June" (6),
"July" (7),
"August" (8),
"September" (9),
"October" (10),
"November" (11),
"December" (12).

The result is affected by localization using the "Wt.WDate.January" to "Wt.WDate.December" keys.

See also: shortDayName()

◆ month()

int Wt::WDate::month ( ) const

Returns the month (1-12).

Returns 0 if the date is invalid.

◆ previousWeekday()

WDate Wt::WDate::previousWeekday	(	WDate &	d,
		int	weekday
	)

static

Returns a date object representing the previous weekday.

Weekday [1 - 7]

◆ setDate()

void Wt::WDate::setDate	(	int	year,
		int	month,
		int	day
	)

Sets the date by year, month, and day.

The month has range 1-12 and the day has range 1-31. When the new date is invalid, isValid() will return false.

See also: WDate(int year, int month, int day), year(), month(), day()

◆ shortDayName()

WString Wt::WDate::shortDayName	(	int	weekday,
		bool	localizedString = `true`
	)

static

Returns the short day name.

Results (for given weekDay) are (default English):
"Mon" (1),
"Tue" (2),
"Wed" (3),
"Thu" (4),
"Fri" (5),
"Sat" (6),
"Sun" (7).

The result is affected by localization using the "Wt.WDate.3.Mon" to "Wt.WDate.3.Sun" keys.

See also: longDayName()

◆ shortMonthName()

WString Wt::WDate::shortMonthName	(	int	month,
		bool	localizedString = `true`
	)

static

Returns the short month name.

Results (for given month) are (default English):
"Jan" (1),
"Feb" (2),
"Mar" (3),
"Apr" (4),
"May" (5),
"Jun" (6),
"Jul" (7),
"Aug" (8),
"Sep" (9),
"Oct" (10),
"Nov" (11),
"Dec" (12)
.

The result is affected by localization using the "Wt.WDate.3.Jan" to "Wt.WDate.3.Dec" keys.

See also: longMonthName()

◆ toJulianDay()

int Wt::WDate::toJulianDay ( ) const

Converts the date to a Julian day.

Returns 0 if the date is invalid.

See also: fromJulianDay()

◆ toString() [1/2]

WString Wt::WDate::toString ( ) const

Formats this date to a string using a default format.

The default format is "ddd MMM d yyyy". For example, a date constructed as:

WDate d(2007,8,29);

will be formatted as:

"Wed Aug 29 2007"

See also: toString(const WString& format) const, fromString()

◆ toString() [2/2]

WString Wt::WDate::toString	(	const WString &	format,
		bool	localizedString = `true`
	)		const

Formats this date to a string using a specified format.

The format is a string in which the following contents has a special meaning.

Code	Meaning	Example (for Mon Aug 3 2007)
d	The day without leading zero (1-31)	3
dd	The day with leading zero (01-31)	03
ddd	The day abbreviated using shortDayName()	Mon
dddd	The day abbreviated using longDayName()	Monday
M	The month without leading zero (1-12)	8
MM	The month with leading zero (01-12)	08
MMM	The month abbreviated using shortMonthName()	Aug
MMMM	The month abbreviated using longMonthName()	August
yy	The year as a two-digit number (00-99)	07
yyyy	The year as a four-digit number (-9999-9999)	2007

Any other text is kept literally. String content between single quotes (') are not interpreted as special codes. LabelOption::Inside a string, a literal quote may be specifed using a double quote ('').

Examples of format and result:

Format	Result (for Mon Aug 3 2007)
ddd MMM d yyyy	Mon Aug 3 2007
dd/MM/yyyy	03/08/2007
dddd, MMM d, yyyy	Wednesday, Aug 3, 2007
'MM': MM, 'd': d, 'yyyy': yyyy	MM: 08, d: 3, yyyy: 2007

The localizedString allows for the potential strings that are created to be localized or not.

E.g. If "ddd" is part of the format, the abbreviated day is used. If localizedString is true, and if the abbreviations are defined in a resource bundle (overwriting the default "Wt.WDate.3.Mon" for example), they will be used.

See also: fromString(const WString& value, const WString& format)

◆ year()

int Wt::WDate::year ( ) const

Returns the year.

Returns 0 if the date is invalid.

Public Member Functions

Static Public Member Functions

Detailed Description

i18n

Constructor & Destructor Documentation

◆ WDate() [1/2]

◆ WDate() [2/2]

Member Function Documentation

◆ addDays()

◆ addMonths()

◆ addYears()

◆ currentDate()

◆ currentServerDate()

◆ day()

◆ dayOfWeek()

◆ daysTo()

◆ fromJulianDay()

◆ fromString() [1/2]

◆ fromString() [2/2]

◆ isLeapYear()

◆ isNull()

◆ isValid()

◆ longDayName()

◆ longMonthName()

◆ month()

◆ previousWeekday()

◆ setDate()

◆ shortDayName()

◆ shortMonthName()

◆ toJulianDay()

◆ toString() [1/2]

◆ toString() [2/2]

◆ year()