Wt::WDateTime Class Reference

A calendar date and clock time. More...

#include <Wt/WDateTime.h>

Public Member Functions
	WDateTime ()
	Creates a Null datetime. More...
	WDateTime (const WDate &date)
	Creates a datetime given a date. More...
	WDateTime (const WDate &date, const WTime &time)
	Creates a datetime given a date and time. More...
	WDateTime (const std::chrono::system_clock::time_point timepoint)
	Convert std::chrono::system_clock::time_point to a date time.
void	setTime_t (std::time_t time)
	Sets the time in seconds from the Epoch. More...
void	setTimePoint (const std::chrono::system_clock::time_point &timepoint)
	Sets the date time.
WDateTime	addMSecs (int ms) const
	Adds milliseconds. More...
WDateTime	addSecs (int s) const
	Adds seconds. More...
WDateTime	addDays (int ndays) const
	Adds days. More...
WDateTime	addMonths (int nmonths) const
	Adds months. More...
WDateTime	addYears (int nyears) const
	Adds years. More...
bool	isNull () const
	Returns if this datetime is Null. More...
bool	isValid () const
	Returns if this datetime is valid. More...
void	setDate (const WDate &date)
	Sets the date part. More...
const WDate	date () const
	Returns the date part. More...
void	setTime (const WTime &time)
	Sets the time part. More...
const WTime	time () const
	Returns the time part. More...
std::time_t	toTime_t () const
	Returns the number of seconds since the Epoch. More...
std::chrono::system_clock::time_point	toTimePoint () const
	Returns the boost time. More...
	operator std::chrono::system_clock::time_point () const
	Convert to std::chrono::system_clock::time_point.
WLocalDateTime	toLocalTime (const WLocale &locale=WLocale::currentLocale()) const
	Converts to a local time. More...
int	secsTo (const WDateTime &other) const
	Returns the difference between two datetime values (in seconds). More...
int	daysTo (const WDateTime &other) const
	Returns the difference between two datetime values (in days). More...
WString	timeTo (const WDateTime &other, std::chrono::seconds minValue=std::chrono::seconds(1)) const
	Returns the difference between two datetime values (as text). More...
bool	operator< (const WDateTime &other) const
	Compares two datetime values.
bool	operator<= (const WDateTime &other) const
	Compares two datetime values.
bool	operator> (const WDateTime &other) const
	Compares two datetime values.
bool	operator>= (const WDateTime &other) const
	Compares two datetime values.
bool	operator== (const WDateTime &other) const
	Compares two datetime values.
bool	operator!= (const WDateTime &other) const
	Compares two datetime values.
WString	toString () const
	Formats this datetime to a string using a default format. More...
WString	toString (const WString &format, bool localizedString=true) const
	Formats this time to a string using a specified format. More...

Static Public Member Functions
static WDateTime	fromString (const WString &s)
	Parses a string to a time using a default format. More...
static WDateTime	fromString (const WString &s, const WString &format)
	Parses a string to a time using a specified format. More...
static WDateTime	currentDateTime ()
	Reports the current datetime (UTC clock). More...
static WDateTime	fromTime_t (std::time_t seconds)
	Creates a date time based on a number of seconds since the Epoch. More...
static WDateTime	fromTimePoint (const std::chrono::system_clock::time_point &datetime)
	Creates a date time from boost's date time type. More...

Detailed Description

A calendar date and clock time.

The date time class combines the functionality of a WDate (for a calendar date) and WTime (for clock time) into a single class.

This class stores and represents the date time in UTC. To deal with local (wall clock) time, see WLocalDateTime. To convert from UTC to local time use toLocalTime().

i18n

The strings returned by toString() and timeTo() can be localized. If the thread using a WDateTime is bound to a WApplication (i.e. WApplication::instance() does not return 0), the strings can be localized by overriding the default values for the localized string keys in the resource bundles of the WApplication. If the thread using a WDateTime is not bound to a WApplication (i.e. WApplication::instance() returns 0), English strings will be used.

For toString(), localization is handled through the i18n functionality of the WDate class. An invalid WDateTime is converted to a string as "Null":

• Wt.WDateTime.null: Null

The timeTo() method contains the following localized strings:

• Wt.WDateTime.seconds
• Wt.WDateTime.minutes
• and so on

The default translations of Wt.WDateTime.seconds are "one second" and "{1} seconds". The WString::trn() function is used for the translation, so different strings can be provided for different plural forms. The placeholder {1} will be replaced by the actual number of seconds. The same keys also exist for minutes, hours, days, weeks, months and years.

Constructor & Destructor Documentation

WDateTime() [1/3]

Wt::WDateTime::WDateTime

(

)

Creates a Null datetime.

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

See also

isValid(), isNull()

WDateTime() [2/3]

Wt::WDateTime::WDateTime ( const WDate &  date )

explicit

Creates a datetime given a date.

The time is set to midnight (00:00). The datetime is valid if the date is valid.

WDateTime() [3/3]

Wt::WDateTime::WDateTime	(	const WDate &	date,
		const WTime &	time
	)

Creates a datetime given a date and time.

The datetime is valid if both date and time are valid.

Member Function Documentation

addDays()

WDateTime Wt::WDateTime::addDays

(

int

ndays

)

const

Adds days.

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

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

See also

addMonths(), addYears()

addMonths()

WDateTime Wt::WDateTime::addMonths

(

int

nmonths

)

const

Adds months.

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

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

See also

addDays(), addYears()

addMSecs()

WDateTime Wt::WDateTime::addMSecs

(

int

ms

)

const

Adds milliseconds.

Returns a datetime that is ms milliseconds later than this datetime. Negative values for ms will result in a datetime that is as many milliseconds earlier.

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

addSecs()

WDateTime Wt::WDateTime::addSecs

(

int

s

)

const

Adds seconds.

Returns a datetime that is s seconds later than this datetime. Negative values for s will result in a datetime that is as many seconds earlier.

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

addYears()

WDateTime Wt::WDateTime::addYears

(

int

nyears

)

const

Adds years.

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

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

See also

addDays(), addMonths()

currentDateTime()

static WDateTime Wt::WDateTime::currentDateTime ( )

static

Reports the current datetime (UTC clock).

This method returns the datetime as indicated by the system clock of the server, in UTC.

date()

const WDate Wt::WDateTime::date

(

)

const

Returns the date part.

Returns the date part.

See also

time()

daysTo()

int Wt::WDateTime::daysTo

(

const WDateTime &

other

)

const

Returns the difference between two datetime values (in days).

The result is negative if other is earlier than this.

Returns 0 if either date is invalid.

See also

secsTo()

fromString() [1/2]

static WDateTime Wt::WDateTime::fromString ( const WString &  s )

static

Parses a string to a time using a default format.

The default format is "ddd MMM d hh:mm:ss yyyy".

See also

WDate::fromString(), WTime::fromString().

fromString() [2/2]

static WDateTime Wt::WDateTime::fromString ( const WString &  s, const WString &  format  )

static

Parses a string to a time using a specified format.

The format is a string which mixes the format for WDate and WTime.

See also

WDate::fromString(), WTime::toString().

fromTime_t()

static WDateTime Wt::WDateTime::fromTime_t ( std::time_t  seconds )

static

Creates a date time based on a number of seconds since the Epoch.

See also

setTime_t()

fromTimePoint()

static WDateTime Wt::WDateTime::fromTimePoint ( const std::chrono::system_clock::time_point &  datetime )

static

Creates a date time from boost's date time type.

See also

toPosixTime()

isNull()

bool Wt::WDateTime::isNull

(

)

const

Returns if this datetime is Null.

A null time is also invalid.

See also

isValid(), WDateTime()

isValid()

bool Wt::WDateTime::isValid

(

)

const

Returns if this datetime is valid.

A date time is only valid if its date and time parts are valid.

secsTo()

int Wt::WDateTime::secsTo

(

const WDateTime &

other

)

const

Returns the difference between two datetime values (in seconds).

The result is negative if other is earlier than this.

Returns 0 if either date is invalid.

See also

daysTo()

setDate()

void Wt::WDateTime::setDate

(

const WDate &

date

)

Sets the date part.

Changes the date part part, leaving the time unmodified. If no time was set, it is set to 00:00.

See also

setTime()

setTime()

void Wt::WDateTime::setTime

(

const WTime &

time

)

Sets the time part.

If no valid date is set, the time is not set either.

See also

setDate()

setTime_t()

void Wt::WDateTime::setTime_t

(

std::time_t

time

)

Sets the time in seconds from the Epoch.

The time is the number of seconds since the Epoch (00:00:00 UTC, January 1, 1970).

See also

toTime_t()

time()

const WTime Wt::WDateTime::time

(

)

const

Returns the time part.

See also

setTime()

timeTo()

WString Wt::WDateTime::timeTo	(	const WDateTime &	other,
		std::chrono::seconds	minValue = std::chrono::seconds(1)
	)		const

Returns the difference between two datetime values (as text).

This returns a textual representation of the approximate difference between this time and other. The textual representation returns the difference as a number of seconds, minutes, hours, days, weeks, months, or years, using the coarsest unit that is more than minValue.

Returns an empty string if either date is invalid.

See also

daysTo(), secsTo()

toLocalTime()

WLocalDateTime Wt::WDateTime::toLocalTime

(

const WLocale &

locale = WLocale::currentLocale()

)

const

Converts to a local time.

The conversion is based on the fact that WDateTime represents UTC time.

This is the reverse of WLocalDateTime::toUTC()

toString() [1/2]

WString Wt::WDateTime::toString

(

)

const

Formats this datetime to a string using a default format.

The default format is "ddd MMM d hh:mm:ss yyyy".

toString() [2/2]

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

Formats this time to a string using a specified format.

The format is a string which mixes the format for WDate and WTime.

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

WDate::toString(), WTime::toString()

toTime_t()

std::time_t Wt::WDateTime::toTime_t

(

)

const

Returns the number of seconds since the Epoch.

This returns the number of seconds since the Epoch (00:00:00 UTC, January 1, 1970) represented by this datetime.

toTimePoint()

std::chrono::system_clock::time_point Wt::WDateTime::toTimePoint

(

)

const

Returns the boost time.

See also

fromPosixTime()