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GregorianCalendar Class Reference

Concrete class which provides the standard calendar used by most of the world. More...

#include <gregocal.h>

Class diagram for GregorianCalendar:

Calendar

List of all members.


Public Members

enum  EEras { BC, AD }
Useful constants for GregorianCalendar and TimeZone. More...

 GregorianCalendar (UErrorCode& success)
Constructs a default GregorianCalendar using the current time in the default time zone with the default locale. More...

 GregorianCalendar (TimeZone* zoneToAdopt, UErrorCode& success)
Constructs a GregorianCalendar based on the current time in the given time zone with the default locale. More...

 GregorianCalendar (const TimeZone& zone, UErrorCode& success)
Constructs a GregorianCalendar based on the current time in the given time zone with the default locale. More...

 GregorianCalendar (const Locale& aLocale, UErrorCode& success)
Constructs a GregorianCalendar based on the current time in the default time zone with the given locale. More...

 GregorianCalendar (TimeZone* zoneToAdopt, const Locale& aLocale, UErrorCode& success)
Constructs a GregorianCalendar based on the current time in the given time zone with the given locale. More...

 GregorianCalendar (const TimeZone& zone, const Locale& aLocale, UErrorCode& success)
Constructs a GregorianCalendar based on the current time in the given time zone with the given locale. More...

 GregorianCalendar (int32_t year, int32_t month, int32_t date, UErrorCode& success)
Constructs a GregorianCalendar with the given AD date set in the default time zone with the default locale. More...

 GregorianCalendar (int32_t year, int32_t month, int32_t date, int32_t hour, int32_t minute, UErrorCode& success)
Constructs a GregorianCalendar with the given AD date and time set for the default time zone with the default locale. More...

 GregorianCalendar (int32_t year, int32_t month, int32_t date, int32_t hour, int32_t minute, int32_t second, UErrorCode& success)
Constructs a GregorianCalendar with the given AD date and time set for the default time zone with the default locale. More...

virtual ~GregorianCalendar ()
Destructor. More...

 GregorianCalendar (const GregorianCalendar& source)
Copy constructor. More...

GregorianCalendar& operator= (const GregorianCalendar& right)
Default assignment operator. More...

virtual Calendarclone (void) const
Create and return a polymorphic copy of this calendar. More...

void setGregorianChange (UDate date, UErrorCode& success)
Sets the GregorianCalendar change date. More...

UDate getGregorianChange (void) const
Gets the Gregorian Calendar change date. More...

bool_t isLeapYear (int32_t year) const
Return true if the given year is a leap year. More...

virtual bool_t operator== (const Calendar& that) const
Compares the equality of two GregorianCalendar objects. More...

virtual bool_t equivalentTo (const Calendar& other) const
Calendar override. More...

virtual void add (EDateFields field, int32_t amount, UErrorCode& status)
(Overrides Calendar) UDate Arithmetic function. More...

virtual void roll (EDateFields field, int32_t amount, UErrorCode& status)
(Overrides Calendar) Rolls up or down by the given amount in the specified field. More...

virtual int32_t getMinimum (EDateFields field) const
(Overrides Calendar) Returns minimum value for the given field. More...

virtual int32_t getMaximum (EDateFields field) const
(Overrides Calendar) Returns maximum value for the given field. More...

virtual int32_t getGreatestMinimum (EDateFields field) const
(Overrides Calendar) Returns highest minimum value for the given field if varies. More...

virtual int32_t getLeastMaximum (EDateFields field) const
(Overrides Calendar) Returns lowest maximum value for the given field if varies. More...

int32_t getActualMinimum (EDateFields field) const
Return the minimum value that this field could have, given the current date. More...

int32_t getActualMaximum (EDateFields field) const
Return the maximum value that this field could have, given the current date. More...

virtual bool_t inDaylightTime (UErrorCode& status) const
(Overrides Calendar) Return true if the current date for this Calendar is in Daylight Savings Time. More...

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


Static Public Members

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


Protected Members

virtual void computeFields (UErrorCode& status)
(Overrides Calendar) Converts GMT as milliseconds to time field values. More...

virtual void computeTime (UErrorCode& status)
(Overrides Calendar) Converts Calendar's time field values to GMT as milliseconds. More...


Detailed Description

Concrete class which provides the standard calendar used by most of the world.

The standard (Gregorian) calendar has 2 eras, BC and AD.

This implementation handles a single discontinuity, which corresponds by default to the date the Gregorian calendar was originally instituted (October 15, 1582). Not all countries adopted the Gregorian calendar then, so this cutover date may be changed by the caller.

Prior to the institution of the Gregorian Calendar, New Year's Day was March 25. To avoid confusion, this Calendar always uses January 1. A manual adjustment may be made if desired for dates that are prior to the Gregorian changeover and which fall between January 1 and March 24.

Values calculated for the WEEK_OF_YEAR field range from 1 to 53. Week 1 for a year is the first week that contains at least getMinimalDaysInFirstWeek() days from that year. It thus depends on the values of getMinimalDaysInFirstWeek(), getFirstDayOfWeek(), and the day of the week of January 1. Weeks between week 1 of one year and week 1 of the following year are numbered sequentially from 2 to 52 or 53 (as needed).

For example, January 1, 1998 was a Thursday. If getFirstDayOfWeek() is MONDAY and getMinimalDaysInFirstWeek() is 4 (these are the values reflecting ISO 8601 and many national standards), then week 1 of 1998 starts on December 29, 1997, and ends on January 4, 1998. If, however, getFirstDayOfWeek() is SUNDAY, then week 1 of 1998 starts on January 4, 1998, and ends on January 10, 1998; the first three days of 1998 then are part of week 53 of 1997.

Example for using GregorianCalendar:

 .    // get the supported ids for GMT-08:00 (Pacific Standard Time)
 .    int32_t idsCount;
 .    const UnicodeString** ids = TimeZone::createAvailableIDs(-8 * 60 * 60 * 1000, idsCount);
 .    // if no ids were returned, something is wrong. get out.
 .    if (idsCount == 0) {
 .        return;
 .    }
 .
 .    // begin output
 .    cout << "Current Time" << endl;
 .
 .    // create a Pacific Standard Time time zone
 .    SimpleTimeZone* pdt = new SimpleTimeZone(-8 * 60 * 60 * 1000, *(ids[0]));
 .    
 .    // set up rules for daylight savings time
 .    pdt->setStartRule(Calendar::APRIL, 1, Calendar::SUNDAY, 2 * 60 * 60 * 1000);
 .    pdt->setEndRule(Calendar::OCTOBER, -1, Calendar::SUNDAY, 2 * 60 * 60 * 1000);
 .    
 .    // create a GregorianCalendar with the Pacific Daylight time zone
 .    // and the current date and time
 .    UErrorCode success = U_ZERO_ERROR;
 .    Calendar* calendar = new GregorianCalendar( pdt, success );
 .    
 .    // print out a bunch of interesting things
 .    cout << "ERA: " << calendar->get( Calendar::ERA, success ) << endl;
 .    cout << "YEAR: " << calendar->get( Calendar::YEAR, success ) << endl;
 .    cout << "MONTH: " << calendar->get( Calendar::MONTH, success ) << endl;
 .    cout << "WEEK_OF_YEAR: " << calendar->get( Calendar::WEEK_OF_YEAR, success ) << endl;
 .    cout << "WEEK_OF_MONTH: " << calendar->get( Calendar::WEEK_OF_MONTH, success ) << endl;
 .    cout << "DATE: " << calendar->get( Calendar::DATE, success ) << endl;
 .    cout << "DAY_OF_MONTH: " << calendar->get( Calendar::DAY_OF_MONTH, success ) << endl;
 .    cout << "DAY_OF_YEAR: " << calendar->get( Calendar::DAY_OF_YEAR, success ) << endl;
 .    cout << "DAY_OF_WEEK: " << calendar->get( Calendar::DAY_OF_WEEK, success ) << endl;
 .    cout << "DAY_OF_WEEK_IN_MONTH: " << calendar->get( Calendar::DAY_OF_WEEK_IN_MONTH, success ) << endl;
 .    cout << "AM_PM: " << calendar->get( Calendar::AM_PM, success ) << endl;
 .    cout << "HOUR: " << calendar->get( Calendar::HOUR, success ) << endl;
 .    cout << "HOUR_OF_DAY: " << calendar->get( Calendar::HOUR_OF_DAY, success ) << endl;
 .    cout << "MINUTE: " << calendar->get( Calendar::MINUTE, success ) << endl;
 .    cout << "SECOND: " << calendar->get( Calendar::SECOND, success ) << endl;
 .    cout << "MILLISECOND: " << calendar->get( Calendar::MILLISECOND, success ) << endl;
 .    cout << "ZONE_OFFSET: " << (calendar->get( Calendar::ZONE_OFFSET, success )/(60*60*1000)) << endl;
 .    cout << "DST_OFFSET: " << (calendar->get( Calendar::DST_OFFSET, success )/(60*60*1000)) << endl;
 .
 .    cout << "Current Time, with hour reset to 3" << endl;
 .    calendar->clear(Calendar::HOUR_OF_DAY); // so doesn't override
 .    calendar->set(Calendar::HOUR, 3);
 .    cout << "ERA: " << calendar->get( Calendar::ERA, success ) << endl;
 .    cout << "YEAR: " << calendar->get( Calendar::YEAR, success ) << endl;
 .    cout << "MONTH: " << calendar->get( Calendar::MONTH, success ) << endl;
 .    cout << "WEEK_OF_YEAR: " << calendar->get( Calendar::WEEK_OF_YEAR, success ) << endl;
 .    cout << "WEEK_OF_MONTH: " << calendar->get( Calendar::WEEK_OF_MONTH, success ) << endl;
 .    cout << "DATE: " << calendar->get( Calendar::DATE, success ) << endl;
 .    cout << "DAY_OF_MONTH: " << calendar->get( Calendar::DAY_OF_MONTH, success ) << endl;
 .    cout << "DAY_OF_YEAR: " << calendar->get( Calendar::DAY_OF_YEAR, success ) << endl;
 .    cout << "DAY_OF_WEEK: " << calendar->get( Calendar::DAY_OF_WEEK, success ) << endl;
 .    cout << "DAY_OF_WEEK_IN_MONTH: " << calendar->get( Calendar::DAY_OF_WEEK_IN_MONTH, success ) << endl;
 .    cout << "AM_PM: " << calendar->get( Calendar::AM_PM, success ) << endl;
 .    cout << "HOUR: " << calendar->get( Calendar::HOUR, success ) << endl;
 .    cout << "HOUR_OF_DAY: " << calendar->get( Calendar::HOUR_OF_DAY, success ) << endl;
 .    cout << "MINUTE: " << calendar->get( Calendar::MINUTE, success ) << endl;
 .    cout << "SECOND: " << calendar->get( Calendar::SECOND, success ) << endl;
 .    cout << "MILLISECOND: " << calendar->get( Calendar::MILLISECOND, success ) << endl;
 .    cout << "ZONE_OFFSET: " << (calendar->get( Calendar::ZONE_OFFSET, success )/(60*60*1000)) << endl; // in hours
 .    cout << "DST_OFFSET: " << (calendar->get( Calendar::DST_OFFSET, success )/(60*60*1000)) << endl; // in hours
 .
 .    delete[] ids;
 .    delete calendar; // also deletes pdt
 .
 

Member Enumeration Documentation

enum GregorianCalendar::EEras

Useful constants for GregorianCalendar and TimeZone.

Enumeration values:
BC  
AD  

Member Function Documentation

GregorianCalendar::GregorianCalendar (UErrorCode & success)

Constructs a default GregorianCalendar using the current time in the default time zone with the default locale.

Parameters:
success   Indicates the status of GregorianCalendar object construction. Returns U_ZERO_ERROR if constructed successfully.
Stable:

GregorianCalendar::GregorianCalendar (TimeZone * zoneToAdopt, UErrorCode & success)

Constructs a GregorianCalendar based on the current time in the given time zone with the default locale.

Clients are no longer responsible for deleting the given time zone object after it's adopted.

Parameters:
zoneToAdopt   The given timezone.
success   Indicates the status of GregorianCalendar object construction. Returns U_ZERO_ERROR if constructed successfully.
Stable:

GregorianCalendar::GregorianCalendar (const TimeZone & zone, UErrorCode & success)

Constructs a GregorianCalendar based on the current time in the given time zone with the default locale.

Parameters:
zone   The given timezone.
success   Indicates the status of GregorianCalendar object construction. Returns U_ZERO_ERROR if constructed successfully.
Stable:

GregorianCalendar::GregorianCalendar (const Locale & aLocale, UErrorCode & success)

Constructs a GregorianCalendar based on the current time in the default time zone with the given locale.

Parameters:
aLocale   The given locale.
success   Indicates the status of GregorianCalendar object construction. Returns U_ZERO_ERROR if constructed successfully.
Stable:

GregorianCalendar::GregorianCalendar (TimeZone * zoneToAdopt, const Locale & aLocale, UErrorCode & success)

Constructs a GregorianCalendar based on the current time in the given time zone with the given locale.

Clients are no longer responsible for deleting the given time zone object after it's adopted.

Parameters:
zoneToAdopt   The given timezone.
aLocale   The given locale.
success   Indicates the status of GregorianCalendar object construction. Returns U_ZERO_ERROR if constructed successfully.
Stable:

GregorianCalendar::GregorianCalendar (const TimeZone & zone, const Locale & aLocale, UErrorCode & success)

Constructs a GregorianCalendar based on the current time in the given time zone with the given locale.

Parameters:
zone   The given timezone.
aLocale   The given locale.
success   Indicates the status of GregorianCalendar object construction. Returns U_ZERO_ERROR if constructed successfully.
Stable:

GregorianCalendar::GregorianCalendar (int32_t year, int32_t month, int32_t date, UErrorCode & success)

Constructs a GregorianCalendar with the given AD date set in the default time zone with the default locale.

Parameters:
year   The value used to set the YEAR time field in the calendar.
month   The value used to set the MONTH time field in the calendar. Month value is 0-based. e.g., 0 for January.
date   The value used to set the DATE time field in the calendar.
success   Indicates the status of GregorianCalendar object construction. Returns U_ZERO_ERROR if constructed successfully.
Stable:

GregorianCalendar::GregorianCalendar (int32_t year, int32_t month, int32_t date, int32_t hour, int32_t minute, UErrorCode & success)

Constructs a GregorianCalendar with the given AD date and time set for the default time zone with the default locale.

Parameters:
year   The value used to set the YEAR time field in the calendar.
month   The value used to set the MONTH time field in the calendar. Month value is 0-based. e.g., 0 for January.
date   The value used to set the DATE time field in the calendar.
hour   The value used to set the HOUR_OF_DAY time field in the calendar.
minute   The value used to set the MINUTE time field in the calendar.
success   Indicates the status of GregorianCalendar object construction. Returns U_ZERO_ERROR if constructed successfully.
Stable:

GregorianCalendar::GregorianCalendar (int32_t year, int32_t month, int32_t date, int32_t hour, int32_t minute, int32_t second, UErrorCode & success)

Constructs a GregorianCalendar with the given AD date and time set for the default time zone with the default locale.

Parameters:
year   The value used to set the YEAR time field in the calendar.
month   The value used to set the MONTH time field in the calendar. Month value is 0-based. e.g., 0 for January.
date   The value used to set the DATE time field in the calendar.
hour   The value used to set the HOUR_OF_DAY time field in the calendar.
minute   The value used to set the MINUTE time field in the calendar.
second   The value used to set the SECOND time field in the calendar.
success   Indicates the status of GregorianCalendar object construction. Returns U_ZERO_ERROR if constructed successfully.
Stable:

virtual GregorianCalendar::~GregorianCalendar () [virtual]

Destructor.

Stable:

GregorianCalendar::GregorianCalendar (const GregorianCalendar & source)

Copy constructor.

Stable:

GregorianCalendar & GregorianCalendar::operator= (const GregorianCalendar & right)

Default assignment operator.

Stable:

virtual Calendar * GregorianCalendar::clone (void) const [virtual]

Create and return a polymorphic copy of this calendar.

Stable:

Reimplemented from Calendar.

void GregorianCalendar::setGregorianChange (UDate date, UErrorCode & success)

Sets the GregorianCalendar change date.

This is the point when the switch from Julian dates to Gregorian dates occurred. Default is 00:00:00 local time, October 15, 1582. Previous to this time and date will be Julian dates.

Parameters:
date   The given Gregorian cutover date.
success   Output param set to success/failure code on exit.
Stable:

UDate GregorianCalendar::getGregorianChange (void) const

Gets the Gregorian Calendar change date.

This is the point when the switch from Julian dates to Gregorian dates occurred. Default is 00:00:00 local time, October 15, 1582. Previous to this time and date will be Julian dates.

Returns:
The Gregorian cutover time for this calendar.
Stable:

bool_t GregorianCalendar::isLeapYear (int32_t year) const

Return true if the given year is a leap year.

Determination of whether a year is a leap year is actually very complicated. We do something crude and mostly correct here, but for a real determination you need a lot of contextual information. For example, in Sweden, the change from Julian to Gregorian happened in a complex way resulting in missed leap years and double leap years between 1700 and 1753. Another example is that after the start of the Julian calendar in 45 B.C., the leap years did not regularize until 8 A.D. This method ignores these quirks, and pays attention only to the Julian onset date and the Gregorian cutover (which can be changed).

Parameters:
year   The given year.
Returns:
True if the given year is a leap year; false otherwise.
Stable:

virtual bool_t GregorianCalendar::operator== (const Calendar & that) const [virtual]

Compares the equality of two GregorianCalendar objects.

Objects of different subclasses are considered unequal. This is a strict equality test; see the documentation for Calendar::operator==().

Parameters:
that   The GregorianCalendar object to be compared with.
Returns:
True if the given GregorianCalendar is the same as this GregorianCalendar; false otherwise.
Stable:

Reimplemented from Calendar.

virtual bool_t GregorianCalendar::equivalentTo (const Calendar & other) const [virtual]

Calendar override.

Return true if another Calendar object is equivalent to this one. An equivalent Calendar will behave exactly as this one does, but may be set to a different time.

Stable:

Reimplemented from Calendar.

virtual void GregorianCalendar::add (EDateFields field, int32_t amount, UErrorCode & status) [virtual]

(Overrides Calendar) UDate Arithmetic function.

Adds the specified (signed) amount of time to the given time field, based on the calendar's rules. For more information, see the documentation for Calendar::add().

Parameters:
field   The time field.
amount   The amount of date or time to be added to the field.
status   Output param set to success/failure code on exit. If any value previously set in the time field is invalid, this will be set to an error status.
Stable:

Reimplemented from Calendar.

virtual void GregorianCalendar::roll (EDateFields field, int32_t amount, UErrorCode & status) [virtual]

(Overrides Calendar) Rolls up or down by the given amount in the specified field.

For more information, see the documentation for Calendar::roll().

Parameters:
field   The time field.
amount   Indicates amount to roll.
status   Output param set to success/failure code on exit. If any value previously set in the time field is invalid, this will be set to an error status.
Stable:

Reimplemented from Calendar.

virtual int32_t GregorianCalendar::getMinimum (EDateFields field) const [virtual]

(Overrides Calendar) Returns minimum value for the given field.

e.g. for Gregorian DAY_OF_MONTH, 1.

Stable:

Reimplemented from Calendar.

virtual int32_t GregorianCalendar::getMaximum (EDateFields field) const [virtual]

(Overrides Calendar) Returns maximum value for the given field.

e.g. for Gregorian DAY_OF_MONTH, 31.

Stable:

Reimplemented from Calendar.

virtual int32_t GregorianCalendar::getGreatestMinimum (EDateFields field) const [virtual]

(Overrides Calendar) Returns highest minimum value for the given field if varies.

Otherwise same as getMinimum(). For Gregorian, no difference.

Stable:

Reimplemented from Calendar.

virtual int32_t GregorianCalendar::getLeastMaximum (EDateFields field) const [virtual]

(Overrides Calendar) Returns lowest maximum value for the given field if varies.

Otherwise same as getMaximum(). For Gregorian DAY_OF_MONTH, 28.

Stable:

Reimplemented from Calendar.

int32_t GregorianCalendar::getActualMinimum (EDateFields field) const

Return the minimum value that this field could have, given the current date.

For the Gregorian calendar, this is the same as getMinimum() and getGreatestMinimum().

Stable:

int32_t GregorianCalendar::getActualMaximum (EDateFields field) const

Return the maximum value that this field could have, given the current date.

For example, with the date "Feb 3, 1997" and the DAY_OF_MONTH field, the actual maximum would be 28; for "Feb 3, 1996" it s 29. Similarly for a Hebrew calendar, for some years the actual maximum for MONTH is 12, and for others 13.

Stable:

virtual bool_t GregorianCalendar::inDaylightTime (UErrorCode & status) const [virtual]

(Overrides Calendar) Return true if the current date for this Calendar is in Daylight Savings Time.

Recognizes DST_OFFSET, if it is set.

Parameters:
status   Fill-in parameter which receives the status of this operation.
Returns:
True if the current date for this Calendar is in Daylight Savings Time, false, otherwise.
Stable:

Reimplemented from Calendar.

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

Override Calendar Returns a unique class ID POLYMORPHICALLY.

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

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

Reimplemented from Calendar.

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

Return the class ID for this class.

This is useful only for comparing to a return value from getDynamicClassID(). For example:

Base* polymorphic_pointer = createPolymorphicObject(); if (polymorphic_pointer->getDynamicClassID() == Derived::getStaticClassID()) ...

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

virtual void GregorianCalendar::computeFields (UErrorCode & status) [protected, virtual]

(Overrides Calendar) Converts GMT as milliseconds to time field values.

Stable:

Reimplemented from Calendar.

virtual void GregorianCalendar::computeTime (UErrorCode & status) [protected, virtual]

(Overrides Calendar) Converts Calendar's time field values to GMT as milliseconds.

Parameters:
status   Output param set to success/failure code on exit. If any value previously set in the time field is invalid, this will be set to an error status.
Stable:

Reimplemented from Calendar.


The documentation for this class was generated from the following file:
Generated at Thu Feb 10 15:30:42 2000 for icu by doxygen 1.0.0 written by Dimitri van Heesch, © 1997-1999