TimeZone

class U_I18N_API TimeZone

TimeZone represents a time zone offset, and also figures out daylight savings

Inheritance:

Public Classes
enum EDisplayType: Enum for use with getDisplayName

Public Methods
static TimeZone* createTimeZone(const UnicodeString& ID): Creates a TimeZone for the given ID
static const UnicodeString** const createAvailableIDs(int32_t rawOffset, int32_t& numIDs): Returns a list of time zone IDs, one for each time zone with a given GMT offset
static const UnicodeString** const createAvailableIDs(int32_t& numIDs): Returns a list of all time zone IDs supported by the TimeZone class (i
static TimeZone* createDefault(void): Creates a new copy of the default TimeZone for this host
static void adoptDefault(TimeZone* zone): Sets the default time zone (i
static void setDefault(const TimeZone& zone): Same as adoptDefault(), except that the TimeZone object passed in is NOT adopted; the caller remains responsible for deleting it
virtual bool_t operator==(const TimeZone& that) const: Returns true if the two TimeZones are equal
bool_t operator!=(const TimeZone& that) const: Returns true if the two TimeZones are NOT equal; that is, if operator==() returns false
virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day, uint8_t dayOfWeek, int32_t millis, UErrorCode& status) const: Returns the TimeZone's adjusted GMT offset (i
virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day, uint8_t dayOfWeek, int32_t milliseconds, int32_t monthLength, UErrorCode& status) const: Gets the time zone offset, for current date, modified in case of daylight savings
virtual void setRawOffset(int32_t offsetMillis): Sets the TimeZone's raw GMT offset (i
virtual int32_t getRawOffset(void) const: Returns the TimeZone's raw GMT offset (i
UnicodeString& getID(UnicodeString& ID) const: Fills in "ID" with the TimeZone's ID
void setID(const UnicodeString& ID): Sets the TimeZone's ID to the specified value
UnicodeString& getDisplayName(UnicodeString& result) const: Returns a name of this time zone suitable for presentation to the user in the default locale
UnicodeString& getDisplayName(const Locale& locale, UnicodeString& result) const: Returns a name of this time zone suitable for presentation to the user in the specified locale
UnicodeString& getDisplayName(bool_t daylight, EDisplayType style, UnicodeString& result) const: Returns a name of this time zone suitable for presentation to the user in the default locale
UnicodeString& getDisplayName(bool_t daylight, EDisplayType style, const Locale& locale, UnicodeString& result) const: Returns a name of this time zone suitable for presentation to the user in the specified locale
virtual bool_t useDaylightTime(void) const: Queries if this time zone uses daylight savings time
virtual bool_t inDaylightTime(UDate date, UErrorCode& status) const: Queries if the given date is in daylight savings time in this time zone
virtual bool_t hasSameRules(const TimeZone& other) const: Returns true if this zone has the same rule and offset as another zone
virtual TimeZone* clone(void) const: Clones TimeZone objects polymorphically
static UClassID getStaticClassID(void): Return the class ID for this class
virtual UClassID getDynamicClassID(void) const: Returns a unique class ID POLYMORPHICALLY
static void deleteTimeZone(void*): Delete function for fgHashtable

Protected Methods
TimeZone(): Default constructor
TimeZone(const TimeZone& source): Copy constructor
TimeZone& operator=(const TimeZone& right): Default assignment operator

Documentation

TimeZone represents a time zone offset, and also figures out daylight savings.
Typically, you get a TimeZone using createDefault which creates a TimeZone based on the time zone where the program is running. For example, for a program running in Japan, createDefault creates a TimeZone object based on Japanese Standard Time.
You can also get a TimeZone using createTimeZone along with a time zone ID. For instance, the time zone ID for the Pacific Standard Time zone is "PST". So, you can get a PST TimeZone object with:
TimeZone *tz = TimeZone::createTimeZone("PST");
You can use getAvailableIDs method to iterate through all the supported time zone IDs. You can then choose a supported ID to get a TimeZone. If the time zone you want is not represented by one of the supported IDs, then you can create a custom time zone ID with the following syntax:
GMT[+|-]hh[[:]mm]
For example, you might specify GMT+14:00 as a custom time zone ID. The TimeZone that is returned when you specify a custom time zone ID does not include daylight savings time. TimeZone is an abstract class representing a time zone. A TimeZone is needed for Calendar to produce local time for a particular time zone. A TimeZone comprises three basic pieces of information:

A time zone offset; that, is the number of milliseconds to add or subtract from a time expressed in terms of GMT to convert it to the same time in that time zone (without taking daylight savings time into account).
Logic necessary to take daylight savings time into account if daylight savings time is observed in that time zone (e.g., the days and hours on which daylight savings time begins and ends).
An ID. This is a text string that uniquely identifies the time zone.
(Only the ID is actually implemented in TimeZone; subclasses of TimeZone may handle daylight savings time and GMT offset in different ways. Currently we only have one TimeZone subclass: SimpleTimeZone.)
The TimeZone class contains a static list containing a TimeZone object for every combination of GMT offset and daylight-savings time rules currently in use in the world, each with a unique ID. Each ID consists of a region (usually a continent or ocean) and a city in that region, separated by a slash, (for example, Pacific Standard Time is "America/Los_Angeles.") Because older versions of this class used three- or four-letter abbreviations instead, there is also a table that maps the older abbreviations to the newer ones (for example, "PST" maps to "America/LosAngeles"). Anywhere the API requires an ID, you can use either form.
To create a new TimeZone, you call the factory function TimeZone::createTimeZone() and pass it a time zone ID. You can use the createAvailableIDs() function to obtain a list of all the time zone IDs recognized by createTimeZone().
You can also use TimeZone::createDefault() to create a TimeZone. This function uses platform-specific APIs to produce a TimeZone for the time zone corresponding to the client's computer's physical location. For example, if you're in Japan (assuming your machine is set up correctly), TimeZone::createDefault() will return a TimeZone for Japanese Standard Time ("Asia/Tokyo").

static TimeZone* createTimeZone(const UnicodeString& ID)

Creates a TimeZone for the given ID

Returns:: the specified TimeZone, or the GMT zone if the given ID cannot be understood.
Parameters:: ID - the ID for a TimeZone, either an abbreviation such as "PST", a full name such as "America/Los_Angeles", or a custom ID such as "GMT-8:00".

static const UnicodeString** const createAvailableIDs(int32_t rawOffset, int32_t& numIDs)

Returns a list of time zone IDs, one for each time zone with a given GMT offset. The return value is a list because there may be several times zones with the same GMT offset that differ in the way they handle daylight savings time. For example, the state of Arizona doesn't observe Daylight Savings time. So if you ask for the time zone IDs corresponding to GMT-7:00, you'll get back two time zone IDs: "America/Denver," which corresponds to Mountain Standard Time in the winter and Mountain Daylight Time in the summer, and "America/Phoenix", which corresponds to Mountain Standard Time year-round, even in the summer.

The caller owns the list that is returned, but does not own the strings contained in that list. Delete the array, but DON'T delete the elements in the array.

Returns:: An array of UnicodeString pointers, where each UnicodeString is a time zone ID for a time zone with the given GMT offset. If there is no timezone that matches the GMT offset specified, NULL is returned.
Parameters:: rawOffset - An offset from GMT in milliseconds.
numIDs - Receives the number of items in the array that is returned.

static const UnicodeString** const createAvailableIDs(int32_t& numIDs)

Returns a list of all time zone IDs supported by the TimeZone class (i.e., all IDs that it's legal to pass to createTimeZone()). The caller owns the list that is returned, but does not own the strings contained in that list. Delete the array, but DON'T delete the elements in the array.

Returns:: An array of UnicodeString pointers, where each is a time zone ID supported by the TimeZone class.
Parameters:: numIDs - Receives the number of zone IDs returned.

static TimeZone* createDefault(void)

Creates a new copy of the default TimeZone for this host. Unless the default time zone has already been set using adoptDefault() or setDefault(), the default is determined by querying the system using methods in TPlatformUtilities. If the system routines fail, or if they specify a TimeZone or TimeZone offset which is not recognized, the TimeZone indicated by the ID kLastResortID is instantiated and made the default.

Returns:: A default TimeZone. Clients are responsible for deleting the time zone object returned.

static void adoptDefault(TimeZone* zone)

Sets the default time zone (i.e., what's returned by getDefault()) to be the specified time zone. If NULL is specified for the time zone, the default time zone is set to the default host time zone. This call adopts the TimeZone object passed in; the clent is no longer responsible for deleting it.

Parameters:: zone - A pointer to the new TimeZone object to use as the default.

static void setDefault(const TimeZone& zone)

Same as adoptDefault(), except that the TimeZone object passed in is NOT adopted; the caller remains responsible for deleting it.

Parameters:: zone - The given timezone.

virtual bool_t operator==(const TimeZone& that) const

Returns true if the two TimeZones are equal. (The TimeZone version only compares IDs, but subclasses are expected to also compare the fields they add.)

Returns:: True if the given TimeZone is equal to this TimeZone; false otherwise.
Parameters:: that - The TimeZone object to be compared with.

bool_t operator!=(const TimeZone& that) const

Returns true if the two TimeZones are NOT equal; that is, if operator==() returns false.

Returns:: True if the given TimeZone is not equal to this TimeZone; false otherwise.
Parameters:: that - The TimeZone object to be compared with.

virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day, uint8_t dayOfWeek, int32_t millis, UErrorCode& status) const

Returns the TimeZone's adjusted GMT offset (i.e., the number of milliseconds to add to GMT to get local time in this time zone, taking daylight savings time into account) as of a particular reference date. The reference date is used to determine whether daylight savings time is in effect and needs to be figured into the offset that is returned (in other words, what is the adjusted GMT offset in this time zone at this particular date and time?). For the time zones produced by createTimeZone(), the reference data is specified according to the Gregorian calendar, and the date and time fields are in GMT, NOT local time.

Returns:: The offset in milliseconds to add to GMT to get local time.
Parameters:: era - The reference date's era
year - The reference date's year
month - The reference date's month (0-based; 0 is January)
day - The reference date's day-in-month (1-based)
dayOfWeek - The reference date's day-of-week (1-based; 1 is Sunday)
millis - The reference date's milliseconds in day, UTT (NOT local time).

virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day, uint8_t dayOfWeek, int32_t milliseconds, int32_t monthLength, UErrorCode& status) const

Gets the time zone offset, for current date, modified in case of daylight savings. This is the offset to add *to* UTC to get local time.

Returns:: the offset to add *to* GMT to get local time.
Parameters:: era - the era of the given date.
year - the year in the given date.
month - the month in the given date. Month is 0-based. e.g., 0 for January.
day - the day-in-month of the given date.
dayOfWeek - the day-of-week of the given date.
milliseconds - the millis in day in standard local time.
monthLength - the length of the given month in days.

virtual void setRawOffset(int32_t offsetMillis)

Sets the TimeZone's raw GMT offset (i.e., the number of milliseconds to add to GMT to get local time, before taking daylight savings time into account).

Parameters:: offsetMillis - The new raw GMT offset for this time zone.

virtual int32_t getRawOffset(void) const

Returns the TimeZone's raw GMT offset (i.e., the number of milliseconds to add to GMT to get local time, before taking daylight savings time into account).

Returns:: The TimeZone's raw GMT offset.

UnicodeString& getID(UnicodeString& ID) const

Fills in "ID" with the TimeZone's ID.

Returns:: "ID"
Parameters:: ID - Receives this TimeZone's ID.

void setID(const UnicodeString& ID)

Sets the TimeZone's ID to the specified value. This doesn't affect any other fields (for example, if you say< blockquote>

.     TimeZone* foo = TimeZone::createTimeZone("America/New_York");
.     foo.setID("America/Los_Angeles");

the time zone's GMT offset and daylight-savings rules don't change to those for Los Angeles. They're still those for New York. Only the ID has changed.)

Parameters:: ID - The new timezone ID.

enum EDisplayType

Enum for use with getDisplayName

UnicodeString& getDisplayName(UnicodeString& result) const

Returns a name of this time zone suitable for presentation to the user in the default locale. This method returns the long name, not including daylight savings. If the display name is not available for the locale, then this method returns a string in the format GMT[+-]hh:mm.

Returns:: the human-readable name of this time zone in the default locale.

UnicodeString& getDisplayName(const Locale& locale, UnicodeString& result) const

Returns a name of this time zone suitable for presentation to the user in the specified locale. This method returns the long name, not including daylight savings. If the display name is not available for the locale, then this method returns a string in the format GMT[+-]hh:mm.

Returns:: the human-readable name of this time zone in the given locale or in the default locale if the given locale is not recognized.
Parameters:: locale - the locale in which to supply the display name.

UnicodeString& getDisplayName(bool_t daylight, EDisplayType style, UnicodeString& result) const

Returns a name of this time zone suitable for presentation to the user in the default locale. If the display name is not available for the locale, then this method returns a string in the format GMT[+-]hh:mm.

Returns:: the human-readable name of this time zone in the default locale.
Parameters:: daylight - if true, return the daylight savings name.
style - either LONG or SHORT

UnicodeString& getDisplayName(bool_t daylight, EDisplayType style, const Locale& locale, UnicodeString& result) const

Returns a name of this time zone suitable for presentation to the user in the specified locale. If the display name is not available for the locale, then this method returns a string in the format GMT[+-]hh:mm.

Returns:: the human-readable name of this time zone in the given locale or in the default locale if the given locale is not recognized.
Parameters:: daylight - if true, return the daylight savings name.
style - either LONG or SHORT
locale - the locale in which to supply the display name.

virtual bool_t useDaylightTime(void) const

Queries if this time zone uses daylight savings time

Returns:: true if this time zone uses daylight savings time, false, otherwise.

virtual bool_t inDaylightTime(UDate date, UErrorCode& status) const

Queries if the given date is in daylight savings time in this time zone

Returns:: true if the given date is in daylight savings time, false, otherwise.
Parameters:: date - the given UDate.

virtual bool_t hasSameRules(const TimeZone& other) const

Returns true if this zone has the same rule and offset as another zone. That is, if this zone differs only in ID, if at all.

Returns:: true if the given zone is the same as this one, with the possible exception of the ID
Parameters:: other - the TimeZone object to be compared with

virtual TimeZone* clone(void) const

Clones TimeZone objects polymorphically. Clients are responsible for deleting the TimeZone object cloned.

Returns:: A new copy of this TimeZone object.

static UClassID getStaticClassID(void)

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.

virtual UClassID getDynamicClassID(void) const

Returns a unique class ID POLYMORPHICALLY. Pure virtual method. 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.

Concrete subclasses of TimeZone must implement getDynamicClassID() and also a static method and data member:

.     static UClassID getStaticClassID() { return (UClassID)&fgClassID; }
.     static char fgClassID;

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.

TimeZone()

Default constructor. ID is initialized to the empty string.

TimeZone(const TimeZone& source)

Copy constructor

TimeZone& operator=(const TimeZone& right)

Default assignment operator

static void deleteTimeZone(void*)

Delete function for fgHashtable

Direct child classes:: SimpleTimeZone

alphabetic index hierarchy of classes

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(c)opyright by Malte Zöckler, Roland Wunderling
contact: doc++@zib.de

class U_I18N_API TimeZone

Inheritance:

Public Classes

Public Methods

Protected Methods

Documentation