TimeZone
represents a time zone offset, and also figures out daylight savings.
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#include <timezone.h>
Inheritance diagram for TimeZone:
Public Types | |
enum | EDisplayType { SHORT = 1, LONG } |
Enum for use with getDisplayName. | |
Public Member Functions | |
virtual | ~TimeZone () |
virtual UBool | operator== (const TimeZone &that) const |
Returns true if the two TimeZones are equal. | |
UBool | 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 =0 |
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. | |
virtual int32_t | getOffset (uint8_t era, int32_t year, int32_t month, int32_t day, uint8_t dayOfWeek, int32_t millis) const =0 |
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 =0 |
Gets the time zone offset, for current date, modified in case of daylight savings. | |
virtual void | setRawOffset (int32_t offsetMillis)=0 |
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). | |
virtual int32_t | getRawOffset (void) const =0 |
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). | |
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 (UBool 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 (UBool 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 UBool | useDaylightTime (void) const =0 |
Queries if this time zone uses daylight savings time. | |
virtual UBool | inDaylightTime (UDate date, UErrorCode &status) const =0 |
Queries if the given date is in daylight savings time in this time zone. | |
virtual UBool | hasSameRules (const TimeZone &other) const |
Returns true if this zone has the same rule and offset as another zone. | |
virtual TimeZone * | clone (void) const =0 |
Clones TimeZone objects polymorphically. | |
virtual UClassID | getDynamicClassID (void) const =0 |
Returns a unique class ID POLYMORPHICALLY. | |
Static Public Member Functions | |
const TimeZone * | getGMT (void) |
The GMT time zone has a raw offset of zero and does not use daylight savings time. | |
TimeZone * | createTimeZone (const UnicodeString &ID) |
Creates a TimeZone for the given ID. | |
const UnicodeString ** | createAvailableIDs (int32_t rawOffset, int32_t &numIDs) |
Returns a list of time zone IDs, one for each time zone with a given GMT offset. | |
const UnicodeString ** | createAvailableIDs (const char *country, int32_t &numIDs) |
Returns a list of time zone IDs associated with the given country. | |
const UnicodeString ** | 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()). | |
int32_t | countEquivalentIDs (const UnicodeString &id) |
Returns the number of IDs in the equivalency group that includes the given ID. | |
const UnicodeString | getEquivalentID (const UnicodeString &id, int32_t index) |
Returns an ID in the equivalency group that includes the given ID. | |
TimeZone * | createDefault (void) |
Creates a new copy of the default TimeZone for this host. | |
void | adoptDefault (TimeZone *zone) |
Sets the default time zone (i.e., what's returned by getDefault()) to be the specified time zone. | |
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. | |
UClassID | getStaticClassID (void) |
Return the class ID for this class. | |
Protected Member Functions | |
TimeZone () | |
Default constructor. | |
TimeZone (const UnicodeString &id) | |
Construct a timezone with a given ID. | |
TimeZone (const TimeZone &source) | |
Copy constructor. | |
TimeZone & | operator= (const TimeZone &right) |
Default assignment operator. |
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 usegetAvailableIDs
method to iterate through all the supported time zone IDs. You can then choose a supported ID to get aTimeZone
. 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:
(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").
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Default constructor. ID is initialized to the empty string. |
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Construct a timezone with a given ID.
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Copy constructor.
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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.
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Clones TimeZone objects polymorphically. Clients are responsible for deleting the TimeZone object cloned.
Implemented in SimpleTimeZone. |
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Returns the number of IDs in the equivalency group that includes the given ID. An equivalency group contains zones that have the same GMT offset and rules. The returned count includes the given ID; it is always >= 1. The given ID must be a system time zone. If it is not, returns zero.
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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.
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Returns a list of time zone IDs associated with the given country. Some zones are affiliated with no country (e.g., "UTC"); these may also be retrieved, as a group. 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.
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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.
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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.
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Creates a
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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
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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
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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
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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
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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:
Implemented in SimpleTimeZone. |
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Returns an ID in the equivalency group that includes the given ID. An equivalency group contains zones that have the same GMT offset and rules.
The given index must be in the range 0..n-1, where n is the value returned by
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The GMT time zone has a raw offset of zero and does not use daylight savings time. This is a commonly used time zone. |
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Fills in "ID" with the TimeZone's ID.
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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.
Implemented in SimpleTimeZone. |
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Implemented in SimpleTimeZone. |
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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.
Implemented in SimpleTimeZone. |
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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).
Implemented in SimpleTimeZone. |
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Return the class ID for this class. This is useful only for comparing to a return value from getDynamicClassID(). For example:
Reimplemented in SimpleTimeZone. |
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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.
Reimplemented in SimpleTimeZone. |
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Queries if the given date is in daylight savings time in this time zone.
Implemented in SimpleTimeZone. |
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Returns true if the two TimeZones are NOT equal; that is, if operator==() returns false.
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Default assignment operator.
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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.)
Reimplemented in SimpleTimeZone. |
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Same as adoptDefault(), except that the TimeZone object passed in is NOT adopted; the caller remains responsible for deleting it.
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Sets the TimeZone's ID to the specified value. This doesn't affect any other fields (for example, if you say< blockquote>
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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).
Implemented in SimpleTimeZone. |
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Queries if this time zone uses daylight savings time.
Implemented in SimpleTimeZone. |