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 US Pacific
* Time zone is "America/Los_Angeles". So, you can get a Pacific Time TimeZone object
* with:
* \htmlonly
\endhtmlonly
*
* TimeZone *tz = TimeZone::createTimeZone("America/Los_Angeles");
*
* \htmlonly\endhtmlonly
* You can use the createEnumeration method to iterate through
* all the supported time zone IDs, or the getCanonicalID method to check
* if a time zone ID is supported or not. 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:
*
* \htmlonly\endhtmlonly *\endhtmlonly * * For example, you might specify GMT+14:00 as a custom * time zone ID. The* GMT[+|-]hh[[:]mm] ** \htmlonly
TimeZone that is returned
* when you specify a custom time zone ID uses the specified
* offset from GMT(=UTC) and does not observe daylight saving
* time. For example, you might specify GMT+14:00 as a custom
* time zone ID to create a TimeZone representing 14 hours ahead
* of GMT (with no daylight saving time). In addition,
* getCanonicalID can also be used to
* normalize a custom time zone ID.
*
* 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:
* * 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, US Pacific * 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/Los_Angeles"). * 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 createEnumeration() 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").
*/
class U_I18N_API TimeZone : public UObject {
public:
/**
* @stable ICU 2.0
*/
virtual ~TimeZone();
/**
* Returns the "unknown" time zone.
* It behaves like the GMT/UTC time zone but has the
* UCAL_UNKNOWN_ZONE_ID = "Etc/Unknown".
* createTimeZone() returns a mutable clone of this time zone if the input ID is not recognized.
*
* @return the "unknown" time zone.
* @see UCAL_UNKNOWN_ZONE_ID
* @see createTimeZone
* @see getGMT
* @stable ICU 49
*/
static const TimeZone& U_EXPORT2 getUnknown();
/**
* The GMT (=UTC) time zone has a raw offset of zero and does not use daylight
* savings time. This is a commonly used time zone.
*
*
Note: For backward compatibility reason, the ID used by the time
* zone returned by this method is "GMT", although the ICU's canonical
* ID for the GMT time zone is "Etc/GMT".
*
* @return the GMT/UTC time zone.
* @see getUnknown
* @stable ICU 2.0
*/
static const TimeZone* U_EXPORT2 getGMT(void);
/**
* Creates a TimeZone for the given ID.
* @param ID the ID for a TimeZone, such as "America/Los_Angeles",
* or a custom ID such as "GMT-8:00".
* @return the specified TimeZone, or a mutable clone of getUnknown()
* if the given ID cannot be understood or if the given ID is "Etc/Unknown".
* The return result is guaranteed to be non-NULL.
* If you require that the specific zone asked for be returned,
* compare the result with getUnknown() or check the ID of the return result.
* @stable ICU 2.0
*/
static TimeZone* U_EXPORT2 createTimeZone(const UnicodeString& ID);
/**
* Returns an enumeration over system time zone IDs with the given
* filter conditions.
* @param zoneType The system time zone type.
* @param region The ISO 3166 two-letter country code or UN M.49
* three-digit area code. When NULL, no filtering
* done by region.
* @param rawOffset An offset from GMT in milliseconds, ignoring
* the effect of daylight savings time, if any.
* When NULL, no filtering done by zone offset.
* @param ec Output param to filled in with a success or
* an error.
* @return an enumeration object, owned by the caller.
* @stable ICU 4.8
*/
static StringEnumeration* U_EXPORT2 createTimeZoneIDEnumeration(
USystemTimeZoneType zoneType,
const char* region,
const int32_t* rawOffset,
UErrorCode& ec);
#ifndef U_HIDE_DEPRECATED_API
/**
* Returns an enumeration over all recognized time zone IDs. (i.e.,
* all strings that createTimeZone() accepts)
*
* @return an enumeration object, owned by the caller.
* @deprecated ICU 70 Use createEnumeration(UErrorCode&) instead.
*/
static StringEnumeration* U_EXPORT2 createEnumeration();
#endif // U_HIDE_DEPRECATED_API
/**
* Returns an enumeration over all recognized time zone IDs. (i.e.,
* all strings that createTimeZone() accepts)
*
* @param status Receives the status.
* @return an enumeration object, owned by the caller.
* @stable ICU 70
*/
static StringEnumeration* U_EXPORT2 createEnumeration(UErrorCode& status);
#ifndef U_HIDE_DEPRECATED_API
/**
* Returns an enumeration over time zone IDs with a given raw
* offset from GMT. 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. If you ask for the time zone
* IDs corresponding to GMT-7:00, you'll get back an enumeration
* over 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.
*
* @param rawOffset an offset from GMT in milliseconds, ignoring
* the effect of daylight savings time, if any
* @return an enumeration object, owned by the caller
* @deprecated ICU 70 Use createEnumerationForRawOffset(int32_t,UErrorCode&) instead.
*/
static StringEnumeration* U_EXPORT2 createEnumeration(int32_t rawOffset);
#endif // U_HIDE_DEPRECATED_API
/**
* Returns an enumeration over time zone IDs with a given raw
* offset from GMT. 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. If you ask for the time zone
* IDs corresponding to GMT-7:00, you'll get back an enumeration
* over 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.
*
* @param rawOffset an offset from GMT in milliseconds, ignoring
* the effect of daylight savings time, if any
* @param status Receives the status.
* @return an enumeration object, owned by the caller
* @stable ICU 70
*/
static StringEnumeration* U_EXPORT2 createEnumerationForRawOffset(int32_t rawOffset, UErrorCode& status);
#ifndef U_HIDE_DEPRECATED_API
/**
* Returns an enumeration over time zone IDs associated with the
* given region. Some zones are affiliated with no region
* (e.g., "UTC"); these may also be retrieved, as a group.
*
* @param region The ISO 3166 two-letter country code, or NULL to
* retrieve zones not affiliated with any region.
* @return an enumeration object, owned by the caller
* @deprecated ICU 70 Use createEnumerationForRegion(const char*,UErrorCode&) instead.
*/
static StringEnumeration* U_EXPORT2 createEnumeration(const char* region);
#endif // U_HIDE_DEPRECATED_API
/**
* Returns an enumeration over time zone IDs associated with the
* given region. Some zones are affiliated with no region
* (e.g., "UTC"); these may also be retrieved, as a group.
*
* @param region The ISO 3166 two-letter country code, or NULL to
* retrieve zones not affiliated with any region.
* @param status Receives the status.
* @return an enumeration object, owned by the caller
* @stable ICU 70
*/
static StringEnumeration* U_EXPORT2 createEnumerationForRegion(const char* region, UErrorCode& status);
/**
* 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. * @param id a system time zone ID * @return the number of zones in the equivalency group containing * 'id', or zero if 'id' is not a valid system ID * @see #getEquivalentID * @stable ICU 2.0 */ static int32_t U_EXPORT2 countEquivalentIDs(const UnicodeString& id); /** * 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 countEquivalentIDs(id). For
* some value of 'index', the returned value will be equal to the
* given id. If the given id is not a valid system time zone, or
* if 'index' is out of range, then returns an empty string.
* @param id a system time zone ID
* @param index a value from 0 to n-1, where n is the value
* returned by countEquivalentIDs(id)
* @return the ID of the index-th zone in the equivalency group
* containing 'id', or an empty string if 'id' is not a valid
* system ID or 'index' is out of range
* @see #countEquivalentIDs
* @stable ICU 2.0
*/
static const UnicodeString U_EXPORT2 getEquivalentID(const UnicodeString& id,
int32_t index);
/**
* Creates an instance of TimeZone detected from the current host
* system configuration. If the host system detection routines fail,
* or if they specify a TimeZone or TimeZone offset which is not
* recognized, then the special TimeZone "Etc/Unknown" is returned.
*
* Note that ICU4C does not change the default time zone unless
* `TimeZone::adoptDefault(TimeZone*)` or
* `TimeZone::setDefault(const TimeZone&)` is explicitly called by a
* user. This method does not update the current ICU's default,
* and may return a different TimeZone from the one returned by
* `TimeZone::createDefault()`.
*
*
This function is not thread safe.
* * @return A new instance of TimeZone detected from the current host system * configuration. * @see adoptDefault * @see setDefault * @see createDefault * @see getUnknown * @stable ICU 55 */ static TimeZone* U_EXPORT2 detectHostTimeZone(); /** * 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 host system configuration. If the host system detection * routines fail, or if they specify a TimeZone or TimeZone offset which is not * recognized, then the special TimeZone "Etc/Unknown" is instantiated and made the * default. * * @return A default TimeZone. Clients are responsible for deleting the time zone * object returned. * @see getUnknown * @stable ICU 2.0 */ static TimeZone* U_EXPORT2 createDefault(void); #ifndef U_HIDE_INTERNAL_API /** * If the locale contains the timezone keyword, creates a copy of that TimeZone. * Otherwise, create the default timezone. * * @param locale a locale which may contains 'timezone' keyword/value. * @return A TimeZone. Clients are responsible for deleting the time zone * object returned. * @internal */ static TimeZone* U_EXPORT2 forLocaleOrDefault(const Locale& locale); #endif /* U_HIDE_INTERNAL_API */ /** * Sets the default time zone (i.e., what's returned by createDefault()) 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 client is no longer responsible for deleting it. * * @param zone A pointer to the new TimeZone object to use as the default. * @stable ICU 2.0 */ static void U_EXPORT2 adoptDefault(TimeZone* zone); #ifndef U_HIDE_SYSTEM_API /** * Same as adoptDefault(), except that the TimeZone object passed in is NOT adopted; * the caller remains responsible for deleting it. * * @param zone The given timezone. * @system * @stable ICU 2.0 */ static void U_EXPORT2 setDefault(const TimeZone& zone); #endif /* U_HIDE_SYSTEM_API */ /** * Returns the timezone data version currently used by ICU. * @param status Output param to filled in with a success or an error. * @return the version string, such as "2007f" * @stable ICU 3.8 */ static const char* U_EXPORT2 getTZDataVersion(UErrorCode& status); /** * Returns the canonical system timezone ID or the normalized * custom time zone ID for the given time zone ID. * @param id The input time zone ID to be canonicalized. * @param canonicalID Receives the canonical system time zone ID * or the custom time zone ID in normalized format. * @param status Receives the status. When the given time zone ID * is neither a known system time zone ID nor a * valid custom time zone ID, U_ILLEGAL_ARGUMENT_ERROR * is set. * @return A reference to the result. * @stable ICU 4.0 */ static UnicodeString& U_EXPORT2 getCanonicalID(const UnicodeString& id, UnicodeString& canonicalID, UErrorCode& status); /** * Returns the canonical system time zone ID or the normalized * custom time zone ID for the given time zone ID. * @param id The input time zone ID to be canonicalized. * @param canonicalID Receives the canonical system time zone ID * or the custom time zone ID in normalized format. * @param isSystemID Receives if the given ID is a known system * time zone ID. * @param status Receives the status. When the given time zone ID * is neither a known system time zone ID nor a * valid custom time zone ID, U_ILLEGAL_ARGUMENT_ERROR * is set. * @return A reference to the result. * @stable ICU 4.0 */ static UnicodeString& U_EXPORT2 getCanonicalID(const UnicodeString& id, UnicodeString& canonicalID, UBool& isSystemID, UErrorCode& status); /** * Converts a system time zone ID to an equivalent Windows time zone ID. For example, * Windows time zone ID "Pacific Standard Time" is returned for input "America/Los_Angeles". * *There are system time zones that cannot be mapped to Windows zones. When the input * system time zone ID is unknown or unmappable to a Windows time zone, then the result will be * empty, but the operation itself remains successful (no error status set on return). * *
This implementation utilizes
* Zone-Tzid mapping data. The mapping data is updated time to time. To get the latest changes,
* please read the ICU user guide section
* Updating the Time Zone Data.
*
* @param id A system time zone ID.
* @param winid Receives a Windows time zone ID. When the input system time zone ID is unknown
* or unmappable to a Windows time zone ID, then an empty string is set on return.
* @param status Receives the status.
* @return A reference to the result (winid).
* @see getIDForWindowsID
*
* @stable ICU 52
*/
static UnicodeString& U_EXPORT2 getWindowsID(const UnicodeString& id,
UnicodeString& winid, UErrorCode& status);
/**
* Converts a Windows time zone ID to an equivalent system time zone ID
* for a region. For example, system time zone ID "America/Los_Angeles" is returned
* for input Windows ID "Pacific Standard Time" and region "US" (or null),
* "America/Vancouver" is returned for the same Windows ID "Pacific Standard Time" and
* region "CA".
*
*
Not all Windows time zones can be mapped to system time zones. When the input * Windows time zone ID is unknown or unmappable to a system time zone, then the result * will be empty, but the operation itself remains successful (no error status set on return). * *
This implementation utilizes
* Zone-Tzid mapping data. The mapping data is updated time to time. To get the latest changes,
* please read the ICU user guide section
* Updating the Time Zone Data.
*
* @param winid A Windows time zone ID.
* @param region A null-terminated region code, or NULL if no regional preference.
* @param id Receives a system time zone ID. When the input Windows time zone ID is unknown
* or unmappable to a system time zone ID, then an empty string is set on return.
* @param status Receives the status.
* @return A reference to the result (id).
* @see getWindowsID
*
* @stable ICU 52
*/
static UnicodeString& U_EXPORT2 getIDForWindowsID(const UnicodeString& winid, const char* region,
UnicodeString& id, UErrorCode& status);
/**
* 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.)
*
* @param that The TimeZone object to be compared with.
* @return true if the given TimeZone is equal to this TimeZone; false
* otherwise.
* @stable ICU 2.0
*/
virtual bool operator==(const TimeZone& that) const;
/**
* Returns true if the two TimeZones are NOT equal; that is, if operator==() returns
* false.
*
* @param that The TimeZone object to be compared with.
* @return true if the given TimeZone is not equal to this TimeZone; false
* otherwise.
* @stable ICU 2.0
*/
bool operator!=(const TimeZone& that) const {return !operator==(that);}
/**
* 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 local standard time.
*
*
Note: Don't call this method. Instead, call the getOffset(UDate...) overload, * which returns both the raw and the DST offset for a given time. This method * is retained only for backward compatibility. * * @param era The reference date's era * @param year The reference date's year * @param month The reference date's month (0-based; 0 is January) * @param day The reference date's day-in-month (1-based) * @param dayOfWeek The reference date's day-of-week (1-based; 1 is Sunday) * @param millis The reference date's milliseconds in day, local standard time * @param status Output param to filled in with a success or an error. * @return The offset in milliseconds to add to GMT to get local time. * @stable ICU 2.0 */ 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; /** * 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. * *
Note: Don't call this method. Instead, call the getOffset(UDate...) overload, * which returns both the raw and the DST offset for a given time. This method * is retained only for backward compatibility. * * @param era the era of the given date. * @param year the year in the given date. * @param month the month in the given date. * Month is 0-based. e.g., 0 for January. * @param day the day-in-month of the given date. * @param dayOfWeek the day-of-week of the given date. * @param milliseconds the millis in day in standard local time. * @param monthLength the length of the given month in days. * @param status Output param to filled in with a success or an error. * @return the offset to add *to* GMT to get local time. * @stable ICU 2.0 */ 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; /** * Returns the time zone raw and GMT offset for the given moment * in time. Upon return, local-millis = GMT-millis + rawOffset + * dstOffset. All computations are performed in the proleptic * Gregorian calendar. The default implementation in the TimeZone * class delegates to the 8-argument getOffset(). * * @param date moment in time for which to return offsets, in * units of milliseconds from January 1, 1970 0:00 GMT, either GMT * time or local wall time, depending on `local'. * @param local if true, `date' is local wall time; otherwise it * is in GMT time. * @param rawOffset output parameter to receive the raw offset, that * is, the offset not including DST adjustments * @param dstOffset output parameter to receive the DST offset, * that is, the offset to be added to `rawOffset' to obtain the * total offset between local and GMT time. If DST is not in * effect, this value is zero; otherwise it is a positive value, * typically one hour. * @param ec input-output error code * * @stable ICU 2.8 */ virtual void getOffset(UDate date, UBool local, int32_t& rawOffset, int32_t& dstOffset, UErrorCode& ec) const; /** * 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). * * @param offsetMillis The new raw GMT offset for this time zone. * @stable ICU 2.0 */ virtual void setRawOffset(int32_t offsetMillis) = 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). * * @return The TimeZone's raw GMT offset. * @stable ICU 2.0 */ virtual int32_t getRawOffset(void) const = 0; /** * Fills in "ID" with the TimeZone's ID. * * @param ID Receives this TimeZone's ID. * @return A reference to 'ID' * @stable ICU 2.0 */ UnicodeString& getID(UnicodeString& ID) const; /** * 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");
* \htmlonly\endhtmlonly
* 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.)
*
* @param ID The new time zone ID.
* @stable ICU 2.0
*/
void setID(const UnicodeString& ID);
/**
* Enum for use with getDisplayName
* @stable ICU 2.4
*/
enum EDisplayType {
/**
* Selector for short display name
* @stable ICU 2.4
*/
SHORT = 1,
/**
* Selector for long display name
* @stable ICU 2.4
*/
LONG,
/**
* Selector for short generic display name
* @stable ICU 4.4
*/
SHORT_GENERIC,
/**
* Selector for long generic display name
* @stable ICU 4.4
*/
LONG_GENERIC,
/**
* Selector for short display name derived
* from time zone offset
* @stable ICU 4.4
*/
SHORT_GMT,
/**
* Selector for long display name derived
* from time zone offset
* @stable ICU 4.4
*/
LONG_GMT,
/**
* Selector for short display name derived
* from the time zone's fallback name
* @stable ICU 4.4
*/
SHORT_COMMONLY_USED,
/**
* Selector for long display name derived
* from the time zone's fallback name
* @stable ICU 4.4
*/
GENERIC_LOCATION
};
/**
* 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 localized GMT offset format
* such as GMT[+-]HH:mm.
* @param result the human-readable name of this time zone in the default locale.
* @return A reference to 'result'.
* @stable ICU 2.0
*/
UnicodeString& getDisplayName(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 localized GMT offset format
* such as GMT[+-]HH:mm.
* @param locale the locale in which to supply the display name.
* @param result the human-readable name of this time zone in the given locale
* or in the default locale if the given locale is not recognized.
* @return A reference to 'result'.
* @stable ICU 2.0
*/
UnicodeString& getDisplayName(const Locale& locale, 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 localized GMT offset format
* such as GMT[+-]HH:mm.
* @param inDaylight if true, return the daylight savings name.
* @param style
* @param result the human-readable name of this time zone in the default locale.
* @return A reference to 'result'.
* @stable ICU 2.0
*/
UnicodeString& getDisplayName(UBool inDaylight, EDisplayType style, 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 localized GMT offset format
* such as GMT[+-]HH:mm.
* @param inDaylight if true, return the daylight savings name.
* @param style
* @param locale the locale in which to supply the display name.
* @param result the human-readable name of this time zone in the given locale
* or in the default locale if the given locale is not recognized.
* @return A reference to 'result'.
* @stable ICU 2.0
*/
UnicodeString& getDisplayName(UBool inDaylight, EDisplayType style, const Locale& locale, UnicodeString& result) const;
/**
* Queries if this time zone uses daylight savings time.
* @return true if this time zone uses daylight savings time,
* false, otherwise.
* Note:The default implementation of
* ICU TimeZone uses the tz database, which supports historic
* rule changes, for system time zones. With the implementation,
* there are time zones that used daylight savings time in the
* past, but no longer used currently. For example, Asia/Tokyo has
* never used daylight savings time since 1951. Most clients would
* expect that this method to return false for such case.
* The default implementation of this method returns true
* when the time zone uses daylight savings time in the current
* (Gregorian) calendar year.
*
In Java 7, observesDaylightTime() was added in
* addition to useDaylightTime(). In Java, useDaylightTime()
* only checks if daylight saving time is observed by the last known
* rule. This specification might not be what most users would expect
* if daylight saving time is currently observed, but not scheduled
* in future. In this case, Java's userDaylightTime() returns
* false. To resolve the issue, Java 7 added observesDaylightTime(),
* which takes the current rule into account. The method observesDaylightTime()
* was added in ICU4J for supporting API signature compatibility with JDK.
* In general, ICU4C also provides JDK compatible methods, but the current
* implementation userDaylightTime() serves the purpose
* (takes the current rule into account), observesDaylightTime()
* is not added in ICU4C. In addition to useDaylightTime(), ICU4C
* BasicTimeZone class (Note that TimeZone::createTimeZone(const UnicodeString &ID)
* always returns a BasicTimeZone) provides a series of methods allowing
* historic and future time zone rule iteration, so you can check if daylight saving
* time is observed or not within a given period.
*
* @stable ICU 2.0
*/
virtual UBool useDaylightTime(void) const = 0;
#ifndef U_FORCE_HIDE_DEPRECATED_API
/**
* Queries if the given date is in daylight savings time in
* this time zone.
* This method is wasteful since it creates a new GregorianCalendar and
* deletes it each time it is called. This is a deprecated method
* and provided only for Java compatibility.
*
* @param date the given UDate.
* @param status Output param filled in with success/error code.
* @return true if the given date is in daylight savings time,
* false, otherwise.
* @deprecated ICU 2.4. Use Calendar::inDaylightTime() instead.
*/
virtual UBool inDaylightTime(UDate date, UErrorCode& status) const = 0;
#endif // U_FORCE_HIDE_DEPRECATED_API
/**
* 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.
* @param other the TimeZone object to be compared with
* @return true if the given zone is the same as this one,
* with the possible exception of the ID
* @stable ICU 2.0
*/
virtual UBool hasSameRules(const TimeZone& other) const;
/**
* Clones TimeZone objects polymorphically. Clients are responsible for deleting
* the TimeZone object cloned.
*
* @return A new copy of this TimeZone object.
* @stable ICU 2.0
*/
virtual TimeZone* clone() const = 0;
/**
* Return the class ID for this class. This is useful only for
* comparing to a return value from getDynamicClassID().
* @return The class ID for all objects of this class.
* @stable ICU 2.0
*/
static UClassID U_EXPORT2 getStaticClassID(void);
/**
* Returns a unique class ID POLYMORPHICALLY. 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 use the UOBJECT_DEFINE_RTTI_IMPLEMENTATION * macro from uobject.h in their implementation to provide correct RTTI information. * @return 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 ICU 2.0 */ virtual UClassID getDynamicClassID(void) const override = 0; /** * Returns the amount of time to be added to local standard time * to get local wall clock time. *
* The default implementation always returns 3600000 milliseconds * (i.e., one hour) if this time zone observes Daylight Saving * Time. Otherwise, 0 (zero) is returned. *
* If an underlying TimeZone implementation subclass supports * historical Daylight Saving Time changes, this method returns * the known latest daylight saving value. * * @return the amount of saving time in milliseconds * @stable ICU 3.6 */ virtual int32_t getDSTSavings() const; /** * Gets the region code associated with the given * system time zone ID. The region code is either ISO 3166 * 2-letter country code or UN M.49 3-digit area code. * When the time zone is not associated with a specific location, * for example - "Etc/UTC", "EST5EDT", then this method returns * "001" (UN M.49 area code for World). * * @param id The system time zone ID. * @param region Output buffer for receiving the region code. * @param capacity The size of the output buffer. * @param status Receives the status. When the given time zone ID * is not a known system time zone ID, * U_ILLEGAL_ARGUMENT_ERROR is set. * @return The length of the output region code. * @stable ICU 4.8 */ static int32_t U_EXPORT2 getRegion(const UnicodeString& id, char *region, int32_t capacity, UErrorCode& status); protected: /** * Default constructor. ID is initialized to the empty string. * @stable ICU 2.0 */ TimeZone(); /** * Construct a TimeZone with a given ID. * @param id a system time zone ID * @stable ICU 2.0 */ TimeZone(const UnicodeString &id); /** * Copy constructor. * @param source the object to be copied. * @stable ICU 2.0 */ TimeZone(const TimeZone& source); /** * Default assignment operator. * @param right the object to be copied. * @stable ICU 2.0 */ TimeZone& operator=(const TimeZone& right); #ifndef U_HIDE_INTERNAL_API /** * Utility function. For internally loading rule data. * @param top Top resource bundle for tz data * @param ruleid ID of rule to load * @param oldbundle Old bundle to reuse or NULL * @param status Status parameter * @return either a new bundle or *oldbundle * @internal */ static UResourceBundle* loadRule(const UResourceBundle* top, const UnicodeString& ruleid, UResourceBundle* oldbundle, UErrorCode&status); #endif /* U_HIDE_INTERNAL_API */ private: friend class ZoneMeta; static TimeZone* createCustomTimeZone(const UnicodeString&); // Creates a time zone based on the string. /** * Finds the given ID in the Olson tzdata. If the given ID is found in the tzdata, * returns the pointer to the ID resource. This method is exposed through ZoneMeta class * for ICU internal implementation and useful for building hashtable using a time zone * ID as a key. * @param id zone id string * @return the pointer of the ID resource, or NULL. */ static const char16_t* findID(const UnicodeString& id); /** * Resolve a link in Olson tzdata. When the given id is known and it's not a link, * the id itself is returned. When the given id is known and it is a link, then * dereferenced zone id is returned. When the given id is unknown, then it returns * NULL. * @param id zone id string * @return the dereferenced zone or NULL */ static const char16_t* dereferOlsonLink(const UnicodeString& id); /** * Returns the region code associated with the given zone, * or NULL if the zone is not known. * @param id zone id string * @return the region associated with the given zone */ static const char16_t* getRegion(const UnicodeString& id); public: #ifndef U_HIDE_INTERNAL_API /** * Returns the region code associated with the given zone, * or NULL if the zone is not known. * @param id zone id string * @param status Status parameter * @return the region associated with the given zone * @internal */ static const char16_t* getRegion(const UnicodeString& id, UErrorCode& status); #endif /* U_HIDE_INTERNAL_API */ private: /** * Parses the given custom time zone identifier * @param id id A string of the form GMT[+-]hh:mm, GMT[+-]hhmm, or * GMT[+-]hh. * @param sign Receives parsed sign, 1 for positive, -1 for negative. * @param hour Receives parsed hour field * @param minute Receives parsed minute field * @param second Receives parsed second field * @return Returns true when the given custom id is valid. */ static UBool parseCustomID(const UnicodeString& id, int32_t& sign, int32_t& hour, int32_t& minute, int32_t& second); /** * Parse a custom time zone identifier and return the normalized * custom time zone identifier for the given custom id string. * @param id a string of the form GMT[+-]hh:mm, GMT[+-]hhmm, or * GMT[+-]hh. * @param normalized Receives the normalized custom ID * @param status Receives the status. When the input ID string is invalid, * U_ILLEGAL_ARGUMENT_ERROR is set. * @return The normalized custom id string. */ static UnicodeString& getCustomID(const UnicodeString& id, UnicodeString& normalized, UErrorCode& status); /** * Returns the normalized custom time zone ID for the given offset fields. * @param hour offset hours * @param min offset minutes * @param sec offset seconds * @param negative sign of the offset, true for negative offset. * @param id Receives the format result (normalized custom ID) * @return The reference to id */ static UnicodeString& formatCustomID(int32_t hour, int32_t min, int32_t sec, UBool negative, UnicodeString& id); UnicodeString fID; // this time zone's ID friend class TZEnumeration; }; // ------------------------------------- inline UnicodeString& TimeZone::getID(UnicodeString& ID) const { ID = fID; return ID; } // ------------------------------------- inline void TimeZone::setID(const UnicodeString& ID) { fID = ID; } U_NAMESPACE_END #endif /* #if !UCONFIG_NO_FORMATTING */ #endif /* U_SHOW_CPLUSPLUS_API */ #endif //_TIMEZONE //eof