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 getAvailableIDs method to iterate through
+ * all the supported time zone IDs, or 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);
+
+ /**
+ * Returns an enumeration over all recognized time zone IDs. (i.e.,
+ * all strings that createTimeZone() accepts)
+ *
+ * @return an enumeration object, owned by the caller.
+ * @stable ICU 2.4
+ */
+ static StringEnumeration* U_EXPORT2 createEnumeration();
+
+ /**
+ * 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
+ * @stable ICU 2.4
+ */
+ static StringEnumeration* U_EXPORT2 createEnumeration(int32_t rawOffset);
+
+ /**
+ * Returns an enumeration over 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.
+ *
+ * @param country The ISO 3166 two-letter country code, or NULL to
+ * retrieve zones not affiliated with any country.
+ * @return an enumeration object, owned by the caller
+ * @stable ICU 2.4
+ */
+ static StringEnumeration* U_EXPORT2 createEnumeration(const char* country);
+
+ /**
+ * 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 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.
+ *
+ * @return A default TimeZone. Clients are responsible for deleting the time zone
+ * object returned.
+ * @stable ICU 2.0
+ */
+ static TimeZone* U_EXPORT2 createDefault(void);
+
+ /**
+ * 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.
+ *
+ *
This function is not thread safe. It is an error for multiple threads + * to concurrently attempt to set the default time zone, or for any thread + * to attempt to reference the default zone while another thread is setting 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. + * + *
See the thread safety note under adoptDefault(). + * + * @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 Recevies 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 Recevies 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); + +#ifndef U_HIDE_DRAFT_API + /** + * 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
+ *
+ * @draft 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
+ *
+ * @draft ICU 52
+ */
+ static UnicodeString& U_EXPORT2 getIDForWindowsID(const UnicodeString& winid, const char* region,
+ UnicodeString& id, UErrorCode& status);
+
+#endif /* U_HIDE_DRAFT_API */
+
+ /**
+ * 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 UBool 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
+ */
+ UBool 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 format
+ * 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 format
+ * 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 format
+ * GMT[+-]hh:mm.
+ * @param daylight 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 daylight, 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 format
+ * GMT[+-]hh:mm.
+ * @param daylight 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 refence to 'result'.
+ * @stable ICU 2.0
+ */
+ UnicodeString& getDisplayName(UBool daylight, 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;
+
+ /**
+ * 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;
+
+ /**
+ * 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(void) 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 = 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 UChar* 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 UChar* 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 UChar* 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 UChar* 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 Receves 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 custome 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 Receves 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 //_TIMEZONE +//eof