1// © 2016 and later: Unicode, Inc. and others.
2// License & terms of use: http://www.unicode.org/copyright.html
3/*************************************************************************
4* Copyright (c) 1997-2016, International Business Machines Corporation
5* and others. All Rights Reserved.
6**************************************************************************
7*
8* File TIMEZONE.H
9*
10* Modification History:
11*
12* Date Name Description
13* 04/21/97 aliu Overhauled header.
14* 07/09/97 helena Changed createInstance to createDefault.
15* 08/06/97 aliu Removed dependency on internal header for Hashtable.
16* 08/10/98 stephen Changed getDisplayName() API conventions to match
17* 08/19/98 stephen Changed createTimeZone() to never return 0
18* 09/02/98 stephen Sync to JDK 1.2 8/31
19* - Added getOffset(... monthlen ...)
20* - Added hasSameRules()
21* 09/15/98 stephen Added getStaticClassID
22* 12/03/99 aliu Moved data out of static table into icudata.dll.
23* Hashtable replaced by new static data structures.
24* 12/14/99 aliu Made GMT public.
25* 08/15/01 grhoten Made GMT private and added the getGMT() function
26**************************************************************************
27*/
28
29#ifndef TIMEZONE_H
30#define TIMEZONE_H
31
32#include "unicode/utypes.h"
33
34#if U_SHOW_CPLUSPLUS_API
35
36/**
37 * \file
38 * \brief C++ API: TimeZone object
39 */
40
41#if !UCONFIG_NO_FORMATTING
42
43#include "unicode/uobject.h"
44#include "unicode/unistr.h"
45#include "unicode/ures.h"
46#include "unicode/ucal.h"
47
48U_NAMESPACE_BEGIN
49
50class StringEnumeration;
51
52/**
53 *
54 * <code>TimeZone</code> represents a time zone offset, and also figures out daylight
55 * savings.
56 *
57 * <p>
58 * Typically, you get a <code>TimeZone</code> using <code>createDefault</code>
59 * which creates a <code>TimeZone</code> based on the time zone where the program
60 * is running. For example, for a program running in Japan, <code>createDefault</code>
61 * creates a <code>TimeZone</code> object based on Japanese Standard Time.
62 *
63 * <p>
64 * You can also get a <code>TimeZone</code> using <code>createTimeZone</code> along
65 * with a time zone ID. For instance, the time zone ID for the US Pacific
66 * Time zone is "America/Los_Angeles". So, you can get a Pacific Time <code>TimeZone</code> object
67 * with:
68 * \htmlonly<blockquote>\endhtmlonly
69 * <pre>
70 * TimeZone *tz = TimeZone::createTimeZone("America/Los_Angeles");
71 * </pre>
72 * \htmlonly</blockquote>\endhtmlonly
73 * You can use the <code>createEnumeration</code> method to iterate through
74 * all the supported time zone IDs, or the <code>getCanonicalID</code> method to check
75 * if a time zone ID is supported or not. You can then choose a
76 * supported ID to get a <code>TimeZone</code>.
77 * If the time zone you want is not represented by one of the
78 * supported IDs, then you can create a custom time zone ID with
79 * the following syntax:
80 *
81 * \htmlonly<blockquote>\endhtmlonly
82 * <pre>
83 * GMT[+|-]hh[[:]mm]
84 * </pre>
85 * \htmlonly</blockquote>\endhtmlonly
86 *
87 * For example, you might specify GMT+14:00 as a custom
88 * time zone ID. The <code>TimeZone</code> that is returned
89 * when you specify a custom time zone ID uses the specified
90 * offset from GMT(=UTC) and does not observe daylight saving
91 * time. For example, you might specify GMT+14:00 as a custom
92 * time zone ID to create a TimeZone representing 14 hours ahead
93 * of GMT (with no daylight saving time). In addition,
94 * <code>getCanonicalID</code> can also be used to
95 * normalize a custom time zone ID.
96 *
97 * TimeZone is an abstract class representing a time zone. A TimeZone is needed for
98 * Calendar to produce local time for a particular time zone. A TimeZone comprises
99 * three basic pieces of information:
100 * <ul>
101 * <li>A time zone offset; that, is the number of milliseconds to add or subtract
102 * from a time expressed in terms of GMT to convert it to the same time in that
103 * time zone (without taking daylight savings time into account).</li>
104 * <li>Logic necessary to take daylight savings time into account if daylight savings
105 * time is observed in that time zone (e.g., the days and hours on which daylight
106 * savings time begins and ends).</li>
107 * <li>An ID. This is a text string that uniquely identifies the time zone.</li>
108 * </ul>
109 *
110 * (Only the ID is actually implemented in TimeZone; subclasses of TimeZone may handle
111 * daylight savings time and GMT offset in different ways. Currently we have the following
112 * TimeZone subclasses: RuleBasedTimeZone, SimpleTimeZone, and VTimeZone.)
113 * <P>
114 * The TimeZone class contains a static list containing a TimeZone object for every
115 * combination of GMT offset and daylight-savings time rules currently in use in the
116 * world, each with a unique ID. Each ID consists of a region (usually a continent or
117 * ocean) and a city in that region, separated by a slash, (for example, US Pacific
118 * Time is "America/Los_Angeles.") Because older versions of this class used
119 * three- or four-letter abbreviations instead, there is also a table that maps the older
120 * abbreviations to the newer ones (for example, "PST" maps to "America/Los_Angeles").
121 * Anywhere the API requires an ID, you can use either form.
122 * <P>
123 * To create a new TimeZone, you call the factory function TimeZone::createTimeZone()
124 * and pass it a time zone ID. You can use the createEnumeration() function to
125 * obtain a list of all the time zone IDs recognized by createTimeZone().
126 * <P>
127 * You can also use TimeZone::createDefault() to create a TimeZone. This function uses
128 * platform-specific APIs to produce a TimeZone for the time zone corresponding to
129 * the client's computer's physical location. For example, if you're in Japan (assuming
130 * your machine is set up correctly), TimeZone::createDefault() will return a TimeZone
131 * for Japanese Standard Time ("Asia/Tokyo").
132 */
133class U_I18N_API TimeZone : public UObject {
134public:
135 /**
136 * @stable ICU 2.0
137 */
138 virtual ~TimeZone();
139
140 /**
141 * Returns the "unknown" time zone.
142 * It behaves like the GMT/UTC time zone but has the
143 * <code>UCAL_UNKNOWN_ZONE_ID</code> = "Etc/Unknown".
144 * createTimeZone() returns a mutable clone of this time zone if the input ID is not recognized.
145 *
146 * @return the "unknown" time zone.
147 * @see UCAL_UNKNOWN_ZONE_ID
148 * @see createTimeZone
149 * @see getGMT
150 * @stable ICU 49
151 */
152 static const TimeZone& U_EXPORT2 getUnknown();
153
154 /**
155 * The GMT (=UTC) time zone has a raw offset of zero and does not use daylight
156 * savings time. This is a commonly used time zone.
157 *
158 * <p>Note: For backward compatibility reason, the ID used by the time
159 * zone returned by this method is "GMT", although the ICU's canonical
160 * ID for the GMT time zone is "Etc/GMT".
161 *
162 * @return the GMT/UTC time zone.
163 * @see getUnknown
164 * @stable ICU 2.0
165 */
166 static const TimeZone* U_EXPORT2 getGMT(void);
167
168 /**
169 * Creates a <code>TimeZone</code> for the given ID.
170 * @param ID the ID for a <code>TimeZone</code>, such as "America/Los_Angeles",
171 * or a custom ID such as "GMT-8:00".
172 * @return the specified <code>TimeZone</code>, or a mutable clone of getUnknown()
173 * if the given ID cannot be understood or if the given ID is "Etc/Unknown".
174 * The return result is guaranteed to be non-NULL.
175 * If you require that the specific zone asked for be returned,
176 * compare the result with getUnknown() or check the ID of the return result.
177 * @stable ICU 2.0
178 */
179 static TimeZone* U_EXPORT2 createTimeZone(const UnicodeString& ID);
180
181 /**
182 * Returns an enumeration over system time zone IDs with the given
183 * filter conditions.
184 * @param zoneType The system time zone type.
185 * @param region The ISO 3166 two-letter country code or UN M.49
186 * three-digit area code. When NULL, no filtering
187 * done by region.
188 * @param rawOffset An offset from GMT in milliseconds, ignoring
189 * the effect of daylight savings time, if any.
190 * When NULL, no filtering done by zone offset.
191 * @param ec Output param to filled in with a success or
192 * an error.
193 * @return an enumeration object, owned by the caller.
194 * @stable ICU 4.8
195 */
196 static StringEnumeration* U_EXPORT2 createTimeZoneIDEnumeration(
197 USystemTimeZoneType zoneType,
198 const char* region,
199 const int32_t* rawOffset,
200 UErrorCode& ec);
201
202 /**
203 * Returns an enumeration over all recognized time zone IDs. (i.e.,
204 * all strings that createTimeZone() accepts)
205 *
206 * @return an enumeration object, owned by the caller.
207 * @stable ICU 2.4
208 */
209 static StringEnumeration* U_EXPORT2 createEnumeration();
210
211 /**
212 * Returns an enumeration over time zone IDs with a given raw
213 * offset from GMT. There may be several times zones with the
214 * same GMT offset that differ in the way they handle daylight
215 * savings time. For example, the state of Arizona doesn't
216 * observe daylight savings time. If you ask for the time zone
217 * IDs corresponding to GMT-7:00, you'll get back an enumeration
218 * over two time zone IDs: "America/Denver," which corresponds to
219 * Mountain Standard Time in the winter and Mountain Daylight Time
220 * in the summer, and "America/Phoenix", which corresponds to
221 * Mountain Standard Time year-round, even in the summer.
222 *
223 * @param rawOffset an offset from GMT in milliseconds, ignoring
224 * the effect of daylight savings time, if any
225 * @return an enumeration object, owned by the caller
226 * @stable ICU 2.4
227 */
228 static StringEnumeration* U_EXPORT2 createEnumeration(int32_t rawOffset);
229
230 /**
231 * Returns an enumeration over time zone IDs associated with the
232 * given country. Some zones are affiliated with no country
233 * (e.g., "UTC"); these may also be retrieved, as a group.
234 *
235 * @param country The ISO 3166 two-letter country code, or NULL to
236 * retrieve zones not affiliated with any country.
237 * @return an enumeration object, owned by the caller
238 * @stable ICU 2.4
239 */
240 static StringEnumeration* U_EXPORT2 createEnumeration(const char* country);
241
242 /**
243 * Returns the number of IDs in the equivalency group that
244 * includes the given ID. An equivalency group contains zones
245 * that have the same GMT offset and rules.
246 *
247 * <p>The returned count includes the given ID; it is always >= 1.
248 * The given ID must be a system time zone. If it is not, returns
249 * zero.
250 * @param id a system time zone ID
251 * @return the number of zones in the equivalency group containing
252 * 'id', or zero if 'id' is not a valid system ID
253 * @see #getEquivalentID
254 * @stable ICU 2.0
255 */
256 static int32_t U_EXPORT2 countEquivalentIDs(const UnicodeString& id);
257
258 /**
259 * Returns an ID in the equivalency group that
260 * includes the given ID. An equivalency group contains zones
261 * that have the same GMT offset and rules.
262 *
263 * <p>The given index must be in the range 0..n-1, where n is the
264 * value returned by <code>countEquivalentIDs(id)</code>. For
265 * some value of 'index', the returned value will be equal to the
266 * given id. If the given id is not a valid system time zone, or
267 * if 'index' is out of range, then returns an empty string.
268 * @param id a system time zone ID
269 * @param index a value from 0 to n-1, where n is the value
270 * returned by <code>countEquivalentIDs(id)</code>
271 * @return the ID of the index-th zone in the equivalency group
272 * containing 'id', or an empty string if 'id' is not a valid
273 * system ID or 'index' is out of range
274 * @see #countEquivalentIDs
275 * @stable ICU 2.0
276 */
277 static const UnicodeString U_EXPORT2 getEquivalentID(const UnicodeString& id,
278 int32_t index);
279
280 /**
281 * Creates an instance of TimeZone detected from the current host
282 * system configuration. If the host system detection routines fail,
283 * or if they specify a TimeZone or TimeZone offset which is not
284 * recognized, then the special TimeZone "Etc/Unknown" is returned.
285 *
286 * Note that ICU4C does not change the default time zone unless
287 * `TimeZone::adoptDefault(TimeZone*)` or
288 * `TimeZone::setDefault(const TimeZone&)` is explicitly called by a
289 * user. This method does not update the current ICU's default,
290 * and may return a different TimeZone from the one returned by
291 * `TimeZone::createDefault()`.
292 *
293 * <p>This function is not thread safe.</p>
294 *
295 * @return A new instance of TimeZone detected from the current host system
296 * configuration.
297 * @see adoptDefault
298 * @see setDefault
299 * @see createDefault
300 * @see getUnknown
301 * @stable ICU 55
302 */
303 static TimeZone* U_EXPORT2 detectHostTimeZone();
304
305 /**
306 * Creates a new copy of the default TimeZone for this host. Unless the default time
307 * zone has already been set using adoptDefault() or setDefault(), the default is
308 * determined by querying the host system configuration. If the host system detection
309 * routines fail, or if they specify a TimeZone or TimeZone offset which is not
310 * recognized, then the special TimeZone "Etc/Unknown" is instantiated and made the
311 * default.
312 *
313 * @return A default TimeZone. Clients are responsible for deleting the time zone
314 * object returned.
315 * @see getUnknown
316 * @stable ICU 2.0
317 */
318 static TimeZone* U_EXPORT2 createDefault(void);
319
320 /**
321 * Sets the default time zone (i.e., what's returned by createDefault()) to be the
322 * specified time zone. If NULL is specified for the time zone, the default time
323 * zone is set to the default host time zone. This call adopts the TimeZone object
324 * passed in; the client is no longer responsible for deleting it.
325 *
326 * @param zone A pointer to the new TimeZone object to use as the default.
327 * @stable ICU 2.0
328 */
329 static void U_EXPORT2 adoptDefault(TimeZone* zone);
330
331#ifndef U_HIDE_SYSTEM_API
332 /**
333 * Same as adoptDefault(), except that the TimeZone object passed in is NOT adopted;
334 * the caller remains responsible for deleting it.
335 *
336 * @param zone The given timezone.
337 * @system
338 * @stable ICU 2.0
339 */
340 static void U_EXPORT2 setDefault(const TimeZone& zone);
341#endif /* U_HIDE_SYSTEM_API */
342
343 /**
344 * Returns the timezone data version currently used by ICU.
345 * @param status Output param to filled in with a success or an error.
346 * @return the version string, such as "2007f"
347 * @stable ICU 3.8
348 */
349 static const char* U_EXPORT2 getTZDataVersion(UErrorCode& status);
350
351 /**
352 * Returns the canonical system timezone ID or the normalized
353 * custom time zone ID for the given time zone ID.
354 * @param id The input time zone ID to be canonicalized.
355 * @param canonicalID Receives the canonical system time zone ID
356 * or the custom time zone ID in normalized format.
357 * @param status Receives the status. When the given time zone ID
358 * is neither a known system time zone ID nor a
359 * valid custom time zone ID, U_ILLEGAL_ARGUMENT_ERROR
360 * is set.
361 * @return A reference to the result.
362 * @stable ICU 4.0
363 */
364 static UnicodeString& U_EXPORT2 getCanonicalID(const UnicodeString& id,
365 UnicodeString& canonicalID, UErrorCode& status);
366
367 /**
368 * Returns the canonical system time zone ID or the normalized
369 * custom time zone ID for the given time zone ID.
370 * @param id The input time zone ID to be canonicalized.
371 * @param canonicalID Receives the canonical system time zone ID
372 * or the custom time zone ID in normalized format.
373 * @param isSystemID Receives if the given ID is a known system
374 * time zone ID.
375 * @param status Receives the status. When the given time zone ID
376 * is neither a known system time zone ID nor a
377 * valid custom time zone ID, U_ILLEGAL_ARGUMENT_ERROR
378 * is set.
379 * @return A reference to the result.
380 * @stable ICU 4.0
381 */
382 static UnicodeString& U_EXPORT2 getCanonicalID(const UnicodeString& id,
383 UnicodeString& canonicalID, UBool& isSystemID, UErrorCode& status);
384
385 /**
386 * Converts a system time zone ID to an equivalent Windows time zone ID. For example,
387 * Windows time zone ID "Pacific Standard Time" is returned for input "America/Los_Angeles".
388 *
389 * <p>There are system time zones that cannot be mapped to Windows zones. When the input
390 * system time zone ID is unknown or unmappable to a Windows time zone, then the result will be
391 * empty, but the operation itself remains successful (no error status set on return).
392 *
393 * <p>This implementation utilizes <a href="http://unicode.org/cldr/charts/supplemental/zone_tzid.html">
394 * Zone-Tzid mapping data</a>. The mapping data is updated time to time. To get the latest changes,
395 * please read the ICU user guide section <a href="http://userguide.icu-project.org/datetime/timezone#TOC-Updating-the-Time-Zone-Data">
396 * Updating the Time Zone Data</a>.
397 *
398 * @param id A system time zone ID.
399 * @param winid Receives a Windows time zone ID. When the input system time zone ID is unknown
400 * or unmappable to a Windows time zone ID, then an empty string is set on return.
401 * @param status Receives the status.
402 * @return A reference to the result (<code>winid</code>).
403 * @see getIDForWindowsID
404 *
405 * @stable ICU 52
406 */
407 static UnicodeString& U_EXPORT2 getWindowsID(const UnicodeString& id,
408 UnicodeString& winid, UErrorCode& status);
409
410 /**
411 * Converts a Windows time zone ID to an equivalent system time zone ID
412 * for a region. For example, system time zone ID "America/Los_Angeles" is returned
413 * for input Windows ID "Pacific Standard Time" and region "US" (or <code>null</code>),
414 * "America/Vancouver" is returned for the same Windows ID "Pacific Standard Time" and
415 * region "CA".
416 *
417 * <p>Not all Windows time zones can be mapped to system time zones. When the input
418 * Windows time zone ID is unknown or unmappable to a system time zone, then the result
419 * will be empty, but the operation itself remains successful (no error status set on return).
420 *
421 * <p>This implementation utilizes <a href="http://unicode.org/cldr/charts/supplemental/zone_tzid.html">
422 * Zone-Tzid mapping data</a>. The mapping data is updated time to time. To get the latest changes,
423 * please read the ICU user guide section <a href="http://userguide.icu-project.org/datetime/timezone#TOC-Updating-the-Time-Zone-Data">
424 * Updating the Time Zone Data</a>.
425 *
426 * @param winid A Windows time zone ID.
427 * @param region A null-terminated region code, or <code>NULL</code> if no regional preference.
428 * @param id Receives a system time zone ID. When the input Windows time zone ID is unknown
429 * or unmappable to a system time zone ID, then an empty string is set on return.
430 * @param status Receives the status.
431 * @return A reference to the result (<code>id</code>).
432 * @see getWindowsID
433 *
434 * @stable ICU 52
435 */
436 static UnicodeString& U_EXPORT2 getIDForWindowsID(const UnicodeString& winid, const char* region,
437 UnicodeString& id, UErrorCode& status);
438
439 /**
440 * Returns true if the two TimeZones are equal. (The TimeZone version only compares
441 * IDs, but subclasses are expected to also compare the fields they add.)
442 *
443 * @param that The TimeZone object to be compared with.
444 * @return True if the given TimeZone is equal to this TimeZone; false
445 * otherwise.
446 * @stable ICU 2.0
447 */
448 virtual UBool operator==(const TimeZone& that) const;
449
450 /**
451 * Returns true if the two TimeZones are NOT equal; that is, if operator==() returns
452 * false.
453 *
454 * @param that The TimeZone object to be compared with.
455 * @return True if the given TimeZone is not equal to this TimeZone; false
456 * otherwise.
457 * @stable ICU 2.0
458 */
459 UBool operator!=(const TimeZone& that) const {return !operator==(that);}
460
461 /**
462 * Returns the TimeZone's adjusted GMT offset (i.e., the number of milliseconds to add
463 * to GMT to get local time in this time zone, taking daylight savings time into
464 * account) as of a particular reference date. The reference date is used to determine
465 * whether daylight savings time is in effect and needs to be figured into the offset
466 * that is returned (in other words, what is the adjusted GMT offset in this time zone
467 * at this particular date and time?). For the time zones produced by createTimeZone(),
468 * the reference data is specified according to the Gregorian calendar, and the date
469 * and time fields are local standard time.
470 *
471 * <p>Note: Don't call this method. Instead, call the getOffset(UDate...) overload,
472 * which returns both the raw and the DST offset for a given time. This method
473 * is retained only for backward compatibility.
474 *
475 * @param era The reference date's era
476 * @param year The reference date's year
477 * @param month The reference date's month (0-based; 0 is January)
478 * @param day The reference date's day-in-month (1-based)
479 * @param dayOfWeek The reference date's day-of-week (1-based; 1 is Sunday)
480 * @param millis The reference date's milliseconds in day, local standard time
481 * @param status Output param to filled in with a success or an error.
482 * @return The offset in milliseconds to add to GMT to get local time.
483 * @stable ICU 2.0
484 */
485 virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,
486 uint8_t dayOfWeek, int32_t millis, UErrorCode& status) const = 0;
487
488 /**
489 * Gets the time zone offset, for current date, modified in case of
490 * daylight savings. This is the offset to add *to* UTC to get local time.
491 *
492 * <p>Note: Don't call this method. Instead, call the getOffset(UDate...) overload,
493 * which returns both the raw and the DST offset for a given time. This method
494 * is retained only for backward compatibility.
495 *
496 * @param era the era of the given date.
497 * @param year the year in the given date.
498 * @param month the month in the given date.
499 * Month is 0-based. e.g., 0 for January.
500 * @param day the day-in-month of the given date.
501 * @param dayOfWeek the day-of-week of the given date.
502 * @param milliseconds the millis in day in <em>standard</em> local time.
503 * @param monthLength the length of the given month in days.
504 * @param status Output param to filled in with a success or an error.
505 * @return the offset to add *to* GMT to get local time.
506 * @stable ICU 2.0
507 */
508 virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,
509 uint8_t dayOfWeek, int32_t milliseconds,
510 int32_t monthLength, UErrorCode& status) const = 0;
511
512 /**
513 * Returns the time zone raw and GMT offset for the given moment
514 * in time. Upon return, local-millis = GMT-millis + rawOffset +
515 * dstOffset. All computations are performed in the proleptic
516 * Gregorian calendar. The default implementation in the TimeZone
517 * class delegates to the 8-argument getOffset().
518 *
519 * @param date moment in time for which to return offsets, in
520 * units of milliseconds from January 1, 1970 0:00 GMT, either GMT
521 * time or local wall time, depending on `local'.
522 * @param local if true, `date' is local wall time; otherwise it
523 * is in GMT time.
524 * @param rawOffset output parameter to receive the raw offset, that
525 * is, the offset not including DST adjustments
526 * @param dstOffset output parameter to receive the DST offset,
527 * that is, the offset to be added to `rawOffset' to obtain the
528 * total offset between local and GMT time. If DST is not in
529 * effect, this value is zero; otherwise it is a positive value,
530 * typically one hour.
531 * @param ec input-output error code
532 *
533 * @stable ICU 2.8
534 */
535 virtual void getOffset(UDate date, UBool local, int32_t& rawOffset,
536 int32_t& dstOffset, UErrorCode& ec) const;
537
538 /**
539 * Sets the TimeZone's raw GMT offset (i.e., the number of milliseconds to add
540 * to GMT to get local time, before taking daylight savings time into account).
541 *
542 * @param offsetMillis The new raw GMT offset for this time zone.
543 * @stable ICU 2.0
544 */
545 virtual void setRawOffset(int32_t offsetMillis) = 0;
546
547 /**
548 * Returns the TimeZone's raw GMT offset (i.e., the number of milliseconds to add
549 * to GMT to get local time, before taking daylight savings time into account).
550 *
551 * @return The TimeZone's raw GMT offset.
552 * @stable ICU 2.0
553 */
554 virtual int32_t getRawOffset(void) const = 0;
555
556 /**
557 * Fills in "ID" with the TimeZone's ID.
558 *
559 * @param ID Receives this TimeZone's ID.
560 * @return A reference to 'ID'
561 * @stable ICU 2.0
562 */
563 UnicodeString& getID(UnicodeString& ID) const;
564
565 /**
566 * Sets the TimeZone's ID to the specified value. This doesn't affect any other
567 * fields (for example, if you say<
568 * blockquote><pre>
569 * . TimeZone* foo = TimeZone::createTimeZone("America/New_York");
570 * . foo.setID("America/Los_Angeles");
571 * </pre>\htmlonly</blockquote>\endhtmlonly
572 * the time zone's GMT offset and daylight-savings rules don't change to those for
573 * Los Angeles. They're still those for New York. Only the ID has changed.)
574 *
575 * @param ID The new time zone ID.
576 * @stable ICU 2.0
577 */
578 void setID(const UnicodeString& ID);
579
580 /**
581 * Enum for use with getDisplayName
582 * @stable ICU 2.4
583 */
584 enum EDisplayType {
585 /**
586 * Selector for short display name
587 * @stable ICU 2.4
588 */
589 SHORT = 1,
590 /**
591 * Selector for long display name
592 * @stable ICU 2.4
593 */
594 LONG,
595 /**
596 * Selector for short generic display name
597 * @stable ICU 4.4
598 */
599 SHORT_GENERIC,
600 /**
601 * Selector for long generic display name
602 * @stable ICU 4.4
603 */
604 LONG_GENERIC,
605 /**
606 * Selector for short display name derived
607 * from time zone offset
608 * @stable ICU 4.4
609 */
610 SHORT_GMT,
611 /**
612 * Selector for long display name derived
613 * from time zone offset
614 * @stable ICU 4.4
615 */
616 LONG_GMT,
617 /**
618 * Selector for short display name derived
619 * from the time zone's fallback name
620 * @stable ICU 4.4
621 */
622 SHORT_COMMONLY_USED,
623 /**
624 * Selector for long display name derived
625 * from the time zone's fallback name
626 * @stable ICU 4.4
627 */
628 GENERIC_LOCATION
629 };
630
631 /**
632 * Returns a name of this time zone suitable for presentation to the user
633 * in the default locale.
634 * This method returns the long name, not including daylight savings.
635 * If the display name is not available for the locale,
636 * then this method returns a string in the localized GMT offset format
637 * such as <code>GMT[+-]HH:mm</code>.
638 * @param result the human-readable name of this time zone in the default locale.
639 * @return A reference to 'result'.
640 * @stable ICU 2.0
641 */
642 UnicodeString& getDisplayName(UnicodeString& result) const;
643
644 /**
645 * Returns a name of this time zone suitable for presentation to the user
646 * in the specified locale.
647 * This method returns the long name, not including daylight savings.
648 * If the display name is not available for the locale,
649 * then this method returns a string in the localized GMT offset format
650 * such as <code>GMT[+-]HH:mm</code>.
651 * @param locale the locale in which to supply the display name.
652 * @param result the human-readable name of this time zone in the given locale
653 * or in the default locale if the given locale is not recognized.
654 * @return A reference to 'result'.
655 * @stable ICU 2.0
656 */
657 UnicodeString& getDisplayName(const Locale& locale, UnicodeString& result) const;
658
659 /**
660 * Returns a name of this time zone suitable for presentation to the user
661 * in the default locale.
662 * If the display name is not available for the locale,
663 * then this method returns a string in the localized GMT offset format
664 * such as <code>GMT[+-]HH:mm</code>.
665 * @param inDaylight if true, return the daylight savings name.
666 * @param style
667 * @param result the human-readable name of this time zone in the default locale.
668 * @return A reference to 'result'.
669 * @stable ICU 2.0
670 */
671 UnicodeString& getDisplayName(UBool inDaylight, EDisplayType style, UnicodeString& result) const;
672
673 /**
674 * Returns a name of this time zone suitable for presentation to the user
675 * in the specified locale.
676 * If the display name is not available for the locale,
677 * then this method returns a string in the localized GMT offset format
678 * such as <code>GMT[+-]HH:mm</code>.
679 * @param inDaylight if true, return the daylight savings name.
680 * @param style
681 * @param locale the locale in which to supply the display name.
682 * @param result the human-readable name of this time zone in the given locale
683 * or in the default locale if the given locale is not recognized.
684 * @return A reference to 'result'.
685 * @stable ICU 2.0
686 */
687 UnicodeString& getDisplayName(UBool inDaylight, EDisplayType style, const Locale& locale, UnicodeString& result) const;
688
689 /**
690 * Queries if this time zone uses daylight savings time.
691 * @return true if this time zone uses daylight savings time,
692 * false, otherwise.
693 * <p><strong>Note:</strong>The default implementation of
694 * ICU TimeZone uses the tz database, which supports historic
695 * rule changes, for system time zones. With the implementation,
696 * there are time zones that used daylight savings time in the
697 * past, but no longer used currently. For example, Asia/Tokyo has
698 * never used daylight savings time since 1951. Most clients would
699 * expect that this method to return <code>FALSE</code> for such case.
700 * The default implementation of this method returns <code>TRUE</code>
701 * when the time zone uses daylight savings time in the current
702 * (Gregorian) calendar year.
703 * <p>In Java 7, <code>observesDaylightTime()</code> was added in
704 * addition to <code>useDaylightTime()</code>. In Java, <code>useDaylightTime()</code>
705 * only checks if daylight saving time is observed by the last known
706 * rule. This specification might not be what most users would expect
707 * if daylight saving time is currently observed, but not scheduled
708 * in future. In this case, Java's <code>userDaylightTime()</code> returns
709 * <code>false</code>. To resolve the issue, Java 7 added <code>observesDaylightTime()</code>,
710 * which takes the current rule into account. The method <code>observesDaylightTime()</code>
711 * was added in ICU4J for supporting API signature compatibility with JDK.
712 * In general, ICU4C also provides JDK compatible methods, but the current
713 * implementation <code>userDaylightTime()</code> serves the purpose
714 * (takes the current rule into account), <code>observesDaylightTime()</code>
715 * is not added in ICU4C. In addition to <code>useDaylightTime()</code>, ICU4C
716 * <code>BasicTimeZone</code> class (Note that <code>TimeZone::createTimeZone(const UnicodeString &ID)</code>
717 * always returns a <code>BasicTimeZone</code>) provides a series of methods allowing
718 * historic and future time zone rule iteration, so you can check if daylight saving
719 * time is observed or not within a given period.
720 *
721 * @stable ICU 2.0
722 */
723 virtual UBool useDaylightTime(void) const = 0;
724
725#ifndef U_FORCE_HIDE_DEPRECATED_API
726 /**
727 * Queries if the given date is in daylight savings time in
728 * this time zone.
729 * This method is wasteful since it creates a new GregorianCalendar and
730 * deletes it each time it is called. This is a deprecated method
731 * and provided only for Java compatibility.
732 *
733 * @param date the given UDate.
734 * @param status Output param filled in with success/error code.
735 * @return true if the given date is in daylight savings time,
736 * false, otherwise.
737 * @deprecated ICU 2.4. Use Calendar::inDaylightTime() instead.
738 */
739 virtual UBool inDaylightTime(UDate date, UErrorCode& status) const = 0;
740#endif // U_FORCE_HIDE_DEPRECATED_API
741
742 /**
743 * Returns true if this zone has the same rule and offset as another zone.
744 * That is, if this zone differs only in ID, if at all.
745 * @param other the <code>TimeZone</code> object to be compared with
746 * @return true if the given zone is the same as this one,
747 * with the possible exception of the ID
748 * @stable ICU 2.0
749 */
750 virtual UBool hasSameRules(const TimeZone& other) const;
751
752 /**
753 * Clones TimeZone objects polymorphically. Clients are responsible for deleting
754 * the TimeZone object cloned.
755 *
756 * @return A new copy of this TimeZone object.
757 * @stable ICU 2.0
758 */
759 virtual TimeZone* clone() const = 0;
760
761 /**
762 * Return the class ID for this class. This is useful only for
763 * comparing to a return value from getDynamicClassID().
764 * @return The class ID for all objects of this class.
765 * @stable ICU 2.0
766 */
767 static UClassID U_EXPORT2 getStaticClassID(void);
768
769 /**
770 * Returns a unique class ID POLYMORPHICALLY. This method is to
771 * implement a simple version of RTTI, since not all C++ compilers support genuine
772 * RTTI. Polymorphic operator==() and clone() methods call this method.
773 * <P>
774 * Concrete subclasses of TimeZone must use the UOBJECT_DEFINE_RTTI_IMPLEMENTATION
775 * macro from uobject.h in their implementation to provide correct RTTI information.
776 * @return The class ID for this object. All objects of a given class have the
777 * same class ID. Objects of other classes have different class IDs.
778 * @stable ICU 2.0
779 */
780 virtual UClassID getDynamicClassID(void) const = 0;
781
782 /**
783 * Returns the amount of time to be added to local standard time
784 * to get local wall clock time.
785 * <p>
786 * The default implementation always returns 3600000 milliseconds
787 * (i.e., one hour) if this time zone observes Daylight Saving
788 * Time. Otherwise, 0 (zero) is returned.
789 * <p>
790 * If an underlying TimeZone implementation subclass supports
791 * historical Daylight Saving Time changes, this method returns
792 * the known latest daylight saving value.
793 *
794 * @return the amount of saving time in milliseconds
795 * @stable ICU 3.6
796 */
797 virtual int32_t getDSTSavings() const;
798
799 /**
800 * Gets the region code associated with the given
801 * system time zone ID. The region code is either ISO 3166
802 * 2-letter country code or UN M.49 3-digit area code.
803 * When the time zone is not associated with a specific location,
804 * for example - "Etc/UTC", "EST5EDT", then this method returns
805 * "001" (UN M.49 area code for World).
806 *
807 * @param id The system time zone ID.
808 * @param region Output buffer for receiving the region code.
809 * @param capacity The size of the output buffer.
810 * @param status Receives the status. When the given time zone ID
811 * is not a known system time zone ID,
812 * U_ILLEGAL_ARGUMENT_ERROR is set.
813 * @return The length of the output region code.
814 * @stable ICU 4.8
815 */
816 static int32_t U_EXPORT2 getRegion(const UnicodeString& id,
817 char *region, int32_t capacity, UErrorCode& status);
818
819protected:
820
821 /**
822 * Default constructor. ID is initialized to the empty string.
823 * @stable ICU 2.0
824 */
825 TimeZone();
826
827 /**
828 * Construct a TimeZone with a given ID.
829 * @param id a system time zone ID
830 * @stable ICU 2.0
831 */
832 TimeZone(const UnicodeString &id);
833
834 /**
835 * Copy constructor.
836 * @param source the object to be copied.
837 * @stable ICU 2.0
838 */
839 TimeZone(const TimeZone& source);
840
841 /**
842 * Default assignment operator.
843 * @param right the object to be copied.
844 * @stable ICU 2.0
845 */
846 TimeZone& operator=(const TimeZone& right);
847
848#ifndef U_HIDE_INTERNAL_API
849 /**
850 * Utility function. For internally loading rule data.
851 * @param top Top resource bundle for tz data
852 * @param ruleid ID of rule to load
853 * @param oldbundle Old bundle to reuse or NULL
854 * @param status Status parameter
855 * @return either a new bundle or *oldbundle
856 * @internal
857 */
858 static UResourceBundle* loadRule(const UResourceBundle* top, const UnicodeString& ruleid, UResourceBundle* oldbundle, UErrorCode&status);
859#endif /* U_HIDE_INTERNAL_API */
860
861private:
862 friend class ZoneMeta;
863
864
865 static TimeZone* createCustomTimeZone(const UnicodeString&); // Creates a time zone based on the string.
866
867 /**
868 * Finds the given ID in the Olson tzdata. If the given ID is found in the tzdata,
869 * returns the pointer to the ID resource. This method is exposed through ZoneMeta class
870 * for ICU internal implementation and useful for building hashtable using a time zone
871 * ID as a key.
872 * @param id zone id string
873 * @return the pointer of the ID resource, or NULL.
874 */
875 static const char16_t* findID(const UnicodeString& id);
876
877 /**
878 * Resolve a link in Olson tzdata. When the given id is known and it's not a link,
879 * the id itself is returned. When the given id is known and it is a link, then
880 * dereferenced zone id is returned. When the given id is unknown, then it returns
881 * NULL.
882 * @param id zone id string
883 * @return the dereferenced zone or NULL
884 */
885 static const char16_t* dereferOlsonLink(const UnicodeString& id);
886
887 /**
888 * Returns the region code associated with the given zone,
889 * or NULL if the zone is not known.
890 * @param id zone id string
891 * @return the region associated with the given zone
892 */
893 static const char16_t* getRegion(const UnicodeString& id);
894
895 public:
896#ifndef U_HIDE_INTERNAL_API
897 /**
898 * Returns the region code associated with the given zone,
899 * or NULL if the zone is not known.
900 * @param id zone id string
901 * @param status Status parameter
902 * @return the region associated with the given zone
903 * @internal
904 */
905 static const char16_t* getRegion(const UnicodeString& id, UErrorCode& status);
906#endif /* U_HIDE_INTERNAL_API */
907
908 private:
909 /**
910 * Parses the given custom time zone identifier
911 * @param id id A string of the form GMT[+-]hh:mm, GMT[+-]hhmm, or
912 * GMT[+-]hh.
913 * @param sign Receves parsed sign, 1 for positive, -1 for negative.
914 * @param hour Receives parsed hour field
915 * @param minute Receives parsed minute field
916 * @param second Receives parsed second field
917 * @return Returns TRUE when the given custom id is valid.
918 */
919 static UBool parseCustomID(const UnicodeString& id, int32_t& sign, int32_t& hour,
920 int32_t& minute, int32_t& second);
921
922 /**
923 * Parse a custom time zone identifier and return the normalized
924 * custom time zone identifier for the given custom id string.
925 * @param id a string of the form GMT[+-]hh:mm, GMT[+-]hhmm, or
926 * GMT[+-]hh.
927 * @param normalized Receives the normalized custom ID
928 * @param status Receives the status. When the input ID string is invalid,
929 * U_ILLEGAL_ARGUMENT_ERROR is set.
930 * @return The normalized custom id string.
931 */
932 static UnicodeString& getCustomID(const UnicodeString& id, UnicodeString& normalized,
933 UErrorCode& status);
934
935 /**
936 * Returns the normalized custom time zone ID for the given offset fields.
937 * @param hour offset hours
938 * @param min offset minutes
939 * @param sec offset seconds
940 * @param negative sign of the offset, TRUE for negative offset.
941 * @param id Receves the format result (normalized custom ID)
942 * @return The reference to id
943 */
944 static UnicodeString& formatCustomID(int32_t hour, int32_t min, int32_t sec,
945 UBool negative, UnicodeString& id);
946
947 UnicodeString fID; // this time zone's ID
948
949 friend class TZEnumeration;
950};
951
952
953// -------------------------------------
954
955inline UnicodeString&
956TimeZone::getID(UnicodeString& ID) const
957{
958 ID = fID;
959 return ID;
960}
961
962// -------------------------------------
963
964inline void
965TimeZone::setID(const UnicodeString& ID)
966{
967 fID = ID;
968}
969U_NAMESPACE_END
970
971#endif /* #if !UCONFIG_NO_FORMATTING */
972
973#endif /* U_SHOW_CPLUSPLUS_API */
974
975#endif //_TIMEZONE
976//eof
977