1 /*************************************************************************
2 * Copyright (c) 1997-2007, International Business Machines Corporation
3 * and others. All Rights Reserved.
4 **************************************************************************
5 *
6 * File TIMEZONE.H
7 *
8 * Modification History:
9 *
10 * Date Name Description
11 * 04/21/97 aliu Overhauled header.
12 * 07/09/97 helena Changed createInstance to createDefault.
13 * 08/06/97 aliu Removed dependency on internal header for Hashtable.
14 * 08/10/98 stephen Changed getDisplayName() API conventions to match
15 * 08/19/98 stephen Changed createTimeZone() to never return 0
16 * 09/02/98 stephen Sync to JDK 1.2 8/31
17 * - Added getOffset(... monthlen ...)
18 * - Added hasSameRules()
19 * 09/15/98 stephen Added getStaticClassID
20 * 12/03/99 aliu Moved data out of static table into icudata.dll.
21 * Hashtable replaced by new static data structures.
22 * 12/14/99 aliu Made GMT public.
23 * 08/15/01 grhoten Made GMT private and added the getGMT() function
24 **************************************************************************
25 */
26
27 #ifndef TIMEZONE_H
28 #define TIMEZONE_H
29
30 #include "unicode/utypes.h"
31
32 /**
33 * \file
34 * \brief C++ API: TimeZone object
35 */
36
37 #if !UCONFIG_NO_FORMATTING
38
39 #include "unicode/uobject.h"
40 #include "unicode/unistr.h"
41 #include "unicode/ures.h"
42
43 U_NAMESPACE_BEGIN
44
45 class StringEnumeration;
46
47 /**
48 *
49 * <code>TimeZone</code> represents a time zone offset, and also figures out daylight
50 * savings.
51 *
52 * <p>
53 * Typically, you get a <code>TimeZone</code> using <code>createDefault</code>
54 * which creates a <code>TimeZone</code> based on the time zone where the program
55 * is running. For example, for a program running in Japan, <code>createDefault</code>
56 * creates a <code>TimeZone</code> object based on Japanese Standard Time.
57 *
58 * <p>
59 * You can also get a <code>TimeZone</code> using <code>createTimeZone</code> along
60 * with a time zone ID. For instance, the time zone ID for the Pacific
61 * Standard Time zone is "PST". So, you can get a PST <code>TimeZone</code> object
62 * with:
63 * \htmlonly<blockquote>\endhtmlonly
64 * <pre>
65 * TimeZone *tz = TimeZone::createTimeZone("PST");
66 * </pre>
67 * \htmlonly</blockquote>\endhtmlonly
68 * You can use <code>getAvailableIDs</code> method to iterate through
69 * all the supported time zone IDs. You can then choose a
70 * supported ID to get a <code>TimeZone</code>.
71 * If the time zone you want is not represented by one of the
72 * supported IDs, then you can create a custom time zone ID with
73 * the following syntax:
74 *
75 * \htmlonly<blockquote>\endhtmlonly
76 * <pre>
77 * GMT[+|-]hh[[:]mm]
78 * </pre>
79 * \htmlonly</blockquote>\endhtmlonly
80 *
81 * For example, you might specify GMT+14:00 as a custom
82 * time zone ID. The <code>TimeZone</code> that is returned
83 * when you specify a custom time zone ID does not include
84 * daylight savings time.
85 *
86 * TimeZone is an abstract class representing a time zone. A TimeZone is needed for
87 * Calendar to produce local time for a particular time zone. A TimeZone comprises
88 * three basic pieces of information:
89 * <ul>
90 * <li>A time zone offset; that, is the number of milliseconds to add or subtract
91 * from a time expressed in terms of GMT to convert it to the same time in that
92 * time zone (without taking daylight savings time into account).</li>
93 * <li>Logic necessary to take daylight savings time into account if daylight savings
94 * time is observed in that time zone (e.g., the days and hours on which daylight
95 * savings time begins and ends).</li>
96 * <li>An ID. This is a text string that uniquely identifies the time zone.</li>
97 * </ul>
98 *
99 * (Only the ID is actually implemented in TimeZone; subclasses of TimeZone may handle
100 * daylight savings time and GMT offset in different ways. Currently we only have one
101 * TimeZone subclass: SimpleTimeZone.)
102 * <P>
103 * The TimeZone class contains a static list containing a TimeZone object for every
104 * combination of GMT offset and daylight-savings time rules currently in use in the
105 * world, each with a unique ID. Each ID consists of a region (usually a continent or
106 * ocean) and a city in that region, separated by a slash, (for example, Pacific
107 * Standard Time is "America/Los_Angeles.") Because older versions of this class used
108 * three- or four-letter abbreviations instead, there is also a table that maps the older
109 * abbreviations to the newer ones (for example, "PST" maps to "America/LosAngeles").
110 * Anywhere the API requires an ID, you can use either form.
111 * <P>
112 * To create a new TimeZone, you call the factory function TimeZone::createTimeZone()
113 * and pass it a time zone ID. You can use the createEnumeration() function to
114 * obtain a list of all the time zone IDs recognized by createTimeZone().
115 * <P>
116 * You can also use TimeZone::createDefault() to create a TimeZone. This function uses
117 * platform-specific APIs to produce a TimeZone for the time zone corresponding to
118 * the client's computer's physical location. For example, if you're in Japan (assuming
119 * your machine is set up correctly), TimeZone::createDefault() will return a TimeZone
120 * for Japanese Standard Time ("Asia/Tokyo").
121 */
122 class U_I18N_API TimeZone : public UObject {
123 public:
124 /**
125 * @stable ICU 2.0
126 */
127 virtual ~TimeZone();
128
129 /**
130 * The GMT time zone has a raw offset of zero and does not use daylight
131 * savings time. This is a commonly used time zone.
132 * @return the GMT time zone.
133 * @stable ICU 2.0
134 */
135 static const TimeZone* U_EXPORT2 getGMT(void);
136
137 /**
138 * Creates a <code>TimeZone</code> for the given ID.
139 * @param ID the ID for a <code>TimeZone</code>, either an abbreviation such as
140 * "PST", a full name such as "America/Los_Angeles", or a custom ID
141 * such as "GMT-8:00".
142 * @return the specified <code>TimeZone</code>, or the GMT zone if the given ID
143 * cannot be understood. Return result guaranteed to be non-null. If you
144 * require that the specific zone asked for be returned, check the ID of the
145 * return result.
146 * @stable ICU 2.0
147 */
148 static TimeZone* U_EXPORT2 createTimeZone(const UnicodeString& ID);
149
150 /**
151 * Returns an enumeration over all recognized time zone IDs. (i.e.,
152 * all strings that createTimeZone() accepts)
153 *
154 * @return an enumeration object, owned by the caller.
155 * @stable ICU 2.4
156 */
157 static StringEnumeration* U_EXPORT2 createEnumeration();
158
159 /**
160 * Returns an enumeration over time zone IDs with a given raw
161 * offset from GMT. There may be several times zones with the
162 * same GMT offset that differ in the way they handle daylight
163 * savings time. For example, the state of Arizona doesn't
164 * observe daylight savings time. If you ask for the time zone
165 * IDs corresponding to GMT-7:00, you'll get back an enumeration
166 * over two time zone IDs: "America/Denver," which corresponds to
167 * Mountain Standard Time in the winter and Mountain Daylight Time
168 * in the summer, and "America/Phoenix", which corresponds to
169 * Mountain Standard Time year-round, even in the summer.
170 *
171 * @param rawOffset an offset from GMT in milliseconds, ignoring
172 * the effect of daylight savings time, if any
173 * @return an enumeration object, owned by the caller
174 * @stable ICU 2.4
175 */
176 static StringEnumeration* U_EXPORT2 createEnumeration(int32_t rawOffset);
177
178 /**
179 * Returns an enumeration over time zone IDs associated with the
180 * given country. Some zones are affiliated with no country
181 * (e.g., "UTC"); these may also be retrieved, as a group.
182 *
183 * @param country The ISO 3166 two-letter country code, or NULL to
184 * retrieve zones not affiliated with any country.
185 * @return an enumeration object, owned by the caller
186 * @stable ICU 2.4
187 */
188 static StringEnumeration* U_EXPORT2 createEnumeration(const char* country);
189
190 #ifdef U_USE_TIMEZONE_OBSOLETE_2_8
191 /**
192 * Returns a list of time zone IDs, one for each time zone with a given GMT offset.
193 * The return value is a list because there may be several times zones with the same
194 * GMT offset that differ in the way they handle daylight savings time. For example,
195 * the state of Arizona doesn't observe Daylight Savings time. So if you ask for
196 * the time zone IDs corresponding to GMT-7:00, you'll get back two time zone IDs:
197 * "America/Denver," which corresponds to Mountain Standard Time in the winter and
198 * Mountain Daylight Time in the summer, and "America/Phoenix", which corresponds to
199 * Mountain Standard Time year-round, even in the summer.
200 * <P>
201 * The caller owns the list that is returned, but does not own the strings contained
202 * in that list. Delete the array with uprv_free(), but DON'T delete the elements in the array.
203 *
204 * <p>NOTE: uprv_free() is declared in the private header source/common/cmemory.h.
205 *
206 * @param rawOffset An offset from GMT in milliseconds.
207 * @param numIDs Receives the number of items in the array that is returned.
208 * @return An array of UnicodeString pointers, where each UnicodeString is
209 * a time zone ID for a time zone with the given GMT offset. If
210 * there is no timezone that matches the GMT offset
211 * specified, NULL is returned.
212 * @obsolete ICU 2.8. Use createEnumeration(int32_t) instead since this API will be removed in that release.
213 */
214 static const UnicodeString** createAvailableIDs(int32_t rawOffset, int32_t& numIDs);
215
216 /**
217 * Returns a list of time zone IDs associated with the given
218 * country. Some zones are affiliated with no country (e.g.,
219 * "UTC"); these may also be retrieved, as a group.
220 *
221 * <P>The caller owns the list that is returned, but does not own
222 * the strings contained in that list. Delete the array with uprv_free(), but
223 * <b>DON'T</b> delete the elements in the array.
224 *
225 * <p>NOTE: uprv_free() is declared in the private header source/common/cmemory.h.
226 *
227 * @param country The ISO 3166 two-letter country code, or NULL to
228 * retrieve zones not affiliated with any country.
229 * @param numIDs Receives the number of items in the array that is
230 * returned.
231 * @return An array of UnicodeString pointers, where each
232 * UnicodeString is a time zone ID for a time zone with the given
233 * country. If there is no timezone that matches the country
234 * specified, NULL is returned.
235 * @obsolete ICU 2.8. Use createEnumeration(const char*) instead since this API will be removed in that release.
236 */
237 static const UnicodeString** createAvailableIDs(const char* country,
238 int32_t& numIDs);
239
240 /**
241 * Returns a list of all time zone IDs supported by the TimeZone class (i.e., all
242 * IDs that it's legal to pass to createTimeZone()). The caller owns the list that
243 * is returned, but does not own the strings contained in that list. Delete the array with uprv_free(),
244 * but DON'T delete the elements in the array.
245 *
246 * <p>NOTE: uprv_free() is declared in the private header source/common/cmemory.h.
247 *
248 * @param numIDs Receives the number of zone IDs returned.
249 * @return An array of UnicodeString pointers, where each is a time zone ID
250 * supported by the TimeZone class.
251 * @obsolete ICU 2.8. Use createEnumeration(void) instead since this API will be removed in that release.
252 */
253 static const UnicodeString** createAvailableIDs(int32_t& numIDs);
254 #endif
255
256 /**
257 * Returns the number of IDs in the equivalency group that
258 * includes the given ID. An equivalency group contains zones
259 * that have the same GMT offset and rules.
260 *
261 * <p>The returned count includes the given ID; it is always >= 1.
262 * The given ID must be a system time zone. If it is not, returns
263 * zero.
264 * @param id a system time zone ID
265 * @return the number of zones in the equivalency group containing
266 * 'id', or zero if 'id' is not a valid system ID
267 * @see #getEquivalentID
268 * @stable ICU 2.0
269 */
270 static int32_t U_EXPORT2 countEquivalentIDs(const UnicodeString& id);
271
272 /**
273 * Returns an ID in the equivalency group that
274 * includes the given ID. An equivalency group contains zones
275 * that have the same GMT offset and rules.
276 *
277 * <p>The given index must be in the range 0..n-1, where n is the
278 * value returned by <code>countEquivalentIDs(id)</code>. For
279 * some value of 'index', the returned value will be equal to the
280 * given id. If the given id is not a valid system time zone, or
281 * if 'index' is out of range, then returns an empty string.
282 * @param id a system time zone ID
283 * @param index a value from 0 to n-1, where n is the value
284 * returned by <code>countEquivalentIDs(id)</code>
285 * @return the ID of the index-th zone in the equivalency group
286 * containing 'id', or an empty string if 'id' is not a valid
287 * system ID or 'index' is out of range
288 * @see #countEquivalentIDs
289 * @stable ICU 2.0
290 */
291 static const UnicodeString U_EXPORT2 getEquivalentID(const UnicodeString& id,
292 int32_t index);
293
294 /**
295 * Creates a new copy of the default TimeZone for this host. Unless the default time
296 * zone has already been set using adoptDefault() or setDefault(), the default is
297 * determined by querying the system using methods in TPlatformUtilities. If the
298 * system routines fail, or if they specify a TimeZone or TimeZone offset which is not
299 * recognized, the TimeZone indicated by the ID kLastResortID is instantiated
300 * and made the default.
301 *
302 * @return A default TimeZone. Clients are responsible for deleting the time zone
303 * object returned.
304 * @stable ICU 2.0
305 */
306 static TimeZone* U_EXPORT2 createDefault(void);
307
308 /**
309 * Sets the default time zone (i.e., what's returned by createDefault()) to be the
310 * specified time zone. If NULL is specified for the time zone, the default time
311 * zone is set to the default host time zone. This call adopts the TimeZone object
312 * passed in; the clent is no longer responsible for deleting it.
313 *
314 * @param zone A pointer to the new TimeZone object to use as the default.
315 * @stable ICU 2.0
316 */
317 static void U_EXPORT2 adoptDefault(TimeZone* zone);
318
319 /**
320 * Same as adoptDefault(), except that the TimeZone object passed in is NOT adopted;
321 * the caller remains responsible for deleting it.
322 *
323 * @param zone The given timezone.
324 * @system
325 */
326 static void U_EXPORT2 setDefault(const TimeZone& zone);
327
328 /**
329 * Returns the timezone data version currently used by ICU.
330 * @param status Output param to filled in with a success or an error.
331 * @return the version string, such as "2007f"
332 * @draft ICU 3.8
333 */
334 static const char* U_EXPORT2 getTZDataVersion(UErrorCode& status);
335
336 /**
337 * Returns true if the two TimeZones are equal. (The TimeZone version only compares
338 * IDs, but subclasses are expected to also compare the fields they add.)
339 *
340 * @param that The TimeZone object to be compared with.
341 * @return True if the given TimeZone is equal to this TimeZone; false
342 * otherwise.
343 * @stable ICU 2.0
344 */
345 virtual UBool operator==(const TimeZone& that) const;
346
347 /**
348 * Returns true if the two TimeZones are NOT equal; that is, if operator==() returns
349 * false.
350 *
351 * @param that The TimeZone object to be compared with.
352 * @return True if the given TimeZone is not equal to this TimeZone; false
353 * otherwise.
354 * @stable ICU 2.0
355 */
356 UBool operator!=(const TimeZone& that) const {return !operator==(that);}
357
358 /**
359 * Returns the TimeZone's adjusted GMT offset (i.e., the number of milliseconds to add
360 * to GMT to get local time in this time zone, taking daylight savings time into
361 * account) as of a particular reference date. The reference date is used to determine
362 * whether daylight savings time is in effect and needs to be figured into the offset
363 * that is returned (in other words, what is the adjusted GMT offset in this time zone
364 * at this particular date and time?). For the time zones produced by createTimeZone(),
365 * the reference data is specified according to the Gregorian calendar, and the date
366 * and time fields are local standard time.
367 *
368 * <p>Note: Don't call this method. Instead, call the getOffset(UDate...) overload,
369 * which returns both the raw and the DST offset for a given time. This method
370 * is retained only for backward compatibility.
371 *
372 * @param era The reference date's era
373 * @param year The reference date's year
374 * @param month The reference date's month (0-based; 0 is January)
375 * @param day The reference date's day-in-month (1-based)
376 * @param dayOfWeek The reference date's day-of-week (1-based; 1 is Sunday)
377 * @param millis The reference date's milliseconds in day, local standard time
378 * @param status Output param to filled in with a success or an error.
379 * @return The offset in milliseconds to add to GMT to get local time.
380 * @stable ICU 2.0
381 */
382 virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,
383 uint8_t dayOfWeek, int32_t millis, UErrorCode& status) const = 0;
384
385 /**
386 * Gets the time zone offset, for current date, modified in case of
387 * daylight savings. This is the offset to add *to* UTC to get local time.
388 *
389 * <p>Note: Don't call this method. Instead, call the getOffset(UDate...) overload,
390 * which returns both the raw and the DST offset for a given time. This method
391 * is retained only for backward compatibility.
392 *
393 * @param era the era of the given date.
394 * @param year the year in the given date.
395 * @param month the month in the given date.
396 * Month is 0-based. e.g., 0 for January.
397 * @param day the day-in-month of the given date.
398 * @param dayOfWeek the day-of-week of the given date.
399 * @param milliseconds the millis in day in <em>standard</em> local time.
400 * @param monthLength the length of the given month in days.
401 * @param status Output param to filled in with a success or an error.
402 * @return the offset to add *to* GMT to get local time.
403 * @stable ICU 2.0
404 */
405 virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day,
406 uint8_t dayOfWeek, int32_t milliseconds,
407 int32_t monthLength, UErrorCode& status) const = 0;
408
409 /**
410 * Returns the time zone raw and GMT offset for the given moment
411 * in time. Upon return, local-millis = GMT-millis + rawOffset +
412 * dstOffset. All computations are performed in the proleptic
413 * Gregorian calendar. The default implementation in the TimeZone
414 * class delegates to the 8-argument getOffset().
415 *
416 * @param date moment in time for which to return offsets, in
417 * units of milliseconds from January 1, 1970 0:00 GMT, either GMT
418 * time or local wall time, depending on `local'.
419 * @param local if true, `date' is local wall time; otherwise it
420 * is in GMT time.
421 * @param rawOffset output parameter to receive the raw offset, that
422 * is, the offset not including DST adjustments
423 * @param dstOffset output parameter to receive the DST offset,
424 * that is, the offset to be added to `rawOffset' to obtain the
425 * total offset between local and GMT time. If DST is not in
426 * effect, this value is zero; otherwise it is a positive value,
427 * typically one hour.
428 * @param ec input-output error code
429 *
430 * @stable ICU 2.8
431 */
432 virtual void getOffset(UDate date, UBool local, int32_t& rawOffset,
433 int32_t& dstOffset, UErrorCode& ec) const;
434
435 /**
436 * Sets the TimeZone's raw GMT offset (i.e., the number of milliseconds to add
437 * to GMT to get local time, before taking daylight savings time into account).
438 *
439 * @param offsetMillis The new raw GMT offset for this time zone.
440 * @stable ICU 2.0
441 */
442 virtual void setRawOffset(int32_t offsetMillis) = 0;
443
444 /**
445 * Returns the TimeZone's raw GMT offset (i.e., the number of milliseconds to add
446 * to GMT to get local time, before taking daylight savings time into account).
447 *
448 * @return The TimeZone's raw GMT offset.
449 * @stable ICU 2.0
450 */
451 virtual int32_t getRawOffset(void) const = 0;
452
453 /**
454 * Fills in "ID" with the TimeZone's ID.
455 *
456 * @param ID Receives this TimeZone's ID.
457 * @return A reference to 'ID'
458 * @stable ICU 2.0
459 */
460 UnicodeString& getID(UnicodeString& ID) const;
461
462 /**
463 * Sets the TimeZone's ID to the specified value. This doesn't affect any other
464 * fields (for example, if you say<
465 * blockquote><pre>
466 * . TimeZone* foo = TimeZone::createTimeZone("America/New_York");
467 * . foo.setID("America/Los_Angeles");
468 * </pre>\htmlonly</blockquote>\endhtmlonly
469 * the time zone's GMT offset and daylight-savings rules don't change to those for
470 * Los Angeles. They're still those for New York. Only the ID has changed.)
471 *
472 * @param ID The new timezone ID.
473 * @stable ICU 2.0
474 */
475 void setID(const UnicodeString& ID);
476
477 /**
478 * Enum for use with getDisplayName
479 * @stable ICU 2.4
480 */
481 enum EDisplayType {
482 /**
483 * Selector for short display name
484 * @stable ICU 2.4
485 */
486 SHORT = 1,
487 /**
488 * Selector for long display name
489 * @stable ICU 2.4
490 */
491 LONG
492 };
493
494 /**
495 * Returns a name of this time zone suitable for presentation to the user
496 * in the default locale.
497 * This method returns the long name, not including daylight savings.
498 * If the display name is not available for the locale,
499 * then this method returns a string in the format
500 * <code>GMT[+-]hh:mm</code>.
501 * @param result the human-readable name of this time zone in the default locale.
502 * @return A reference to 'result'.
503 * @stable ICU 2.0
504 */
505 UnicodeString& getDisplayName(UnicodeString& result) const;
506
507 /**
508 * Returns a name of this time zone suitable for presentation to the user
509 * in the specified locale.
510 * This method returns the long name, not including daylight savings.
511 * If the display name is not available for the locale,
512 * then this method returns a string in the format
513 * <code>GMT[+-]hh:mm</code>.
514 * @param locale the locale in which to supply the display name.
515 * @param result the human-readable name of this time zone in the given locale
516 * or in the default locale if the given locale is not recognized.
517 * @return A reference to 'result'.
518 * @stable ICU 2.0
519 */
520 UnicodeString& getDisplayName(const Locale& locale, UnicodeString& result) const;
521
522 /**
523 * Returns a name of this time zone suitable for presentation to the user
524 * in the default locale.
525 * If the display name is not available for the locale,
526 * then this method returns a string in the format
527 * <code>GMT[+-]hh:mm</code>.
528 * @param daylight if true, return the daylight savings name.
529 * @param style either <code>LONG</code> or <code>SHORT</code>
530 * @param result the human-readable name of this time zone in the default locale.
531 * @return A reference to 'result'.
532 * @stable ICU 2.0
533 */
534 UnicodeString& getDisplayName(UBool daylight, EDisplayType style, UnicodeString& result) const;
535
536 /**
537 * Returns a name of this time zone suitable for presentation to the user
538 * in the specified locale.
539 * If the display name is not available for the locale,
540 * then this method returns a string in the format
541 * <code>GMT[+-]hh:mm</code>.
542 * @param daylight if true, return the daylight savings name.
543 * @param style either <code>LONG</code> or <code>SHORT</code>
544 * @param locale the locale in which to supply the display name.
545 * @param result the human-readable name of this time zone in the given locale
546 * or in the default locale if the given locale is not recognized.
547 * @return A refence to 'result'.
548 * @stable ICU 2.0
549 */
550 UnicodeString& getDisplayName(UBool daylight, EDisplayType style, const Locale& locale, UnicodeString& result) const;
551
552 /**
553 * Queries if this time zone uses daylight savings time.
554 * @return true if this time zone uses daylight savings time,
555 * false, otherwise.
556 * @stable ICU 2.0
557 */
558 virtual UBool useDaylightTime(void) const = 0;
559
560 /**
561 * Queries if the given date is in daylight savings time in
562 * this time zone.
563 * This method is wasteful since it creates a new GregorianCalendar and
564 * deletes it each time it is called. This is a deprecated method
565 * and provided only for Java compatibility.
566 *
567 * @param date the given UDate.
568 * @param status Output param filled in with success/error code.
569 * @return true if the given date is in daylight savings time,
570 * false, otherwise.
571 * @deprecated ICU 2.4. Use Calendar::inDaylightTime() instead.
572 */
573 virtual UBool inDaylightTime(UDate date, UErrorCode& status) const = 0;
574
575 /**
576 * Returns true if this zone has the same rule and offset as another zone.
577 * That is, if this zone differs only in ID, if at all.
578 * @param other the <code>TimeZone</code> object to be compared with
579 * @return true if the given zone is the same as this one,
580 * with the possible exception of the ID
581 * @stable ICU 2.0
582 */
583 virtual UBool hasSameRules(const TimeZone& other) const;
584
585 /**
586 * Clones TimeZone objects polymorphically. Clients are responsible for deleting
587 * the TimeZone object cloned.
588 *
589 * @return A new copy of this TimeZone object.
590 * @stable ICU 2.0
591 */
592 virtual TimeZone* clone(void) const = 0;
593
594 /**
595 * Return the class ID for this class. This is useful only for
596 * comparing to a return value from getDynamicClassID().
597 * @return The class ID for all objects of this class.
598 * @stable ICU 2.0
599 */
600 static UClassID U_EXPORT2 getStaticClassID(void);
601
602 /**
603 * Returns a unique class ID POLYMORPHICALLY. This method is to
604 * implement a simple version of RTTI, since not all C++ compilers support genuine
605 * RTTI. Polymorphic operator==() and clone() methods call this method.
606 * <P>
607 * Concrete subclasses of TimeZone must use the UOBJECT_DEFINE_RTTI_IMPLEMENTATION
608 * macro from uobject.h in their implementation to provide correct RTTI information.
609 * @return The class ID for this object. All objects of a given class have the
610 * same class ID. Objects of other classes have different class IDs.
611 * @stable ICU 2.0
612 */
613 virtual UClassID getDynamicClassID(void) const = 0;
614
615 /**
616 * Returns the amount of time to be added to local standard time
617 * to get local wall clock time.
618 * <p>
619 * The default implementation always returns 3600000 milliseconds
620 * (i.e., one hour) if this time zone observes Daylight Saving
621 * Time. Otherwise, 0 (zero) is returned.
622 * <p>
623 * If an underlying TimeZone implementation subclass supports
624 * historical Daylight Saving Time changes, this method returns
625 * the known latest daylight saving value.
626 *
627 * @return the amount of saving time in milliseconds
628 * @stable ICU 3.6
629 */
630 virtual int32_t getDSTSavings() const;
631
632 protected:
633
634 /**
635 * Default constructor. ID is initialized to the empty string.
636 * @stable ICU 2.0
637 */
638 TimeZone();
639
640 /**
641 * Construct a timezone with a given ID.
642 * @param id a system time zone ID
643 * @stable ICU 2.0
644 */
645 TimeZone(const UnicodeString &id);
646
647 /**
648 * Copy constructor.
649 * @param source the object to be copied.
650 * @stable ICU 2.0
651 */
652 TimeZone(const TimeZone& source);
653
654 /**
655 * Default assignment operator.
656 * @param right the object to be copied.
657 * @stable ICU 2.0
658 */
659 TimeZone& operator=(const TimeZone& right);
660
661 /**
662 * Utility function. For internally loading rule data.
663 * @param top Top resource bundle for tz data
664 * @param ruleid ID of rule to load
665 * @param oldbundle Old bundle to reuse or NULL
666 * @param status Status parameter
667 * @return either a new bundle or *oldbundle
668 * @internal
669 */
670 static UResourceBundle* loadRule(const UResourceBundle* top, const UnicodeString& ruleid, UResourceBundle* oldbundle, UErrorCode&status);
671
672 private:
673 friend class ZoneMeta;
674
675 /**
676 * Get a canonical Olson zone ID for the given ID. If the given ID is not valid,
677 * this method returns empty string as the result. If the given ID is a link, then the
678 * referenced ID (canonical ID) is returned.
679 */
680 static UnicodeString& getOlsonCanonicalID(const UnicodeString &id, UnicodeString &canonical);
681
682 static TimeZone* createCustomTimeZone(const UnicodeString&); // Creates a time zone based on the string.
683
684 /**
685 * Responsible for setting up DEFAULT_ZONE. Uses routines in TPlatformUtilities
686 * (i.e., platform-specific calls) to get the current system time zone. Failing
687 * that, uses the platform-specific default time zone. Failing that, uses GMT.
688 */
689 static void initDefault(void);
690
691 // See source file for documentation
692 /**
693 * Lookup the given name in our system zone table. If found,
694 * instantiate a new zone of that name and return it. If not
695 * found, return 0.
696 * @param name tthe given name of a system time zone.
697 * @return the timezone indicated by the 'name'.
698 */
699 static TimeZone* createSystemTimeZone(const UnicodeString& name);
700
701 UnicodeString fID; // this time zone's ID
702 };
703
704
705 // -------------------------------------
706
707 inline UnicodeString&
getID(UnicodeString & ID)708 TimeZone::getID(UnicodeString& ID) const
709 {
710 ID = fID;
711 return ID;
712 }
713
714 // -------------------------------------
715
716 inline void
setID(const UnicodeString & ID)717 TimeZone::setID(const UnicodeString& ID)
718 {
719 fID = ID;
720 }
721 U_NAMESPACE_END
722
723 #endif /* #if !UCONFIG_NO_FORMATTING */
724
725 #endif //_TIMEZONE
726 //eof
727