1 /************************************************************************* 2 * Copyright (c) 1997-2012, 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 #include "unicode/ucal.h" 43 44 U_NAMESPACE_BEGIN 45 46 class StringEnumeration; 47 48 /** 49 * 50 * <code>TimeZone</code> represents a time zone offset, and also figures out daylight 51 * savings. 52 * 53 * <p> 54 * Typically, you get a <code>TimeZone</code> using <code>createDefault</code> 55 * which creates a <code>TimeZone</code> based on the time zone where the program 56 * is running. For example, for a program running in Japan, <code>createDefault</code> 57 * creates a <code>TimeZone</code> object based on Japanese Standard Time. 58 * 59 * <p> 60 * You can also get a <code>TimeZone</code> using <code>createTimeZone</code> along 61 * with a time zone ID. For instance, the time zone ID for the US Pacific 62 * Time zone is "America/Los_Angeles". So, you can get a Pacific Time <code>TimeZone</code> object 63 * with: 64 * \htmlonly<blockquote>\endhtmlonly 65 * <pre> 66 * TimeZone *tz = TimeZone::createTimeZone("America/Los_Angeles"); 67 * </pre> 68 * \htmlonly</blockquote>\endhtmlonly 69 * You can use <code>getAvailableIDs</code> method to iterate through 70 * all the supported time zone IDs, or getCanonicalID method to check 71 * if a time zone ID is supported or not. You can then choose a 72 * supported ID to get a <code>TimeZone</code>. 73 * If the time zone you want is not represented by one of the 74 * supported IDs, then you can create a custom time zone ID with 75 * the following syntax: 76 * 77 * \htmlonly<blockquote>\endhtmlonly 78 * <pre> 79 * GMT[+|-]hh[[:]mm] 80 * </pre> 81 * \htmlonly</blockquote>\endhtmlonly 82 * 83 * For example, you might specify GMT+14:00 as a custom 84 * time zone ID. The <code>TimeZone</code> that is returned 85 * when you specify a custom time zone ID uses the specified 86 * offset from GMT(=UTC) and does not observe daylight saving 87 * time. For example, you might specify GMT+14:00 as a custom 88 * time zone ID to create a TimeZone representing 14 hours ahead 89 * of GMT (with no daylight saving time). In addition, 90 * <code>getCanonicalID</code> can also be used to 91 * normalize a custom time zone ID. 92 * 93 * TimeZone is an abstract class representing a time zone. A TimeZone is needed for 94 * Calendar to produce local time for a particular time zone. A TimeZone comprises 95 * three basic pieces of information: 96 * <ul> 97 * <li>A time zone offset; that, is the number of milliseconds to add or subtract 98 * from a time expressed in terms of GMT to convert it to the same time in that 99 * time zone (without taking daylight savings time into account).</li> 100 * <li>Logic necessary to take daylight savings time into account if daylight savings 101 * time is observed in that time zone (e.g., the days and hours on which daylight 102 * savings time begins and ends).</li> 103 * <li>An ID. This is a text string that uniquely identifies the time zone.</li> 104 * </ul> 105 * 106 * (Only the ID is actually implemented in TimeZone; subclasses of TimeZone may handle 107 * daylight savings time and GMT offset in different ways. Currently we have the following 108 * TimeZone subclasses: RuleBasedTimeZone, SimpleTimeZone, and VTimeZone.) 109 * <P> 110 * The TimeZone class contains a static list containing a TimeZone object for every 111 * combination of GMT offset and daylight-savings time rules currently in use in the 112 * world, each with a unique ID. Each ID consists of a region (usually a continent or 113 * ocean) and a city in that region, separated by a slash, (for example, US Pacific 114 * Time is "America/Los_Angeles.") Because older versions of this class used 115 * three- or four-letter abbreviations instead, there is also a table that maps the older 116 * abbreviations to the newer ones (for example, "PST" maps to "America/Los_Angeles"). 117 * Anywhere the API requires an ID, you can use either form. 118 * <P> 119 * To create a new TimeZone, you call the factory function TimeZone::createTimeZone() 120 * and pass it a time zone ID. You can use the createEnumeration() function to 121 * obtain a list of all the time zone IDs recognized by createTimeZone(). 122 * <P> 123 * You can also use TimeZone::createDefault() to create a TimeZone. This function uses 124 * platform-specific APIs to produce a TimeZone for the time zone corresponding to 125 * the client's computer's physical location. For example, if you're in Japan (assuming 126 * your machine is set up correctly), TimeZone::createDefault() will return a TimeZone 127 * for Japanese Standard Time ("Asia/Tokyo"). 128 */ 129 class U_I18N_API TimeZone : public UObject { 130 public: 131 /** 132 * @stable ICU 2.0 133 */ 134 virtual ~TimeZone(); 135 136 #ifndef U_HIDE_DRAFT_API 137 /** 138 * Returns the "unknown" time zone. 139 * It behaves like the GMT/UTC time zone but has the 140 * <code>UCAL_UNKNOWN_ZONE_ID</code> = "Etc/Unknown". 141 * createTimeZone() returns a mutable clone of this time zone if the input ID is not recognized. 142 * 143 * @return the "unknown" time zone. 144 * @see UCAL_UNKNOWN_ZONE_ID 145 * @see createTimeZone 146 * @see getGMT 147 * @draft ICU 49 148 */ 149 static const TimeZone& U_EXPORT2 getUnknown(); 150 #endif /* U_HIDE_DRAFT_API */ 151 152 /** 153 * The GMT (=UTC) time zone has a raw offset of zero and does not use daylight 154 * savings time. This is a commonly used time zone. 155 * 156 * <p>Note: For backward compatibility reason, the ID used by the time 157 * zone returned by this method is "GMT", although the ICU's canonical 158 * ID for the GMT time zone is "Etc/GMT". 159 * 160 * @return the GMT/UTC time zone. 161 * @see getUnknown 162 * @stable ICU 2.0 163 */ 164 static const TimeZone* U_EXPORT2 getGMT(void); 165 166 /** 167 * Creates a <code>TimeZone</code> for the given ID. 168 * @param ID the ID for a <code>TimeZone</code>, such as "America/Los_Angeles", 169 * or a custom ID such as "GMT-8:00". 170 * @return the specified <code>TimeZone</code>, or a mutable clone of getUnknown() 171 * if the given ID cannot be understood or if the given ID is "Etc/Unknown". 172 * The return result is guaranteed to be non-NULL. 173 * If you require that the specific zone asked for be returned, 174 * compare the result with getUnknown() or check the ID of the return result. 175 * @stable ICU 2.0 176 */ 177 static TimeZone* U_EXPORT2 createTimeZone(const UnicodeString& ID); 178 179 /** 180 * Returns an enumeration over system time zone IDs with the given 181 * filter conditions. 182 * @param zoneType The system time zone type. 183 * @param region The ISO 3166 two-letter country code or UN M.49 184 * three-digit area code. When NULL, no filtering 185 * done by region. 186 * @param rawOffset An offset from GMT in milliseconds, ignoring 187 * the effect of daylight savings time, if any. 188 * When NULL, no filtering done by zone offset. 189 * @param ec Output param to filled in with a success or 190 * an error. 191 * @return an enumeration object, owned by the caller. 192 * @stable ICU 4.8 193 */ 194 static StringEnumeration* U_EXPORT2 createTimeZoneIDEnumeration( 195 USystemTimeZoneType zoneType, 196 const char* region, 197 const int32_t* rawOffset, 198 UErrorCode& ec); 199 200 /** 201 * Returns an enumeration over all recognized time zone IDs. (i.e., 202 * all strings that createTimeZone() accepts) 203 * 204 * @return an enumeration object, owned by the caller. 205 * @stable ICU 2.4 206 */ 207 static StringEnumeration* U_EXPORT2 createEnumeration(); 208 209 /** 210 * Returns an enumeration over time zone IDs with a given raw 211 * offset from GMT. There may be several times zones with the 212 * same GMT offset that differ in the way they handle daylight 213 * savings time. For example, the state of Arizona doesn't 214 * observe daylight savings time. If you ask for the time zone 215 * IDs corresponding to GMT-7:00, you'll get back an enumeration 216 * over two time zone IDs: "America/Denver," which corresponds to 217 * Mountain Standard Time in the winter and Mountain Daylight Time 218 * in the summer, and "America/Phoenix", which corresponds to 219 * Mountain Standard Time year-round, even in the summer. 220 * 221 * @param rawOffset an offset from GMT in milliseconds, ignoring 222 * the effect of daylight savings time, if any 223 * @return an enumeration object, owned by the caller 224 * @stable ICU 2.4 225 */ 226 static StringEnumeration* U_EXPORT2 createEnumeration(int32_t rawOffset); 227 228 /** 229 * Returns an enumeration over time zone IDs associated with the 230 * given country. Some zones are affiliated with no country 231 * (e.g., "UTC"); these may also be retrieved, as a group. 232 * 233 * @param country The ISO 3166 two-letter country code, or NULL to 234 * retrieve zones not affiliated with any country. 235 * @return an enumeration object, owned by the caller 236 * @stable ICU 2.4 237 */ 238 static StringEnumeration* U_EXPORT2 createEnumeration(const char* country); 239 240 /** 241 * Returns the number of IDs in the equivalency group that 242 * includes the given ID. An equivalency group contains zones 243 * that have the same GMT offset and rules. 244 * 245 * <p>The returned count includes the given ID; it is always >= 1. 246 * The given ID must be a system time zone. If it is not, returns 247 * zero. 248 * @param id a system time zone ID 249 * @return the number of zones in the equivalency group containing 250 * 'id', or zero if 'id' is not a valid system ID 251 * @see #getEquivalentID 252 * @stable ICU 2.0 253 */ 254 static int32_t U_EXPORT2 countEquivalentIDs(const UnicodeString& id); 255 256 /** 257 * Returns an ID 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 given index must be in the range 0..n-1, where n is the 262 * value returned by <code>countEquivalentIDs(id)</code>. For 263 * some value of 'index', the returned value will be equal to the 264 * given id. If the given id is not a valid system time zone, or 265 * if 'index' is out of range, then returns an empty string. 266 * @param id a system time zone ID 267 * @param index a value from 0 to n-1, where n is the value 268 * returned by <code>countEquivalentIDs(id)</code> 269 * @return the ID of the index-th zone in the equivalency group 270 * containing 'id', or an empty string if 'id' is not a valid 271 * system ID or 'index' is out of range 272 * @see #countEquivalentIDs 273 * @stable ICU 2.0 274 */ 275 static const UnicodeString U_EXPORT2 getEquivalentID(const UnicodeString& id, 276 int32_t index); 277 278 /** 279 * Creates a new copy of the default TimeZone for this host. Unless the default time 280 * zone has already been set using adoptDefault() or setDefault(), the default is 281 * determined by querying the system using methods in TPlatformUtilities. If the 282 * system routines fail, or if they specify a TimeZone or TimeZone offset which is not 283 * recognized, the TimeZone indicated by the ID kLastResortID is instantiated 284 * and made the default. 285 * 286 * @return A default TimeZone. Clients are responsible for deleting the time zone 287 * object returned. 288 * @stable ICU 2.0 289 */ 290 static TimeZone* U_EXPORT2 createDefault(void); 291 292 /** 293 * Sets the default time zone (i.e., what's returned by createDefault()) to be the 294 * specified time zone. If NULL is specified for the time zone, the default time 295 * zone is set to the default host time zone. This call adopts the TimeZone object 296 * passed in; the clent is no longer responsible for deleting it. 297 * 298 * @param zone A pointer to the new TimeZone object to use as the default. 299 * @stable ICU 2.0 300 */ 301 static void U_EXPORT2 adoptDefault(TimeZone* zone); 302 303 #ifndef U_HIDE_SYSTEM_API 304 /** 305 * Same as adoptDefault(), except that the TimeZone object passed in is NOT adopted; 306 * the caller remains responsible for deleting it. 307 * 308 * @param zone The given timezone. 309 * @system 310 * @stable ICU 2.0 311 */ 312 static void U_EXPORT2 setDefault(const TimeZone& zone); 313 #endif /* U_HIDE_SYSTEM_API */ 314 315 /** 316 * Returns the timezone data version currently used by ICU. 317 * @param status Output param to filled in with a success or an error. 318 * @return the version string, such as "2007f" 319 * @stable ICU 3.8 320 */ 321 static const char* U_EXPORT2 getTZDataVersion(UErrorCode& status); 322 323 /** 324 * Returns the canonical system timezone ID or the normalized 325 * custom time zone ID for the given time zone ID. 326 * @param id The input time zone ID to be canonicalized. 327 * @param canonicalID Receives the canonical system time zone ID 328 * or the custom time zone ID in normalized format. 329 * @param status Recevies the status. When the given time zone ID 330 * is neither a known system time zone ID nor a 331 * valid custom time zone ID, U_ILLEGAL_ARGUMENT_ERROR 332 * is set. 333 * @return A reference to the result. 334 * @stable ICU 4.0 335 */ 336 static UnicodeString& U_EXPORT2 getCanonicalID(const UnicodeString& id, 337 UnicodeString& canonicalID, UErrorCode& status); 338 339 /** 340 * Returns the canonical system time zone ID or the normalized 341 * custom time zone ID for the given time zone ID. 342 * @param id The input time zone ID to be canonicalized. 343 * @param canonicalID Receives the canonical system time zone ID 344 * or the custom time zone ID in normalized format. 345 * @param isSystemID Receives if the given ID is a known system 346 * time zone ID. 347 * @param status Recevies the status. When the given time zone ID 348 * is neither a known system time zone ID nor a 349 * valid custom time zone ID, U_ILLEGAL_ARGUMENT_ERROR 350 * is set. 351 * @return A reference to the result. 352 * @stable ICU 4.0 353 */ 354 static UnicodeString& U_EXPORT2 getCanonicalID(const UnicodeString& id, 355 UnicodeString& canonicalID, UBool& isSystemID, UErrorCode& status); 356 357 /** 358 * Returns true if the two TimeZones are equal. (The TimeZone version only compares 359 * IDs, but subclasses are expected to also compare the fields they add.) 360 * 361 * @param that The TimeZone object to be compared with. 362 * @return True if the given TimeZone is equal to this TimeZone; false 363 * otherwise. 364 * @stable ICU 2.0 365 */ 366 virtual UBool operator==(const TimeZone& that) const; 367 368 /** 369 * Returns true if the two TimeZones are NOT equal; that is, if operator==() returns 370 * false. 371 * 372 * @param that The TimeZone object to be compared with. 373 * @return True if the given TimeZone is not equal to this TimeZone; false 374 * otherwise. 375 * @stable ICU 2.0 376 */ 377 UBool operator!=(const TimeZone& that) const {return !operator==(that);} 378 379 /** 380 * Returns the TimeZone's adjusted GMT offset (i.e., the number of milliseconds to add 381 * to GMT to get local time in this time zone, taking daylight savings time into 382 * account) as of a particular reference date. The reference date is used to determine 383 * whether daylight savings time is in effect and needs to be figured into the offset 384 * that is returned (in other words, what is the adjusted GMT offset in this time zone 385 * at this particular date and time?). For the time zones produced by createTimeZone(), 386 * the reference data is specified according to the Gregorian calendar, and the date 387 * and time fields are local standard 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 reference date's era 394 * @param year The reference date's year 395 * @param month The reference date's month (0-based; 0 is January) 396 * @param day The reference date's day-in-month (1-based) 397 * @param dayOfWeek The reference date's day-of-week (1-based; 1 is Sunday) 398 * @param millis The reference date's milliseconds in day, local standard time 399 * @param status Output param to filled in with a success or an error. 400 * @return The offset in milliseconds to add to GMT to get local time. 401 * @stable ICU 2.0 402 */ 403 virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day, 404 uint8_t dayOfWeek, int32_t millis, UErrorCode& status) const = 0; 405 406 /** 407 * Gets the time zone offset, for current date, modified in case of 408 * daylight savings. This is the offset to add *to* UTC to get local time. 409 * 410 * <p>Note: Don't call this method. Instead, call the getOffset(UDate...) overload, 411 * which returns both the raw and the DST offset for a given time. This method 412 * is retained only for backward compatibility. 413 * 414 * @param era the era of the given date. 415 * @param year the year in the given date. 416 * @param month the month in the given date. 417 * Month is 0-based. e.g., 0 for January. 418 * @param day the day-in-month of the given date. 419 * @param dayOfWeek the day-of-week of the given date. 420 * @param milliseconds the millis in day in <em>standard</em> local time. 421 * @param monthLength the length of the given month in days. 422 * @param status Output param to filled in with a success or an error. 423 * @return the offset to add *to* GMT to get local time. 424 * @stable ICU 2.0 425 */ 426 virtual int32_t getOffset(uint8_t era, int32_t year, int32_t month, int32_t day, 427 uint8_t dayOfWeek, int32_t milliseconds, 428 int32_t monthLength, UErrorCode& status) const = 0; 429 430 /** 431 * Returns the time zone raw and GMT offset for the given moment 432 * in time. Upon return, local-millis = GMT-millis + rawOffset + 433 * dstOffset. All computations are performed in the proleptic 434 * Gregorian calendar. The default implementation in the TimeZone 435 * class delegates to the 8-argument getOffset(). 436 * 437 * @param date moment in time for which to return offsets, in 438 * units of milliseconds from January 1, 1970 0:00 GMT, either GMT 439 * time or local wall time, depending on `local'. 440 * @param local if true, `date' is local wall time; otherwise it 441 * is in GMT time. 442 * @param rawOffset output parameter to receive the raw offset, that 443 * is, the offset not including DST adjustments 444 * @param dstOffset output parameter to receive the DST offset, 445 * that is, the offset to be added to `rawOffset' to obtain the 446 * total offset between local and GMT time. If DST is not in 447 * effect, this value is zero; otherwise it is a positive value, 448 * typically one hour. 449 * @param ec input-output error code 450 * 451 * @stable ICU 2.8 452 */ 453 virtual void getOffset(UDate date, UBool local, int32_t& rawOffset, 454 int32_t& dstOffset, UErrorCode& ec) const; 455 456 /** 457 * Sets the TimeZone's raw GMT offset (i.e., the number of milliseconds to add 458 * to GMT to get local time, before taking daylight savings time into account). 459 * 460 * @param offsetMillis The new raw GMT offset for this time zone. 461 * @stable ICU 2.0 462 */ 463 virtual void setRawOffset(int32_t offsetMillis) = 0; 464 465 /** 466 * Returns the TimeZone's raw GMT offset (i.e., the number of milliseconds to add 467 * to GMT to get local time, before taking daylight savings time into account). 468 * 469 * @return The TimeZone's raw GMT offset. 470 * @stable ICU 2.0 471 */ 472 virtual int32_t getRawOffset(void) const = 0; 473 474 /** 475 * Fills in "ID" with the TimeZone's ID. 476 * 477 * @param ID Receives this TimeZone's ID. 478 * @return A reference to 'ID' 479 * @stable ICU 2.0 480 */ 481 UnicodeString& getID(UnicodeString& ID) const; 482 483 /** 484 * Sets the TimeZone's ID to the specified value. This doesn't affect any other 485 * fields (for example, if you say< 486 * blockquote><pre> 487 * . TimeZone* foo = TimeZone::createTimeZone("America/New_York"); 488 * . foo.setID("America/Los_Angeles"); 489 * </pre>\htmlonly</blockquote>\endhtmlonly 490 * the time zone's GMT offset and daylight-savings rules don't change to those for 491 * Los Angeles. They're still those for New York. Only the ID has changed.) 492 * 493 * @param ID The new time zone ID. 494 * @stable ICU 2.0 495 */ 496 void setID(const UnicodeString& ID); 497 498 /** 499 * Enum for use with getDisplayName 500 * @stable ICU 2.4 501 */ 502 enum EDisplayType { 503 /** 504 * Selector for short display name 505 * @stable ICU 2.4 506 */ 507 SHORT = 1, 508 /** 509 * Selector for long display name 510 * @stable ICU 2.4 511 */ 512 LONG, 513 /** 514 * Selector for short generic display name 515 * @stable ICU 4.4 516 */ 517 SHORT_GENERIC, 518 /** 519 * Selector for long generic display name 520 * @stable ICU 4.4 521 */ 522 LONG_GENERIC, 523 /** 524 * Selector for short display name derived 525 * from time zone offset 526 * @stable ICU 4.4 527 */ 528 SHORT_GMT, 529 /** 530 * Selector for long display name derived 531 * from time zone offset 532 * @stable ICU 4.4 533 */ 534 LONG_GMT, 535 /** 536 * Selector for short display name derived 537 * from the time zone's fallback name 538 * @stable ICU 4.4 539 */ 540 SHORT_COMMONLY_USED, 541 /** 542 * Selector for long display name derived 543 * from the time zone's fallback name 544 * @stable ICU 4.4 545 */ 546 GENERIC_LOCATION 547 }; 548 549 /** 550 * Returns a name of this time zone suitable for presentation to the user 551 * in the default locale. 552 * This method returns the long name, not including daylight savings. 553 * If the display name is not available for the locale, 554 * then this method returns a string in the format 555 * <code>GMT[+-]hh:mm</code>. 556 * @param result the human-readable name of this time zone in the default locale. 557 * @return A reference to 'result'. 558 * @stable ICU 2.0 559 */ 560 UnicodeString& getDisplayName(UnicodeString& result) const; 561 562 /** 563 * Returns a name of this time zone suitable for presentation to the user 564 * in the specified locale. 565 * This method returns the long name, not including daylight savings. 566 * If the display name is not available for the locale, 567 * then this method returns a string in the format 568 * <code>GMT[+-]hh:mm</code>. 569 * @param locale the locale in which to supply the display name. 570 * @param result the human-readable name of this time zone in the given locale 571 * or in the default locale if the given locale is not recognized. 572 * @return A reference to 'result'. 573 * @stable ICU 2.0 574 */ 575 UnicodeString& getDisplayName(const Locale& locale, UnicodeString& result) const; 576 577 /** 578 * Returns a name of this time zone suitable for presentation to the user 579 * in the default locale. 580 * If the display name is not available for the locale, 581 * then this method returns a string in the format 582 * <code>GMT[+-]hh:mm</code>. 583 * @param daylight if true, return the daylight savings name. 584 * @param style 585 * @param result the human-readable name of this time zone in the default locale. 586 * @return A reference to 'result'. 587 * @stable ICU 2.0 588 */ 589 UnicodeString& getDisplayName(UBool daylight, EDisplayType style, UnicodeString& result) const; 590 591 /** 592 * Returns a name of this time zone suitable for presentation to the user 593 * in the specified locale. 594 * If the display name is not available for the locale, 595 * then this method returns a string in the format 596 * <code>GMT[+-]hh:mm</code>. 597 * @param daylight if true, return the daylight savings name. 598 * @param style 599 * @param locale the locale in which to supply the display name. 600 * @param result the human-readable name of this time zone in the given locale 601 * or in the default locale if the given locale is not recognized. 602 * @return A refence to 'result'. 603 * @stable ICU 2.0 604 */ 605 UnicodeString& getDisplayName(UBool daylight, EDisplayType style, const Locale& locale, UnicodeString& result) const; 606 607 /** 608 * Queries if this time zone uses daylight savings time. 609 * @return true if this time zone uses daylight savings time, 610 * false, otherwise. 611 * <p><strong>Note:</strong>The default implementation of 612 * ICU TimeZone uses the tz database, which supports historic 613 * rule changes, for system time zones. With the implementation, 614 * there are time zones that used daylight savings time in the 615 * past, but no longer used currently. For example, Asia/Tokyo has 616 * never used daylight savings time since 1951. Most clients would 617 * expect that this method to return <code>FALSE</code> for such case. 618 * The default implementation of this method returns <code>TRUE</code> 619 * when the time zone uses daylight savings time in the current 620 * (Gregorian) calendar year. 621 * <p>In Java 7, <code>observesDaylightTime()</code> was added in 622 * addition to <code>useDaylightTime()</code>. In Java, <code>useDaylightTime()</code> 623 * only checks if daylight saving time is observed by the last known 624 * rule. This specification might not be what most users would expect 625 * if daylight saving time is currently observed, but not scheduled 626 * in future. In this case, Java's <code>userDaylightTime()</code> returns 627 * <code>false</code>. To resolve the issue, Java 7 added <code>observesDaylightTime()</code>, 628 * which takes the current rule into account. The method <code>observesDaylightTime()</code> 629 * was added in ICU4J for supporting API signature compatibility with JDK. 630 * In general, ICU4C also provides JDK compatible methods, but the current 631 * implementation <code>userDaylightTime()</code> serves the purpose 632 * (takes the current rule into account), <code>observesDaylightTime()</code> 633 * is not added in ICU4C. In addition to <code>useDaylightTime()</code>, ICU4C 634 * <code>BasicTimeZone</code> class (Note that <code>TimeZone::createTimeZone(const UnicodeString &ID)</code> 635 * always returns a <code>BasicTimeZone</code>) provides a series of methods allowing 636 * historic and future time zone rule iteration, so you can check if daylight saving 637 * time is observed or not within a given period. 638 * 639 * @stable ICU 2.0 640 */ 641 virtual UBool useDaylightTime(void) const = 0; 642 643 /** 644 * Queries if the given date is in daylight savings time in 645 * this time zone. 646 * This method is wasteful since it creates a new GregorianCalendar and 647 * deletes it each time it is called. This is a deprecated method 648 * and provided only for Java compatibility. 649 * 650 * @param date the given UDate. 651 * @param status Output param filled in with success/error code. 652 * @return true if the given date is in daylight savings time, 653 * false, otherwise. 654 * @deprecated ICU 2.4. Use Calendar::inDaylightTime() instead. 655 */ 656 virtual UBool inDaylightTime(UDate date, UErrorCode& status) const = 0; 657 658 /** 659 * Returns true if this zone has the same rule and offset as another zone. 660 * That is, if this zone differs only in ID, if at all. 661 * @param other the <code>TimeZone</code> object to be compared with 662 * @return true if the given zone is the same as this one, 663 * with the possible exception of the ID 664 * @stable ICU 2.0 665 */ 666 virtual UBool hasSameRules(const TimeZone& other) const; 667 668 /** 669 * Clones TimeZone objects polymorphically. Clients are responsible for deleting 670 * the TimeZone object cloned. 671 * 672 * @return A new copy of this TimeZone object. 673 * @stable ICU 2.0 674 */ 675 virtual TimeZone* clone(void) const = 0; 676 677 /** 678 * Return the class ID for this class. This is useful only for 679 * comparing to a return value from getDynamicClassID(). 680 * @return The class ID for all objects of this class. 681 * @stable ICU 2.0 682 */ 683 static UClassID U_EXPORT2 getStaticClassID(void); 684 685 /** 686 * Returns a unique class ID POLYMORPHICALLY. This method is to 687 * implement a simple version of RTTI, since not all C++ compilers support genuine 688 * RTTI. Polymorphic operator==() and clone() methods call this method. 689 * <P> 690 * Concrete subclasses of TimeZone must use the UOBJECT_DEFINE_RTTI_IMPLEMENTATION 691 * macro from uobject.h in their implementation to provide correct RTTI information. 692 * @return The class ID for this object. All objects of a given class have the 693 * same class ID. Objects of other classes have different class IDs. 694 * @stable ICU 2.0 695 */ 696 virtual UClassID getDynamicClassID(void) const = 0; 697 698 /** 699 * Returns the amount of time to be added to local standard time 700 * to get local wall clock time. 701 * <p> 702 * The default implementation always returns 3600000 milliseconds 703 * (i.e., one hour) if this time zone observes Daylight Saving 704 * Time. Otherwise, 0 (zero) is returned. 705 * <p> 706 * If an underlying TimeZone implementation subclass supports 707 * historical Daylight Saving Time changes, this method returns 708 * the known latest daylight saving value. 709 * 710 * @return the amount of saving time in milliseconds 711 * @stable ICU 3.6 712 */ 713 virtual int32_t getDSTSavings() const; 714 715 /** 716 * Gets the region code associated with the given 717 * system time zone ID. The region code is either ISO 3166 718 * 2-letter country code or UN M.49 3-digit area code. 719 * When the time zone is not associated with a specific location, 720 * for example - "Etc/UTC", "EST5EDT", then this method returns 721 * "001" (UN M.49 area code for World). 722 * 723 * @param id The system time zone ID. 724 * @param region Output buffer for receiving the region code. 725 * @param capacity The size of the output buffer. 726 * @param status Receives the status. When the given time zone ID 727 * is not a known system time zone ID, 728 * U_ILLEGAL_ARGUMENT_ERROR is set. 729 * @return The length of the output region code. 730 * @stable ICU 4.8 731 */ 732 static int32_t U_EXPORT2 getRegion(const UnicodeString& id, 733 char *region, int32_t capacity, UErrorCode& status); 734 735 protected: 736 737 /** 738 * Default constructor. ID is initialized to the empty string. 739 * @stable ICU 2.0 740 */ 741 TimeZone(); 742 743 /** 744 * Construct a TimeZone with a given ID. 745 * @param id a system time zone ID 746 * @stable ICU 2.0 747 */ 748 TimeZone(const UnicodeString &id); 749 750 /** 751 * Copy constructor. 752 * @param source the object to be copied. 753 * @stable ICU 2.0 754 */ 755 TimeZone(const TimeZone& source); 756 757 /** 758 * Default assignment operator. 759 * @param right the object to be copied. 760 * @stable ICU 2.0 761 */ 762 TimeZone& operator=(const TimeZone& right); 763 764 #ifndef U_HIDE_INTERNAL_API 765 /** 766 * Utility function. For internally loading rule data. 767 * @param top Top resource bundle for tz data 768 * @param ruleid ID of rule to load 769 * @param oldbundle Old bundle to reuse or NULL 770 * @param status Status parameter 771 * @return either a new bundle or *oldbundle 772 * @internal 773 */ 774 static UResourceBundle* loadRule(const UResourceBundle* top, const UnicodeString& ruleid, UResourceBundle* oldbundle, UErrorCode&status); 775 #endif /* U_HIDE_INTERNAL_API */ 776 777 private: 778 friend class ZoneMeta; 779 780 781 static TimeZone* createCustomTimeZone(const UnicodeString&); // Creates a time zone based on the string. 782 783 /** 784 * Finds the given ID in the Olson tzdata. If the given ID is found in the tzdata, 785 * returns the pointer to the ID resource. This method is exposed through ZoneMeta class 786 * for ICU internal implementation and useful for building hashtable using a time zone 787 * ID as a key. 788 * @param id zone id string 789 * @return the pointer of the ID resource, or NULL. 790 */ 791 static const UChar* findID(const UnicodeString& id); 792 793 /** 794 * Resolve a link in Olson tzdata. When the given id is known and it's not a link, 795 * the id itself is returned. When the given id is known and it is a link, then 796 * dereferenced zone id is returned. When the given id is unknown, then it returns 797 * NULL. 798 * @param id zone id string 799 * @return the dereferenced zone or NULL 800 */ 801 static const UChar* dereferOlsonLink(const UnicodeString& id); 802 803 /** 804 * Returns the region code associated with the given zone, 805 * or NULL if the zone is not known. 806 * @param id zone id string 807 * @return the region associated with the given zone 808 */ 809 static const UChar* getRegion(const UnicodeString& id); 810 811 /** 812 * Returns the region code associated with the given zone, 813 * or NULL if the zone is not known. 814 * @param id zone id string 815 * @param status Status parameter 816 * @return the region associated with the given zone 817 */ 818 static const UChar* getRegion(const UnicodeString& id, UErrorCode& status); 819 820 /** 821 * Parses the given custom time zone identifier 822 * @param id id A string of the form GMT[+-]hh:mm, GMT[+-]hhmm, or 823 * GMT[+-]hh. 824 * @param sign Receves parsed sign, 1 for positive, -1 for negative. 825 * @param hour Receives parsed hour field 826 * @param minute Receives parsed minute field 827 * @param second Receives parsed second field 828 * @return Returns TRUE when the given custom id is valid. 829 */ 830 static UBool parseCustomID(const UnicodeString& id, int32_t& sign, int32_t& hour, 831 int32_t& minute, int32_t& second); 832 833 /** 834 * Parse a custom time zone identifier and return the normalized 835 * custom time zone identifier for the given custom id string. 836 * @param id a string of the form GMT[+-]hh:mm, GMT[+-]hhmm, or 837 * GMT[+-]hh. 838 * @param normalized Receives the normalized custom ID 839 * @param status Receives the status. When the input ID string is invalid, 840 * U_ILLEGAL_ARGUMENT_ERROR is set. 841 * @return The normalized custom id string. 842 */ 843 static UnicodeString& getCustomID(const UnicodeString& id, UnicodeString& normalized, 844 UErrorCode& status); 845 846 /** 847 * Returns the normalized custome time zone ID for the given offset fields. 848 * @param hour offset hours 849 * @param min offset minutes 850 * @param sec offset seconds 851 * @param negative sign of the offset, TRUE for negative offset. 852 * @param id Receves the format result (normalized custom ID) 853 * @return The reference to id 854 */ 855 static UnicodeString& formatCustomID(int32_t hour, int32_t min, int32_t sec, 856 UBool negative, UnicodeString& id); 857 858 /** 859 * Responsible for setting up DEFAULT_ZONE. Uses routines in TPlatformUtilities 860 * (i.e., platform-specific calls) to get the current system time zone. Failing 861 * that, uses the platform-specific default time zone. Failing that, uses GMT. 862 */ 863 static void initDefault(void); 864 865 // See source file for documentation 866 /** 867 * Lookup the given name in our system zone table. If found, 868 * instantiate a new zone of that name and return it. If not 869 * found, return 0. 870 * @param name tthe given name of a system time zone. 871 * @return the TimeZone indicated by the 'name'. 872 */ 873 static TimeZone* createSystemTimeZone(const UnicodeString& name); 874 static TimeZone* createSystemTimeZone(const UnicodeString& name, UErrorCode& ec); 875 876 UnicodeString fID; // this time zone's ID 877 878 friend class TZEnumeration; 879 }; 880 881 882 // ------------------------------------- 883 884 inline UnicodeString& 885 TimeZone::getID(UnicodeString& ID) const 886 { 887 ID = fID; 888 return ID; 889 } 890 891 // ------------------------------------- 892 893 inline void 894 TimeZone::setID(const UnicodeString& ID) 895 { 896 fID = ID; 897 } 898 U_NAMESPACE_END 899 900 #endif /* #if !UCONFIG_NO_FORMATTING */ 901 902 #endif //_TIMEZONE 903 //eof 904
