1 /* 2 * Copyright (c) 1996, 2011, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 /* 27 * (C) Copyright Taligent, Inc. 1996 - All Rights Reserved 28 * (C) Copyright IBM Corp. 1996 - All Rights Reserved 29 * 30 * The original version of this source code and documentation is copyrighted 31 * and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These 32 * materials are provided under terms of a License Agreement between Taligent 33 * and Sun. This technology is protected by multiple US and International 34 * patents. This notice and attribution to Taligent may not be removed. 35 * Taligent is a registered trademark of Taligent, Inc. 36 * 37 */ 38 39 package java.util; 40 41 import java.io.Serializable; 42 import java.lang.ref.SoftReference; 43 import java.security.AccessController; 44 import java.security.PrivilegedAction; 45 import java.util.concurrent.ConcurrentHashMap; 46 import sun.security.action.GetPropertyAction; 47 import sun.util.TimeZoneNameUtility; 48 import sun.util.calendar.ZoneInfo; 49 import sun.util.calendar.ZoneInfoFile; 50 51 /** 52 * <code>TimeZone</code> represents a time zone offset, and also figures out daylight 53 * savings. 54 * 55 * <p> 56 * Typically, you get a <code>TimeZone</code> using <code>getDefault</code> 57 * which creates a <code>TimeZone</code> based on the time zone where the program 58 * is running. For example, for a program running in Japan, <code>getDefault</code> 59 * creates a <code>TimeZone</code> object based on Japanese Standard Time. 60 * 61 * <p> 62 * You can also get a <code>TimeZone</code> using <code>getTimeZone</code> 63 * along with a time zone ID. For instance, the time zone ID for the 64 * U.S. Pacific Time zone is "America/Los_Angeles". So, you can get a 65 * U.S. Pacific Time <code>TimeZone</code> object with: 66 * <blockquote><pre> 67 * TimeZone tz = TimeZone.getTimeZone("America/Los_Angeles"); 68 * </pre></blockquote> 69 * You can use the <code>getAvailableIDs</code> method to iterate through 70 * all the supported time zone IDs. You can then choose a 71 * supported ID to get a <code>TimeZone</code>. 72 * If the time zone you want is not represented by one of the 73 * supported IDs, then a custom time zone ID can be specified to 74 * produce a TimeZone. The syntax of a custom time zone ID is: 75 * 76 * <blockquote><pre> 77 * <a name="CustomID"><i>CustomID:</i></a> 78 * <code>GMT</code> <i>Sign</i> <i>Hours</i> <code>:</code> <i>Minutes</i> 79 * <code>GMT</code> <i>Sign</i> <i>Hours</i> <i>Minutes</i> 80 * <code>GMT</code> <i>Sign</i> <i>Hours</i> 81 * <i>Sign:</i> one of 82 * <code>+ -</code> 83 * <i>Hours:</i> 84 * <i>Digit</i> 85 * <i>Digit</i> <i>Digit</i> 86 * <i>Minutes:</i> 87 * <i>Digit</i> <i>Digit</i> 88 * <i>Digit:</i> one of 89 * <code>0 1 2 3 4 5 6 7 8 9</code> 90 * </pre></blockquote> 91 * 92 * <i>Hours</i> must be between 0 to 23 and <i>Minutes</i> must be 93 * between 00 to 59. For example, "GMT+10" and "GMT+0010" mean ten 94 * hours and ten minutes ahead of GMT, respectively. 95 * <p> 96 * The format is locale independent and digits must be taken from the 97 * Basic Latin block of the Unicode standard. No daylight saving time 98 * transition schedule can be specified with a custom time zone ID. If 99 * the specified string doesn't match the syntax, <code>"GMT"</code> 100 * is used. 101 * <p> 102 * When creating a <code>TimeZone</code>, the specified custom time 103 * zone ID is normalized in the following syntax: 104 * <blockquote><pre> 105 * <a name="NormalizedCustomID"><i>NormalizedCustomID:</i></a> 106 * <code>GMT</code> <i>Sign</i> <i>TwoDigitHours</i> <code>:</code> <i>Minutes</i> 107 * <i>Sign:</i> one of 108 * <code>+ -</code> 109 * <i>TwoDigitHours:</i> 110 * <i>Digit</i> <i>Digit</i> 111 * <i>Minutes:</i> 112 * <i>Digit</i> <i>Digit</i> 113 * <i>Digit:</i> one of 114 * <code>0 1 2 3 4 5 6 7 8 9</code> 115 * </pre></blockquote> 116 * For example, TimeZone.getTimeZone("GMT-8").getID() returns "GMT-08:00". 117 * 118 * <h4>Three-letter time zone IDs</h4> 119 * 120 * For compatibility with JDK 1.1.x, some other three-letter time zone IDs 121 * (such as "PST", "CTT", "AST") are also supported. However, <strong>their 122 * use is deprecated</strong> because the same abbreviation is often used 123 * for multiple time zones (for example, "CST" could be U.S. "Central Standard 124 * Time" and "China Standard Time"), and the Java platform can then only 125 * recognize one of them. 126 * 127 * 128 * @see Calendar 129 * @see GregorianCalendar 130 * @see SimpleTimeZone 131 * @author Mark Davis, David Goldsmith, Chen-Lieh Huang, Alan Liu 132 * @since JDK1.1 133 */ 134 abstract public class TimeZone implements Serializable, Cloneable { 135 /** 136 * Sole constructor. (For invocation by subclass constructors, typically 137 * implicit.) 138 */ 139 public TimeZone() { 140 } 141 142 /** 143 * A style specifier for <code>getDisplayName()</code> indicating 144 * a short name, such as "PST." 145 * @see #LONG 146 * @since 1.2 147 */ 148 public static final int SHORT = 0; 149 150 /** 151 * A style specifier for <code>getDisplayName()</code> indicating 152 * a long name, such as "Pacific Standard Time." 153 * @see #SHORT 154 * @since 1.2 155 */ 156 public static final int LONG = 1; 157 158 // Constants used internally; unit is milliseconds 159 private static final int ONE_MINUTE = 60*1000; 160 private static final int ONE_HOUR = 60*ONE_MINUTE; 161 private static final int ONE_DAY = 24*ONE_HOUR; 162 163 // Proclaim serialization compatibility with JDK 1.1 164 static final long serialVersionUID = 3581463369166924961L; 165 166 /** 167 * Gets the time zone offset, for current date, modified in case of 168 * daylight savings. This is the offset to add to UTC to get local time. 169 * <p> 170 * This method returns a historically correct offset if an 171 * underlying <code>TimeZone</code> implementation subclass 172 * supports historical Daylight Saving Time schedule and GMT 173 * offset changes. 174 * 175 * @param era the era of the given date. 176 * @param year the year in the given date. 177 * @param month the month in the given date. 178 * Month is 0-based. e.g., 0 for January. 179 * @param day the day-in-month of the given date. 180 * @param dayOfWeek the day-of-week of the given date. 181 * @param milliseconds the milliseconds in day in <em>standard</em> 182 * local time. 183 * 184 * @return the offset in milliseconds to add to GMT to get local time. 185 * 186 * @see Calendar#ZONE_OFFSET 187 * @see Calendar#DST_OFFSET 188 */ 189 public abstract int getOffset(int era, int year, int month, int day, 190 int dayOfWeek, int milliseconds); 191 192 /** 193 * Returns the offset of this time zone from UTC at the specified 194 * date. If Daylight Saving Time is in effect at the specified 195 * date, the offset value is adjusted with the amount of daylight 196 * saving. 197 * <p> 198 * This method returns a historically correct offset value if an 199 * underlying TimeZone implementation subclass supports historical 200 * Daylight Saving Time schedule and GMT offset changes. 201 * 202 * @param date the date represented in milliseconds since January 1, 1970 00:00:00 GMT 203 * @return the amount of time in milliseconds to add to UTC to get local time. 204 * 205 * @see Calendar#ZONE_OFFSET 206 * @see Calendar#DST_OFFSET 207 * @since 1.4 208 */ 209 public int getOffset(long date) { 210 if (inDaylightTime(new Date(date))) { 211 return getRawOffset() + getDSTSavings(); 212 } 213 return getRawOffset(); 214 } 215 216 /** 217 * Gets the raw GMT offset and the amount of daylight saving of this 218 * time zone at the given time. 219 * @param date the milliseconds (since January 1, 1970, 220 * 00:00:00.000 GMT) at which the time zone offset and daylight 221 * saving amount are found 222 * @param offset an array of int where the raw GMT offset 223 * (offset[0]) and daylight saving amount (offset[1]) are stored, 224 * or null if those values are not needed. The method assumes that 225 * the length of the given array is two or larger. 226 * @return the total amount of the raw GMT offset and daylight 227 * saving at the specified date. 228 * 229 * @see Calendar#ZONE_OFFSET 230 * @see Calendar#DST_OFFSET 231 */ 232 int getOffsets(long date, int[] offsets) { 233 int rawoffset = getRawOffset(); 234 int dstoffset = 0; 235 if (inDaylightTime(new Date(date))) { 236 dstoffset = getDSTSavings(); 237 } 238 if (offsets != null) { 239 offsets[0] = rawoffset; 240 offsets[1] = dstoffset; 241 } 242 return rawoffset + dstoffset; 243 } 244 245 /** 246 * Sets the base time zone offset to GMT. 247 * This is the offset to add to UTC to get local time. 248 * <p> 249 * If an underlying <code>TimeZone</code> implementation subclass 250 * supports historical GMT offset changes, the specified GMT 251 * offset is set as the latest GMT offset and the difference from 252 * the known latest GMT offset value is used to adjust all 253 * historical GMT offset values. 254 * 255 * @param offsetMillis the given base time zone offset to GMT. 256 */ 257 abstract public void setRawOffset(int offsetMillis); 258 259 /** 260 * Returns the amount of time in milliseconds to add to UTC to get 261 * standard time in this time zone. Because this value is not 262 * affected by daylight saving time, it is called <I>raw 263 * offset</I>. 264 * <p> 265 * If an underlying <code>TimeZone</code> implementation subclass 266 * supports historical GMT offset changes, the method returns the 267 * raw offset value of the current date. In Honolulu, for example, 268 * its raw offset changed from GMT-10:30 to GMT-10:00 in 1947, and 269 * this method always returns -36000000 milliseconds (i.e., -10 270 * hours). 271 * 272 * @return the amount of raw offset time in milliseconds to add to UTC. 273 * @see Calendar#ZONE_OFFSET 274 */ 275 public abstract int getRawOffset(); 276 277 /** 278 * Gets the ID of this time zone. 279 * @return the ID of this time zone. 280 */ 281 public String getID() 282 { 283 return ID; 284 } 285 286 /** 287 * Sets the time zone ID. This does not change any other data in 288 * the time zone object. 289 * @param ID the new time zone ID. 290 */ 291 public void setID(String ID) 292 { 293 if (ID == null) { 294 throw new NullPointerException(); 295 } 296 this.ID = ID; 297 } 298 299 /** 300 * Returns a long standard time name of this {@code TimeZone} suitable for 301 * presentation to the user in the default locale. 302 * 303 * <p>This method is equivalent to: 304 * <pre><blockquote> 305 * getDisplayName(false, {@link #LONG}, 306 * Locale.getDefault({@link Locale.Category#DISPLAY})) 307 * </blockquote></pre> 308 * 309 * @return the human-readable name of this time zone in the default locale. 310 * @since 1.2 311 * @see #getDisplayName(boolean, int, Locale) 312 * @see Locale#getDefault(Locale.Category) 313 * @see Locale.Category 314 */ 315 public final String getDisplayName() { 316 return getDisplayName(false, LONG, 317 Locale.getDefault(Locale.Category.DISPLAY)); 318 } 319 320 /** 321 * Returns a long standard time name of this {@code TimeZone} suitable for 322 * presentation to the user in the specified {@code locale}. 323 * 324 * <p>This method is equivalent to: 325 * <pre><blockquote> 326 * getDisplayName(false, {@link #LONG}, locale) 327 * </blockquote></pre> 328 * 329 * @param locale the locale in which to supply the display name. 330 * @return the human-readable name of this time zone in the given locale. 331 * @exception NullPointerException if {@code locale} is {@code null}. 332 * @since 1.2 333 * @see #getDisplayName(boolean, int, Locale) 334 */ 335 public final String getDisplayName(Locale locale) { 336 return getDisplayName(false, LONG, locale); 337 } 338 339 /** 340 * Returns a name in the specified {@code style} of this {@code TimeZone} 341 * suitable for presentation to the user in the default locale. If the 342 * specified {@code daylight} is {@code true}, a Daylight Saving Time name 343 * is returned (even if this {@code TimeZone} doesn't observe Daylight Saving 344 * Time). Otherwise, a Standard Time name is returned. 345 * 346 * <p>This method is equivalent to: 347 * <pre><blockquote> 348 * getDisplayName(daylight, style, 349 * Locale.getDefault({@link Locale.Category#DISPLAY})) 350 * </blockquote></pre> 351 * 352 * @param daylight {@code true} specifying a Daylight Saving Time name, or 353 * {@code false} specifying a Standard Time name 354 * @param style either {@link #LONG} or {@link #SHORT} 355 * @return the human-readable name of this time zone in the default locale. 356 * @exception IllegalArgumentException if {@code style} is invalid. 357 * @since 1.2 358 * @see #getDisplayName(boolean, int, Locale) 359 * @see Locale#getDefault(Locale.Category) 360 * @see Locale.Category 361 * @see java.text.DateFormatSymbols#getZoneStrings() 362 */ 363 public final String getDisplayName(boolean daylight, int style) { 364 return getDisplayName(daylight, style, 365 Locale.getDefault(Locale.Category.DISPLAY)); 366 } 367 368 /** 369 * Returns a name in the specified {@code style} of this {@code TimeZone} 370 * suitable for presentation to the user in the specified {@code 371 * locale}. If the specified {@code daylight} is {@code true}, a Daylight 372 * Saving Time name is returned (even if this {@code TimeZone} doesn't 373 * observe Daylight Saving Time). Otherwise, a Standard Time name is 374 * returned. 375 * 376 * <p>When looking up a time zone name, the {@linkplain 377 * ResourceBundle.Control#getCandidateLocales(String,Locale) default 378 * <code>Locale</code> search path of <code>ResourceBundle</code>} derived 379 * from the specified {@code locale} is used. (No {@linkplain 380 * ResourceBundle.Control#getFallbackLocale(String,Locale) fallback 381 * <code>Locale</code>} search is performed.) If a time zone name in any 382 * {@code Locale} of the search path, including {@link Locale#ROOT}, is 383 * found, the name is returned. Otherwise, a string in the 384 * <a href="#NormalizedCustomID">normalized custom ID format</a> is returned. 385 * 386 * @param daylight {@code true} specifying a Daylight Saving Time name, or 387 * {@code false} specifying a Standard Time name 388 * @param style either {@link #LONG} or {@link #SHORT} 389 * @param locale the locale in which to supply the display name. 390 * @return the human-readable name of this time zone in the given locale. 391 * @exception IllegalArgumentException if {@code style} is invalid. 392 * @exception NullPointerException if {@code locale} is {@code null}. 393 * @since 1.2 394 * @see java.text.DateFormatSymbols#getZoneStrings() 395 */ 396 public String getDisplayName(boolean daylight, int style, Locale locale) { 397 if (style != SHORT && style != LONG) { 398 throw new IllegalArgumentException("Illegal style: " + style); 399 } 400 401 String id = getID(); 402 String[] names = getDisplayNames(id, locale); 403 if (names == null) { 404 if (id.startsWith("GMT")) { 405 char sign = id.charAt(3); 406 if (sign == '+' || sign == '-') { 407 return id; 408 } 409 } 410 int offset = getRawOffset(); 411 if (daylight) { 412 offset += getDSTSavings(); 413 } 414 return ZoneInfoFile.toCustomID(offset); 415 } 416 417 int index = daylight ? 3 : 1; 418 if (style == SHORT) { 419 index++; 420 } 421 return names[index]; 422 } 423 424 private static class DisplayNames { 425 // Cache for managing display names per timezone per locale 426 // The structure is: 427 // Map(key=id, value=SoftReference(Map(key=locale, value=displaynames))) 428 private static final Map<String, SoftReference<Map<Locale, String[]>>> CACHE = 429 new ConcurrentHashMap<>(); 430 } 431 432 private static final String[] getDisplayNames(String id, Locale locale) { 433 Map<String, SoftReference<Map<Locale, String[]>>> displayNames = DisplayNames.CACHE; 434 435 SoftReference<Map<Locale, String[]>> ref = displayNames.get(id); 436 if (ref != null) { 437 Map<Locale, String[]> perLocale = ref.get(); 438 if (perLocale != null) { 439 String[] names = perLocale.get(locale); 440 if (names != null) { 441 return names; 442 } 443 names = TimeZoneNameUtility.retrieveDisplayNames(id, locale); 444 if (names != null) { 445 perLocale.put(locale, names); 446 } 447 return names; 448 } 449 } 450 451 String[] names = TimeZoneNameUtility.retrieveDisplayNames(id, locale); 452 if (names != null) { 453 Map<Locale, String[]> perLocale = new ConcurrentHashMap<>(); 454 perLocale.put(locale, names); 455 ref = new SoftReference<>(perLocale); 456 displayNames.put(id, ref); 457 } 458 return names; 459 } 460 461 /** 462 * Returns the amount of time to be added to local standard time 463 * to get local wall clock time. 464 * 465 * <p>The default implementation returns 3600000 milliseconds 466 * (i.e., one hour) if a call to {@link #useDaylightTime()} 467 * returns {@code true}. Otherwise, 0 (zero) is returned. 468 * 469 * <p>If an underlying {@code TimeZone} implementation subclass 470 * supports historical and future Daylight Saving Time schedule 471 * changes, this method returns the amount of saving time of the 472 * last known Daylight Saving Time rule that can be a future 473 * prediction. 474 * 475 * <p>If the amount of saving time at any given time stamp is 476 * required, construct a {@link Calendar} with this {@code 477 * TimeZone} and the time stamp, and call {@link Calendar#get(int) 478 * Calendar.get}{@code (}{@link Calendar#DST_OFFSET}{@code )}. 479 * 480 * @return the amount of saving time in milliseconds 481 * @since 1.4 482 * @see #inDaylightTime(Date) 483 * @see #getOffset(long) 484 * @see #getOffset(int,int,int,int,int,int) 485 * @see Calendar#ZONE_OFFSET 486 */ 487 public int getDSTSavings() { 488 if (useDaylightTime()) { 489 return 3600000; 490 } 491 return 0; 492 } 493 494 /** 495 * Queries if this {@code TimeZone} uses Daylight Saving Time. 496 * 497 * <p>If an underlying {@code TimeZone} implementation subclass 498 * supports historical and future Daylight Saving Time schedule 499 * changes, this method refers to the last known Daylight Saving Time 500 * rule that can be a future prediction and may not be the same as 501 * the current rule. Consider calling {@link #observesDaylightTime()} 502 * if the current rule should also be taken into account. 503 * 504 * @return {@code true} if this {@code TimeZone} uses Daylight Saving Time, 505 * {@code false}, otherwise. 506 * @see #inDaylightTime(Date) 507 * @see Calendar#DST_OFFSET 508 */ 509 public abstract boolean useDaylightTime(); 510 511 /** 512 * Returns {@code true} if this {@code TimeZone} is currently in 513 * Daylight Saving Time, or if a transition from Standard Time to 514 * Daylight Saving Time occurs at any future time. 515 * 516 * <p>The default implementation returns {@code true} if 517 * {@code useDaylightTime()} or {@code inDaylightTime(new Date())} 518 * returns {@code true}. 519 * 520 * @return {@code true} if this {@code TimeZone} is currently in 521 * Daylight Saving Time, or if a transition from Standard Time to 522 * Daylight Saving Time occurs at any future time; {@code false} 523 * otherwise. 524 * @since 1.7 525 * @see #useDaylightTime() 526 * @see #inDaylightTime(Date) 527 * @see Calendar#DST_OFFSET 528 */ 529 public boolean observesDaylightTime() { 530 return useDaylightTime() || inDaylightTime(new Date()); 531 } 532 533 /** 534 * Queries if the given {@code date} is in Daylight Saving Time in 535 * this time zone. 536 * 537 * @param date the given Date. 538 * @return {@code true} if the given date is in Daylight Saving Time, 539 * {@code false}, otherwise. 540 */ 541 abstract public boolean inDaylightTime(Date date); 542 543 /** 544 * Gets the <code>TimeZone</code> for the given ID. 545 * 546 * @param ID the ID for a <code>TimeZone</code>, either an abbreviation 547 * such as "PST", a full name such as "America/Los_Angeles", or a custom 548 * ID such as "GMT-8:00". Note that the support of abbreviations is 549 * for JDK 1.1.x compatibility only and full names should be used. 550 * 551 * @return the specified <code>TimeZone</code>, or the GMT zone if the given ID 552 * cannot be understood. 553 */ 554 public static synchronized TimeZone getTimeZone(String ID) { 555 return getTimeZone(ID, true); 556 } 557 558 private static TimeZone getTimeZone(String ID, boolean fallback) { 559 TimeZone tz = ZoneInfo.getTimeZone(ID); 560 if (tz == null) { 561 tz = parseCustomTimeZone(ID); 562 if (tz == null && fallback) { 563 tz = new ZoneInfo(GMT_ID, 0); 564 } 565 } 566 return tz; 567 } 568 569 /** 570 * Gets the available IDs according to the given time zone offset in milliseconds. 571 * 572 * @param rawOffset the given time zone GMT offset in milliseconds. 573 * @return an array of IDs, where the time zone for that ID has 574 * the specified GMT offset. For example, "America/Phoenix" and "America/Denver" 575 * both have GMT-07:00, but differ in daylight saving behavior. 576 * @see #getRawOffset() 577 */ 578 public static synchronized String[] getAvailableIDs(int rawOffset) { 579 return ZoneInfo.getAvailableIDs(rawOffset); 580 } 581 582 /** 583 * Gets all the available IDs supported. 584 * @return an array of IDs. 585 */ 586 public static synchronized String[] getAvailableIDs() { 587 return ZoneInfo.getAvailableIDs(); 588 } 589 590 /** 591 * Gets the platform defined TimeZone ID. 592 **/ 593 private static native String getSystemTimeZoneID(String javaHome, 594 String country); 595 596 /** 597 * Gets the custom time zone ID based on the GMT offset of the 598 * platform. (e.g., "GMT+08:00") 599 */ 600 private static native String getSystemGMTOffsetID(); 601 602 /** 603 * Gets the default <code>TimeZone</code> for this host. 604 * The source of the default <code>TimeZone</code> 605 * may vary with implementation. 606 * @return a default <code>TimeZone</code>. 607 * @see #setDefault 608 */ 609 public static TimeZone getDefault() { 610 return (TimeZone) getDefaultRef().clone(); 611 } 612 613 /** 614 * Returns the reference to the default TimeZone object. This 615 * method doesn't create a clone. 616 */ 617 static TimeZone getDefaultRef() { 618 TimeZone defaultZone = defaultZoneTL.get(); 619 if (defaultZone == null) { 620 defaultZone = defaultTimeZone; 621 if (defaultZone == null) { 622 // Need to initialize the default time zone. 623 defaultZone = setDefaultZone(); 624 assert defaultZone != null; 625 } 626 } 627 // Don't clone here. 628 return defaultZone; 629 } 630 631 private static synchronized TimeZone setDefaultZone() { 632 TimeZone tz = null; 633 // get the time zone ID from the system properties 634 String zoneID = AccessController.doPrivileged( 635 new GetPropertyAction("user.timezone")); 636 637 // if the time zone ID is not set (yet), perform the 638 // platform to Java time zone ID mapping. 639 if (zoneID == null || zoneID.equals("")) { 640 String country = AccessController.doPrivileged( 641 new GetPropertyAction("user.country")); 642 String javaHome = AccessController.doPrivileged( 643 new GetPropertyAction("java.home")); 644 try { 645 zoneID = getSystemTimeZoneID(javaHome, country); 646 if (zoneID == null) { 647 zoneID = GMT_ID; 648 } 649 } catch (NullPointerException e) { 650 zoneID = GMT_ID; 651 } 652 } 653 654 // Get the time zone for zoneID. But not fall back to 655 // "GMT" here. 656 tz = getTimeZone(zoneID, false); 657 658 if (tz == null) { 659 // If the given zone ID is unknown in Java, try to 660 // get the GMT-offset-based time zone ID, 661 // a.k.a. custom time zone ID (e.g., "GMT-08:00"). 662 String gmtOffsetID = getSystemGMTOffsetID(); 663 if (gmtOffsetID != null) { 664 zoneID = gmtOffsetID; 665 } 666 tz = getTimeZone(zoneID, true); 667 } 668 assert tz != null; 669 670 final String id = zoneID; 671 AccessController.doPrivileged(new PrivilegedAction<Object>() { 672 public Object run() { 673 System.setProperty("user.timezone", id); 674 return null; 675 } 676 }); 677 678 defaultTimeZone = tz; 679 return tz; 680 } 681 682 private static boolean hasPermission() { 683 boolean hasPermission = true; 684 SecurityManager sm = System.getSecurityManager(); 685 if (sm != null) { 686 try { 687 sm.checkPermission(new PropertyPermission 688 ("user.timezone", "write")); 689 } catch (SecurityException e) { 690 hasPermission = false; 691 } 692 } 693 return hasPermission; 694 } 695 696 /** 697 * Sets the <code>TimeZone</code> that is 698 * returned by the <code>getDefault</code> method. If <code>zone</code> 699 * is null, reset the default to the value it had originally when the 700 * VM first started. 701 * @param zone the new default time zone 702 * @see #getDefault 703 */ 704 public static void setDefault(TimeZone zone) 705 { 706 if (hasPermission()) { 707 synchronized (TimeZone.class) { 708 defaultTimeZone = zone; 709 defaultZoneTL.set(null); 710 } 711 } else { 712 defaultZoneTL.set(zone); 713 } 714 } 715 716 /** 717 * Returns true if this zone has the same rule and offset as another zone. 718 * That is, if this zone differs only in ID, if at all. Returns false 719 * if the other zone is null. 720 * @param other the <code>TimeZone</code> object to be compared with 721 * @return true if the other zone is not null and is the same as this one, 722 * with the possible exception of the ID 723 * @since 1.2 724 */ 725 public boolean hasSameRules(TimeZone other) { 726 return other != null && getRawOffset() == other.getRawOffset() && 727 useDaylightTime() == other.useDaylightTime(); 728 } 729 730 /** 731 * Creates a copy of this <code>TimeZone</code>. 732 * 733 * @return a clone of this <code>TimeZone</code> 734 */ 735 public Object clone() 736 { 737 try { 738 TimeZone other = (TimeZone) super.clone(); 739 other.ID = ID; 740 return other; 741 } catch (CloneNotSupportedException e) { 742 throw new InternalError(e); 743 } 744 } 745 746 /** 747 * The null constant as a TimeZone. 748 */ 749 static final TimeZone NO_TIMEZONE = null; 750 751 // =======================privates=============================== 752 753 /** 754 * The string identifier of this <code>TimeZone</code>. This is a 755 * programmatic identifier used internally to look up <code>TimeZone</code> 756 * objects from the system table and also to map them to their localized 757 * display names. <code>ID</code> values are unique in the system 758 * table but may not be for dynamically created zones. 759 * @serial 760 */ 761 private String ID; 762 private static volatile TimeZone defaultTimeZone; 763 private static final InheritableThreadLocal<TimeZone> defaultZoneTL 764 = new InheritableThreadLocal<>(); 765 766 static final String GMT_ID = "GMT"; 767 private static final int GMT_ID_LENGTH = 3; 768 769 /** 770 * Parses a custom time zone identifier and returns a corresponding zone. 771 * This method doesn't support the RFC 822 time zone format. (e.g., +hhmm) 772 * 773 * @param id a string of the <a href="#CustomID">custom ID form</a>. 774 * @return a newly created TimeZone with the given offset and 775 * no daylight saving time, or null if the id cannot be parsed. 776 */ 777 private static final TimeZone parseCustomTimeZone(String id) { 778 int length; 779 780 // Error if the length of id isn't long enough or id doesn't 781 // start with "GMT". 782 if ((length = id.length()) < (GMT_ID_LENGTH + 2) || 783 id.indexOf(GMT_ID) != 0) { 784 return null; 785 } 786 787 ZoneInfo zi; 788 789 // First, we try to find it in the cache with the given 790 // id. Even the id is not normalized, the returned ZoneInfo 791 // should have its normalized id. 792 zi = ZoneInfoFile.getZoneInfo(id); 793 if (zi != null) { 794 return zi; 795 } 796 797 int index = GMT_ID_LENGTH; 798 boolean negative = false; 799 char c = id.charAt(index++); 800 if (c == '-') { 801 negative = true; 802 } else if (c != '+') { 803 return null; 804 } 805 806 int hours = 0; 807 int num = 0; 808 int countDelim = 0; 809 int len = 0; 810 while (index < length) { 811 c = id.charAt(index++); 812 if (c == ':') { 813 if (countDelim > 0) { 814 return null; 815 } 816 if (len > 2) { 817 return null; 818 } 819 hours = num; 820 countDelim++; 821 num = 0; 822 len = 0; 823 continue; 824 } 825 if (c < '0' || c > '9') { 826 return null; 827 } 828 num = num * 10 + (c - '0'); 829 len++; 830 } 831 if (index != length) { 832 return null; 833 } 834 if (countDelim == 0) { 835 if (len <= 2) { 836 hours = num; 837 num = 0; 838 } else { 839 hours = num / 100; 840 num %= 100; 841 } 842 } else { 843 if (len != 2) { 844 return null; 845 } 846 } 847 if (hours > 23 || num > 59) { 848 return null; 849 } 850 int gmtOffset = (hours * 60 + num) * 60 * 1000; 851 852 if (gmtOffset == 0) { 853 zi = ZoneInfoFile.getZoneInfo(GMT_ID); 854 if (negative) { 855 zi.setID("GMT-00:00"); 856 } else { 857 zi.setID("GMT+00:00"); 858 } 859 } else { 860 zi = ZoneInfoFile.getCustomTimeZone(id, negative ? -gmtOffset : gmtOffset); 861 } 862 return zi; 863 } 864 }