1 /* 2 * Copyright (c) 1996, 2014, 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.security.AccessController; 43 import java.security.PrivilegedAction; 44 import java.time.ZoneId; 45 import sun.security.action.GetPropertyAction; 46 import sun.util.calendar.ZoneInfo; 47 import sun.util.calendar.ZoneInfoFile; 48 import sun.util.locale.provider.TimeZoneNameUtility; 49 50 /** 51 * <code>TimeZone</code> represents a time zone offset, and also figures out daylight 52 * savings. 53 * 54 * <p> 55 * Typically, you get a <code>TimeZone</code> using <code>getDefault</code> 56 * which creates a <code>TimeZone</code> based on the time zone where the program 57 * is running. For example, for a program running in Japan, <code>getDefault</code> 58 * creates a <code>TimeZone</code> object based on Japanese Standard Time. 59 * 60 * <p> 61 * You can also get a <code>TimeZone</code> using <code>getTimeZone</code> 62 * along with a time zone ID. For instance, the time zone ID for the 63 * U.S. Pacific Time zone is "America/Los_Angeles". So, you can get a 64 * U.S. Pacific Time <code>TimeZone</code> object with: 65 * <blockquote><pre> 66 * TimeZone tz = TimeZone.getTimeZone("America/Los_Angeles"); 67 * </pre></blockquote> 68 * You can use the <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 a custom time zone ID can be specified to 73 * produce a TimeZone. The syntax of a custom time zone ID is: 74 * 75 * <blockquote><pre> 76 * <a name="CustomID"><i>CustomID:</i></a> 77 * <code>GMT</code> <i>Sign</i> <i>Hours</i> <code>:</code> <i>Minutes</i> 78 * <code>GMT</code> <i>Sign</i> <i>Hours</i> <i>Minutes</i> 79 * <code>GMT</code> <i>Sign</i> <i>Hours</i> 80 * <i>Sign:</i> one of 81 * <code>+ -</code> 82 * <i>Hours:</i> 83 * <i>Digit</i> 84 * <i>Digit</i> <i>Digit</i> 85 * <i>Minutes:</i> 86 * <i>Digit</i> <i>Digit</i> 87 * <i>Digit:</i> one of 88 * <code>0 1 2 3 4 5 6 7 8 9</code> 89 * </pre></blockquote> 90 * 91 * <i>Hours</i> must be between 0 to 23 and <i>Minutes</i> must be 92 * between 00 to 59. For example, "GMT+10" and "GMT+0010" mean ten 93 * hours and ten minutes ahead of GMT, respectively. 94 * <p> 95 * The format is locale independent and digits must be taken from the 96 * Basic Latin block of the Unicode standard. No daylight saving time 97 * transition schedule can be specified with a custom time zone ID. If 98 * the specified string doesn't match the syntax, <code>"GMT"</code> 99 * is used. 100 * <p> 101 * When creating a <code>TimeZone</code>, the specified custom time 102 * zone ID is normalized in the following syntax: 103 * <blockquote><pre> 104 * <a name="NormalizedCustomID"><i>NormalizedCustomID:</i></a> 105 * <code>GMT</code> <i>Sign</i> <i>TwoDigitHours</i> <code>:</code> <i>Minutes</i> 106 * <i>Sign:</i> one of 107 * <code>+ -</code> 108 * <i>TwoDigitHours:</i> 109 * <i>Digit</i> <i>Digit</i> 110 * <i>Minutes:</i> 111 * <i>Digit</i> <i>Digit</i> 112 * <i>Digit:</i> one of 113 * <code>0 1 2 3 4 5 6 7 8 9</code> 114 * </pre></blockquote> 115 * For example, TimeZone.getTimeZone("GMT-8").getID() returns "GMT-08:00". 116 * 117 * <h3>Three-letter time zone IDs</h3> 118 * 119 * For compatibility with JDK 1.1.x, some other three-letter time zone IDs 120 * (such as "PST", "CTT", "AST") are also supported. However, <strong>their 121 * use is deprecated</strong> because the same abbreviation is often used 122 * for multiple time zones (for example, "CST" could be U.S. "Central Standard 123 * Time" and "China Standard Time"), and the Java platform can then only 124 * recognize one of them. 125 * 126 * 127 * @see Calendar 128 * @see GregorianCalendar 129 * @see SimpleTimeZone 130 * @author Mark Davis, David Goldsmith, Chen-Lieh Huang, Alan Liu 131 * @since 1.1 132 */ 133 abstract public class TimeZone implements Serializable, Cloneable { 134 /** 135 * Sole constructor. (For invocation by subclass constructors, typically 136 * implicit.) 137 */ 138 public TimeZone() { 139 } 140 141 /** 142 * A style specifier for <code>getDisplayName()</code> indicating 143 * a short name, such as "PST." 144 * @see #LONG 145 * @since 1.2 146 */ 147 public static final int SHORT = 0; 148 149 /** 150 * A style specifier for <code>getDisplayName()</code> indicating 151 * a long name, such as "Pacific Standard Time." 152 * @see #SHORT 153 * @since 1.2 154 */ 155 public static final int LONG = 1; 156 157 // Constants used internally; unit is milliseconds 158 private static final int ONE_MINUTE = 60*1000; 159 private static final int ONE_HOUR = 60*ONE_MINUTE; 160 private static final int ONE_DAY = 24*ONE_HOUR; 161 162 // Proclaim serialization compatibility with JDK 1.1 163 static final long serialVersionUID = 3581463369166924961L; 164 165 /** 166 * Gets the time zone offset, for current date, modified in case of 167 * daylight savings. This is the offset to add to UTC to get local time. 168 * <p> 169 * This method returns a historically correct offset if an 170 * underlying <code>TimeZone</code> implementation subclass 171 * supports historical Daylight Saving Time schedule and GMT 172 * offset changes. 173 * 174 * @param era the era of the given date. 175 * @param year the year in the given date. 176 * @param month the month in the given date. 177 * Month is 0-based. e.g., 0 for January. 178 * @param day the day-in-month of the given date. 179 * @param dayOfWeek the day-of-week of the given date. 180 * @param milliseconds the milliseconds in day in <em>standard</em> 181 * local time. 182 * 183 * @return the offset in milliseconds to add to GMT to get local time. 184 * 185 * @see Calendar#ZONE_OFFSET 186 * @see Calendar#DST_OFFSET 187 */ 188 public abstract int getOffset(int era, int year, int month, int day, 189 int dayOfWeek, int milliseconds); 190 191 /** 192 * Returns the offset of this time zone from UTC at the specified 193 * date. If Daylight Saving Time is in effect at the specified 194 * date, the offset value is adjusted with the amount of daylight 195 * saving. 196 * <p> 197 * This method returns a historically correct offset value if an 198 * underlying TimeZone implementation subclass supports historical 199 * Daylight Saving Time schedule and GMT offset changes. 200 * 201 * @param date the date represented in milliseconds since January 1, 1970 00:00:00 GMT 202 * @return the amount of time in milliseconds to add to UTC to get local time. 203 * 204 * @see Calendar#ZONE_OFFSET 205 * @see Calendar#DST_OFFSET 206 * @since 1.4 207 */ 208 public int getOffset(long date) { 209 if (inDaylightTime(new Date(date))) { 210 return getRawOffset() + getDSTSavings(); 211 } 212 return getRawOffset(); 213 } 214 215 /** 216 * Gets the raw GMT offset and the amount of daylight saving of this 217 * time zone at the given time. 218 * @param date the milliseconds (since January 1, 1970, 219 * 00:00:00.000 GMT) at which the time zone offset and daylight 220 * saving amount are found 221 * @param offsets an array of int where the raw GMT offset 222 * (offset[0]) and daylight saving amount (offset[1]) are stored, 223 * or null if those values are not needed. The method assumes that 224 * the length of the given array is two or larger. 225 * @return the total amount of the raw GMT offset and daylight 226 * saving at the specified date. 227 * 228 * @see Calendar#ZONE_OFFSET 229 * @see Calendar#DST_OFFSET 230 */ 231 int getOffsets(long date, int[] offsets) { 232 int rawoffset = getRawOffset(); 233 int dstoffset = 0; 234 if (inDaylightTime(new Date(date))) { 235 dstoffset = getDSTSavings(); 236 } 237 if (offsets != null) { 238 offsets[0] = rawoffset; 239 offsets[1] = dstoffset; 240 } 241 return rawoffset + dstoffset; 242 } 243 244 /** 245 * Sets the base time zone offset to GMT. 246 * This is the offset to add to UTC to get local time. 247 * <p> 248 * If an underlying <code>TimeZone</code> implementation subclass 249 * supports historical GMT offset changes, the specified GMT 250 * offset is set as the latest GMT offset and the difference from 251 * the known latest GMT offset value is used to adjust all 252 * historical GMT offset values. 253 * 254 * @param offsetMillis the given base time zone offset to GMT. 255 */ 256 abstract public void setRawOffset(int offsetMillis); 257 258 /** 259 * Returns the amount of time in milliseconds to add to UTC to get 260 * standard time in this time zone. Because this value is not 261 * affected by daylight saving time, it is called <I>raw 262 * offset</I>. 263 * <p> 264 * If an underlying <code>TimeZone</code> implementation subclass 265 * supports historical GMT offset changes, the method returns the 266 * raw offset value of the current date. In Honolulu, for example, 267 * its raw offset changed from GMT-10:30 to GMT-10:00 in 1947, and 268 * this method always returns -36000000 milliseconds (i.e., -10 269 * hours). 270 * 271 * @return the amount of raw offset time in milliseconds to add to UTC. 272 * @see Calendar#ZONE_OFFSET 273 */ 274 public abstract int getRawOffset(); 275 276 /** 277 * Gets the ID of this time zone. 278 * @return the ID of this time zone. 279 */ 280 public String getID() 281 { 282 return ID; 283 } 284 285 /** 286 * Sets the time zone ID. This does not change any other data in 287 * the time zone object. 288 * @param ID the new time zone ID. 289 */ 290 public void setID(String ID) 291 { 292 if (ID == null) { 293 throw new NullPointerException(); 294 } 295 this.ID = ID; 296 } 297 298 /** 299 * Returns a long standard time name of this {@code TimeZone} suitable for 300 * presentation to the user in the default locale. 301 * 302 * <p>This method is equivalent to: 303 * <blockquote><pre> 304 * getDisplayName(false, {@link #LONG}, 305 * Locale.getDefault({@link Locale.Category#DISPLAY})) 306 * </pre></blockquote> 307 * 308 * @return the human-readable name of this time zone in the default locale. 309 * @since 1.2 310 * @see #getDisplayName(boolean, int, Locale) 311 * @see Locale#getDefault(Locale.Category) 312 * @see Locale.Category 313 */ 314 public final String getDisplayName() { 315 return getDisplayName(false, LONG, 316 Locale.getDefault(Locale.Category.DISPLAY)); 317 } 318 319 /** 320 * Returns a long standard time name of this {@code TimeZone} suitable for 321 * presentation to the user in the specified {@code locale}. 322 * 323 * <p>This method is equivalent to: 324 * <blockquote><pre> 325 * getDisplayName(false, {@link #LONG}, locale) 326 * </pre></blockquote> 327 * 328 * @param locale the locale in which to supply the display name. 329 * @return the human-readable name of this time zone in the given locale. 330 * @exception NullPointerException if {@code locale} is {@code null}. 331 * @since 1.2 332 * @see #getDisplayName(boolean, int, Locale) 333 */ 334 public final String getDisplayName(Locale locale) { 335 return getDisplayName(false, LONG, locale); 336 } 337 338 /** 339 * Returns a name in the specified {@code style} of this {@code TimeZone} 340 * suitable for presentation to the user in the default locale. If the 341 * specified {@code daylight} is {@code true}, a Daylight Saving Time name 342 * is returned (even if this {@code TimeZone} doesn't observe Daylight Saving 343 * Time). Otherwise, a Standard Time name is returned. 344 * 345 * <p>This method is equivalent to: 346 * <blockquote><pre> 347 * getDisplayName(daylight, style, 348 * Locale.getDefault({@link Locale.Category#DISPLAY})) 349 * </pre></blockquote> 350 * 351 * @param daylight {@code true} specifying a Daylight Saving Time name, or 352 * {@code false} specifying a Standard Time name 353 * @param style either {@link #LONG} or {@link #SHORT} 354 * @return the human-readable name of this time zone in the default locale. 355 * @exception IllegalArgumentException if {@code style} is invalid. 356 * @since 1.2 357 * @see #getDisplayName(boolean, int, Locale) 358 * @see Locale#getDefault(Locale.Category) 359 * @see Locale.Category 360 * @see java.text.DateFormatSymbols#getZoneStrings() 361 */ 362 public final String getDisplayName(boolean daylight, int style) { 363 return getDisplayName(daylight, style, 364 Locale.getDefault(Locale.Category.DISPLAY)); 365 } 366 367 /** 368 * Returns a name in the specified {@code style} of this {@code TimeZone} 369 * suitable for presentation to the user in the specified {@code 370 * locale}. If the specified {@code daylight} is {@code true}, a Daylight 371 * Saving Time name is returned (even if this {@code TimeZone} doesn't 372 * observe Daylight Saving Time). Otherwise, a Standard Time name is 373 * returned. 374 * 375 * <p>When looking up a time zone name, the {@linkplain 376 * ResourceBundle.Control#getCandidateLocales(String,Locale) default 377 * <code>Locale</code> search path of <code>ResourceBundle</code>} derived 378 * from the specified {@code locale} is used. (No {@linkplain 379 * ResourceBundle.Control#getFallbackLocale(String,Locale) fallback 380 * <code>Locale</code>} search is performed.) If a time zone name in any 381 * {@code Locale} of the search path, including {@link Locale#ROOT}, is 382 * found, the name is returned. Otherwise, a string in the 383 * <a href="#NormalizedCustomID">normalized custom ID format</a> is returned. 384 * 385 * @param daylight {@code true} specifying a Daylight Saving Time name, or 386 * {@code false} specifying a Standard Time name 387 * @param style either {@link #LONG} or {@link #SHORT} 388 * @param locale the locale in which to supply the display name. 389 * @return the human-readable name of this time zone in the given locale. 390 * @exception IllegalArgumentException if {@code style} is invalid. 391 * @exception NullPointerException if {@code locale} is {@code null}. 392 * @since 1.2 393 * @see java.text.DateFormatSymbols#getZoneStrings() 394 */ 395 public String getDisplayName(boolean daylight, int style, Locale locale) { 396 if (style != SHORT && style != LONG) { 397 throw new IllegalArgumentException("Illegal style: " + style); 398 } 399 String id = getID(); 400 String name = TimeZoneNameUtility.retrieveDisplayName(id, daylight, style, locale); 401 if (name != null) { 402 return name; 403 } 404 405 if (id.startsWith("GMT") && id.length() > 3) { 406 char sign = id.charAt(3); 407 if (sign == '+' || sign == '-') { 408 return id; 409 } 410 } 411 int offset = getRawOffset(); 412 if (daylight) { 413 offset += getDSTSavings(); 414 } 415 return ZoneInfoFile.toCustomID(offset); 416 } 417 418 private static String[] getDisplayNames(String id, Locale locale) { 419 return TimeZoneNameUtility.retrieveDisplayNames(id, locale); 420 } 421 422 /** 423 * Returns the amount of time to be added to local standard time 424 * to get local wall clock time. 425 * 426 * <p>The default implementation returns 3600000 milliseconds 427 * (i.e., one hour) if a call to {@link #useDaylightTime()} 428 * returns {@code true}. Otherwise, 0 (zero) is returned. 429 * 430 * <p>If an underlying {@code TimeZone} implementation subclass 431 * supports historical and future Daylight Saving Time schedule 432 * changes, this method returns the amount of saving time of the 433 * last known Daylight Saving Time rule that can be a future 434 * prediction. 435 * 436 * <p>If the amount of saving time at any given time stamp is 437 * required, construct a {@link Calendar} with this {@code 438 * TimeZone} and the time stamp, and call {@link Calendar#get(int) 439 * Calendar.get}{@code (}{@link Calendar#DST_OFFSET}{@code )}. 440 * 441 * @return the amount of saving time in milliseconds 442 * @since 1.4 443 * @see #inDaylightTime(Date) 444 * @see #getOffset(long) 445 * @see #getOffset(int,int,int,int,int,int) 446 * @see Calendar#ZONE_OFFSET 447 */ 448 public int getDSTSavings() { 449 if (useDaylightTime()) { 450 return 3600000; 451 } 452 return 0; 453 } 454 455 /** 456 * Queries if this {@code TimeZone} uses Daylight Saving Time. 457 * 458 * <p>If an underlying {@code TimeZone} implementation subclass 459 * supports historical and future Daylight Saving Time schedule 460 * changes, this method refers to the last known Daylight Saving Time 461 * rule that can be a future prediction and may not be the same as 462 * the current rule. Consider calling {@link #observesDaylightTime()} 463 * if the current rule should also be taken into account. 464 * 465 * @return {@code true} if this {@code TimeZone} uses Daylight Saving Time, 466 * {@code false}, otherwise. 467 * @see #inDaylightTime(Date) 468 * @see Calendar#DST_OFFSET 469 */ 470 public abstract boolean useDaylightTime(); 471 472 /** 473 * Returns {@code true} if this {@code TimeZone} is currently in 474 * Daylight Saving Time, or if a transition from Standard Time to 475 * Daylight Saving Time occurs at any future time. 476 * 477 * <p>The default implementation returns {@code true} if 478 * {@code useDaylightTime()} or {@code inDaylightTime(new Date())} 479 * returns {@code true}. 480 * 481 * @return {@code true} if this {@code TimeZone} is currently in 482 * Daylight Saving Time, or if a transition from Standard Time to 483 * Daylight Saving Time occurs at any future time; {@code false} 484 * otherwise. 485 * @since 1.7 486 * @see #useDaylightTime() 487 * @see #inDaylightTime(Date) 488 * @see Calendar#DST_OFFSET 489 */ 490 public boolean observesDaylightTime() { 491 return useDaylightTime() || inDaylightTime(new Date()); 492 } 493 494 /** 495 * Queries if the given {@code date} is in Daylight Saving Time in 496 * this time zone. 497 * 498 * @param date the given Date. 499 * @return {@code true} if the given date is in Daylight Saving Time, 500 * {@code false}, otherwise. 501 */ 502 abstract public boolean inDaylightTime(Date date); 503 504 /** 505 * Gets the <code>TimeZone</code> for the given ID. 506 * 507 * @param ID the ID for a <code>TimeZone</code>, either an abbreviation 508 * such as "PST", a full name such as "America/Los_Angeles", or a custom 509 * ID such as "GMT-8:00". Note that the support of abbreviations is 510 * for JDK 1.1.x compatibility only and full names should be used. 511 * 512 * @return the specified <code>TimeZone</code>, or the GMT zone if the given ID 513 * cannot be understood. 514 */ 515 public static synchronized TimeZone getTimeZone(String ID) { 516 return getTimeZone(ID, true); 517 } 518 519 /** 520 * Gets the {@code TimeZone} for the given {@code zoneId}. 521 * 522 * @param zoneId a {@link ZoneId} from which the time zone ID is obtained 523 * @return the specified {@code TimeZone}, or the GMT zone if the given ID 524 * cannot be understood. 525 * @throws NullPointerException if {@code zoneId} is {@code null} 526 * @since 1.8 527 */ 528 public static TimeZone getTimeZone(ZoneId zoneId) { 529 String tzid = zoneId.getId(); // throws an NPE if null 530 char c = tzid.charAt(0); 531 if (c == '+' || c == '-') { 532 tzid = "GMT" + tzid; 533 } else if (c == 'Z' && tzid.length() == 1) { 534 tzid = "UTC"; 535 } 536 return getTimeZone(tzid, true); 537 } 538 539 /** 540 * Converts this {@code TimeZone} object to a {@code ZoneId}. 541 * 542 * @return a {@code ZoneId} representing the same time zone as this 543 * {@code TimeZone} 544 * @since 1.8 545 */ 546 public ZoneId toZoneId() { 547 String id = getID(); 548 if (ZoneInfoFile.useOldMapping() && id.length() == 3) { 549 if ("EST".equals(id)) 550 return ZoneId.of("America/New_York"); 551 if ("MST".equals(id)) 552 return ZoneId.of("America/Denver"); 553 if ("HST".equals(id)) 554 return ZoneId.of("America/Honolulu"); 555 } 556 return ZoneId.of(id, ZoneId.SHORT_IDS); 557 } 558 559 private static TimeZone getTimeZone(String ID, boolean fallback) { 560 TimeZone tz = ZoneInfo.getTimeZone(ID); 561 if (tz == null) { 562 tz = parseCustomTimeZone(ID); 563 if (tz == null && fallback) { 564 tz = new ZoneInfo(GMT_ID, 0); 565 } 566 } 567 return tz; 568 } 569 570 /** 571 * Gets the available IDs according to the given time zone offset in milliseconds. 572 * 573 * @param rawOffset the given time zone GMT offset in milliseconds. 574 * @return an array of IDs, where the time zone for that ID has 575 * the specified GMT offset. For example, "America/Phoenix" and "America/Denver" 576 * both have GMT-07:00, but differ in daylight saving behavior. 577 * @see #getRawOffset() 578 */ 579 public static synchronized String[] getAvailableIDs(int rawOffset) { 580 return ZoneInfo.getAvailableIDs(rawOffset); 581 } 582 583 /** 584 * Gets all the available IDs supported. 585 * @return an array of IDs. 586 */ 587 public static synchronized String[] getAvailableIDs() { 588 return ZoneInfo.getAvailableIDs(); 589 } 590 591 /** 592 * Gets the platform defined TimeZone ID. 593 **/ 594 private static native String getSystemTimeZoneID(String javaHome); 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} of the Java virtual machine. If the 604 * cached default {@code TimeZone} is available, its clone is returned. 605 * Otherwise, the method takes the following steps to determine the default 606 * time zone. 607 * 608 * <ul> 609 * <li>Use the {@code user.timezone} property value as the default 610 * time zone ID if it's available.</li> 611 * <li>Detect the platform time zone ID. The source of the 612 * platform time zone and ID mapping may vary with implementation.</li> 613 * <li>Use {@code GMT} as the last resort if the given or detected 614 * time zone ID is unknown.</li> 615 * </ul> 616 * 617 * <p>The default {@code TimeZone} created from the ID is cached, 618 * and its clone is returned. The {@code user.timezone} property 619 * value is set to the ID upon return. 620 * 621 * @return the default {@code TimeZone} 622 * @see #setDefault(TimeZone) 623 */ 624 public static TimeZone getDefault() { 625 return (TimeZone) getDefaultRef().clone(); 626 } 627 628 /** 629 * Returns the reference to the default TimeZone object. This 630 * method doesn't create a clone. 631 */ 632 static TimeZone getDefaultRef() { 633 TimeZone defaultZone = defaultTimeZone; 634 if (defaultZone == null) { 635 // Need to initialize the default time zone. 636 defaultZone = setDefaultZone(); 637 assert defaultZone != null; 638 } 639 // Don't clone here. 640 return defaultZone; 641 } 642 643 private static synchronized TimeZone setDefaultZone() { 644 TimeZone tz; 645 // get the time zone ID from the system properties 646 String zoneID = AccessController.doPrivileged( 647 new GetPropertyAction("user.timezone")); 648 649 // if the time zone ID is not set (yet), perform the 650 // platform to Java time zone ID mapping. 651 if (zoneID == null || zoneID.isEmpty()) { 652 String javaHome = AccessController.doPrivileged( 653 new GetPropertyAction("java.home")); 654 try { 655 zoneID = getSystemTimeZoneID(javaHome); 656 if (zoneID == null) { 657 zoneID = GMT_ID; 658 } 659 } catch (NullPointerException e) { 660 zoneID = GMT_ID; 661 } 662 } 663 664 // Get the time zone for zoneID. But not fall back to 665 // "GMT" here. 666 tz = getTimeZone(zoneID, false); 667 668 if (tz == null) { 669 // If the given zone ID is unknown in Java, try to 670 // get the GMT-offset-based time zone ID, 671 // a.k.a. custom time zone ID (e.g., "GMT-08:00"). 672 String gmtOffsetID = getSystemGMTOffsetID(); 673 if (gmtOffsetID != null) { 674 zoneID = gmtOffsetID; 675 } 676 tz = getTimeZone(zoneID, true); 677 } 678 assert tz != null; 679 680 final String id = zoneID; 681 AccessController.doPrivileged(new PrivilegedAction<Void>() { 682 @Override 683 public Void run() { 684 System.setProperty("user.timezone", id); 685 return null; 686 } 687 }); 688 689 defaultTimeZone = tz; 690 return tz; 691 } 692 693 /** 694 * Sets the {@code TimeZone} that is returned by the {@code getDefault} 695 * method. {@code zone} is cached. If {@code zone} is null, the cached 696 * default {@code TimeZone} is cleared. This method doesn't change the value 697 * of the {@code user.timezone} property. 698 * 699 * @param zone the new default {@code TimeZone}, or null 700 * @throws SecurityException if the security manager's {@code checkPermission} 701 * denies {@code PropertyPermission("user.timezone", 702 * "write")} 703 * @see #getDefault 704 * @see PropertyPermission 705 */ 706 public static void setDefault(TimeZone zone) 707 { 708 SecurityManager sm = System.getSecurityManager(); 709 if (sm != null) { 710 sm.checkPermission(new PropertyPermission 711 ("user.timezone", "write")); 712 } 713 defaultTimeZone = zone; 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; 763 764 static final String GMT_ID = "GMT"; 765 private static final int GMT_ID_LENGTH = 3; 766 767 // a static TimeZone we can reference if no AppContext is in place 768 private static volatile TimeZone mainAppContextDefault; 769 770 /** 771 * Parses a custom time zone identifier and returns a corresponding zone. 772 * This method doesn't support the RFC 822 time zone format. (e.g., +hhmm) 773 * 774 * @param id a string of the <a href="#CustomID">custom ID form</a>. 775 * @return a newly created TimeZone with the given offset and 776 * no daylight saving time, or null if the id cannot be parsed. 777 */ 778 private static final TimeZone parseCustomTimeZone(String id) { 779 int length; 780 781 // Error if the length of id isn't long enough or id doesn't 782 // start with "GMT". 783 if ((length = id.length()) < (GMT_ID_LENGTH + 2) || 784 id.indexOf(GMT_ID) != 0) { 785 return null; 786 } 787 788 ZoneInfo zi; 789 790 // First, we try to find it in the cache with the given 791 // id. Even the id is not normalized, the returned ZoneInfo 792 // should have its normalized id. 793 zi = ZoneInfoFile.getZoneInfo(id); 794 if (zi != null) { 795 return zi; 796 } 797 798 int index = GMT_ID_LENGTH; 799 boolean negative = false; 800 char c = id.charAt(index++); 801 if (c == '-') { 802 negative = true; 803 } else if (c != '+') { 804 return null; 805 } 806 807 int hours = 0; 808 int num = 0; 809 int countDelim = 0; 810 int len = 0; 811 while (index < length) { 812 c = id.charAt(index++); 813 if (c == ':') { 814 if (countDelim > 0) { 815 return null; 816 } 817 if (len > 2) { 818 return null; 819 } 820 hours = num; 821 countDelim++; 822 num = 0; 823 len = 0; 824 continue; 825 } 826 if (c < '0' || c > '9') { 827 return null; 828 } 829 num = num * 10 + (c - '0'); 830 len++; 831 } 832 if (index != length) { 833 return null; 834 } 835 if (countDelim == 0) { 836 if (len <= 2) { 837 hours = num; 838 num = 0; 839 } else { 840 hours = num / 100; 841 num %= 100; 842 } 843 } else { 844 if (len != 2) { 845 return null; 846 } 847 } 848 if (hours > 23 || num > 59) { 849 return null; 850 } 851 int gmtOffset = (hours * 60 + num) * 60 * 1000; 852 853 if (gmtOffset == 0) { 854 zi = ZoneInfoFile.getZoneInfo(GMT_ID); 855 if (negative) { 856 zi.setID("GMT-00:00"); 857 } else { 858 zi.setID("GMT+00:00"); 859 } 860 } else { 861 zi = ZoneInfoFile.getCustomTimeZone(id, negative ? -gmtOffset : gmtOffset); 862 } 863 return zi; 864 } 865 }