1 /*
2 * Copyright (c) 1996, 2012, 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.misc.JavaAWTAccess;
47 import sun.misc.SharedSecrets;
48 import sun.security.action.GetPropertyAction;
49 import sun.util.calendar.ZoneInfo;
50 import sun.util.calendar.ZoneInfoFile;
51 import sun.util.locale.provider.TimeZoneNameUtility;
52
53 /**
54 * <code>TimeZone</code> represents a time zone offset, and also figures out daylight
55 * savings.
56 *
57 * <p>
58 * Typically, you get a <code>TimeZone</code> using <code>getDefault</code>
59 * which creates a <code>TimeZone</code> based on the time zone where the program
60 * is running. For example, for a program running in Japan, <code>getDefault</code>
61 * creates a <code>TimeZone</code> object based on Japanese Standard Time.
62 *
63 * <p>
64 * You can also get a <code>TimeZone</code> using <code>getTimeZone</code>
65 * along with a time zone ID. For instance, the time zone ID for the
66 * U.S. Pacific Time zone is "America/Los_Angeles". So, you can get a
67 * U.S. Pacific Time <code>TimeZone</code> object with:
68 * <blockquote><pre>
69 * TimeZone tz = TimeZone.getTimeZone("America/Los_Angeles");
70 * </pre></blockquote>
71 * You can use the <code>getAvailableIDs</code> method to iterate through
72 * all the supported time zone IDs. You can then choose a
73 * supported ID to get a <code>TimeZone</code>.
74 * If the time zone you want is not represented by one of the
75 * supported IDs, then a custom time zone ID can be specified to
76 * produce a TimeZone. The syntax of a custom time zone ID is:
77 *
78 * <blockquote><pre>
79 * <a name="CustomID"><i>CustomID:</i></a>
80 * <code>GMT</code> <i>Sign</i> <i>Hours</i> <code>:</code> <i>Minutes</i>
81 * <code>GMT</code> <i>Sign</i> <i>Hours</i> <i>Minutes</i>
82 * <code>GMT</code> <i>Sign</i> <i>Hours</i>
83 * <i>Sign:</i> one of
84 * <code>+ -</code>
85 * <i>Hours:</i>
86 * <i>Digit</i>
87 * <i>Digit</i> <i>Digit</i>
88 * <i>Minutes:</i>
89 * <i>Digit</i> <i>Digit</i>
90 * <i>Digit:</i> one of
91 * <code>0 1 2 3 4 5 6 7 8 9</code>
92 * </pre></blockquote>
93 *
94 * <i>Hours</i> must be between 0 to 23 and <i>Minutes</i> must be
95 * between 00 to 59. For example, "GMT+10" and "GMT+0010" mean ten
96 * hours and ten minutes ahead of GMT, respectively.
97 * <p>
98 * The format is locale independent and digits must be taken from the
99 * Basic Latin block of the Unicode standard. No daylight saving time
100 * transition schedule can be specified with a custom time zone ID. If
101 * the specified string doesn't match the syntax, <code>"GMT"</code>
102 * is used.
103 * <p>
104 * When creating a <code>TimeZone</code>, the specified custom time
105 * zone ID is normalized in the following syntax:
106 * <blockquote><pre>
107 * <a name="NormalizedCustomID"><i>NormalizedCustomID:</i></a>
108 * <code>GMT</code> <i>Sign</i> <i>TwoDigitHours</i> <code>:</code> <i>Minutes</i>
109 * <i>Sign:</i> one of
110 * <code>+ -</code>
111 * <i>TwoDigitHours:</i>
112 * <i>Digit</i> <i>Digit</i>
113 * <i>Minutes:</i>
114 * <i>Digit</i> <i>Digit</i>
115 * <i>Digit:</i> one of
116 * <code>0 1 2 3 4 5 6 7 8 9</code>
117 * </pre></blockquote>
118 * For example, TimeZone.getTimeZone("GMT-8").getID() returns "GMT-08:00".
119 *
120 * <h4>Three-letter time zone IDs</h4>
121 *
122 * For compatibility with JDK 1.1.x, some other three-letter time zone IDs
123 * (such as "PST", "CTT", "AST") are also supported. However, <strong>their
124 * use is deprecated</strong> because the same abbreviation is often used
125 * for multiple time zones (for example, "CST" could be U.S. "Central Standard
126 * Time" and "China Standard Time"), and the Java platform can then only
127 * recognize one of them.
128 *
129 *
130 * @see Calendar
131 * @see GregorianCalendar
132 * @see SimpleTimeZone
133 * @author Mark Davis, David Goldsmith, Chen-Lieh Huang, Alan Liu
134 * @since JDK1.1
135 */
136 abstract public class TimeZone implements Serializable, Cloneable {
137 /**
138 * Sole constructor. (For invocation by subclass constructors, typically
139 * implicit.)
140 */
141 public TimeZone() {
142 }
143
144 /**
145 * A style specifier for <code>getDisplayName()</code> indicating
146 * a short name, such as "PST."
147 * @see #LONG
148 * @since 1.2
149 */
150 public static final int SHORT = 0;
151
152 /**
153 * A style specifier for <code>getDisplayName()</code> indicating
154 * a long name, such as "Pacific Standard Time."
155 * @see #SHORT
156 * @since 1.2
157 */
158 public static final int LONG = 1;
159
160 // Constants used internally; unit is milliseconds
161 private static final int ONE_MINUTE = 60*1000;
162 private static final int ONE_HOUR = 60*ONE_MINUTE;
163 private static final int ONE_DAY = 24*ONE_HOUR;
164
165 // Proclaim serialization compatibility with JDK 1.1
166 static final long serialVersionUID = 3581463369166924961L;
167
168 /**
169 * Gets the time zone offset, for current date, modified in case of
170 * daylight savings. This is the offset to add to UTC to get local time.
171 * <p>
172 * This method returns a historically correct offset if an
173 * underlying <code>TimeZone</code> implementation subclass
174 * supports historical Daylight Saving Time schedule and GMT
175 * offset changes.
176 *
177 * @param era the era of the given date.
178 * @param year the year in the given date.
179 * @param month the month in the given date.
180 * Month is 0-based. e.g., 0 for January.
181 * @param day the day-in-month of the given date.
182 * @param dayOfWeek the day-of-week of the given date.
183 * @param milliseconds the milliseconds in day in <em>standard</em>
184 * local time.
185 *
186 * @return the offset in milliseconds to add to GMT to get local time.
187 *
188 * @see Calendar#ZONE_OFFSET
189 * @see Calendar#DST_OFFSET
190 */
191 public abstract int getOffset(int era, int year, int month, int day,
192 int dayOfWeek, int milliseconds);
193
194 /**
195 * Returns the offset of this time zone from UTC at the specified
196 * date. If Daylight Saving Time is in effect at the specified
197 * date, the offset value is adjusted with the amount of daylight
198 * saving.
199 * <p>
200 * This method returns a historically correct offset value if an
201 * underlying TimeZone implementation subclass supports historical
202 * Daylight Saving Time schedule and GMT offset changes.
203 *
204 * @param date the date represented in milliseconds since January 1, 1970 00:00:00 GMT
205 * @return the amount of time in milliseconds to add to UTC to get local time.
206 *
207 * @see Calendar#ZONE_OFFSET
208 * @see Calendar#DST_OFFSET
209 * @since 1.4
210 */
211 public int getOffset(long date) {
212 if (inDaylightTime(new Date(date))) {
213 return getRawOffset() + getDSTSavings();
214 }
215 return getRawOffset();
216 }
217
218 /**
219 * Gets the raw GMT offset and the amount of daylight saving of this
220 * time zone at the given time.
221 * @param date the milliseconds (since January 1, 1970,
222 * 00:00:00.000 GMT) at which the time zone offset and daylight
223 * saving amount are found
224 * @param offsets an array of int where the raw GMT offset
225 * (offset[0]) and daylight saving amount (offset[1]) are stored,
226 * or null if those values are not needed. The method assumes that
227 * the length of the given array is two or larger.
228 * @return the total amount of the raw GMT offset and daylight
229 * saving at the specified date.
230 *
231 * @see Calendar#ZONE_OFFSET
232 * @see Calendar#DST_OFFSET
233 */
234 int getOffsets(long date, int[] offsets) {
235 int rawoffset = getRawOffset();
236 int dstoffset = 0;
237 if (inDaylightTime(new Date(date))) {
238 dstoffset = getDSTSavings();
239 }
240 if (offsets != null) {
241 offsets[0] = rawoffset;
242 offsets[1] = dstoffset;
243 }
244 return rawoffset + dstoffset;
245 }
246
247 /**
248 * Sets the base time zone offset to GMT.
249 * This is the offset to add to UTC to get local time.
250 * <p>
251 * If an underlying <code>TimeZone</code> implementation subclass
252 * supports historical GMT offset changes, the specified GMT
253 * offset is set as the latest GMT offset and the difference from
254 * the known latest GMT offset value is used to adjust all
255 * historical GMT offset values.
256 *
257 * @param offsetMillis the given base time zone offset to GMT.
258 */
259 abstract public void setRawOffset(int offsetMillis);
260
261 /**
262 * Returns the amount of time in milliseconds to add to UTC to get
263 * standard time in this time zone. Because this value is not
264 * affected by daylight saving time, it is called <I>raw
265 * offset</I>.
266 * <p>
267 * If an underlying <code>TimeZone</code> implementation subclass
268 * supports historical GMT offset changes, the method returns the
269 * raw offset value of the current date. In Honolulu, for example,
270 * its raw offset changed from GMT-10:30 to GMT-10:00 in 1947, and
271 * this method always returns -36000000 milliseconds (i.e., -10
272 * hours).
273 *
274 * @return the amount of raw offset time in milliseconds to add to UTC.
275 * @see Calendar#ZONE_OFFSET
276 */
277 public abstract int getRawOffset();
278
279 /**
280 * Gets the ID of this time zone.
281 * @return the ID of this time zone.
282 */
283 public String getID()
284 {
285 return ID;
286 }
287
288 /**
289 * Sets the time zone ID. This does not change any other data in
290 * the time zone object.
291 * @param ID the new time zone ID.
292 */
293 public void setID(String ID)
294 {
295 if (ID == null) {
296 throw new NullPointerException();
297 }
298 this.ID = ID;
299 }
300
301 /**
302 * Returns a long standard time name of this {@code TimeZone} suitable for
303 * presentation to the user in the default locale.
304 *
305 * <p>This method is equivalent to:
306 * <pre><blockquote>
307 * getDisplayName(false, {@link #LONG},
308 * Locale.getDefault({@link Locale.Category#DISPLAY}))
309 * </blockquote></pre>
310 *
311 * @return the human-readable name of this time zone in the default locale.
312 * @since 1.2
313 * @see #getDisplayName(boolean, int, Locale)
314 * @see Locale#getDefault(Locale.Category)
315 * @see Locale.Category
316 */
317 public final String getDisplayName() {
318 return getDisplayName(false, LONG,
319 Locale.getDefault(Locale.Category.DISPLAY));
320 }
321
322 /**
323 * Returns a long standard time name of this {@code TimeZone} suitable for
324 * presentation to the user in the specified {@code locale}.
325 *
326 * <p>This method is equivalent to:
327 * <pre><blockquote>
328 * getDisplayName(false, {@link #LONG}, locale)
329 * </blockquote></pre>
330 *
331 * @param locale the locale in which to supply the display name.
332 * @return the human-readable name of this time zone in the given locale.
333 * @exception NullPointerException if {@code locale} is {@code null}.
334 * @since 1.2
335 * @see #getDisplayName(boolean, int, Locale)
336 */
337 public final String getDisplayName(Locale locale) {
338 return getDisplayName(false, LONG, locale);
339 }
340
341 /**
342 * Returns a name in the specified {@code style} of this {@code TimeZone}
343 * suitable for presentation to the user in the default locale. If the
344 * specified {@code daylight} is {@code true}, a Daylight Saving Time name
345 * is returned (even if this {@code TimeZone} doesn't observe Daylight Saving
346 * Time). Otherwise, a Standard Time name is returned.
347 *
348 * <p>This method is equivalent to:
349 * <pre><blockquote>
350 * getDisplayName(daylight, style,
351 * Locale.getDefault({@link Locale.Category#DISPLAY}))
352 * </blockquote></pre>
353 *
354 * @param daylight {@code true} specifying a Daylight Saving Time name, or
355 * {@code false} specifying a Standard Time name
356 * @param style either {@link #LONG} or {@link #SHORT}
357 * @return the human-readable name of this time zone in the default locale.
358 * @exception IllegalArgumentException if {@code style} is invalid.
359 * @since 1.2
360 * @see #getDisplayName(boolean, int, Locale)
361 * @see Locale#getDefault(Locale.Category)
362 * @see Locale.Category
363 * @see java.text.DateFormatSymbols#getZoneStrings()
364 */
365 public final String getDisplayName(boolean daylight, int style) {
366 return getDisplayName(daylight, style,
367 Locale.getDefault(Locale.Category.DISPLAY));
368 }
369
370 /**
371 * Returns a name in the specified {@code style} of this {@code TimeZone}
372 * suitable for presentation to the user in the specified {@code
373 * locale}. If the specified {@code daylight} is {@code true}, a Daylight
374 * Saving Time name is returned (even if this {@code TimeZone} doesn't
375 * observe Daylight Saving Time). Otherwise, a Standard Time name is
376 * returned.
377 *
378 * <p>When looking up a time zone name, the {@linkplain
379 * ResourceBundle.Control#getCandidateLocales(String,Locale) default
380 * <code>Locale</code> search path of <code>ResourceBundle</code>} derived
381 * from the specified {@code locale} is used. (No {@linkplain
382 * ResourceBundle.Control#getFallbackLocale(String,Locale) fallback
383 * <code>Locale</code>} search is performed.) If a time zone name in any
384 * {@code Locale} of the search path, including {@link Locale#ROOT}, is
385 * found, the name is returned. Otherwise, a string in the
386 * <a href="#NormalizedCustomID">normalized custom ID format</a> is returned.
387 *
388 * @param daylight {@code true} specifying a Daylight Saving Time name, or
389 * {@code false} specifying a Standard Time name
390 * @param style either {@link #LONG} or {@link #SHORT}
391 * @param locale the locale in which to supply the display name.
392 * @return the human-readable name of this time zone in the given locale.
393 * @exception IllegalArgumentException if {@code style} is invalid.
394 * @exception NullPointerException if {@code locale} is {@code null}.
395 * @since 1.2
396 * @see java.text.DateFormatSymbols#getZoneStrings()
397 */
398 public String getDisplayName(boolean daylight, int style, Locale locale) {
399 if (style != SHORT && style != LONG) {
400 throw new IllegalArgumentException("Illegal style: " + style);
401 }
402 String id = getID();
403 String name = TimeZoneNameUtility.retrieveDisplayName(id, daylight, style, locale);
404 if (name != null) {
405 return name;
406 }
407
408 if (id.startsWith("GMT") && id.length() > 3) {
409 char sign = id.charAt(3);
410 if (sign == '+' || sign == '-') {
411 return id;
412 }
413 }
414 int offset = getRawOffset();
415 if (daylight) {
416 offset += getDSTSavings();
417 }
418 return ZoneInfoFile.toCustomID(offset);
419 }
420
421 private static class DisplayNames {
422 // Cache for managing display names per timezone per locale
423 // The structure is:
424 // Map(key=id, value=SoftReference(Map(key=locale, value=displaynames)))
425 private static final Map<String, SoftReference<Map<Locale, String[]>>> CACHE =
426 new ConcurrentHashMap<>();
427
428 private DisplayNames() {
429 }
430 }
431
432 private static String[] getDisplayNames(String id, Locale locale) {
433 return TimeZoneNameUtility.retrieveDisplayNames(id, locale);
434 }
435
436 /**
437 * Returns the amount of time to be added to local standard time
438 * to get local wall clock time.
439 *
440 * <p>The default implementation returns 3600000 milliseconds
441 * (i.e., one hour) if a call to {@link #useDaylightTime()}
442 * returns {@code true}. Otherwise, 0 (zero) is returned.
443 *
444 * <p>If an underlying {@code TimeZone} implementation subclass
445 * supports historical and future Daylight Saving Time schedule
446 * changes, this method returns the amount of saving time of the
447 * last known Daylight Saving Time rule that can be a future
448 * prediction.
449 *
450 * <p>If the amount of saving time at any given time stamp is
451 * required, construct a {@link Calendar} with this {@code
452 * TimeZone} and the time stamp, and call {@link Calendar#get(int)
453 * Calendar.get}{@code (}{@link Calendar#DST_OFFSET}{@code )}.
454 *
455 * @return the amount of saving time in milliseconds
456 * @since 1.4
457 * @see #inDaylightTime(Date)
458 * @see #getOffset(long)
459 * @see #getOffset(int,int,int,int,int,int)
460 * @see Calendar#ZONE_OFFSET
461 */
462 public int getDSTSavings() {
463 if (useDaylightTime()) {
464 return 3600000;
465 }
466 return 0;
467 }
468
469 /**
470 * Queries if this {@code TimeZone} uses Daylight Saving Time.
471 *
472 * <p>If an underlying {@code TimeZone} implementation subclass
473 * supports historical and future Daylight Saving Time schedule
474 * changes, this method refers to the last known Daylight Saving Time
475 * rule that can be a future prediction and may not be the same as
476 * the current rule. Consider calling {@link #observesDaylightTime()}
477 * if the current rule should also be taken into account.
478 *
479 * @return {@code true} if this {@code TimeZone} uses Daylight Saving Time,
480 * {@code false}, otherwise.
481 * @see #inDaylightTime(Date)
482 * @see Calendar#DST_OFFSET
483 */
484 public abstract boolean useDaylightTime();
485
486 /**
487 * Returns {@code true} if this {@code TimeZone} is currently in
488 * Daylight Saving Time, or if a transition from Standard Time to
489 * Daylight Saving Time occurs at any future time.
490 *
491 * <p>The default implementation returns {@code true} if
492 * {@code useDaylightTime()} or {@code inDaylightTime(new Date())}
493 * returns {@code true}.
494 *
495 * @return {@code true} if this {@code TimeZone} is currently in
496 * Daylight Saving Time, or if a transition from Standard Time to
497 * Daylight Saving Time occurs at any future time; {@code false}
498 * otherwise.
499 * @since 1.7
500 * @see #useDaylightTime()
501 * @see #inDaylightTime(Date)
502 * @see Calendar#DST_OFFSET
503 */
504 public boolean observesDaylightTime() {
505 return useDaylightTime() || inDaylightTime(new Date());
506 }
507
508 /**
509 * Queries if the given {@code date} is in Daylight Saving Time in
510 * this time zone.
511 *
512 * @param date the given Date.
513 * @return {@code true} if the given date is in Daylight Saving Time,
514 * {@code false}, otherwise.
515 */
516 abstract public boolean inDaylightTime(Date date);
517
518 /**
519 * Gets the <code>TimeZone</code> for the given ID.
520 *
521 * @param ID the ID for a <code>TimeZone</code>, either an abbreviation
522 * such as "PST", a full name such as "America/Los_Angeles", or a custom
523 * ID such as "GMT-8:00". Note that the support of abbreviations is
524 * for JDK 1.1.x compatibility only and full names should be used.
525 *
526 * @return the specified <code>TimeZone</code>, or the GMT zone if the given ID
527 * cannot be understood.
528 */
529 public static synchronized TimeZone getTimeZone(String ID) {
530 return getTimeZone(ID, true);
531 }
532
533 private static TimeZone getTimeZone(String ID, boolean fallback) {
534 TimeZone tz = ZoneInfo.getTimeZone(ID);
535 if (tz == null) {
536 tz = parseCustomTimeZone(ID);
537 if (tz == null && fallback) {
538 tz = new ZoneInfo(GMT_ID, 0);
539 }
540 }
541 return tz;
542 }
543
544 /**
545 * Gets the available IDs according to the given time zone offset in milliseconds.
546 *
547 * @param rawOffset the given time zone GMT offset in milliseconds.
548 * @return an array of IDs, where the time zone for that ID has
549 * the specified GMT offset. For example, "America/Phoenix" and "America/Denver"
550 * both have GMT-07:00, but differ in daylight saving behavior.
551 * @see #getRawOffset()
552 */
553 public static synchronized String[] getAvailableIDs(int rawOffset) {
554 return ZoneInfo.getAvailableIDs(rawOffset);
555 }
556
557 /**
558 * Gets all the available IDs supported.
559 * @return an array of IDs.
560 */
561 public static synchronized String[] getAvailableIDs() {
562 return ZoneInfo.getAvailableIDs();
563 }
564
565 /**
566 * Gets the platform defined TimeZone ID.
567 **/
568 private static native String getSystemTimeZoneID(String javaHome,
569 String country);
570
571 /**
572 * Gets the custom time zone ID based on the GMT offset of the
573 * platform. (e.g., "GMT+08:00")
574 */
575 private static native String getSystemGMTOffsetID();
576
577 /**
578 * Gets the default <code>TimeZone</code> for this host.
579 * The source of the default <code>TimeZone</code>
580 * may vary with implementation.
581 * @return a default <code>TimeZone</code>.
582 * @see #setDefault
583 */
584 public static TimeZone getDefault() {
585 return (TimeZone) getDefaultRef().clone();
586 }
587
588 /**
589 * Returns the reference to the default TimeZone object. This
590 * method doesn't create a clone.
591 */
592 static TimeZone getDefaultRef() {
593 TimeZone defaultZone = getDefaultInAppContext();
594 if (defaultZone == null) {
595 defaultZone = defaultTimeZone;
596 if (defaultZone == null) {
597 // Need to initialize the default time zone.
598 defaultZone = setDefaultZone();
599 assert defaultZone != null;
600 }
601 }
602 // Don't clone here.
603 return defaultZone;
604 }
605
606 private static synchronized TimeZone setDefaultZone() {
607 TimeZone tz;
608 // get the time zone ID from the system properties
609 String zoneID = AccessController.doPrivileged(
610 new GetPropertyAction("user.timezone"));
611
612 // if the time zone ID is not set (yet), perform the
613 // platform to Java time zone ID mapping.
614 if (zoneID == null || zoneID.isEmpty()) {
615 String country = AccessController.doPrivileged(
616 new GetPropertyAction("user.country"));
617 String javaHome = AccessController.doPrivileged(
618 new GetPropertyAction("java.home"));
619 try {
620 zoneID = getSystemTimeZoneID(javaHome, country);
621 if (zoneID == null) {
622 zoneID = GMT_ID;
623 }
624 } catch (NullPointerException e) {
625 zoneID = GMT_ID;
626 }
627 }
628
629 // Get the time zone for zoneID. But not fall back to
630 // "GMT" here.
631 tz = getTimeZone(zoneID, false);
632
633 if (tz == null) {
634 // If the given zone ID is unknown in Java, try to
635 // get the GMT-offset-based time zone ID,
636 // a.k.a. custom time zone ID (e.g., "GMT-08:00").
637 String gmtOffsetID = getSystemGMTOffsetID();
638 if (gmtOffsetID != null) {
639 zoneID = gmtOffsetID;
640 }
641 tz = getTimeZone(zoneID, true);
642 }
643 assert tz != null;
644
645 final String id = zoneID;
646 AccessController.doPrivileged(new PrivilegedAction<Void>() {
647 @Override
648 public Void run() {
649 System.setProperty("user.timezone", id);
650 return null;
651 }
652 });
653
654 defaultTimeZone = tz;
655 return tz;
656 }
657
658 private static boolean hasPermission() {
659 boolean hasPermission = true;
660 SecurityManager sm = System.getSecurityManager();
661 if (sm != null) {
662 try {
663 sm.checkPermission(new PropertyPermission
664 ("user.timezone", "write"));
665 } catch (SecurityException e) {
666 hasPermission = false;
667 }
668 }
669 return hasPermission;
670 }
671
672 /**
673 * Sets the <code>TimeZone</code> that is
674 * returned by the <code>getDefault</code> method. If <code>zone</code>
675 * is null, reset the default to the value it had originally when the
676 * VM first started.
677 * @param zone the new default time zone
678 * @see #getDefault
679 */
680 public static void setDefault(TimeZone zone)
681 {
682 if (hasPermission()) {
683 synchronized (TimeZone.class) {
684 defaultTimeZone = zone;
685 setDefaultInAppContext(null);
686 }
687 } else {
688 setDefaultInAppContext(zone);
689 }
690 }
691
692 /**
693 * Returns the default TimeZone in an AppContext if any AppContext
694 * has ever used. null is returned if any AppContext hasn't been
695 * used or if the AppContext doesn't have the default TimeZone.
696 *
697 * Note that javaAWTAccess may be null if sun.awt.AppContext class hasn't
698 * been loaded. If so, it implies that AWTSecurityManager is not our
699 * SecurityManager and we can use a local static variable.
700 * This works around a build time issue.
701 */
702 private static TimeZone getDefaultInAppContext() {
703 // JavaAWTAccess provides access implementation-private methods without using reflection.
704 JavaAWTAccess javaAWTAccess = SharedSecrets.getJavaAWTAccess();
705
706 if (javaAWTAccess == null) {
707 return mainAppContextDefault;
708 } else {
709 if (!javaAWTAccess.isDisposed()) {
710 TimeZone tz = (TimeZone)
711 javaAWTAccess.get(TimeZone.class);
712 if (tz == null && javaAWTAccess.isMainAppContext()) {
713 return mainAppContextDefault;
714 } else {
715 return tz;
716 }
717 }
718 }
719 return null;
720 }
721
722 /**
723 * Sets the default TimeZone in the AppContext to the given
724 * tz. null is handled special: do nothing if any AppContext
725 * hasn't been used, remove the default TimeZone in the
726 * AppContext otherwise.
727 *
728 * Note that javaAWTAccess may be null if sun.awt.AppContext class hasn't
729 * been loaded. If so, it implies that AWTSecurityManager is not our
730 * SecurityManager and we can use a local static variable.
731 * This works around a build time issue.
732 */
733 private static void setDefaultInAppContext(TimeZone tz) {
734 // JavaAWTAccess provides access implementation-private methods without using reflection.
735 JavaAWTAccess javaAWTAccess = SharedSecrets.getJavaAWTAccess();
736
737 if (javaAWTAccess == null) {
738 mainAppContextDefault = tz;
739 } else {
740 if (!javaAWTAccess.isDisposed()) {
741 javaAWTAccess.put(TimeZone.class, tz);
742 if (javaAWTAccess.isMainAppContext()) {
743 mainAppContextDefault = null;
744 }
745 }
746 }
747 }
748
749 /**
750 * Returns true if this zone has the same rule and offset as another zone.
751 * That is, if this zone differs only in ID, if at all. Returns false
752 * if the other zone is null.
753 * @param other the <code>TimeZone</code> object to be compared with
754 * @return true if the other zone is not null and is the same as this one,
755 * with the possible exception of the ID
756 * @since 1.2
757 */
758 public boolean hasSameRules(TimeZone other) {
759 return other != null && getRawOffset() == other.getRawOffset() &&
760 useDaylightTime() == other.useDaylightTime();
761 }
762
763 /**
764 * Creates a copy of this <code>TimeZone</code>.
765 *
766 * @return a clone of this <code>TimeZone</code>
767 */
768 public Object clone()
769 {
770 try {
771 TimeZone other = (TimeZone) super.clone();
772 other.ID = ID;
773 return other;
774 } catch (CloneNotSupportedException e) {
775 throw new InternalError(e);
776 }
777 }
778
779 /**
780 * The null constant as a TimeZone.
781 */
782 static final TimeZone NO_TIMEZONE = null;
783
784 // =======================privates===============================
785
786 /**
787 * The string identifier of this <code>TimeZone</code>. This is a
788 * programmatic identifier used internally to look up <code>TimeZone</code>
789 * objects from the system table and also to map them to their localized
790 * display names. <code>ID</code> values are unique in the system
791 * table but may not be for dynamically created zones.
792 * @serial
793 */
794 private String ID;
795 private static volatile TimeZone defaultTimeZone;
796
797 static final String GMT_ID = "GMT";
798 private static final int GMT_ID_LENGTH = 3;
799
800 // a static TimeZone we can reference if no AppContext is in place
801 private static volatile TimeZone mainAppContextDefault;
802
803 /**
804 * Parses a custom time zone identifier and returns a corresponding zone.
805 * This method doesn't support the RFC 822 time zone format. (e.g., +hhmm)
806 *
807 * @param id a string of the <a href="#CustomID">custom ID form</a>.
808 * @return a newly created TimeZone with the given offset and
809 * no daylight saving time, or null if the id cannot be parsed.
810 */
811 private static final TimeZone parseCustomTimeZone(String id) {
812 int length;
813
814 // Error if the length of id isn't long enough or id doesn't
815 // start with "GMT".
816 if ((length = id.length()) < (GMT_ID_LENGTH + 2) ||
817 id.indexOf(GMT_ID) != 0) {
818 return null;
819 }
820
821 ZoneInfo zi;
822
823 // First, we try to find it in the cache with the given
824 // id. Even the id is not normalized, the returned ZoneInfo
825 // should have its normalized id.
826 zi = ZoneInfoFile.getZoneInfo(id);
827 if (zi != null) {
828 return zi;
829 }
830
831 int index = GMT_ID_LENGTH;
832 boolean negative = false;
833 char c = id.charAt(index++);
834 if (c == '-') {
835 negative = true;
836 } else if (c != '+') {
837 return null;
838 }
839
840 int hours = 0;
841 int num = 0;
842 int countDelim = 0;
843 int len = 0;
844 while (index < length) {
845 c = id.charAt(index++);
846 if (c == ':') {
847 if (countDelim > 0) {
848 return null;
849 }
850 if (len > 2) {
851 return null;
852 }
853 hours = num;
854 countDelim++;
855 num = 0;
856 len = 0;
857 continue;
858 }
859 if (c < '0' || c > '9') {
860 return null;
861 }
862 num = num * 10 + (c - '0');
863 len++;
864 }
865 if (index != length) {
866 return null;
867 }
868 if (countDelim == 0) {
869 if (len <= 2) {
870 hours = num;
871 num = 0;
872 } else {
873 hours = num / 100;
874 num %= 100;
875 }
876 } else {
877 if (len != 2) {
878 return null;
879 }
880 }
881 if (hours > 23 || num > 59) {
882 return null;
883 }
884 int gmtOffset = (hours * 60 + num) * 60 * 1000;
885
886 if (gmtOffset == 0) {
887 zi = ZoneInfoFile.getZoneInfo(GMT_ID);
888 if (negative) {
889 zi.setID("GMT-00:00");
890 } else {
891 zi.setID("GMT+00:00");
892 }
893 } else {
894 zi = ZoneInfoFile.getCustomTimeZone(id, negative ? -gmtOffset : gmtOffset);
895 }
896 return zi;
897 }
898 }