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.time.ZoneId;
46 import java.util.concurrent.ConcurrentHashMap;
47 import sun.misc.JavaAWTAccess;
48 import sun.misc.SharedSecrets;
49 import sun.security.action.GetPropertyAction;
50 import sun.util.calendar.ZoneInfo;
51 import sun.util.calendar.ZoneInfoFile;
52 import sun.util.locale.provider.TimeZoneNameUtility;
53
54 /**
55 * <code>TimeZone</code> represents a time zone offset, and also figures out daylight
56 * savings.
57 *
58 * <p>
59 * Typically, you get a <code>TimeZone</code> using <code>getDefault</code>
60 * which creates a <code>TimeZone</code> based on the time zone where the program
61 * is running. For example, for a program running in Japan, <code>getDefault</code>
62 * creates a <code>TimeZone</code> object based on Japanese Standard Time.
63 *
64 * <p>
65 * You can also get a <code>TimeZone</code> using <code>getTimeZone</code>
66 * along with a time zone ID. For instance, the time zone ID for the
67 * U.S. Pacific Time zone is "America/Los_Angeles". So, you can get a
68 * U.S. Pacific Time <code>TimeZone</code> object with:
69 * <blockquote><pre>
70 * TimeZone tz = TimeZone.getTimeZone("America/Los_Angeles");
71 * </pre></blockquote>
72 * You can use the <code>getAvailableIDs</code> method to iterate through
73 * all the supported time zone IDs. You can then choose a
74 * supported ID to get a <code>TimeZone</code>.
75 * If the time zone you want is not represented by one of the
76 * supported IDs, then a custom time zone ID can be specified to
77 * produce a TimeZone. The syntax of a custom time zone ID is:
78 *
79 * <blockquote><pre>
80 * <a name="CustomID"><i>CustomID:</i></a>
81 * <code>GMT</code> <i>Sign</i> <i>Hours</i> <code>:</code> <i>Minutes</i>
82 * <code>GMT</code> <i>Sign</i> <i>Hours</i> <i>Minutes</i>
83 * <code>GMT</code> <i>Sign</i> <i>Hours</i>
84 * <i>Sign:</i> one of
85 * <code>+ -</code>
86 * <i>Hours:</i>
87 * <i>Digit</i>
88 * <i>Digit</i> <i>Digit</i>
89 * <i>Minutes:</i>
90 * <i>Digit</i> <i>Digit</i>
91 * <i>Digit:</i> one of
92 * <code>0 1 2 3 4 5 6 7 8 9</code>
93 * </pre></blockquote>
94 *
95 * <i>Hours</i> must be between 0 to 23 and <i>Minutes</i> must be
96 * between 00 to 59. For example, "GMT+10" and "GMT+0010" mean ten
97 * hours and ten minutes ahead of GMT, respectively.
98 * <p>
99 * The format is locale independent and digits must be taken from the
100 * Basic Latin block of the Unicode standard. No daylight saving time
101 * transition schedule can be specified with a custom time zone ID. If
102 * the specified string doesn't match the syntax, <code>"GMT"</code>
103 * is used.
104 * <p>
105 * When creating a <code>TimeZone</code>, the specified custom time
106 * zone ID is normalized in the following syntax:
107 * <blockquote><pre>
108 * <a name="NormalizedCustomID"><i>NormalizedCustomID:</i></a>
109 * <code>GMT</code> <i>Sign</i> <i>TwoDigitHours</i> <code>:</code> <i>Minutes</i>
110 * <i>Sign:</i> one of
111 * <code>+ -</code>
112 * <i>TwoDigitHours:</i>
113 * <i>Digit</i> <i>Digit</i>
114 * <i>Minutes:</i>
115 * <i>Digit</i> <i>Digit</i>
116 * <i>Digit:</i> one of
117 * <code>0 1 2 3 4 5 6 7 8 9</code>
118 * </pre></blockquote>
119 * For example, TimeZone.getTimeZone("GMT-8").getID() returns "GMT-08:00".
120 *
121 * <h3>Three-letter time zone IDs</h3>
122 *
123 * For compatibility with JDK 1.1.x, some other three-letter time zone IDs
124 * (such as "PST", "CTT", "AST") are also supported. However, <strong>their
125 * use is deprecated</strong> because the same abbreviation is often used
126 * for multiple time zones (for example, "CST" could be U.S. "Central Standard
127 * Time" and "China Standard Time"), and the Java platform can then only
128 * recognize one of them.
129 *
130 *
131 * @see Calendar
132 * @see GregorianCalendar
133 * @see SimpleTimeZone
134 * @author Mark Davis, David Goldsmith, Chen-Lieh Huang, Alan Liu
135 * @since JDK1.1
136 */
137 abstract public class TimeZone implements Serializable, Cloneable {
138 /**
139 * Sole constructor. (For invocation by subclass constructors, typically
140 * implicit.)
141 */
142 public TimeZone() {
143 }
144
145 /**
146 * A style specifier for <code>getDisplayName()</code> indicating
147 * a short name, such as "PST."
148 * @see #LONG
149 * @since 1.2
150 */
151 public static final int SHORT = 0;
152
153 /**
154 * A style specifier for <code>getDisplayName()</code> indicating
155 * a long name, such as "Pacific Standard Time."
156 * @see #SHORT
157 * @since 1.2
158 */
159 public static final int LONG = 1;
160
161 // Constants used internally; unit is milliseconds
162 private static final int ONE_MINUTE = 60*1000;
163 private static final int ONE_HOUR = 60*ONE_MINUTE;
164 private static final int ONE_DAY = 24*ONE_HOUR;
165
166 // Proclaim serialization compatibility with JDK 1.1
167 static final long serialVersionUID = 3581463369166924961L;
168
169 /**
170 * Gets the time zone offset, for current date, modified in case of
171 * daylight savings. This is the offset to add to UTC to get local time.
172 * <p>
173 * This method returns a historically correct offset if an
174 * underlying <code>TimeZone</code> implementation subclass
175 * supports historical Daylight Saving Time schedule and GMT
176 * offset changes.
177 *
178 * @param era the era of the given date.
179 * @param year the year in the given date.
180 * @param month the month in the given date.
181 * Month is 0-based. e.g., 0 for January.
182 * @param day the day-in-month of the given date.
183 * @param dayOfWeek the day-of-week of the given date.
184 * @param milliseconds the milliseconds in day in <em>standard</em>
185 * local time.
186 *
187 * @return the offset in milliseconds to add to GMT to get local time.
188 *
189 * @see Calendar#ZONE_OFFSET
190 * @see Calendar#DST_OFFSET
191 */
192 public abstract int getOffset(int era, int year, int month, int day,
193 int dayOfWeek, int milliseconds);
194
195 /**
196 * Returns the offset of this time zone from UTC at the specified
197 * date. If Daylight Saving Time is in effect at the specified
198 * date, the offset value is adjusted with the amount of daylight
199 * saving.
200 * <p>
201 * This method returns a historically correct offset value if an
202 * underlying TimeZone implementation subclass supports historical
203 * Daylight Saving Time schedule and GMT offset changes.
204 *
205 * @param date the date represented in milliseconds since January 1, 1970 00:00:00 GMT
206 * @return the amount of time in milliseconds to add to UTC to get local time.
207 *
208 * @see Calendar#ZONE_OFFSET
209 * @see Calendar#DST_OFFSET
210 * @since 1.4
211 */
212 public int getOffset(long date) {
213 if (inDaylightTime(new Date(date))) {
214 return getRawOffset() + getDSTSavings();
215 }
216 return getRawOffset();
217 }
218
219 /**
220 * Gets the raw GMT offset and the amount of daylight saving of this
221 * time zone at the given time.
222 * @param date the milliseconds (since January 1, 1970,
223 * 00:00:00.000 GMT) at which the time zone offset and daylight
224 * saving amount are found
225 * @param offsets an array of int where the raw GMT offset
226 * (offset[0]) and daylight saving amount (offset[1]) are stored,
227 * or null if those values are not needed. The method assumes that
228 * the length of the given array is two or larger.
229 * @return the total amount of the raw GMT offset and daylight
230 * saving at the specified date.
231 *
232 * @see Calendar#ZONE_OFFSET
233 * @see Calendar#DST_OFFSET
234 */
235 int getOffsets(long date, int[] offsets) {
236 int rawoffset = getRawOffset();
237 int dstoffset = 0;
238 if (inDaylightTime(new Date(date))) {
239 dstoffset = getDSTSavings();
240 }
241 if (offsets != null) {
242 offsets[0] = rawoffset;
243 offsets[1] = dstoffset;
244 }
245 return rawoffset + dstoffset;
246 }
247
248 /**
249 * Sets the base time zone offset to GMT.
250 * This is the offset to add to UTC to get local time.
251 * <p>
252 * If an underlying <code>TimeZone</code> implementation subclass
253 * supports historical GMT offset changes, the specified GMT
254 * offset is set as the latest GMT offset and the difference from
255 * the known latest GMT offset value is used to adjust all
256 * historical GMT offset values.
257 *
258 * @param offsetMillis the given base time zone offset to GMT.
259 */
260 abstract public void setRawOffset(int offsetMillis);
261
262 /**
263 * Returns the amount of time in milliseconds to add to UTC to get
264 * standard time in this time zone. Because this value is not
265 * affected by daylight saving time, it is called <I>raw
266 * offset</I>.
267 * <p>
268 * If an underlying <code>TimeZone</code> implementation subclass
269 * supports historical GMT offset changes, the method returns the
270 * raw offset value of the current date. In Honolulu, for example,
271 * its raw offset changed from GMT-10:30 to GMT-10:00 in 1947, and
272 * this method always returns -36000000 milliseconds (i.e., -10
273 * hours).
274 *
275 * @return the amount of raw offset time in milliseconds to add to UTC.
276 * @see Calendar#ZONE_OFFSET
277 */
278 public abstract int getRawOffset();
279
280 /**
281 * Gets the ID of this time zone.
282 * @return the ID of this time zone.
283 */
284 public String getID()
285 {
286 return ID;
287 }
288
289 /**
290 * Sets the time zone ID. This does not change any other data in
291 * the time zone object.
292 * @param ID the new time zone ID.
293 */
294 public void setID(String ID)
295 {
296 if (ID == null) {
297 throw new NullPointerException();
298 }
299 this.ID = ID;
300 }
301
302 /**
303 * Returns a long standard time name of this {@code TimeZone} suitable for
304 * presentation to the user in the default locale.
305 *
306 * <p>This method is equivalent to:
307 * <blockquote><pre>
308 * getDisplayName(false, {@link #LONG},
309 * Locale.getDefault({@link Locale.Category#DISPLAY}))
310 * </pre></blockquote>
311 *
312 * @return the human-readable name of this time zone in the default locale.
313 * @since 1.2
314 * @see #getDisplayName(boolean, int, Locale)
315 * @see Locale#getDefault(Locale.Category)
316 * @see Locale.Category
317 */
318 public final String getDisplayName() {
319 return getDisplayName(false, LONG,
320 Locale.getDefault(Locale.Category.DISPLAY));
321 }
322
323 /**
324 * Returns a long standard time name of this {@code TimeZone} suitable for
325 * presentation to the user in the specified {@code locale}.
326 *
327 * <p>This method is equivalent to:
328 * <blockquote><pre>
329 * getDisplayName(false, {@link #LONG}, locale)
330 * </pre></blockquote>
331 *
332 * @param locale the locale in which to supply the display name.
333 * @return the human-readable name of this time zone in the given locale.
334 * @exception NullPointerException if {@code locale} is {@code null}.
335 * @since 1.2
336 * @see #getDisplayName(boolean, int, Locale)
337 */
338 public final String getDisplayName(Locale locale) {
339 return getDisplayName(false, LONG, locale);
340 }
341
342 /**
343 * Returns a name in the specified {@code style} of this {@code TimeZone}
344 * suitable for presentation to the user in the default locale. If the
345 * specified {@code daylight} is {@code true}, a Daylight Saving Time name
346 * is returned (even if this {@code TimeZone} doesn't observe Daylight Saving
347 * Time). Otherwise, a Standard Time name is returned.
348 *
349 * <p>This method is equivalent to:
350 * <blockquote><pre>
351 * getDisplayName(daylight, style,
352 * Locale.getDefault({@link Locale.Category#DISPLAY}))
353 * </pre></blockquote>
354 *
355 * @param daylight {@code true} specifying a Daylight Saving Time name, or
356 * {@code false} specifying a Standard Time name
357 * @param style either {@link #LONG} or {@link #SHORT}
358 * @return the human-readable name of this time zone in the default locale.
359 * @exception IllegalArgumentException if {@code style} is invalid.
360 * @since 1.2
361 * @see #getDisplayName(boolean, int, Locale)
362 * @see Locale#getDefault(Locale.Category)
363 * @see Locale.Category
364 * @see java.text.DateFormatSymbols#getZoneStrings()
365 */
366 public final String getDisplayName(boolean daylight, int style) {
367 return getDisplayName(daylight, style,
368 Locale.getDefault(Locale.Category.DISPLAY));
369 }
370
371 /**
372 * Returns a name in the specified {@code style} of this {@code TimeZone}
373 * suitable for presentation to the user in the specified {@code
374 * locale}. If the specified {@code daylight} is {@code true}, a Daylight
375 * Saving Time name is returned (even if this {@code TimeZone} doesn't
376 * observe Daylight Saving Time). Otherwise, a Standard Time name is
377 * returned.
378 *
379 * <p>When looking up a time zone name, the {@linkplain
380 * ResourceBundle.Control#getCandidateLocales(String,Locale) default
381 * <code>Locale</code> search path of <code>ResourceBundle</code>} derived
382 * from the specified {@code locale} is used. (No {@linkplain
383 * ResourceBundle.Control#getFallbackLocale(String,Locale) fallback
384 * <code>Locale</code>} search is performed.) If a time zone name in any
385 * {@code Locale} of the search path, including {@link Locale#ROOT}, is
386 * found, the name is returned. Otherwise, a string in the
387 * <a href="#NormalizedCustomID">normalized custom ID format</a> is returned.
388 *
389 * @param daylight {@code true} specifying a Daylight Saving Time name, or
390 * {@code false} specifying a Standard Time name
391 * @param style either {@link #LONG} or {@link #SHORT}
392 * @param locale the locale in which to supply the display name.
393 * @return the human-readable name of this time zone in the given locale.
394 * @exception IllegalArgumentException if {@code style} is invalid.
395 * @exception NullPointerException if {@code locale} is {@code null}.
396 * @since 1.2
397 * @see java.text.DateFormatSymbols#getZoneStrings()
398 */
399 public String getDisplayName(boolean daylight, int style, Locale locale) {
400 if (style != SHORT && style != LONG) {
401 throw new IllegalArgumentException("Illegal style: " + style);
402 }
403 String id = getID();
404 String name = TimeZoneNameUtility.retrieveDisplayName(id, daylight, style, locale);
405 if (name != null) {
406 return name;
407 }
408
409 if (id.startsWith("GMT") && id.length() > 3) {
410 char sign = id.charAt(3);
411 if (sign == '+' || sign == '-') {
412 return id;
413 }
414 }
415 int offset = getRawOffset();
416 if (daylight) {
417 offset += getDSTSavings();
418 }
419 return ZoneInfoFile.toCustomID(offset);
420 }
421
422 private static String[] getDisplayNames(String id, Locale locale) {
423 return TimeZoneNameUtility.retrieveDisplayNames(id, locale);
424 }
425
426 /**
427 * Returns the amount of time to be added to local standard time
428 * to get local wall clock time.
429 *
430 * <p>The default implementation returns 3600000 milliseconds
431 * (i.e., one hour) if a call to {@link #useDaylightTime()}
432 * returns {@code true}. Otherwise, 0 (zero) is returned.
433 *
434 * <p>If an underlying {@code TimeZone} implementation subclass
435 * supports historical and future Daylight Saving Time schedule
436 * changes, this method returns the amount of saving time of the
437 * last known Daylight Saving Time rule that can be a future
438 * prediction.
439 *
440 * <p>If the amount of saving time at any given time stamp is
441 * required, construct a {@link Calendar} with this {@code
442 * TimeZone} and the time stamp, and call {@link Calendar#get(int)
443 * Calendar.get}{@code (}{@link Calendar#DST_OFFSET}{@code )}.
444 *
445 * @return the amount of saving time in milliseconds
446 * @since 1.4
447 * @see #inDaylightTime(Date)
448 * @see #getOffset(long)
449 * @see #getOffset(int,int,int,int,int,int)
450 * @see Calendar#ZONE_OFFSET
451 */
452 public int getDSTSavings() {
453 if (useDaylightTime()) {
454 return 3600000;
455 }
456 return 0;
457 }
458
459 /**
460 * Queries if this {@code TimeZone} uses Daylight Saving Time.
461 *
462 * <p>If an underlying {@code TimeZone} implementation subclass
463 * supports historical and future Daylight Saving Time schedule
464 * changes, this method refers to the last known Daylight Saving Time
465 * rule that can be a future prediction and may not be the same as
466 * the current rule. Consider calling {@link #observesDaylightTime()}
467 * if the current rule should also be taken into account.
468 *
469 * @return {@code true} if this {@code TimeZone} uses Daylight Saving Time,
470 * {@code false}, otherwise.
471 * @see #inDaylightTime(Date)
472 * @see Calendar#DST_OFFSET
473 */
474 public abstract boolean useDaylightTime();
475
476 /**
477 * Returns {@code true} if this {@code TimeZone} is currently in
478 * Daylight Saving Time, or if a transition from Standard Time to
479 * Daylight Saving Time occurs at any future time.
480 *
481 * <p>The default implementation returns {@code true} if
482 * {@code useDaylightTime()} or {@code inDaylightTime(new Date())}
483 * returns {@code true}.
484 *
485 * @return {@code true} if this {@code TimeZone} is currently in
486 * Daylight Saving Time, or if a transition from Standard Time to
487 * Daylight Saving Time occurs at any future time; {@code false}
488 * otherwise.
489 * @since 1.7
490 * @see #useDaylightTime()
491 * @see #inDaylightTime(Date)
492 * @see Calendar#DST_OFFSET
493 */
494 public boolean observesDaylightTime() {
495 return useDaylightTime() || inDaylightTime(new Date());
496 }
497
498 /**
499 * Queries if the given {@code date} is in Daylight Saving Time in
500 * this time zone.
501 *
502 * @param date the given Date.
503 * @return {@code true} if the given date is in Daylight Saving Time,
504 * {@code false}, otherwise.
505 */
506 abstract public boolean inDaylightTime(Date date);
507
508 /**
509 * Gets the <code>TimeZone</code> for the given ID.
510 *
511 * @param ID the ID for a <code>TimeZone</code>, either an abbreviation
512 * such as "PST", a full name such as "America/Los_Angeles", or a custom
513 * ID such as "GMT-8:00". Note that the support of abbreviations is
514 * for JDK 1.1.x compatibility only and full names should be used.
515 *
516 * @return the specified <code>TimeZone</code>, or the GMT zone if the given ID
517 * cannot be understood.
518 */
519 public static synchronized TimeZone getTimeZone(String ID) {
520 return getTimeZone(ID, true);
521 }
522
523 /**
524 * Gets the {@code TimeZone} for the given {@code zoneId}.
525 *
526 * @param zoneId a {@link ZoneId} from which the time zone ID is obtained
527 * @return the specified {@code TimeZone}, or the GMT zone if the given ID
528 * cannot be understood.
529 * @throws NullPointerException if {@code zoneId} is {@code null}
530 * @since 1.8
531 */
532 public static TimeZone getTimeZone(ZoneId zoneId) {
533 String tzid = zoneId.getId(); // throws an NPE if null
534 char c = tzid.charAt(0);
535 if (c == '+' || c == '-') {
536 tzid = "GMT" + tzid;
537 } else if (c == 'Z' && tzid.length() == 1) {
538 tzid = "UTC";
539 }
540 return getTimeZone(tzid, true);
541 }
542
543 /**
544 * Converts this {@code TimeZone} object to a {@code ZoneId}.
545 *
546 * @return a {@code ZoneId} representing the same time zone as this
547 * {@code TimeZone}
548 * @since 1.8
549 */
550 public ZoneId toZoneId() {
551 return ZoneId.of(getID(), ZoneId.SHORT_IDS);
552 }
553
554 private static TimeZone getTimeZone(String ID, boolean fallback) {
555 TimeZone tz = ZoneInfo.getTimeZone(ID);
556 if (tz == null) {
557 tz = parseCustomTimeZone(ID);
558 if (tz == null && fallback) {
559 tz = new ZoneInfo(GMT_ID, 0);
560 }
561 }
562 return tz;
563 }
564
565 /**
566 * Gets the available IDs according to the given time zone offset in milliseconds.
567 *
568 * @param rawOffset the given time zone GMT offset in milliseconds.
569 * @return an array of IDs, where the time zone for that ID has
570 * the specified GMT offset. For example, "America/Phoenix" and "America/Denver"
571 * both have GMT-07:00, but differ in daylight saving behavior.
572 * @see #getRawOffset()
573 */
574 public static synchronized String[] getAvailableIDs(int rawOffset) {
575 return ZoneInfo.getAvailableIDs(rawOffset);
576 }
577
578 /**
579 * Gets all the available IDs supported.
580 * @return an array of IDs.
581 */
582 public static synchronized String[] getAvailableIDs() {
583 return ZoneInfo.getAvailableIDs();
584 }
585
586 /**
587 * Gets the platform defined TimeZone ID.
588 **/
589 private static native String getSystemTimeZoneID(String javaHome,
590 String country);
591
592 /**
593 * Gets the custom time zone ID based on the GMT offset of the
594 * platform. (e.g., "GMT+08:00")
595 */
596 private static native String getSystemGMTOffsetID();
597
598 /**
599 * Gets the default <code>TimeZone</code> for this host.
600 * The source of the default <code>TimeZone</code>
601 * may vary with implementation.
602 * @return a default <code>TimeZone</code>.
603 * @see #setDefault
604 */
605 public static TimeZone getDefault() {
606 return (TimeZone) getDefaultRef().clone();
607 }
608
609 /**
610 * Returns the reference to the default TimeZone object. This
611 * method doesn't create a clone.
612 */
613 static TimeZone getDefaultRef() {
614 TimeZone defaultZone = getDefaultInAppContext();
615 if (defaultZone == null) {
616 defaultZone = defaultTimeZone;
617 if (defaultZone == null) {
618 // Need to initialize the default time zone.
619 defaultZone = setDefaultZone();
620 assert defaultZone != null;
621 }
622 }
623 // Don't clone here.
624 return defaultZone;
625 }
626
627 private static synchronized TimeZone setDefaultZone() {
628 TimeZone tz;
629 // get the time zone ID from the system properties
630 String zoneID = AccessController.doPrivileged(
631 new GetPropertyAction("user.timezone"));
632
633 // if the time zone ID is not set (yet), perform the
634 // platform to Java time zone ID mapping.
635 if (zoneID == null || zoneID.isEmpty()) {
636 String country = AccessController.doPrivileged(
637 new GetPropertyAction("user.country"));
638 String javaHome = AccessController.doPrivileged(
639 new GetPropertyAction("java.home"));
640 try {
641 zoneID = getSystemTimeZoneID(javaHome, country);
642 if (zoneID == null) {
643 zoneID = GMT_ID;
644 }
645 } catch (NullPointerException e) {
646 zoneID = GMT_ID;
647 }
648 }
649
650 // Get the time zone for zoneID. But not fall back to
651 // "GMT" here.
652 tz = getTimeZone(zoneID, false);
653
654 if (tz == null) {
655 // If the given zone ID is unknown in Java, try to
656 // get the GMT-offset-based time zone ID,
657 // a.k.a. custom time zone ID (e.g., "GMT-08:00").
658 String gmtOffsetID = getSystemGMTOffsetID();
659 if (gmtOffsetID != null) {
660 zoneID = gmtOffsetID;
661 }
662 tz = getTimeZone(zoneID, true);
663 }
664 assert tz != null;
665
666 final String id = zoneID;
667 AccessController.doPrivileged(new PrivilegedAction<Void>() {
668 @Override
669 public Void run() {
670 System.setProperty("user.timezone", id);
671 return null;
672 }
673 });
674
675 defaultTimeZone = tz;
676 return tz;
677 }
678
679 private static boolean hasPermission() {
680 boolean hasPermission = true;
681 SecurityManager sm = System.getSecurityManager();
682 if (sm != null) {
683 try {
684 sm.checkPermission(new PropertyPermission
685 ("user.timezone", "write"));
686 } catch (SecurityException e) {
687 hasPermission = false;
688 }
689 }
690 return hasPermission;
691 }
692
693 /**
694 * Sets the <code>TimeZone</code> that is
695 * returned by the <code>getDefault</code> method. If <code>zone</code>
696 * is null, reset the default to the value it had originally when the
697 * VM first started.
698 * @param zone the new default time zone
699 * @see #getDefault
700 */
701 public static void setDefault(TimeZone zone)
702 {
703 if (hasPermission()) {
704 synchronized (TimeZone.class) {
705 defaultTimeZone = zone;
706 setDefaultInAppContext(null);
707 }
708 } else {
709 setDefaultInAppContext(zone);
710 }
711 }
712
713 /**
714 * Returns the default TimeZone in an AppContext if any AppContext
715 * has ever used. null is returned if any AppContext hasn't been
716 * used or if the AppContext doesn't have the default TimeZone.
717 *
718 * Note that javaAWTAccess may be null if sun.awt.AppContext class hasn't
719 * been loaded. If so, it implies that AWTSecurityManager is not our
720 * SecurityManager and we can use a local static variable.
721 * This works around a build time issue.
722 */
723 private static TimeZone getDefaultInAppContext() {
724 // JavaAWTAccess provides access implementation-private methods without using reflection.
725 JavaAWTAccess javaAWTAccess = SharedSecrets.getJavaAWTAccess();
726
727 if (javaAWTAccess == null) {
728 return mainAppContextDefault;
729 } else {
730 if (!javaAWTAccess.isDisposed()) {
731 TimeZone tz = (TimeZone)
732 javaAWTAccess.get(TimeZone.class);
733 if (tz == null && javaAWTAccess.isMainAppContext()) {
734 return mainAppContextDefault;
735 } else {
736 return tz;
737 }
738 }
739 }
740 return null;
741 }
742
743 /**
744 * Sets the default TimeZone in the AppContext to the given
745 * tz. null is handled special: do nothing if any AppContext
746 * hasn't been used, remove the default TimeZone in the
747 * AppContext otherwise.
748 *
749 * Note that javaAWTAccess may be null if sun.awt.AppContext class hasn't
750 * been loaded. If so, it implies that AWTSecurityManager is not our
751 * SecurityManager and we can use a local static variable.
752 * This works around a build time issue.
753 */
754 private static void setDefaultInAppContext(TimeZone tz) {
755 // JavaAWTAccess provides access implementation-private methods without using reflection.
756 JavaAWTAccess javaAWTAccess = SharedSecrets.getJavaAWTAccess();
757
758 if (javaAWTAccess == null) {
759 mainAppContextDefault = tz;
760 } else {
761 if (!javaAWTAccess.isDisposed()) {
762 javaAWTAccess.put(TimeZone.class, tz);
763 if (javaAWTAccess.isMainAppContext()) {
764 mainAppContextDefault = null;
765 }
766 }
767 }
768 }
769
770 /**
771 * Returns true if this zone has the same rule and offset as another zone.
772 * That is, if this zone differs only in ID, if at all. Returns false
773 * if the other zone is null.
774 * @param other the <code>TimeZone</code> object to be compared with
775 * @return true if the other zone is not null and is the same as this one,
776 * with the possible exception of the ID
777 * @since 1.2
778 */
779 public boolean hasSameRules(TimeZone other) {
780 return other != null && getRawOffset() == other.getRawOffset() &&
781 useDaylightTime() == other.useDaylightTime();
782 }
783
784 /**
785 * Creates a copy of this <code>TimeZone</code>.
786 *
787 * @return a clone of this <code>TimeZone</code>
788 */
789 public Object clone()
790 {
791 try {
792 TimeZone other = (TimeZone) super.clone();
793 other.ID = ID;
794 return other;
795 } catch (CloneNotSupportedException e) {
796 throw new InternalError(e);
797 }
798 }
799
800 /**
801 * The null constant as a TimeZone.
802 */
803 static final TimeZone NO_TIMEZONE = null;
804
805 // =======================privates===============================
806
807 /**
808 * The string identifier of this <code>TimeZone</code>. This is a
809 * programmatic identifier used internally to look up <code>TimeZone</code>
810 * objects from the system table and also to map them to their localized
811 * display names. <code>ID</code> values are unique in the system
812 * table but may not be for dynamically created zones.
813 * @serial
814 */
815 private String ID;
816 private static volatile TimeZone defaultTimeZone;
817
818 static final String GMT_ID = "GMT";
819 private static final int GMT_ID_LENGTH = 3;
820
821 // a static TimeZone we can reference if no AppContext is in place
822 private static volatile TimeZone mainAppContextDefault;
823
824 /**
825 * Parses a custom time zone identifier and returns a corresponding zone.
826 * This method doesn't support the RFC 822 time zone format. (e.g., +hhmm)
827 *
828 * @param id a string of the <a href="#CustomID">custom ID form</a>.
829 * @return a newly created TimeZone with the given offset and
830 * no daylight saving time, or null if the id cannot be parsed.
831 */
832 private static final TimeZone parseCustomTimeZone(String id) {
833 int length;
834
835 // Error if the length of id isn't long enough or id doesn't
836 // start with "GMT".
837 if ((length = id.length()) < (GMT_ID_LENGTH + 2) ||
838 id.indexOf(GMT_ID) != 0) {
839 return null;
840 }
841
842 ZoneInfo zi;
843
844 // First, we try to find it in the cache with the given
845 // id. Even the id is not normalized, the returned ZoneInfo
846 // should have its normalized id.
847 zi = ZoneInfoFile.getZoneInfo(id);
848 if (zi != null) {
849 return zi;
850 }
851
852 int index = GMT_ID_LENGTH;
853 boolean negative = false;
854 char c = id.charAt(index++);
855 if (c == '-') {
856 negative = true;
857 } else if (c != '+') {
858 return null;
859 }
860
861 int hours = 0;
862 int num = 0;
863 int countDelim = 0;
864 int len = 0;
865 while (index < length) {
866 c = id.charAt(index++);
867 if (c == ':') {
868 if (countDelim > 0) {
869 return null;
870 }
871 if (len > 2) {
872 return null;
873 }
874 hours = num;
875 countDelim++;
876 num = 0;
877 len = 0;
878 continue;
879 }
880 if (c < '0' || c > '9') {
881 return null;
882 }
883 num = num * 10 + (c - '0');
884 len++;
885 }
886 if (index != length) {
887 return null;
888 }
889 if (countDelim == 0) {
890 if (len <= 2) {
891 hours = num;
892 num = 0;
893 } else {
894 hours = num / 100;
895 num %= 100;
896 }
897 } else {
898 if (len != 2) {
899 return null;
900 }
901 }
902 if (hours > 23 || num > 59) {
903 return null;
904 }
905 int gmtOffset = (hours * 60 + num) * 60 * 1000;
906
907 if (gmtOffset == 0) {
908 zi = ZoneInfoFile.getZoneInfo(GMT_ID);
909 if (negative) {
910 zi.setID("GMT-00:00");
911 } else {
912 zi.setID("GMT+00:00");
913 }
914 } else {
915 zi = ZoneInfoFile.getCustomTimeZone(id, negative ? -gmtOffset : gmtOffset);
916 }
917 return zi;
918 }
919 }