1 /*
2 * Copyright 1996-2005 Sun Microsystems, Inc. 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. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 /*
27 * (C) Copyright Taligent, Inc. 1996 - All Rights Reserved
28 * (C) Copyright IBM Corp. 1996 - All Rights Reserved
29 *
30 * The original version of this source code and documentation is copyrighted
31 * and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These
32 * materials are provided under terms of a License Agreement between Taligent
33 * and Sun. This technology is protected by multiple US and International
34 * patents. This notice and attribution to Taligent may not be removed.
35 * Taligent is a registered trademark of Taligent, Inc.
36 *
37 */
38
39 package java.util;
40
41 import java.io.Serializable;
42 import java.lang.ref.SoftReference;
43 import java.security.AccessController;
44 import java.security.PrivilegedAction;
45 import java.util.concurrent.ConcurrentHashMap;
46 import sun.security.action.GetPropertyAction;
47 import sun.util.TimeZoneNameUtility;
48 import sun.util.calendar.ZoneInfo;
49 import sun.util.calendar.ZoneInfoFile;
50
51 /**
52 * <code>TimeZone</code> represents a time zone offset, and also figures out daylight
53 * savings.
54 *
55 * <p>
56 * Typically, you get a <code>TimeZone</code> using <code>getDefault</code>
57 * which creates a <code>TimeZone</code> based on the time zone where the program
58 * is running. For example, for a program running in Japan, <code>getDefault</code>
59 * creates a <code>TimeZone</code> object based on Japanese Standard Time.
60 *
61 * <p>
62 * You can also get a <code>TimeZone</code> using <code>getTimeZone</code>
63 * along with a time zone ID. For instance, the time zone ID for the
64 * U.S. Pacific Time zone is "America/Los_Angeles". So, you can get a
65 * U.S. Pacific Time <code>TimeZone</code> object with:
66 * <blockquote><pre>
67 * TimeZone tz = TimeZone.getTimeZone("America/Los_Angeles");
68 * </pre></blockquote>
69 * You can use the <code>getAvailableIDs</code> method to iterate through
70 * all the supported time zone IDs. You can then choose a
71 * supported ID to get a <code>TimeZone</code>.
72 * If the time zone you want is not represented by one of the
73 * supported IDs, then a custom time zone ID can be specified to
74 * produce a TimeZone. The syntax of a custom time zone ID is:
75 *
76 * <blockquote><pre>
77 * <a name="CustomID"><i>CustomID:</i></a>
78 * <code>GMT</code> <i>Sign</i> <i>Hours</i> <code>:</code> <i>Minutes</i>
79 * <code>GMT</code> <i>Sign</i> <i>Hours</i> <i>Minutes</i>
80 * <code>GMT</code> <i>Sign</i> <i>Hours</i>
81 * <i>Sign:</i> one of
82 * <code>+ -</code>
83 * <i>Hours:</i>
84 * <i>Digit</i>
85 * <i>Digit</i> <i>Digit</i>
86 * <i>Minutes:</i>
87 * <i>Digit</i> <i>Digit</i>
88 * <i>Digit:</i> one of
89 * <code>0 1 2 3 4 5 6 7 8 9</code>
90 * </pre></blockquote>
91 *
92 * <i>Hours</i> must be between 0 to 23 and <i>Minutes</i> must be
93 * between 00 to 59. For example, "GMT+10" and "GMT+0010" mean ten
94 * hours and ten minutes ahead of GMT, respectively.
95 * <p>
96 * The format is locale independent and digits must be taken from the
97 * Basic Latin block of the Unicode standard. No daylight saving time
98 * transition schedule can be specified with a custom time zone ID. If
99 * the specified string doesn't match the syntax, <code>"GMT"</code>
100 * is used.
101 * <p>
102 * When creating a <code>TimeZone</code>, the specified custom time
103 * zone ID is normalized in the following syntax:
104 * <blockquote><pre>
105 * <a name="NormalizedCustomID"><i>NormalizedCustomID:</i></a>
106 * <code>GMT</code> <i>Sign</i> <i>TwoDigitHours</i> <code>:</code> <i>Minutes</i>
107 * <i>Sign:</i> one of
108 * <code>+ -</code>
109 * <i>TwoDigitHours:</i>
110 * <i>Digit</i> <i>Digit</i>
111 * <i>Minutes:</i>
112 * <i>Digit</i> <i>Digit</i>
113 * <i>Digit:</i> one of
114 * <code>0 1 2 3 4 5 6 7 8 9</code>
115 * </pre></blockquote>
116 * For example, TimeZone.getTimeZone("GMT-8").getID() returns "GMT-08:00".
117 *
118 * <h4>Three-letter time zone IDs</h4>
119 *
120 * For compatibility with JDK 1.1.x, some other three-letter time zone IDs
121 * (such as "PST", "CTT", "AST") are also supported. However, <strong>their
122 * use is deprecated</strong> because the same abbreviation is often used
123 * for multiple time zones (for example, "CST" could be U.S. "Central Standard
124 * Time" and "China Standard Time"), and the Java platform can then only
125 * recognize one of them.
126 *
127 *
128 * @see Calendar
129 * @see GregorianCalendar
130 * @see SimpleTimeZone
131 * @author Mark Davis, David Goldsmith, Chen-Lieh Huang, Alan Liu
132 * @since JDK1.1
133 */
134 abstract public class TimeZone implements Serializable, Cloneable {
135 /**
136 * Sole constructor. (For invocation by subclass constructors, typically
137 * implicit.)
138 */
139 public TimeZone() {
140 }
141
142 /**
143 * A style specifier for <code>getDisplayName()</code> indicating
144 * a short name, such as "PST."
145 * @see #LONG
146 * @since 1.2
147 */
148 public static final int SHORT = 0;
149
150 /**
151 * A style specifier for <code>getDisplayName()</code> indicating
152 * a long name, such as "Pacific Standard Time."
153 * @see #SHORT
154 * @since 1.2
155 */
156 public static final int LONG = 1;
157
158 // Constants used internally; unit is milliseconds
159 private static final int ONE_MINUTE = 60*1000;
160 private static final int ONE_HOUR = 60*ONE_MINUTE;
161 private static final int ONE_DAY = 24*ONE_HOUR;
162
163 /**
164 * Cache to hold the SimpleDateFormat objects for a Locale.
165 */
166 private static Hashtable cachedLocaleData = new Hashtable(3);
167
168 // Proclaim serialization compatibility with JDK 1.1
169 static final long serialVersionUID = 3581463369166924961L;
170
171 /**
172 * Gets the time zone offset, for current date, modified in case of
173 * daylight savings. This is the offset to add to UTC to get local time.
174 * <p>
175 * This method returns a historically correct offset if an
176 * underlying <code>TimeZone</code> implementation subclass
177 * supports historical Daylight Saving Time schedule and GMT
178 * offset changes.
179 *
180 * @param era the era of the given date.
181 * @param year the year in the given date.
182 * @param month the month in the given date.
183 * Month is 0-based. e.g., 0 for January.
184 * @param day the day-in-month of the given date.
185 * @param dayOfWeek the day-of-week of the given date.
186 * @param milliseconds the milliseconds in day in <em>standard</em>
187 * local time.
188 *
189 * @return the offset in milliseconds to add to GMT to get local time.
190 *
191 * @see Calendar#ZONE_OFFSET
192 * @see Calendar#DST_OFFSET
193 */
194 public abstract int getOffset(int era, int year, int month, int day,
195 int dayOfWeek, int milliseconds);
196
197 /**
198 * Returns the offset of this time zone from UTC at the specified
199 * date. If Daylight Saving Time is in effect at the specified
200 * date, the offset value is adjusted with the amount of daylight
201 * saving.
202 * <p>
203 * This method returns a historically correct offset value if an
204 * underlying TimeZone implementation subclass supports historical
205 * Daylight Saving Time schedule and GMT offset changes.
206 *
207 * @param date the date represented in milliseconds since January 1, 1970 00:00:00 GMT
208 * @return the amount of time in milliseconds to add to UTC to get local time.
209 *
210 * @see Calendar#ZONE_OFFSET
211 * @see Calendar#DST_OFFSET
212 * @since 1.4
213 */
214 public int getOffset(long date) {
215 if (inDaylightTime(new Date(date))) {
216 return getRawOffset() + getDSTSavings();
217 }
218 return getRawOffset();
219 }
220
221 /**
222 * Gets the raw GMT offset and the amount of daylight saving of this
223 * time zone at the given time.
224 * @param date the milliseconds (since January 1, 1970,
225 * 00:00:00.000 GMT) at which the time zone offset and daylight
226 * saving amount are found
227 * @param offset an array of int where the raw GMT offset
228 * (offset[0]) and daylight saving amount (offset[1]) are stored,
229 * or null if those values are not needed. The method assumes that
230 * the length of the given array is two or larger.
231 * @return the total amount of the raw GMT offset and daylight
232 * saving at the specified date.
233 *
234 * @see Calendar#ZONE_OFFSET
235 * @see Calendar#DST_OFFSET
236 */
237 int getOffsets(long date, int[] offsets) {
238 int rawoffset = getRawOffset();
239 int dstoffset = 0;
240 if (inDaylightTime(new Date(date))) {
241 dstoffset = getDSTSavings();
242 }
243 if (offsets != null) {
244 offsets[0] = rawoffset;
245 offsets[1] = dstoffset;
246 }
247 return rawoffset + dstoffset;
248 }
249
250 /**
251 * Sets the base time zone offset to GMT.
252 * This is the offset to add to UTC to get local time.
253 * <p>
254 * If an underlying <code>TimeZone</code> implementation subclass
255 * supports historical GMT offset changes, the specified GMT
256 * offset is set as the latest GMT offset and the difference from
257 * the known latest GMT offset value is used to adjust all
258 * historical GMT offset values.
259 *
260 * @param offsetMillis the given base time zone offset to GMT.
261 */
262 abstract public void setRawOffset(int offsetMillis);
263
264 /**
265 * Returns the amount of time in milliseconds to add to UTC to get
266 * standard time in this time zone. Because this value is not
267 * affected by daylight saving time, it is called <I>raw
268 * offset</I>.
269 * <p>
270 * If an underlying <code>TimeZone</code> implementation subclass
271 * supports historical GMT offset changes, the method returns the
272 * raw offset value of the current date. In Honolulu, for example,
273 * its raw offset changed from GMT-10:30 to GMT-10:00 in 1947, and
274 * this method always returns -36000000 milliseconds (i.e., -10
275 * hours).
276 *
277 * @return the amount of raw offset time in milliseconds to add to UTC.
278 * @see Calendar#ZONE_OFFSET
279 */
280 public abstract int getRawOffset();
281
282 /**
283 * Gets the ID of this time zone.
284 * @return the ID of this time zone.
285 */
286 public String getID()
287 {
288 return ID;
289 }
290
291 /**
292 * Sets the time zone ID. This does not change any other data in
293 * the time zone object.
294 * @param ID the new time zone ID.
295 */
296 public void setID(String ID)
297 {
298 if (ID == null) {
299 throw new NullPointerException();
300 }
301 this.ID = ID;
302 }
303
304 /**
305 * Returns a name of this time zone suitable for presentation to the user
306 * in the default locale.
307 * This method returns the long name, not including daylight savings.
308 * If the display name is not available for the locale,
309 * then this method returns a string in the
310 * <a href="#NormalizedCustomID">normalized custom ID format</a>.
311 * @return the human-readable name of this time zone in the default locale.
312 * @since 1.2
313 */
314 public final String getDisplayName() {
315 return getDisplayName(false, LONG, Locale.getDefault());
316 }
317
318 /**
319 * Returns a name of this time zone suitable for presentation to the user
320 * in the specified locale.
321 * This method returns the long name, not including daylight savings.
322 * If the display name is not available for the locale,
323 * then this method returns a string in the
324 * <a href="#NormalizedCustomID">normalized custom ID format</a>.
325 * @param locale the locale in which to supply the display name.
326 * @return the human-readable name of this time zone in the given locale.
327 * @since 1.2
328 */
329 public final String getDisplayName(Locale locale) {
330 return getDisplayName(false, LONG, locale);
331 }
332
333 /**
334 * Returns a name of this time zone suitable for presentation to the user
335 * in the default locale.
336 * If the display name is not available for the locale, then this
337 * method returns a string in the
338 * <a href="#NormalizedCustomID">normalized custom ID format</a>.
339 * @param daylight if true, return the daylight savings name.
340 * @param style either <code>LONG</code> or <code>SHORT</code>
341 * @return the human-readable name of this time zone in the default locale.
342 * @since 1.2
343 */
344 public final String getDisplayName(boolean daylight, int style) {
345 return getDisplayName(daylight, style, Locale.getDefault());
346 }
347
348 /**
349 * Returns a name of this time zone suitable for presentation to the user
350 * in the specified locale.
351 * If the display name is not available for the locale,
352 * then this method returns a string in the
353 * <a href="#NormalizedCustomID">normalized custom ID format</a>.
354 * @param daylight if true, return the daylight savings name.
355 * @param style either <code>LONG</code> or <code>SHORT</code>
356 * @param locale the locale in which to supply the display name.
357 * @return the human-readable name of this time zone in the given locale.
358 * @exception IllegalArgumentException style is invalid.
359 * @since 1.2
360 */
361 public String getDisplayName(boolean daylight, int style, Locale locale) {
362 if (style != SHORT && style != LONG) {
363 throw new IllegalArgumentException("Illegal style: " + style);
364 }
365
366 String id = getID();
367 String[] names = getDisplayNames(id, locale);
368 if (names == null) {
369 if (id.startsWith("GMT")) {
370 char sign = id.charAt(3);
371 if (sign == '+' || sign == '-') {
372 return id;
373 }
374 }
375 int offset = getRawOffset();
376 if (daylight) {
377 offset += getDSTSavings();
378 }
379 return ZoneInfoFile.toCustomID(offset);
380 }
381
382 int index = daylight ? 3 : 1;
383 if (style == SHORT) {
384 index++;
385 }
386 return names[index];
387 }
388
389 private static class DisplayNames {
390 // Cache for managing display names per timezone per locale
391 // The structure is:
392 // Map(key=id, value=SoftReference(Map(key=locale, value=displaynames)))
393 private static final Map<String, SoftReference<Map<Locale, String[]>>> CACHE =
394 new ConcurrentHashMap<String, SoftReference<Map<Locale, String[]>>>();
395 }
396
397 private static final String[] getDisplayNames(String id, Locale locale) {
398 Map<String, SoftReference<Map<Locale, String[]>>> displayNames = DisplayNames.CACHE;
399
400 SoftReference<Map<Locale, String[]>> ref = displayNames.get(id);
401 if (ref != null) {
402 Map<Locale, String[]> perLocale = ref.get();
403 if (perLocale != null) {
404 String[] names = perLocale.get(locale);
405 if (names != null) {
406 return names;
407 }
408 names = TimeZoneNameUtility.retrieveDisplayNames(id, locale);
409 if (names != null) {
410 perLocale.put(locale, names);
411 }
412 return names;
413 }
414 }
415
416 String[] names = TimeZoneNameUtility.retrieveDisplayNames(id, locale);
417 if (names != null) {
418 Map<Locale, String[]> perLocale = new ConcurrentHashMap<Locale, String[]>();
419 perLocale.put(locale, names);
420 ref = new SoftReference<Map<Locale, String[]>>(perLocale);
421 displayNames.put(id, ref);
422 }
423 return names;
424 }
425
426 /**
427 * Returns the amount of time to be added to local standard time
428 * to get local wall clock time.
429 * <p>
430 * The default implementation always returns 3600000 milliseconds
431 * (i.e., one hour) if this time zone observes Daylight Saving
432 * Time. Otherwise, 0 (zero) is returned.
433 * <p>
434 * If an underlying TimeZone implementation subclass supports
435 * historical Daylight Saving Time changes, this method returns
436 * the known latest daylight saving value.
437 *
438 * @return the amount of saving time in milliseconds
439 * @since 1.4
440 */
441 public int getDSTSavings() {
442 if (useDaylightTime()) {
443 return 3600000;
444 }
445 return 0;
446 }
447
448 /**
449 * Queries if this time zone uses daylight savings time.
450 * <p>
451 * If an underlying <code>TimeZone</code> implementation subclass
452 * supports historical Daylight Saving Time schedule changes, the
453 * method refers to the latest Daylight Saving Time schedule
454 * information.
455 *
456 * @return true if this time zone uses daylight savings time,
457 * false, otherwise.
458 */
459 public abstract boolean useDaylightTime();
460
461 /**
462 * Queries if the given date is in daylight savings time in
463 * this time zone.
464 * @param date the given Date.
465 * @return true if the given date is in daylight savings time,
466 * false, otherwise.
467 */
468 abstract public boolean inDaylightTime(Date date);
469
470 /**
471 * Gets the <code>TimeZone</code> for the given ID.
472 *
473 * @param ID the ID for a <code>TimeZone</code>, either an abbreviation
474 * such as "PST", a full name such as "America/Los_Angeles", or a custom
475 * ID such as "GMT-8:00". Note that the support of abbreviations is
476 * for JDK 1.1.x compatibility only and full names should be used.
477 *
478 * @return the specified <code>TimeZone</code>, or the GMT zone if the given ID
479 * cannot be understood.
480 */
481 public static synchronized TimeZone getTimeZone(String ID) {
482 return getTimeZone(ID, true);
483 }
484
485 private static TimeZone getTimeZone(String ID, boolean fallback) {
486 TimeZone tz = ZoneInfo.getTimeZone(ID);
487 if (tz == null) {
488 tz = parseCustomTimeZone(ID);
489 if (tz == null && fallback) {
490 tz = new ZoneInfo(GMT_ID, 0);
491 }
492 }
493 return tz;
494 }
495
496 /**
497 * Gets the available IDs according to the given time zone offset in milliseconds.
498 *
499 * @param rawOffset the given time zone GMT offset in milliseconds.
500 * @return an array of IDs, where the time zone for that ID has
501 * the specified GMT offset. For example, "America/Phoenix" and "America/Denver"
502 * both have GMT-07:00, but differ in daylight savings behavior.
503 * @see #getRawOffset()
504 */
505 public static synchronized String[] getAvailableIDs(int rawOffset) {
506 return ZoneInfo.getAvailableIDs(rawOffset);
507 }
508
509 /**
510 * Gets all the available IDs supported.
511 * @return an array of IDs.
512 */
513 public static synchronized String[] getAvailableIDs() {
514 return ZoneInfo.getAvailableIDs();
515 }
516
517 /**
518 * Gets the platform defined TimeZone ID.
519 **/
520 private static native String getSystemTimeZoneID(String javaHome,
521 String country);
522
523 /**
524 * Gets the custom time zone ID based on the GMT offset of the
525 * platform. (e.g., "GMT+08:00")
526 */
527 private static native String getSystemGMTOffsetID();
528
529 /**
530 * Gets the default <code>TimeZone</code> for this host.
531 * The source of the default <code>TimeZone</code>
532 * may vary with implementation.
533 * @return a default <code>TimeZone</code>.
534 * @see #setDefault
535 */
536 public static TimeZone getDefault() {
537 return (TimeZone) getDefaultRef().clone();
538 }
539
540 /**
541 * Returns the reference to the default TimeZone object. This
542 * method doesn't create a clone.
543 */
544 static TimeZone getDefaultRef() {
545 TimeZone defaultZone = defaultZoneTL.get();
546 if (defaultZone == null) {
547 defaultZone = defaultTimeZone;
548 if (defaultZone == null) {
549 // Need to initialize the default time zone.
550 defaultZone = setDefaultZone();
551 assert defaultZone != null;
552 }
553 }
554 // Don't clone here.
555 return defaultZone;
556 }
557
558 private static synchronized TimeZone setDefaultZone() {
559 TimeZone tz = null;
560 // get the time zone ID from the system properties
561 String zoneID = AccessController.doPrivileged(
562 new GetPropertyAction("user.timezone"));
563
564 // if the time zone ID is not set (yet), perform the
565 // platform to Java time zone ID mapping.
566 if (zoneID == null || zoneID.equals("")) {
567 String country = AccessController.doPrivileged(
568 new GetPropertyAction("user.country"));
569 String javaHome = AccessController.doPrivileged(
570 new GetPropertyAction("java.home"));
571 try {
572 zoneID = getSystemTimeZoneID(javaHome, country);
573 if (zoneID == null) {
574 zoneID = GMT_ID;
575 }
576 } catch (NullPointerException e) {
577 zoneID = GMT_ID;
578 }
579 }
580
581 // Get the time zone for zoneID. But not fall back to
582 // "GMT" here.
583 tz = getTimeZone(zoneID, false);
584
585 if (tz == null) {
586 // If the given zone ID is unknown in Java, try to
587 // get the GMT-offset-based time zone ID,
588 // a.k.a. custom time zone ID (e.g., "GMT-08:00").
589 String gmtOffsetID = getSystemGMTOffsetID();
590 if (gmtOffsetID != null) {
591 zoneID = gmtOffsetID;
592 }
593 tz = getTimeZone(zoneID, true);
594 }
595 assert tz != null;
596
597 final String id = zoneID;
598 AccessController.doPrivileged(new PrivilegedAction<Object>() {
599 public Object run() {
600 System.setProperty("user.timezone", id);
601 return null;
602 }
603 });
604
605 defaultTimeZone = tz;
606 return tz;
607 }
608
609 private static boolean hasPermission() {
610 boolean hasPermission = true;
611 SecurityManager sm = System.getSecurityManager();
612 if (sm != null) {
613 try {
614 sm.checkPermission(new PropertyPermission
615 ("user.timezone", "write"));
616 } catch (SecurityException e) {
617 hasPermission = false;
618 }
619 }
620 return hasPermission;
621 }
622
623 /**
624 * Sets the <code>TimeZone</code> that is
625 * returned by the <code>getDefault</code> method. If <code>zone</code>
626 * is null, reset the default to the value it had originally when the
627 * VM first started.
628 * @param zone the new default time zone
629 * @see #getDefault
630 */
631 public static void setDefault(TimeZone zone)
632 {
633 if (hasPermission()) {
634 synchronized (TimeZone.class) {
635 defaultTimeZone = zone;
636 defaultZoneTL.set(null);
637 }
638 } else {
639 defaultZoneTL.set(zone);
640 }
641 }
642
643 /**
644 * Returns true if this zone has the same rule and offset as another zone.
645 * That is, if this zone differs only in ID, if at all. Returns false
646 * if the other zone is null.
647 * @param other the <code>TimeZone</code> object to be compared with
648 * @return true if the other zone is not null and is the same as this one,
649 * with the possible exception of the ID
650 * @since 1.2
651 */
652 public boolean hasSameRules(TimeZone other) {
653 return other != null && getRawOffset() == other.getRawOffset() &&
654 useDaylightTime() == other.useDaylightTime();
655 }
656
657 /**
658 * Creates a copy of this <code>TimeZone</code>.
659 *
660 * @return a clone of this <code>TimeZone</code>
661 */
662 public Object clone()
663 {
664 try {
665 TimeZone other = (TimeZone) super.clone();
666 other.ID = ID;
667 return other;
668 } catch (CloneNotSupportedException e) {
669 throw new InternalError();
670 }
671 }
672
673 /**
674 * The null constant as a TimeZone.
675 */
676 static final TimeZone NO_TIMEZONE = null;
677
678 // =======================privates===============================
679
680 /**
681 * The string identifier of this <code>TimeZone</code>. This is a
682 * programmatic identifier used internally to look up <code>TimeZone</code>
683 * objects from the system table and also to map them to their localized
684 * display names. <code>ID</code> values are unique in the system
685 * table but may not be for dynamically created zones.
686 * @serial
687 */
688 private String ID;
689 private static volatile TimeZone defaultTimeZone;
690 private static final InheritableThreadLocal<TimeZone> defaultZoneTL
691 = new InheritableThreadLocal<TimeZone>();
692
693 static final String GMT_ID = "GMT";
694 private static final int GMT_ID_LENGTH = 3;
695
696 /**
697 * Parses a custom time zone identifier and returns a corresponding zone.
698 * This method doesn't support the RFC 822 time zone format. (e.g., +hhmm)
699 *
700 * @param id a string of the <a href="#CustomID">custom ID form</a>.
701 * @return a newly created TimeZone with the given offset and
702 * no daylight saving time, or null if the id cannot be parsed.
703 */
704 private static final TimeZone parseCustomTimeZone(String id) {
705 int length;
706
707 // Error if the length of id isn't long enough or id doesn't
708 // start with "GMT".
709 if ((length = id.length()) < (GMT_ID_LENGTH + 2) ||
710 id.indexOf(GMT_ID) != 0) {
711 return null;
712 }
713
714 ZoneInfo zi;
715
716 // First, we try to find it in the cache with the given
717 // id. Even the id is not normalized, the returned ZoneInfo
718 // should have its normalized id.
719 zi = ZoneInfoFile.getZoneInfo(id);
720 if (zi != null) {
721 return zi;
722 }
723
724 int index = GMT_ID_LENGTH;
725 boolean negative = false;
726 char c = id.charAt(index++);
727 if (c == '-') {
728 negative = true;
729 } else if (c != '+') {
730 return null;
731 }
732
733 int hours = 0;
734 int num = 0;
735 int countDelim = 0;
736 int len = 0;
737 while (index < length) {
738 c = id.charAt(index++);
739 if (c == ':') {
740 if (countDelim > 0) {
741 return null;
742 }
743 if (len > 2) {
744 return null;
745 }
746 hours = num;
747 countDelim++;
748 num = 0;
749 len = 0;
750 continue;
751 }
752 if (c < '0' || c > '9') {
753 return null;
754 }
755 num = num * 10 + (c - '0');
756 len++;
757 }
758 if (index != length) {
759 return null;
760 }
761 if (countDelim == 0) {
762 if (len <= 2) {
763 hours = num;
764 num = 0;
765 } else {
766 hours = num / 100;
767 num %= 100;
768 }
769 } else {
770 if (len != 2) {
771 return null;
772 }
773 }
774 if (hours > 23 || num > 59) {
775 return null;
776 }
777 int gmtOffset = (hours * 60 + num) * 60 * 1000;
778
779 if (gmtOffset == 0) {
780 zi = ZoneInfoFile.getZoneInfo(GMT_ID);
781 if (negative) {
782 zi.setID("GMT-00:00");
783 } else {
784 zi.setID("GMT+00:00");
785 }
786 } else {
787 zi = ZoneInfoFile.getCustomTimeZone(id, negative ? -gmtOffset : gmtOffset);
788 }
789 return zi;
790 }
791 }
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