001 /*
002 * Copyright 1996-2005 Sun Microsystems, Inc. All Rights Reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation. Sun designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Sun in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022 * CA 95054 USA or visit www.sun.com if you need additional information or
023 * have any questions.
024 */
025
026 /*
027 * (C) Copyright Taligent, Inc. 1996 - All Rights Reserved
028 * (C) Copyright IBM Corp. 1996 - All Rights Reserved
029 *
030 * The original version of this source code and documentation is copyrighted
031 * and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These
032 * materials are provided under terms of a License Agreement between Taligent
033 * and Sun. This technology is protected by multiple US and International
034 * patents. This notice and attribution to Taligent may not be removed.
035 * Taligent is a registered trademark of Taligent, Inc.
036 *
037 */
038
039 package java.util;
040
041 import java.io.Serializable;
042 import java.lang.ref.SoftReference;
043 import java.security.AccessController;
044 import java.security.PrivilegedAction;
045 import java.util.concurrent.ConcurrentHashMap;
046 import sun.security.action.GetPropertyAction;
047 import sun.util.TimeZoneNameUtility;
048 import sun.util.calendar.ZoneInfo;
049 import sun.util.calendar.ZoneInfoFile;
050
051 /**
052 * <code>TimeZone</code> represents a time zone offset, and also figures out daylight
053 * savings.
054 *
055 * <p>
056 * Typically, you get a <code>TimeZone</code> using <code>getDefault</code>
057 * which creates a <code>TimeZone</code> based on the time zone where the program
058 * is running. For example, for a program running in Japan, <code>getDefault</code>
059 * creates a <code>TimeZone</code> object based on Japanese Standard Time.
060 *
061 * <p>
062 * You can also get a <code>TimeZone</code> using <code>getTimeZone</code>
063 * along with a time zone ID. For instance, the time zone ID for the
064 * U.S. Pacific Time zone is "America/Los_Angeles". So, you can get a
065 * U.S. Pacific Time <code>TimeZone</code> object with:
066 * <blockquote><pre>
067 * TimeZone tz = TimeZone.getTimeZone("America/Los_Angeles");
068 * </pre></blockquote>
069 * You can use the <code>getAvailableIDs</code> method to iterate through
070 * all the supported time zone IDs. You can then choose a
071 * supported ID to get a <code>TimeZone</code>.
072 * If the time zone you want is not represented by one of the
073 * supported IDs, then a custom time zone ID can be specified to
074 * produce a TimeZone. The syntax of a custom time zone ID is:
075 *
076 * <blockquote><pre>
077 * <a name="CustomID"><i>CustomID:</i></a>
078 * <code>GMT</code> <i>Sign</i> <i>Hours</i> <code>:</code> <i>Minutes</i>
079 * <code>GMT</code> <i>Sign</i> <i>Hours</i> <i>Minutes</i>
080 * <code>GMT</code> <i>Sign</i> <i>Hours</i>
081 * <i>Sign:</i> one of
082 * <code>+ -</code>
083 * <i>Hours:</i>
084 * <i>Digit</i>
085 * <i>Digit</i> <i>Digit</i>
086 * <i>Minutes:</i>
087 * <i>Digit</i> <i>Digit</i>
088 * <i>Digit:</i> one of
089 * <code>0 1 2 3 4 5 6 7 8 9</code>
090 * </pre></blockquote>
091 *
092 * <i>Hours</i> must be between 0 to 23 and <i>Minutes</i> must be
093 * between 00 to 59. For example, "GMT+10" and "GMT+0010" mean ten
094 * hours and ten minutes ahead of GMT, respectively.
095 * <p>
096 * The format is locale independent and digits must be taken from the
097 * Basic Latin block of the Unicode standard. No daylight saving time
098 * transition schedule can be specified with a custom time zone ID. If
099 * 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 * @version 1.81 05/05/07
132 * @author Mark Davis, David Goldsmith, Chen-Lieh Huang, Alan Liu
133 * @since JDK1.1
134 */
135 abstract public class TimeZone implements Serializable, Cloneable {
136 /**
137 * Sole constructor. (For invocation by subclass constructors, typically
138 * implicit.)
139 */
140 public TimeZone() {
141 }
142
143 /**
144 * A style specifier for <code>getDisplayName()</code> indicating
145 * a short name, such as "PST."
146 * @see #LONG
147 * @since 1.2
148 */
149 public static final int SHORT = 0;
150
151 /**
152 * A style specifier for <code>getDisplayName()</code> indicating
153 * a long name, such as "Pacific Standard Time."
154 * @see #SHORT
155 * @since 1.2
156 */
157 public static final int LONG = 1;
158
159 // Constants used internally; unit is milliseconds
160 private static final int ONE_MINUTE = 60 * 1000;
161 private static final int ONE_HOUR = 60 * ONE_MINUTE;
162 private static final int ONE_DAY = 24 * ONE_HOUR;
163
164 /**
165 * Cache to hold the SimpleDateFormat objects for a Locale.
166 */
167 private static Hashtable cachedLocaleData = new Hashtable(3);
168
169 // Proclaim serialization compatibility with JDK 1.1
170 static final long serialVersionUID = 3581463369166924961L;
171
172 /**
173 * Gets the time zone offset, for current date, modified in case of
174 * daylight savings. This is the offset to add to UTC to get local time.
175 * <p>
176 * This method returns a historically correct offset if an
177 * underlying <code>TimeZone</code> implementation subclass
178 * supports historical Daylight Saving Time schedule and GMT
179 * offset changes.
180 *
181 * @param era the era of the given date.
182 * @param year the year in the given date.
183 * @param month the month in the given date.
184 * Month is 0-based. e.g., 0 for January.
185 * @param day the day-in-month of the given date.
186 * @param dayOfWeek the day-of-week of the given date.
187 * @param milliseconds the milliseconds in day in <em>standard</em>
188 * local time.
189 *
190 * @return the offset in milliseconds to add to GMT to get local time.
191 *
192 * @see Calendar#ZONE_OFFSET
193 * @see Calendar#DST_OFFSET
194 */
195 public abstract int getOffset(int era, int year, int month,
196 int day, int dayOfWeek, int milliseconds);
197
198 /**
199 * Returns the offset of this time zone from UTC at the specified
200 * date. If Daylight Saving Time is in effect at the specified
201 * date, the offset value is adjusted with the amount of daylight
202 * saving.
203 * <p>
204 * This method returns a historically correct offset value if an
205 * underlying TimeZone implementation subclass supports historical
206 * Daylight Saving Time schedule and GMT offset changes.
207 *
208 * @param date the date represented in milliseconds since January 1, 1970 00:00:00 GMT
209 * @return the amount of time in milliseconds to add to UTC to get local time.
210 *
211 * @see Calendar#ZONE_OFFSET
212 * @see Calendar#DST_OFFSET
213 * @since 1.4
214 */
215 public int getOffset(long date) {
216 if (inDaylightTime(new Date(date))) {
217 return getRawOffset() + getDSTSavings();
218 }
219 return getRawOffset();
220 }
221
222 /**
223 * Gets the raw GMT offset and the amount of daylight saving of this
224 * time zone at the given time.
225 * @param date the milliseconds (since January 1, 1970,
226 * 00:00:00.000 GMT) at which the time zone offset and daylight
227 * saving amount are found
228 * @param offset an array of int where the raw GMT offset
229 * (offset[0]) and daylight saving amount (offset[1]) are stored,
230 * or null if those values are not needed. The method assumes that
231 * the length of the given array is two or larger.
232 * @return the total amount of the raw GMT offset and daylight
233 * saving at the specified date.
234 *
235 * @see Calendar#ZONE_OFFSET
236 * @see Calendar#DST_OFFSET
237 */
238 int getOffsets(long date, int[] offsets) {
239 int rawoffset = getRawOffset();
240 int dstoffset = 0;
241 if (inDaylightTime(new Date(date))) {
242 dstoffset = getDSTSavings();
243 }
244 if (offsets != null) {
245 offsets[0] = rawoffset;
246 offsets[1] = dstoffset;
247 }
248 return rawoffset + dstoffset;
249 }
250
251 /**
252 * Sets the base time zone offset to GMT.
253 * This is the offset to add to UTC to get local time.
254 * <p>
255 * If an underlying <code>TimeZone</code> implementation subclass
256 * supports historical GMT offset changes, the specified GMT
257 * offset is set as the latest GMT offset and the difference from
258 * the known latest GMT offset value is used to adjust all
259 * historical GMT offset values.
260 *
261 * @param offsetMillis the given base time zone offset to GMT.
262 */
263 abstract public void setRawOffset(int offsetMillis);
264
265 /**
266 * Returns the amount of time in milliseconds to add to UTC to get
267 * standard time in this time zone. Because this value is not
268 * affected by daylight saving time, it is called <I>raw
269 * offset</I>.
270 * <p>
271 * If an underlying <code>TimeZone</code> implementation subclass
272 * supports historical GMT offset changes, the method returns the
273 * raw offset value of the current date. In Honolulu, for example,
274 * its raw offset changed from GMT-10:30 to GMT-10:00 in 1947, and
275 * this method always returns -36000000 milliseconds (i.e., -10
276 * hours).
277 *
278 * @return the amount of raw offset time in milliseconds to add to UTC.
279 * @see Calendar#ZONE_OFFSET
280 */
281 public abstract int getRawOffset();
282
283 /**
284 * Gets the ID of this time zone.
285 * @return the ID of this time zone.
286 */
287 public String getID() {
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 if (ID == null) {
298 throw new NullPointerException();
299 }
300 this .ID = ID;
301 }
302
303 /**
304 * Returns a name of this time zone suitable for presentation to the user
305 * in the default locale.
306 * This method returns the long name, not including daylight savings.
307 * If the display name is not available for the locale,
308 * then this method returns a string in the
309 * <a href="#NormalizedCustomID">normalized custom ID format</a>.
310 * @return the human-readable name of this time zone in the default locale.
311 * @since 1.2
312 */
313 public final String getDisplayName() {
314 return getDisplayName(false, LONG, Locale.getDefault());
315 }
316
317 /**
318 * Returns a name of this time zone suitable for presentation to the user
319 * in the specified locale.
320 * This method returns the long name, not including daylight savings.
321 * If the display name is not available for the locale,
322 * then this method returns a string in the
323 * <a href="#NormalizedCustomID">normalized custom ID format</a>.
324 * @param locale the locale in which to supply the display name.
325 * @return the human-readable name of this time zone in the given locale.
326 * @since 1.2
327 */
328 public final String getDisplayName(Locale locale) {
329 return getDisplayName(false, LONG, locale);
330 }
331
332 /**
333 * Returns a name of this time zone suitable for presentation to the user
334 * in the default locale.
335 * If the display name is not available for the locale, then this
336 * method returns a string in the
337 * <a href="#NormalizedCustomID">normalized custom ID format</a>.
338 * @param daylight if true, return the daylight savings name.
339 * @param style either <code>LONG</code> or <code>SHORT</code>
340 * @return the human-readable name of this time zone in the default locale.
341 * @since 1.2
342 */
343 public final String getDisplayName(boolean daylight, int style) {
344 return getDisplayName(daylight, style, Locale.getDefault());
345 }
346
347 /**
348 * Returns a name of this time zone suitable for presentation to the user
349 * in the specified locale.
350 * If the display name is not available for the locale,
351 * then this method returns a string in the
352 * <a href="#NormalizedCustomID">normalized custom ID format</a>.
353 * @param daylight if true, return the daylight savings name.
354 * @param style either <code>LONG</code> or <code>SHORT</code>
355 * @param locale the locale in which to supply the display name.
356 * @return the human-readable name of this time zone in the given locale.
357 * @exception IllegalArgumentException style is invalid.
358 * @since 1.2
359 */
360 public String getDisplayName(boolean daylight, int style,
361 Locale locale) {
362 if (style != SHORT && style != LONG) {
363 throw new IllegalArgumentException("Illegal style: "
364 + style);
365 }
366
367 String id = getID();
368 String[] names = getDisplayNames(id, locale);
369 if (names == null) {
370 if (id.startsWith("GMT")) {
371 char sign = id.charAt(3);
372 if (sign == '+' || sign == '-') {
373 return id;
374 }
375 }
376 int offset = getRawOffset();
377 if (daylight) {
378 offset += getDSTSavings();
379 }
380 return ZoneInfoFile.toCustomID(offset);
381 }
382
383 int index = daylight ? 3 : 1;
384 if (style == SHORT) {
385 index++;
386 }
387 return names[index];
388 }
389
390 private static class DisplayNames {
391 // Cache for managing display names per timezone per locale
392 // The structure is:
393 // Map(key=id, value=SoftReference(Map(key=locale, value=displaynames)))
394 private static final Map<String, SoftReference<Map<Locale, String[]>>> CACHE = new ConcurrentHashMap<String, SoftReference<Map<Locale, String[]>>>();
395 }
396
397 private static final String[] getDisplayNames(String id,
398 Locale locale) {
399 Map<String, SoftReference<Map<Locale, String[]>>> displayNames = DisplayNames.CACHE;
400
401 SoftReference<Map<Locale, String[]>> ref = displayNames.get(id);
402 if (ref != null) {
403 Map<Locale, String[]> perLocale = ref.get();
404 if (perLocale != null) {
405 String[] names = perLocale.get(locale);
406 if (names != null) {
407 return names;
408 }
409 names = TimeZoneNameUtility.retrieveDisplayNames(id,
410 locale);
411 if (names != null) {
412 perLocale.put(locale, names);
413 }
414 return names;
415 }
416 }
417
418 String[] names = TimeZoneNameUtility.retrieveDisplayNames(id,
419 locale);
420 if (names != null) {
421 Map<Locale, String[]> perLocale = new ConcurrentHashMap<Locale, String[]>();
422 perLocale.put(locale, names);
423 ref = new SoftReference<Map<Locale, String[]>>(perLocale);
424 displayNames.put(id, ref);
425 }
426 return names;
427 }
428
429 /**
430 * Returns the amount of time to be added to local standard time
431 * to get local wall clock time.
432 * <p>
433 * The default implementation always returns 3600000 milliseconds
434 * (i.e., one hour) if this time zone observes Daylight Saving
435 * Time. Otherwise, 0 (zero) is returned.
436 * <p>
437 * If an underlying TimeZone implementation subclass supports
438 * historical Daylight Saving Time changes, this method returns
439 * the known latest daylight saving value.
440 *
441 * @return the amount of saving time in milliseconds
442 * @since 1.4
443 */
444 public int getDSTSavings() {
445 if (useDaylightTime()) {
446 return 3600000;
447 }
448 return 0;
449 }
450
451 /**
452 * Queries if this time zone uses daylight savings time.
453 * <p>
454 * If an underlying <code>TimeZone</code> implementation subclass
455 * supports historical Daylight Saving Time schedule changes, the
456 * method refers to the latest Daylight Saving Time schedule
457 * information.
458 *
459 * @return true if this time zone uses daylight savings time,
460 * false, otherwise.
461 */
462 public abstract boolean useDaylightTime();
463
464 /**
465 * Queries if the given date is in daylight savings time in
466 * this time zone.
467 * @param date the given Date.
468 * @return true if the given date is in daylight savings time,
469 * false, otherwise.
470 */
471 abstract public boolean inDaylightTime(Date date);
472
473 /**
474 * Gets the <code>TimeZone</code> for the given ID.
475 *
476 * @param ID the ID for a <code>TimeZone</code>, either an abbreviation
477 * such as "PST", a full name such as "America/Los_Angeles", or a custom
478 * ID such as "GMT-8:00". Note that the support of abbreviations is
479 * for JDK 1.1.x compatibility only and full names should be used.
480 *
481 * @return the specified <code>TimeZone</code>, or the GMT zone if the given ID
482 * cannot be understood.
483 */
484 public static synchronized TimeZone getTimeZone(String ID) {
485 return getTimeZone(ID, true);
486 }
487
488 private static TimeZone getTimeZone(String ID, boolean fallback) {
489 TimeZone tz = ZoneInfo.getTimeZone(ID);
490 if (tz == null) {
491 tz = parseCustomTimeZone(ID);
492 if (tz == null && fallback) {
493 tz = new ZoneInfo(GMT_ID, 0);
494 }
495 }
496 return tz;
497 }
498
499 /**
500 * Gets the available IDs according to the given time zone offset in milliseconds.
501 *
502 * @param rawOffset the given time zone GMT offset in milliseconds.
503 * @return an array of IDs, where the time zone for that ID has
504 * the specified GMT offset. For example, "America/Phoenix" and "America/Denver"
505 * both have GMT-07:00, but differ in daylight savings behavior.
506 * @see #getRawOffset()
507 */
508 public static synchronized String[] getAvailableIDs(int rawOffset) {
509 return ZoneInfo.getAvailableIDs(rawOffset);
510 }
511
512 /**
513 * Gets all the available IDs supported.
514 * @return an array of IDs.
515 */
516 public static synchronized String[] getAvailableIDs() {
517 return ZoneInfo.getAvailableIDs();
518 }
519
520 /**
521 * Gets the platform defined TimeZone ID.
522 **/
523 private static native String getSystemTimeZoneID(String javaHome,
524 String country);
525
526 /**
527 * Gets the custom time zone ID based on the GMT offset of the
528 * platform. (e.g., "GMT+08:00")
529 */
530 private static native String getSystemGMTOffsetID();
531
532 /**
533 * Gets the default <code>TimeZone</code> for this host.
534 * The source of the default <code>TimeZone</code>
535 * may vary with implementation.
536 * @return a default <code>TimeZone</code>.
537 * @see #setDefault
538 */
539 public static TimeZone getDefault() {
540 return (TimeZone) getDefaultRef().clone();
541 }
542
543 /**
544 * Returns the reference to the default TimeZone object. This
545 * method doesn't create a clone.
546 */
547 static TimeZone getDefaultRef() {
548 TimeZone defaultZone = defaultZoneTL.get();
549 if (defaultZone == null) {
550 defaultZone = defaultTimeZone;
551 if (defaultZone == null) {
552 // Need to initialize the default time zone.
553 defaultZone = setDefaultZone();
554 assert defaultZone != null;
555 }
556 }
557 // Don't clone here.
558 return defaultZone;
559 }
560
561 private static synchronized TimeZone setDefaultZone() {
562 TimeZone tz = null;
563 // get the time zone ID from the system properties
564 String zoneID = AccessController
565 .doPrivileged(new GetPropertyAction("user.timezone"));
566
567 // if the time zone ID is not set (yet), perform the
568 // platform to Java time zone ID mapping.
569 if (zoneID == null || zoneID.equals("")) {
570 String country = AccessController
571 .doPrivileged(new GetPropertyAction("user.country"));
572 String javaHome = AccessController
573 .doPrivileged(new GetPropertyAction("java.home"));
574 try {
575 zoneID = getSystemTimeZoneID(javaHome, country);
576 if (zoneID == null) {
577 zoneID = GMT_ID;
578 }
579 } catch (NullPointerException e) {
580 zoneID = GMT_ID;
581 }
582 }
583
584 // Get the time zone for zoneID. But not fall back to
585 // "GMT" here.
586 tz = getTimeZone(zoneID, false);
587
588 if (tz == null) {
589 // If the given zone ID is unknown in Java, try to
590 // get the GMT-offset-based time zone ID,
591 // a.k.a. custom time zone ID (e.g., "GMT-08:00").
592 String gmtOffsetID = getSystemGMTOffsetID();
593 if (gmtOffsetID != null) {
594 zoneID = gmtOffsetID;
595 }
596 tz = getTimeZone(zoneID, true);
597 }
598 assert tz != null;
599
600 final String id = zoneID;
601 AccessController.doPrivileged(new PrivilegedAction<Object>() {
602 public Object run() {
603 System.setProperty("user.timezone", id);
604 return null;
605 }
606 });
607
608 if (hasPermission()) {
609 defaultTimeZone = tz;
610 } else {
611 defaultZoneTL.set(tz);
612 }
613 return tz;
614 }
615
616 private static boolean hasPermission() {
617 boolean hasPermission = true;
618 SecurityManager sm = System.getSecurityManager();
619 if (sm != null) {
620 try {
621 sm.checkPermission(new PropertyPermission(
622 "user.timezone", "write"));
623 } catch (SecurityException e) {
624 hasPermission = false;
625 }
626 }
627 return hasPermission;
628 }
629
630 /**
631 * Sets the <code>TimeZone</code> that is
632 * returned by the <code>getDefault</code> method. If <code>zone</code>
633 * is null, reset the default to the value it had originally when the
634 * VM first started.
635 * @param zone the new default time zone
636 * @see #getDefault
637 */
638 public static void setDefault(TimeZone zone) {
639 if (hasPermission()) {
640 synchronized (TimeZone.class) {
641 defaultTimeZone = zone;
642 }
643 } else {
644 defaultZoneTL.set(zone);
645 }
646 }
647
648 /**
649 * Returns true if this zone has the same rule and offset as another zone.
650 * That is, if this zone differs only in ID, if at all. Returns false
651 * if the other zone is null.
652 * @param other the <code>TimeZone</code> object to be compared with
653 * @return true if the other zone is not null and is the same as this one,
654 * with the possible exception of the ID
655 * @since 1.2
656 */
657 public boolean hasSameRules(TimeZone other) {
658 return other != null && getRawOffset() == other.getRawOffset()
659 && useDaylightTime() == other.useDaylightTime();
660 }
661
662 /**
663 * Creates a copy of this <code>TimeZone</code>.
664 *
665 * @return a clone of this <code>TimeZone</code>
666 */
667 public Object clone() {
668 try {
669 TimeZone other = (TimeZone) super .clone();
670 other.ID = ID;
671 return other;
672 } catch (CloneNotSupportedException e) {
673 throw new InternalError();
674 }
675 }
676
677 /**
678 * The null constant as a TimeZone.
679 */
680 static final TimeZone NO_TIMEZONE = null;
681
682 // =======================privates===============================
683
684 /**
685 * The string identifier of this <code>TimeZone</code>. This is a
686 * programmatic identifier used internally to look up <code>TimeZone</code>
687 * objects from the system table and also to map them to their localized
688 * display names. <code>ID</code> values are unique in the system
689 * table but may not be for dynamically created zones.
690 * @serial
691 */
692 private String ID;
693 private static volatile TimeZone defaultTimeZone;
694 private static final InheritableThreadLocal<TimeZone> defaultZoneTL = new InheritableThreadLocal<TimeZone>();
695
696 static final String GMT_ID = "GMT";
697 private static final int GMT_ID_LENGTH = 3;
698
699 /**
700 * Parses a custom time zone identifier and returns a corresponding zone.
701 * This method doesn't support the RFC 822 time zone format. (e.g., +hhmm)
702 *
703 * @param id a string of the <a href="#CustomID">custom ID form</a>.
704 * @return a newly created TimeZone with the given offset and
705 * no daylight saving time, or null if the id cannot be parsed.
706 */
707 private static final TimeZone parseCustomTimeZone(String id) {
708 int length;
709
710 // Error if the length of id isn't long enough or id doesn't
711 // start with "GMT".
712 if ((length = id.length()) < (GMT_ID_LENGTH + 2)
713 || id.indexOf(GMT_ID) != 0) {
714 return null;
715 }
716
717 ZoneInfo zi;
718
719 // First, we try to find it in the cache with the given
720 // id. Even the id is not normalized, the returned ZoneInfo
721 // should have its normalized id.
722 zi = ZoneInfoFile.getZoneInfo(id);
723 if (zi != null) {
724 return zi;
725 }
726
727 int index = GMT_ID_LENGTH;
728 boolean negative = false;
729 char c = id.charAt(index++);
730 if (c == '-') {
731 negative = true;
732 } else if (c != '+') {
733 return null;
734 }
735
736 int hours = 0;
737 int num = 0;
738 int countDelim = 0;
739 int len = 0;
740 while (index < length) {
741 c = id.charAt(index++);
742 if (c == ':') {
743 if (countDelim > 0) {
744 return null;
745 }
746 if (len > 2) {
747 return null;
748 }
749 hours = num;
750 countDelim++;
751 num = 0;
752 len = 0;
753 continue;
754 }
755 if (c < '0' || c > '9') {
756 return null;
757 }
758 num = num * 10 + (c - '0');
759 len++;
760 }
761 if (index != length) {
762 return null;
763 }
764 if (countDelim == 0) {
765 if (len <= 2) {
766 hours = num;
767 num = 0;
768 } else {
769 hours = num / 100;
770 num %= 100;
771 }
772 } else {
773 if (len != 2) {
774 return null;
775 }
776 }
777 if (hours > 23 || num > 59) {
778 return null;
779 }
780 int gmtOffset = (hours * 60 + num) * 60 * 1000;
781
782 if (gmtOffset == 0) {
783 zi = ZoneInfoFile.getZoneInfo(GMT_ID);
784 if (negative) {
785 zi.setID("GMT-00:00");
786 } else {
787 zi.setID("GMT+00:00");
788 }
789 } else {
790 zi = ZoneInfoFile.getCustomTimeZone(id,
791 negative ? -gmtOffset : gmtOffset);
792 }
793 return zi;
794 }
795 }
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