1 /*
2 * Copyright (c) 1996, 2011, 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.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 // Proclaim serialization compatibility with JDK 1.1
164 static final long serialVersionUID = 3581463369166924961L;
165
166 /**
167 * Gets the time zone offset, for current date, modified in case of
168 * daylight savings. This is the offset to add to UTC to get local time.
169 * <p>
170 * This method returns a historically correct offset if an
171 * underlying <code>TimeZone</code> implementation subclass
172 * supports historical Daylight Saving Time schedule and GMT
173 * offset changes.
174 *
175 * @param era the era of the given date.
176 * @param year the year in the given date.
177 * @param month the month in the given date.
178 * Month is 0-based. e.g., 0 for January.
179 * @param day the day-in-month of the given date.
180 * @param dayOfWeek the day-of-week of the given date.
181 * @param milliseconds the milliseconds in day in <em>standard</em>
182 * local time.
183 *
184 * @return the offset in milliseconds to add to GMT to get local time.
185 *
186 * @see Calendar#ZONE_OFFSET
187 * @see Calendar#DST_OFFSET
188 */
189 public abstract int getOffset(int era, int year, int month, int day,
190 int dayOfWeek, int milliseconds);
191
192 /**
193 * Returns the offset of this time zone from UTC at the specified
194 * date. If Daylight Saving Time is in effect at the specified
195 * date, the offset value is adjusted with the amount of daylight
196 * saving.
197 * <p>
198 * This method returns a historically correct offset value if an
199 * underlying TimeZone implementation subclass supports historical
200 * Daylight Saving Time schedule and GMT offset changes.
201 *
202 * @param date the date represented in milliseconds since January 1, 1970 00:00:00 GMT
203 * @return the amount of time in milliseconds to add to UTC to get local time.
204 *
205 * @see Calendar#ZONE_OFFSET
206 * @see Calendar#DST_OFFSET
207 * @since 1.4
208 */
209 public int getOffset(long date) {
210 if (inDaylightTime(new Date(date))) {
211 return getRawOffset() + getDSTSavings();
212 }
213 return getRawOffset();
214 }
215
216 /**
217 * Gets the raw GMT offset and the amount of daylight saving of this
218 * time zone at the given time.
219 * @param date the milliseconds (since January 1, 1970,
220 * 00:00:00.000 GMT) at which the time zone offset and daylight
221 * saving amount are found
222 * @param offset an array of int where the raw GMT offset
223 * (offset[0]) and daylight saving amount (offset[1]) are stored,
224 * or null if those values are not needed. The method assumes that
225 * the length of the given array is two or larger.
226 * @return the total amount of the raw GMT offset and daylight
227 * saving at the specified date.
228 *
229 * @see Calendar#ZONE_OFFSET
230 * @see Calendar#DST_OFFSET
231 */
232 int getOffsets(long date, int[] offsets) {
233 int rawoffset = getRawOffset();
234 int dstoffset = 0;
235 if (inDaylightTime(new Date(date))) {
236 dstoffset = getDSTSavings();
237 }
238 if (offsets != null) {
239 offsets[0] = rawoffset;
240 offsets[1] = dstoffset;
241 }
242 return rawoffset + dstoffset;
243 }
244
245 /**
246 * Sets the base time zone offset to GMT.
247 * This is the offset to add to UTC to get local time.
248 * <p>
249 * If an underlying <code>TimeZone</code> implementation subclass
250 * supports historical GMT offset changes, the specified GMT
251 * offset is set as the latest GMT offset and the difference from
252 * the known latest GMT offset value is used to adjust all
253 * historical GMT offset values.
254 *
255 * @param offsetMillis the given base time zone offset to GMT.
256 */
257 abstract public void setRawOffset(int offsetMillis);
258
259 /**
260 * Returns the amount of time in milliseconds to add to UTC to get
261 * standard time in this time zone. Because this value is not
262 * affected by daylight saving time, it is called <I>raw
263 * offset</I>.
264 * <p>
265 * If an underlying <code>TimeZone</code> implementation subclass
266 * supports historical GMT offset changes, the method returns the
267 * raw offset value of the current date. In Honolulu, for example,
268 * its raw offset changed from GMT-10:30 to GMT-10:00 in 1947, and
269 * this method always returns -36000000 milliseconds (i.e., -10
270 * hours).
271 *
272 * @return the amount of raw offset time in milliseconds to add to UTC.
273 * @see Calendar#ZONE_OFFSET
274 */
275 public abstract int getRawOffset();
276
277 /**
278 * Gets the ID of this time zone.
279 * @return the ID of this time zone.
280 */
281 public String getID()
282 {
283 return ID;
284 }
285
286 /**
287 * Sets the time zone ID. This does not change any other data in
288 * the time zone object.
289 * @param ID the new time zone ID.
290 */
291 public void setID(String ID)
292 {
293 if (ID == null) {
294 throw new NullPointerException();
295 }
296 this.ID = ID;
297 }
298
299 /**
300 * Returns a long standard time name of this {@code TimeZone} suitable for
301 * presentation to the user in the default locale.
302 *
303 * <p>This method is equivalent to:
304 * <pre><blockquote>
305 * getDisplayName(false, {@link #LONG},
306 * Locale.getDefault({@link Locale.Category#DISPLAY}))
307 * </blockquote></pre>
308 *
309 * @return the human-readable name of this time zone in the default locale.
310 * @since 1.2
311 * @see #getDisplayName(boolean, int, Locale)
312 * @see Locale#getDefault(Locale.Category)
313 * @see Locale.Category
314 */
315 public final String getDisplayName() {
316 return getDisplayName(false, LONG,
317 Locale.getDefault(Locale.Category.DISPLAY));
318 }
319
320 /**
321 * Returns a long standard time name of this {@code TimeZone} suitable for
322 * presentation to the user in the specified {@code locale}.
323 *
324 * <p>This method is equivalent to:
325 * <pre><blockquote>
326 * getDisplayName(false, {@link #LONG}, locale)
327 * </blockquote></pre>
328 *
329 * @param locale the locale in which to supply the display name.
330 * @return the human-readable name of this time zone in the given locale.
331 * @exception NullPointerException if {@code locale} is {@code null}.
332 * @since 1.2
333 * @see #getDisplayName(boolean, int, Locale)
334 */
335 public final String getDisplayName(Locale locale) {
336 return getDisplayName(false, LONG, locale);
337 }
338
339 /**
340 * Returns a name in the specified {@code style} of this {@code TimeZone}
341 * suitable for presentation to the user in the default locale. If the
342 * specified {@code daylight} is {@code true}, a Daylight Saving Time name
343 * is returned (even if this {@code TimeZone} doesn't observe Daylight Saving
344 * Time). Otherwise, a Standard Time name is returned.
345 *
346 * <p>This method is equivalent to:
347 * <pre><blockquote>
348 * getDisplayName(daylight, style,
349 * Locale.getDefault({@link Locale.Category#DISPLAY}))
350 * </blockquote></pre>
351 *
352 * @param daylight {@code true} specifying a Daylight Saving Time name, or
353 * {@code false} specifying a Standard Time name
354 * @param style either {@link #LONG} or {@link #SHORT}
355 * @return the human-readable name of this time zone in the default locale.
356 * @exception IllegalArgumentException if {@code style} is invalid.
357 * @since 1.2
358 * @see #getDisplayName(boolean, int, Locale)
359 * @see Locale#getDefault(Locale.Category)
360 * @see Locale.Category
361 * @see java.text.DateFormatSymbols#getZoneStrings()
362 */
363 public final String getDisplayName(boolean daylight, int style) {
364 return getDisplayName(daylight, style,
365 Locale.getDefault(Locale.Category.DISPLAY));
366 }
367
368 /**
369 * Returns a name in the specified {@code style} of this {@code TimeZone}
370 * suitable for presentation to the user in the specified {@code
371 * locale}. If the specified {@code daylight} is {@code true}, a Daylight
372 * Saving Time name is returned (even if this {@code TimeZone} doesn't
373 * observe Daylight Saving Time). Otherwise, a Standard Time name is
374 * returned.
375 *
376 * <p>When looking up a time zone name, the {@linkplain
377 * ResourceBundle.Control#getCandidateLocales(String,Locale) default
378 * <code>Locale</code> search path of <code>ResourceBundle</code>} derived
379 * from the specified {@code locale} is used. (No {@linkplain
380 * ResourceBundle.Control#getFallbackLocale(String,Locale) fallback
381 * <code>Locale</code>} search is performed.) If a time zone name in any
382 * {@code Locale} of the search path, including {@link Locale#ROOT}, is
383 * found, the name is returned. Otherwise, a string in the
384 * <a href="#NormalizedCustomID">normalized custom ID format</a> is returned.
385 *
386 * @param daylight {@code true} specifying a Daylight Saving Time name, or
387 * {@code false} specifying a Standard Time name
388 * @param style either {@link #LONG} or {@link #SHORT}
389 * @param locale the locale in which to supply the display name.
390 * @return the human-readable name of this time zone in the given locale.
391 * @exception IllegalArgumentException if {@code style} is invalid.
392 * @exception NullPointerException if {@code locale} is {@code null}.
393 * @since 1.2
394 * @see java.text.DateFormatSymbols#getZoneStrings()
395 */
396 public String getDisplayName(boolean daylight, int style, Locale locale) {
397 if (style != SHORT && style != LONG) {
398 throw new IllegalArgumentException("Illegal style: " + style);
399 }
400
401 String id = getID();
402 String[] names = getDisplayNames(id, locale);
403 if (names == null) {
404 if (id.startsWith("GMT")) {
405 char sign = id.charAt(3);
406 if (sign == '+' || sign == '-') {
407 return id;
408 }
409 }
410 int offset = getRawOffset();
411 if (daylight) {
412 offset += getDSTSavings();
413 }
414 return ZoneInfoFile.toCustomID(offset);
415 }
416
417 int index = daylight ? 3 : 1;
418 if (style == SHORT) {
419 index++;
420 }
421 return names[index];
422 }
423
424 private static class DisplayNames {
425 // Cache for managing display names per timezone per locale
426 // The structure is:
427 // Map(key=id, value=SoftReference(Map(key=locale, value=displaynames)))
428 private static final Map<String, SoftReference<Map<Locale, String[]>>> CACHE =
429 new ConcurrentHashMap<String, SoftReference<Map<Locale, String[]>>>();
430 }
431
432 private static final String[] getDisplayNames(String id, Locale locale) {
433 Map<String, SoftReference<Map<Locale, String[]>>> displayNames = DisplayNames.CACHE;
434
435 SoftReference<Map<Locale, String[]>> ref = displayNames.get(id);
436 if (ref != null) {
437 Map<Locale, String[]> perLocale = ref.get();
438 if (perLocale != null) {
439 String[] names = perLocale.get(locale);
440 if (names != null) {
441 return names;
442 }
443 names = TimeZoneNameUtility.retrieveDisplayNames(id, locale);
444 if (names != null) {
445 perLocale.put(locale, names);
446 }
447 return names;
448 }
449 }
450
451 String[] names = TimeZoneNameUtility.retrieveDisplayNames(id, locale);
452 if (names != null) {
453 Map<Locale, String[]> perLocale = new ConcurrentHashMap<Locale, String[]>();
454 perLocale.put(locale, names);
455 ref = new SoftReference<Map<Locale, String[]>>(perLocale);
456 displayNames.put(id, ref);
457 }
458 return names;
459 }
460
461 /**
462 * Returns the amount of time to be added to local standard time
463 * to get local wall clock time.
464 *
465 * <p>The default implementation returns 3600000 milliseconds
466 * (i.e., one hour) if a call to {@link #useDaylightTime()}
467 * returns {@code true}. Otherwise, 0 (zero) is returned.
468 *
469 * <p>If an underlying {@code TimeZone} implementation subclass
470 * supports historical and future Daylight Saving Time schedule
471 * changes, this method returns the amount of saving time of the
472 * last known Daylight Saving Time rule that can be a future
473 * prediction.
474 *
475 * <p>If the amount of saving time at any given time stamp is
476 * required, construct a {@link Calendar} with this {@code
477 * TimeZone} and the time stamp, and call {@link Calendar#get(int)
478 * Calendar.get}{@code (}{@link Calendar#DST_OFFSET}{@code )}.
479 *
480 * @return the amount of saving time in milliseconds
481 * @since 1.4
482 * @see #inDaylightTime(Date)
483 * @see #getOffset(long)
484 * @see #getOffset(int,int,int,int,int,int)
485 * @see Calendar#ZONE_OFFSET
486 */
487 public int getDSTSavings() {
488 if (useDaylightTime()) {
489 return 3600000;
490 }
491 return 0;
492 }
493
494 /**
495 * Queries if this {@code TimeZone} uses Daylight Saving Time.
496 *
497 * <p>If an underlying {@code TimeZone} implementation subclass
498 * supports historical and future Daylight Saving Time schedule
499 * changes, this method refers to the last known Daylight Saving Time
500 * rule that can be a future prediction and may not be the same as
501 * the current rule. Consider calling {@link #observesDaylightTime()}
502 * if the current rule should also be taken into account.
503 *
504 * @return {@code true} if this {@code TimeZone} uses Daylight Saving Time,
505 * {@code false}, otherwise.
506 * @see #inDaylightTime(Date)
507 * @see Calendar#DST_OFFSET
508 */
509 public abstract boolean useDaylightTime();
510
511 /**
512 * Returns {@code true} if this {@code TimeZone} is currently in
513 * Daylight Saving Time, or if a transition from Standard Time to
514 * Daylight Saving Time occurs at any future time.
515 *
516 * <p>The default implementation returns {@code true} if
517 * {@code useDaylightTime()} or {@code inDaylightTime(new Date())}
518 * returns {@code true}.
519 *
520 * @return {@code true} if this {@code TimeZone} is currently in
521 * Daylight Saving Time, or if a transition from Standard Time to
522 * Daylight Saving Time occurs at any future time; {@code false}
523 * otherwise.
524 * @since 1.7
525 * @see #useDaylightTime()
526 * @see #inDaylightTime(Date)
527 * @see Calendar#DST_OFFSET
528 */
529 public boolean observesDaylightTime() {
530 return useDaylightTime() || inDaylightTime(new Date());
531 }
532
533 /**
534 * Queries if the given {@code date} is in Daylight Saving Time in
535 * this time zone.
536 *
537 * @param date the given Date.
538 * @return {@code true} if the given date is in Daylight Saving Time,
539 * {@code false}, otherwise.
540 */
541 abstract public boolean inDaylightTime(Date date);
542
543 /**
544 * Gets the <code>TimeZone</code> for the given ID.
545 *
546 * @param ID the ID for a <code>TimeZone</code>, either an abbreviation
547 * such as "PST", a full name such as "America/Los_Angeles", or a custom
548 * ID such as "GMT-8:00". Note that the support of abbreviations is
549 * for JDK 1.1.x compatibility only and full names should be used.
550 *
551 * @return the specified <code>TimeZone</code>, or the GMT zone if the given ID
552 * cannot be understood.
553 */
554 public static synchronized TimeZone getTimeZone(String ID) {
555 return getTimeZone(ID, true);
556 }
557
558 private static TimeZone getTimeZone(String ID, boolean fallback) {
559 TimeZone tz = ZoneInfo.getTimeZone(ID);
560 if (tz == null) {
561 tz = parseCustomTimeZone(ID);
562 if (tz == null && fallback) {
563 tz = new ZoneInfo(GMT_ID, 0);
564 }
565 }
566 return tz;
567 }
568
569 /**
570 * Gets the available IDs according to the given time zone offset in milliseconds.
571 *
572 * @param rawOffset the given time zone GMT offset in milliseconds.
573 * @return an array of IDs, where the time zone for that ID has
574 * the specified GMT offset. For example, "America/Phoenix" and "America/Denver"
575 * both have GMT-07:00, but differ in daylight saving behavior.
576 * @see #getRawOffset()
577 */
578 public static synchronized String[] getAvailableIDs(int rawOffset) {
579 return ZoneInfo.getAvailableIDs(rawOffset);
580 }
581
582 /**
583 * Gets all the available IDs supported.
584 * @return an array of IDs.
585 */
586 public static synchronized String[] getAvailableIDs() {
587 return ZoneInfo.getAvailableIDs();
588 }
589
590 /**
591 * Gets the platform defined TimeZone ID.
592 **/
593 private static native String getSystemTimeZoneID(String javaHome,
594 String country);
595
596 /**
597 * Gets the custom time zone ID based on the GMT offset of the
598 * platform. (e.g., "GMT+08:00")
599 */
600 private static native String getSystemGMTOffsetID();
601
602 /**
603 * Gets the default <code>TimeZone</code> for this host.
604 * The source of the default <code>TimeZone</code>
605 * may vary with implementation.
606 * @return a default <code>TimeZone</code>.
607 * @see #setDefault
608 */
609 public static TimeZone getDefault() {
610 return (TimeZone) getDefaultRef().clone();
611 }
612
613 /**
614 * Returns the reference to the default TimeZone object. This
615 * method doesn't create a clone.
616 */
617 static TimeZone getDefaultRef() {
618 TimeZone defaultZone = defaultZoneTL.get();
619 if (defaultZone == null) {
620 defaultZone = defaultTimeZone;
621 if (defaultZone == null) {
622 // Need to initialize the default time zone.
623 defaultZone = setDefaultZone();
624 assert defaultZone != null;
625 }
626 }
627 // Don't clone here.
628 return defaultZone;
629 }
630
631 private static synchronized TimeZone setDefaultZone() {
632 TimeZone tz = null;
633 // get the time zone ID from the system properties
634 String zoneID = AccessController.doPrivileged(
635 new GetPropertyAction("user.timezone"));
636
637 // if the time zone ID is not set (yet), perform the
638 // platform to Java time zone ID mapping.
639 if (zoneID == null || zoneID.equals("")) {
640 String country = AccessController.doPrivileged(
641 new GetPropertyAction("user.country"));
642 String javaHome = AccessController.doPrivileged(
643 new GetPropertyAction("java.home"));
644 try {
645 zoneID = getSystemTimeZoneID(javaHome, country);
646 if (zoneID == null) {
647 zoneID = GMT_ID;
648 }
649 } catch (NullPointerException e) {
650 zoneID = GMT_ID;
651 }
652 }
653
654 // Get the time zone for zoneID. But not fall back to
655 // "GMT" here.
656 tz = getTimeZone(zoneID, false);
657
658 if (tz == null) {
659 // If the given zone ID is unknown in Java, try to
660 // get the GMT-offset-based time zone ID,
661 // a.k.a. custom time zone ID (e.g., "GMT-08:00").
662 String gmtOffsetID = getSystemGMTOffsetID();
663 if (gmtOffsetID != null) {
664 zoneID = gmtOffsetID;
665 }
666 tz = getTimeZone(zoneID, true);
667 }
668 assert tz != null;
669
670 final String id = zoneID;
671 AccessController.doPrivileged(new PrivilegedAction<Object>() {
672 public Object run() {
673 System.setProperty("user.timezone", id);
674 return null;
675 }
676 });
677
678 defaultTimeZone = tz;
679 return tz;
680 }
681
682 private static boolean hasPermission() {
683 boolean hasPermission = true;
684 SecurityManager sm = System.getSecurityManager();
685 if (sm != null) {
686 try {
687 sm.checkPermission(new PropertyPermission
688 ("user.timezone", "write"));
689 } catch (SecurityException e) {
690 hasPermission = false;
691 }
692 }
693 return hasPermission;
694 }
695
696 /**
697 * Sets the <code>TimeZone</code> that is
698 * returned by the <code>getDefault</code> method. If <code>zone</code>
699 * is null, reset the default to the value it had originally when the
700 * VM first started.
701 * @param zone the new default time zone
702 * @see #getDefault
703 */
704 public static void setDefault(TimeZone zone)
705 {
706 if (hasPermission()) {
707 synchronized (TimeZone.class) {
708 defaultTimeZone = zone;
709 defaultZoneTL.set(null);
710 }
711 } else {
712 defaultZoneTL.set(zone);
713 }
714 }
715
716 /**
717 * Returns true if this zone has the same rule and offset as another zone.
718 * That is, if this zone differs only in ID, if at all. Returns false
719 * if the other zone is null.
720 * @param other the <code>TimeZone</code> object to be compared with
721 * @return true if the other zone is not null and is the same as this one,
722 * with the possible exception of the ID
723 * @since 1.2
724 */
725 public boolean hasSameRules(TimeZone other) {
726 return other != null && getRawOffset() == other.getRawOffset() &&
727 useDaylightTime() == other.useDaylightTime();
728 }
729
730 /**
731 * Creates a copy of this <code>TimeZone</code>.
732 *
733 * @return a clone of this <code>TimeZone</code>
734 */
735 public Object clone()
736 {
737 try {
738 TimeZone other = (TimeZone) super.clone();
739 other.ID = ID;
740 return other;
741 } catch (CloneNotSupportedException e) {
742 throw new InternalError(e);
743 }
744 }
745
746 /**
747 * The null constant as a TimeZone.
748 */
749 static final TimeZone NO_TIMEZONE = null;
750
751 // =======================privates===============================
752
753 /**
754 * The string identifier of this <code>TimeZone</code>. This is a
755 * programmatic identifier used internally to look up <code>TimeZone</code>
756 * objects from the system table and also to map them to their localized
757 * display names. <code>ID</code> values are unique in the system
758 * table but may not be for dynamically created zones.
759 * @serial
760 */
761 private String ID;
762 private static volatile TimeZone defaultTimeZone;
763 private static final InheritableThreadLocal<TimeZone> defaultZoneTL
764 = new InheritableThreadLocal<TimeZone>();
765
766 static final String GMT_ID = "GMT";
767 private static final int GMT_ID_LENGTH = 3;
768
769 /**
770 * Parses a custom time zone identifier and returns a corresponding zone.
771 * This method doesn't support the RFC 822 time zone format. (e.g., +hhmm)
772 *
773 * @param id a string of the <a href="#CustomID">custom ID form</a>.
774 * @return a newly created TimeZone with the given offset and
775 * no daylight saving time, or null if the id cannot be parsed.
776 */
777 private static final TimeZone parseCustomTimeZone(String id) {
778 int length;
779
780 // Error if the length of id isn't long enough or id doesn't
781 // start with "GMT".
782 if ((length = id.length()) < (GMT_ID_LENGTH + 2) ||
783 id.indexOf(GMT_ID) != 0) {
784 return null;
785 }
786
787 ZoneInfo zi;
788
789 // First, we try to find it in the cache with the given
790 // id. Even the id is not normalized, the returned ZoneInfo
791 // should have its normalized id.
792 zi = ZoneInfoFile.getZoneInfo(id);
793 if (zi != null) {
794 return zi;
795 }
796
797 int index = GMT_ID_LENGTH;
798 boolean negative = false;
799 char c = id.charAt(index++);
800 if (c == '-') {
801 negative = true;
802 } else if (c != '+') {
803 return null;
804 }
805
806 int hours = 0;
807 int num = 0;
808 int countDelim = 0;
809 int len = 0;
810 while (index < length) {
811 c = id.charAt(index++);
812 if (c == ':') {
813 if (countDelim > 0) {
814 return null;
815 }
816 if (len > 2) {
817 return null;
818 }
819 hours = num;
820 countDelim++;
821 num = 0;
822 len = 0;
823 continue;
824 }
825 if (c < '0' || c > '9') {
826 return null;
827 }
828 num = num * 10 + (c - '0');
829 len++;
830 }
831 if (index != length) {
832 return null;
833 }
834 if (countDelim == 0) {
835 if (len <= 2) {
836 hours = num;
837 num = 0;
838 } else {
839 hours = num / 100;
840 num %= 100;
841 }
842 } else {
843 if (len != 2) {
844 return null;
845 }
846 }
847 if (hours > 23 || num > 59) {
848 return null;
849 }
850 int gmtOffset = (hours * 60 + num) * 60 * 1000;
851
852 if (gmtOffset == 0) {
853 zi = ZoneInfoFile.getZoneInfo(GMT_ID);
854 if (negative) {
855 zi.setID("GMT-00:00");
856 } else {
857 zi.setID("GMT+00:00");
858 }
859 } else {
860 zi = ZoneInfoFile.getCustomTimeZone(id, negative ? -gmtOffset : gmtOffset);
861 }
862 return zi;
863 }
864 }