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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