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2  * Copyright (C) 2014 The Android Open Source Project
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14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15  * version 2 for more details (a copy is included in the LICENSE file that
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26 
27 /*
28  * (C) Copyright Taligent, Inc. 1996 - All Rights Reserved
29  * (C) Copyright IBM Corp. 1996 - All Rights Reserved
30  *
31  *   The original version of this source code and documentation is copyrighted
32  * and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These
33  * materials are provided under terms of a License Agreement between Taligent
34  * and Sun. This technology is protected by multiple US and International
35  * patents. This notice and attribution to Taligent may not be removed.
36  *   Taligent is a registered trademark of Taligent, Inc.
37  *
38  */
39 
40 package java.util;
41 
42 import android.icu.text.TimeZoneNames;
43 import com.android.i18n.timezone.ZoneInfoData;
44 import com.android.i18n.timezone.ZoneInfoDb;
45 import com.android.icu.util.ExtendedTimeZone;
46 
47 import java.io.IOException;
48 import java.io.Serializable;
49 import java.time.ZoneId;
50 import java.util.function.Supplier;
51 import java.util.regex.Matcher;
52 import java.util.regex.Pattern;
53 import libcore.io.IoUtils;
54 import libcore.util.ZoneInfo;
55 
56 import dalvik.system.RuntimeHooks;
57 
58 /**
59  * {@code TimeZone} represents a time zone offset, and also figures out daylight
60  * savings.
61  *
62  * <p>
63  * Typically, you get a {@code TimeZone} using {@code getDefault}
64  * which creates a {@code TimeZone} based on the time zone where the program
65  * is running. For example, for a program running in Japan, {@code getDefault}
66  * creates a {@code TimeZone} object based on Japanese Standard Time.
67  *
68  * <p>
69  * You can also get a {@code TimeZone} using {@code getTimeZone}
70  * along with a time zone ID. For instance, the time zone ID for the
71  * U.S. Pacific Time zone is "America/Los_Angeles". So, you can get a
72  * U.S. Pacific Time {@code TimeZone} object with:
73  * <blockquote><pre>
74  * TimeZone tz = TimeZone.getTimeZone("America/Los_Angeles");
75  * </pre></blockquote>
76  * You can use the {@code getAvailableIDs} method to iterate through
77  * all the supported time zone IDs. You can then choose a
78  * supported ID to get a {@code TimeZone}.
79  * If the time zone you want is not represented by one of the
80  * supported IDs, then a custom time zone ID can be specified to
81  * produce a TimeZone. The syntax of a custom time zone ID is:
82  *
83  * <blockquote><pre>
84  * <a id="CustomID"><i>CustomID:</i></a>
85  *         {@code GMT} <i>Sign</i> <i>Hours</i> {@code :} <i>Minutes</i>
86  *         {@code GMT} <i>Sign</i> <i>Hours</i> <i>Minutes</i>
87  *         {@code GMT} <i>Sign</i> <i>Hours</i>
88  * <i>Sign:</i> one of
89  *         {@code + -}
90  * <i>Hours:</i>
91  *         <i>Digit</i>
92  *         <i>Digit</i> <i>Digit</i>
93  * <i>Minutes:</i>
94  *         <i>Digit</i> <i>Digit</i>
95  * <i>Digit:</i> one of
96  *         {@code 0 1 2 3 4 5 6 7 8 9}
97  * </pre></blockquote>
98  *
99  * <i>Hours</i> must be between 0 to 23 and <i>Minutes</i> must be
100  * between 00 to 59.  For example, "GMT+10" and "GMT+0010" mean ten
101  * hours and ten minutes ahead of GMT, respectively.
102  * <p>
103  * The format is locale independent and digits must be taken from the
104  * Basic Latin block of the Unicode standard. No daylight saving time
105  * transition schedule can be specified with a custom time zone ID. If
106  * the specified string doesn't match the syntax, {@code "GMT"}
107  * is used.
108  * <p>
109  * When creating a {@code TimeZone}, the specified custom time
110  * zone ID is normalized in the following syntax:
111  * <blockquote><pre>
112  * <a id="NormalizedCustomID"><i>NormalizedCustomID:</i></a>
113  *         {@code GMT} <i>Sign</i> <i>TwoDigitHours</i> {@code :} <i>Minutes</i>
114  * <i>Sign:</i> one of
115  *         {@code + -}
116  * <i>TwoDigitHours:</i>
117  *         <i>Digit</i> <i>Digit</i>
118  * <i>Minutes:</i>
119  *         <i>Digit</i> <i>Digit</i>
120  * <i>Digit:</i> one of
121  *         {@code 0 1 2 3 4 5 6 7 8 9}
122  * </pre></blockquote>
123  * For example, TimeZone.getTimeZone("GMT-8").getID() returns "GMT-08:00".
124  *
125  * <h2>Three-letter time zone IDs</h2>
126  *
127  * For compatibility with JDK 1.1.x, some other three-letter time zone IDs
128  * (such as "PST", "CTT", "AST") are also supported. However, <strong>their
129  * use is deprecated</strong> because the same abbreviation is often used
130  * for multiple time zones (for example, "CST" could be U.S. "Central Standard
131  * Time" and "China Standard Time"), and the Java platform can then only
132  * recognize one of them.
133  *
134  *
135  * @see          Calendar
136  * @see          GregorianCalendar
137  * @see          SimpleTimeZone
138  * @author       Mark Davis, David Goldsmith, Chen-Lieh Huang, Alan Liu
139  * @since        1.1
140  */
141 public abstract class TimeZone implements Serializable, Cloneable {
142     /**
143      * Sole constructor.  (For invocation by subclass constructors, typically
144      * implicit.)
145      */
TimeZone()146     public TimeZone() {
147     }
148 
149     /**
150      * A style specifier for {@code getDisplayName()} indicating
151      * a short name, such as "PST."
152      * @see #LONG
153      * @since 1.2
154      */
155     public static final int SHORT = 0;
156 
157     /**
158      * A style specifier for {@code getDisplayName()} indicating
159      * a long name, such as "Pacific Standard Time."
160      * @see #SHORT
161      * @since 1.2
162      */
163     public static final int LONG  = 1;
164 
165     // Android-changed: Use a preload holder to allow compile-time initialization of TimeZone and
166     // dependents.
167     private static class NoImagePreloadHolder {
168         public static final Pattern CUSTOM_ZONE_ID_PATTERN = Pattern.compile("^GMT[-+](\\d{1,2})(:?(\\d\\d))?$");
169     }
170 
171     // Proclaim serialization compatibility with JDK 1.1
172     @java.io.Serial
173     static final long serialVersionUID = 3581463369166924961L;
174 
175     // Android-changed: common timezone instances.
176     private static final TimeZone GMT = new SimpleTimeZone(0, "GMT");
177     private static final TimeZone UTC = new SimpleTimeZone(0, "UTC");
178 
179     /**
180      * Gets the time zone offset, for current date, modified in case of
181      * daylight savings. This is the offset to add to UTC to get local time.
182      * <p>
183      * This method returns a historically correct offset if an
184      * underlying {@code TimeZone} implementation subclass
185      * supports historical Daylight Saving Time schedule and GMT
186      * offset changes.
187      *
188      * @param era the era of the given date.
189      * @param year the year in the given date.
190      * @param month the month in the given date.
191      * Month is 0-based. e.g., 0 for January.
192      * @param day the day-in-month of the given date.
193      * @param dayOfWeek the day-of-week of the given date.
194      * @param milliseconds the milliseconds in day in <em>standard</em>
195      * local time.
196      *
197      * @return the offset in milliseconds to add to GMT to get local time.
198      *
199      * @see Calendar#ZONE_OFFSET
200      * @see Calendar#DST_OFFSET
201      */
getOffset(int era, int year, int month, int day, int dayOfWeek, int milliseconds)202     public abstract int getOffset(int era, int year, int month, int day,
203                                   int dayOfWeek, int milliseconds);
204 
205     /**
206      * Returns the offset of this time zone from UTC at the specified
207      * date. If Daylight Saving Time is in effect at the specified
208      * date, the offset value is adjusted with the amount of daylight
209      * saving.
210      * <p>
211      * This method returns a historically correct offset value if an
212      * underlying TimeZone implementation subclass supports historical
213      * Daylight Saving Time schedule and GMT offset changes.
214      *
215      * @param date the date represented in milliseconds since January 1, 1970 00:00:00 GMT
216      * @return the amount of time in milliseconds to add to UTC to get local time.
217      *
218      * @see Calendar#ZONE_OFFSET
219      * @see Calendar#DST_OFFSET
220      * @since 1.4
221      */
getOffset(long date)222     public int getOffset(long date) {
223         if (inDaylightTime(new Date(date))) {
224             return getRawOffset() + getDSTSavings();
225         }
226         return getRawOffset();
227     }
228 
229     /**
230      * Gets the raw GMT offset and the amount of daylight saving of this
231      * time zone at the given time.
232      * @param date the milliseconds (since January 1, 1970,
233      * 00:00:00.000 GMT) at which the time zone offset and daylight
234      * saving amount are found
235      * @param offsets an array of int where the raw GMT offset
236      * (offset[0]) and daylight saving amount (offset[1]) are stored,
237      * or null if those values are not needed. The method assumes that
238      * the length of the given array is two or larger.
239      * @return the total amount of the raw GMT offset and daylight
240      * saving at the specified date.
241      *
242      * @see Calendar#ZONE_OFFSET
243      * @see Calendar#DST_OFFSET
244      */
getOffsets(long date, int[] offsets)245     int getOffsets(long date, int[] offsets) {
246         int rawoffset = getRawOffset();
247         int dstoffset = 0;
248         if (inDaylightTime(new Date(date))) {
249             dstoffset = getDSTSavings();
250         }
251         if (offsets != null) {
252             offsets[0] = rawoffset;
253             offsets[1] = dstoffset;
254         }
255         return rawoffset + dstoffset;
256     }
257 
258     /**
259      * Sets the base time zone offset to GMT.
260      * This is the offset to add to UTC to get local time.
261      * <p>
262      * If an underlying {@code TimeZone} implementation subclass
263      * supports historical GMT offset changes, the specified GMT
264      * offset is set as the latest GMT offset and the difference from
265      * the known latest GMT offset value is used to adjust all
266      * historical GMT offset values.
267      *
268      * @param offsetMillis the given base time zone offset to GMT.
269      */
setRawOffset(int offsetMillis)270     public abstract void setRawOffset(int offsetMillis);
271 
272     /**
273      * Returns the amount of time in milliseconds to add to UTC to get
274      * standard time in this time zone. Because this value is not
275      * affected by daylight saving time, it is called <I>raw
276      * offset</I>.
277      * <p>
278      * If an underlying {@code TimeZone} implementation subclass
279      * supports historical GMT offset changes, the method returns the
280      * raw offset value of the current date. In Honolulu, for example,
281      * its raw offset changed from GMT-10:30 to GMT-10:00 in 1947, and
282      * this method always returns -36000000 milliseconds (i.e., -10
283      * hours).
284      *
285      * @return the amount of raw offset time in milliseconds to add to UTC.
286      * @see Calendar#ZONE_OFFSET
287      */
getRawOffset()288     public abstract int getRawOffset();
289 
290     /**
291      * Gets the ID of this time zone.
292      * @return the ID of this time zone.
293      */
getID()294     public String getID()
295     {
296         return ID;
297     }
298 
299     /**
300      * Sets the time zone ID. This does not change any other data in
301      * the time zone object.
302      * @param ID the new time zone ID.
303      */
setID(String ID)304     public void setID(String ID)
305     {
306         if (ID == null) {
307             throw new NullPointerException();
308         }
309         this.ID = ID;
310     }
311 
312     /**
313      * Returns a long standard time name of this {@code TimeZone} suitable for
314      * presentation to the user in the default locale.
315      *
316      * <p>This method is equivalent to:
317      * <blockquote><pre>
318      * getDisplayName(false, {@link #LONG},
319      *                Locale.getDefault({@link Locale.Category#DISPLAY}))
320      * </pre></blockquote>
321      *
322      * @return the human-readable name of this time zone in the default locale.
323      * @since 1.2
324      * @see #getDisplayName(boolean, int, Locale)
325      * @see Locale#getDefault(Locale.Category)
326      * @see Locale.Category
327      */
getDisplayName()328     public final String getDisplayName() {
329         return getDisplayName(false, LONG,
330                               Locale.getDefault(Locale.Category.DISPLAY));
331     }
332 
333     /**
334      * Returns a long standard time name of this {@code TimeZone} suitable for
335      * presentation to the user in the specified {@code locale}.
336      *
337      * <p>This method is equivalent to:
338      * <blockquote><pre>
339      * getDisplayName(false, {@link #LONG}, locale)
340      * </pre></blockquote>
341      *
342      * @param locale the locale in which to supply the display name.
343      * @return the human-readable name of this time zone in the given locale.
344      * @throws    NullPointerException if {@code locale} is {@code null}.
345      * @since 1.2
346      * @see #getDisplayName(boolean, int, Locale)
347      */
getDisplayName(Locale locale)348     public final String getDisplayName(Locale locale) {
349         return getDisplayName(false, LONG, locale);
350     }
351 
352     /**
353      * Returns a name in the specified {@code style} of this {@code TimeZone}
354      * suitable for presentation to the user in the default locale. If the
355      * specified {@code daylight} is {@code true}, a Daylight Saving Time name
356      * is returned (even if this {@code TimeZone} doesn't observe Daylight Saving
357      * Time). Otherwise, a Standard Time name is returned.
358      *
359      * <p>This method is equivalent to:
360      * <blockquote><pre>
361      * getDisplayName(daylight, style,
362      *                Locale.getDefault({@link Locale.Category#DISPLAY}))
363      * </pre></blockquote>
364      *
365      * @param daylight {@code true} specifying a Daylight Saving Time name, or
366      *                 {@code false} specifying a Standard Time name
367      * @param style either {@link #LONG} or {@link #SHORT}
368      * @return the human-readable name of this time zone in the default locale.
369      * @throws    IllegalArgumentException if {@code style} is invalid.
370      * @since 1.2
371      * @see #getDisplayName(boolean, int, Locale)
372      * @see Locale#getDefault(Locale.Category)
373      * @see Locale.Category
374      * @see java.text.DateFormatSymbols#getZoneStrings()
375      */
getDisplayName(boolean daylight, int style)376     public final String getDisplayName(boolean daylight, int style) {
377         return getDisplayName(daylight, style,
378                               Locale.getDefault(Locale.Category.DISPLAY));
379     }
380 
381     /**
382      * Returns the {@link #SHORT short} or {@link #LONG long} name of this time
383      * zone with either standard or daylight time, as written in {@code locale}.
384      * If the name is not available, the result is in the format
385      * {@code GMT[+-]hh:mm}.
386      *
387      * @param daylightTime true for daylight time, false for standard time.
388      * @param style either {@link TimeZone#LONG} or {@link TimeZone#SHORT}.
389      * @param locale the display locale.
390      */
getDisplayName(boolean daylightTime, int style, Locale locale)391     public String getDisplayName(boolean daylightTime, int style, Locale locale) {
392         // BEGIN Android-changed: implement using android.icu.text.TimeZoneNames
393         TimeZoneNames.NameType nameType;
394         switch (style) {
395             case SHORT:
396                 nameType = daylightTime
397                         ? TimeZoneNames.NameType.SHORT_DAYLIGHT
398                         : TimeZoneNames.NameType.SHORT_STANDARD;
399                 break;
400             case LONG:
401                 nameType = daylightTime
402                         ? TimeZoneNames.NameType.LONG_DAYLIGHT
403                         : TimeZoneNames.NameType.LONG_STANDARD;
404                 break;
405             default:
406                 throw new IllegalArgumentException("Illegal style: " + style);
407         }
408         String canonicalID = android.icu.util.TimeZone.getCanonicalID(getID());
409         if (canonicalID != null) {
410             TimeZoneNames names = TimeZoneNames.getInstance(locale);
411             long now = System.currentTimeMillis();
412             String displayName = names.getDisplayName(canonicalID, nameType, now);
413             if (displayName != null) {
414                 return displayName;
415             }
416         }
417 
418         // We get here if this is a custom timezone or ICU doesn't have name data for the specific
419         // style and locale.
420         int offsetMillis = getRawOffset();
421         if (daylightTime) {
422             offsetMillis += getDSTSavings();
423         }
424         return createGmtOffsetString(true /* includeGmt */, true /* includeMinuteSeparator */,
425                 offsetMillis);
426         // END Android-changed: implement using android.icu.text.TimeZoneNames
427     }
428 
429     // BEGIN Android-added: utility method to format an offset as a GMT offset string.
430     /**
431      * Returns a string representation of an offset from UTC.
432      *
433      * <p>The format is "[GMT](+|-)HH[:]MM". The output is not localized.
434      *
435      * @param includeGmt true to include "GMT", false to exclude
436      * @param includeMinuteSeparator true to include the separator between hours and minutes, false
437      *     to exclude.
438      * @param offsetMillis the offset from UTC
439      *
440      * @hide used internally by SimpleDateFormat
441      */
createGmtOffsetString(boolean includeGmt, boolean includeMinuteSeparator, int offsetMillis)442     public static String createGmtOffsetString(boolean includeGmt,
443             boolean includeMinuteSeparator, int offsetMillis) {
444         int offsetMinutes = offsetMillis / 60000;
445         char sign = '+';
446         if (offsetMinutes < 0) {
447             sign = '-';
448             offsetMinutes = -offsetMinutes;
449         }
450         StringBuilder builder = new StringBuilder(9);
451         if (includeGmt) {
452             builder.append("GMT");
453         }
454         builder.append(sign);
455         appendNumber(builder, 2, offsetMinutes / 60);
456         if (includeMinuteSeparator) {
457             builder.append(':');
458         }
459         appendNumber(builder, 2, offsetMinutes % 60);
460         return builder.toString();
461     }
462 
appendNumber(StringBuilder builder, int count, int value)463     private static void appendNumber(StringBuilder builder, int count, int value) {
464         String string = Integer.toString(value);
465         for (int i = 0; i < count - string.length(); i++) {
466             builder.append('0');
467         }
468         builder.append(string);
469     }
470     // END Android-added: utility method to format an offset as a GMT offset string.
471 
472     /**
473      * Returns the amount of time to be added to local standard time
474      * to get local wall clock time.
475      *
476      * <p>The default implementation returns 3600000 milliseconds
477      * (i.e., one hour) if a call to {@link #useDaylightTime()}
478      * returns {@code true}. Otherwise, 0 (zero) is returned.
479      *
480      * <p>If an underlying {@code TimeZone} implementation subclass
481      * supports historical and future Daylight Saving Time schedule
482      * changes, this method returns the amount of saving time of the
483      * last known Daylight Saving Time rule that can be a future
484      * prediction.
485      *
486      * <p>If the amount of saving time at any given time stamp is
487      * required, construct a {@link Calendar} with this {@code
488      * TimeZone} and the time stamp, and call {@link Calendar#get(int)
489      * Calendar.get}{@code (}{@link Calendar#DST_OFFSET}{@code )}.
490      *
491      * @return the amount of saving time in milliseconds
492      * @since 1.4
493      * @see #inDaylightTime(Date)
494      * @see #getOffset(long)
495      * @see #getOffset(int,int,int,int,int,int)
496      * @see Calendar#ZONE_OFFSET
497      */
getDSTSavings()498     public int getDSTSavings() {
499         if (useDaylightTime()) {
500             return 3600000;
501         }
502         return 0;
503     }
504 
505     /**
506      * Queries if this {@code TimeZone} uses Daylight Saving Time.
507      *
508      * <p>If an underlying {@code TimeZone} implementation subclass
509      * supports historical and future Daylight Saving Time schedule
510      * changes, this method refers to the last known Daylight Saving Time
511      * rule that can be a future prediction and may not be the same as
512      * the current rule. Consider calling {@link #observesDaylightTime()}
513      * if the current rule should also be taken into account.
514      *
515      * @return {@code true} if this {@code TimeZone} uses Daylight Saving Time,
516      *         {@code false}, otherwise.
517      * @see #inDaylightTime(Date)
518      * @see Calendar#DST_OFFSET
519      */
useDaylightTime()520     public abstract boolean useDaylightTime();
521 
522     /**
523      * Returns {@code true} if this {@code TimeZone} is currently in
524      * Daylight Saving Time, or if a transition from Standard Time to
525      * Daylight Saving Time occurs at any future time.
526      *
527      * <p>The default implementation returns {@code true} if
528      * {@code useDaylightTime()} or {@code inDaylightTime(new Date())}
529      * returns {@code true}.
530      *
531      * @return {@code true} if this {@code TimeZone} is currently in
532      * Daylight Saving Time, or if a transition from Standard Time to
533      * Daylight Saving Time occurs at any future time; {@code false}
534      * otherwise.
535      * @since 1.7
536      * @see #useDaylightTime()
537      * @see #inDaylightTime(Date)
538      * @see Calendar#DST_OFFSET
539      */
observesDaylightTime()540     public boolean observesDaylightTime() {
541         return useDaylightTime() || inDaylightTime(new Date());
542     }
543 
544     /**
545      * Queries if the given {@code date} is in Daylight Saving Time in
546      * this time zone.
547      *
548      * @param date the given Date.
549      * @return {@code true} if the given date is in Daylight Saving Time,
550      *         {@code false}, otherwise.
551      */
inDaylightTime(Date date)552     public abstract boolean inDaylightTime(Date date);
553 
554     /**
555      * Gets the {@code TimeZone} for the given ID.
556      *
557      * @param id the ID for a <code>TimeZone</code>, either an abbreviation
558      * such as "PST", a full name such as "America/Los_Angeles", or a custom
559      * ID such as "GMT-8:00". Note that the support of abbreviations is
560      * for JDK 1.1.x compatibility only and full names should be used.
561      *
562      * @return the specified {@code TimeZone}, or the GMT zone if the given ID
563      * cannot be understood.
564      */
565     // Android-changed: param s/ID/id; use ZoneInfoDb instead of ZoneInfo class.
getTimeZone(String id)566     public static synchronized TimeZone getTimeZone(String id) {
567         if (id == null) {
568             throw new NullPointerException("id == null");
569         }
570 
571         // Special cases? These can clone an existing instance.
572         if (id.length() == 3) {
573             if (id.equals("GMT")) {
574                 return (TimeZone) GMT.clone();
575             }
576             if (id.equals("UTC")) {
577                 return (TimeZone) UTC.clone();
578             }
579         }
580 
581         // In the database?
582 
583         ZoneInfoData zoneInfoData = ZoneInfoDb.getInstance().makeZoneInfoData(id);
584         TimeZone zone = zoneInfoData == null ? null : ZoneInfo.createZoneInfo(zoneInfoData);
585 
586         // Custom time zone?
587         if (zone == null && id.length() > 3 && id.startsWith("GMT")) {
588             zone = getCustomTimeZone(id);
589         }
590 
591         // We never return null; on failure we return the equivalent of "GMT".
592         return (zone != null) ? zone : (TimeZone) GMT.clone();
593     }
594 
595     /**
596      * Gets the {@code TimeZone} for the given {@code zoneId}.
597      *
598      * @param zoneId a {@link ZoneId} from which the time zone ID is obtained
599      * @return the specified {@code TimeZone}, or the GMT zone if the given ID
600      *         cannot be understood.
601      * @throws NullPointerException if {@code zoneId} is {@code null}
602      * @since 1.8
603      */
getTimeZone(ZoneId zoneId)604     public static TimeZone getTimeZone(ZoneId zoneId) {
605         String tzid = zoneId.getId(); // throws an NPE if null
606         char c = tzid.charAt(0);
607         if (c == '+' || c == '-') {
608             tzid = "GMT" + tzid;
609         } else if (c == 'Z' && tzid.length() == 1) {
610             tzid = "UTC";
611         }
612         return getTimeZone(tzid);
613     }
614 
615     /**
616      * Converts this {@code TimeZone} object to a {@code ZoneId}.
617      *
618      * @return a {@code ZoneId} representing the same time zone as this
619      *         {@code TimeZone}
620      * @since 1.8
621      */
toZoneId()622     public ZoneId toZoneId() {
623         // Android-changed: don't support "old mapping"
624         return ZoneId.of(getID(), ZoneId.SHORT_IDS);
625     }
626 
627     /**
628      * Returns a new SimpleTimeZone for an ID of the form "GMT[+|-]hh[[:]mm]", or null.
629      */
getCustomTimeZone(String id)630     private static TimeZone getCustomTimeZone(String id) {
631         Matcher m = NoImagePreloadHolder.CUSTOM_ZONE_ID_PATTERN.matcher(id);
632         if (!m.matches()) {
633             return null;
634         }
635 
636         int hour;
637         int minute = 0;
638         try {
639             hour = Integer.parseInt(m.group(1));
640             if (m.group(3) != null) {
641                 minute = Integer.parseInt(m.group(3));
642             }
643         } catch (NumberFormatException impossible) {
644             throw new AssertionError(impossible);
645         }
646 
647         if (hour < 0 || hour > 23 || minute < 0 || minute > 59) {
648             return null;
649         }
650 
651         char sign = id.charAt(3);
652         int raw = (hour * 3600000) + (minute * 60000);
653         if (sign == '-') {
654             raw = -raw;
655         }
656 
657         String cleanId = String.format(Locale.ROOT, "GMT%c%02d:%02d", sign, hour, minute);
658 
659         return new SimpleTimeZone(raw, cleanId);
660     }
661 
662     /**
663      * Gets the available IDs according to the given time zone offset in milliseconds.
664      *
665      * @param rawOffset the given time zone GMT offset in milliseconds.
666      * @return an array of IDs, where the time zone for that ID has
667      * the specified GMT offset. For example, "America/Phoenix" and "America/Denver"
668      * both have GMT-07:00, but differ in daylight saving behavior.
669      * @see #getRawOffset()
670      */
getAvailableIDs(int rawOffset)671     public static synchronized String[] getAvailableIDs(int rawOffset) {
672         return ZoneInfoDb.getInstance().getAvailableIDs(rawOffset);
673     }
674 
675     /**
676      * Gets all the available IDs supported.
677      * @return an array of IDs.
678      */
getAvailableIDs()679     public static synchronized String[] getAvailableIDs() {
680         return ZoneInfoDb.getInstance().getAvailableIDs();
681     }
682 
683     /**
684      * Gets the platform defined TimeZone ID.
685      **/
getSystemTimeZoneID(String javaHome, String country)686     private static native String getSystemTimeZoneID(String javaHome,
687                                                      String country);
688 
689     /**
690      * Gets the custom time zone ID based on the GMT offset of the
691      * platform. (e.g., "GMT+08:00")
692      */
getSystemGMTOffsetID()693     private static native String getSystemGMTOffsetID();
694 
695     /**
696      * Gets the default <code>TimeZone</code> for this host.
697      * The source of the default <code>TimeZone</code>
698      * may vary with implementation.
699      * @return a default <code>TimeZone</code>.
700      * @see #setDefault
701      */
getDefault()702     public static TimeZone getDefault() {
703         return (TimeZone) getDefaultRef().clone();
704     }
705 
706     /**
707      * Returns the reference to the default TimeZone object. This
708      * method doesn't create a clone.
709      */
getDefaultRef()710     static synchronized TimeZone getDefaultRef() {
711         if (defaultTimeZone == null) {
712             Supplier<String> tzGetter = RuntimeHooks.getTimeZoneIdSupplier();
713             String zoneName = (tzGetter != null) ? tzGetter.get() : null;
714             if (zoneName != null) {
715                 zoneName = zoneName.trim();
716             }
717             if (zoneName == null || zoneName.isEmpty()) {
718                 try {
719                     // On the host, we can find the configured timezone here.
720                     zoneName = IoUtils.readFileAsString("/etc/timezone");
721                 } catch (IOException ex) {
722                     // "vogar --mode device" can end up here.
723                     // TODO: give libcore access to Android system properties and read "persist.sys.timezone".
724                     zoneName = "GMT";
725                 }
726             }
727             defaultTimeZone = TimeZone.getTimeZone(zoneName);
728         }
729         return defaultTimeZone;
730     }
731 
732     /**
733      * Sets the {@code TimeZone} that is returned by the {@code getDefault}
734      * method. {@code timeZone} is cached. If {@code timeZone} is null, the cached
735      * default {@code TimeZone} is cleared. This method doesn't change the value
736      * of the {@code user.timezone} property.
737      *
738      * @param timeZone the new default {@code TimeZone}, or null
739      * @see #getDefault
740      */
741     // Android-changed: s/zone/timeZone, synchronized, removed mention of SecurityException
setDefault(TimeZone timeZone)742     public synchronized static void setDefault(TimeZone timeZone)
743     {
744         @SuppressWarnings("removal")
745         SecurityManager sm = System.getSecurityManager();
746         if (sm != null) {
747             sm.checkPermission(new PropertyPermission
748                     ("user.timezone", "write"));
749         }
750         defaultTimeZone = timeZone != null ? (TimeZone) timeZone.clone() : null;
751         // Android-changed: notify ICU4J of changed default TimeZone.
752         ExtendedTimeZone.clearDefaultTimeZone();
753     }
754 
755     /**
756      * Returns true if this zone has the same rule and offset as another zone.
757      * That is, if this zone differs only in ID, if at all.  Returns false
758      * if the other zone is null.
759      * @param other the {@code TimeZone} object to be compared with
760      * @return true if the other zone is not null and is the same as this one,
761      * with the possible exception of the ID
762      * @since 1.2
763      */
hasSameRules(TimeZone other)764     public boolean hasSameRules(TimeZone other) {
765         return other != null && getRawOffset() == other.getRawOffset() &&
766             useDaylightTime() == other.useDaylightTime();
767     }
768 
769     /**
770      * Creates a copy of this {@code TimeZone}.
771      *
772      * @return a clone of this {@code TimeZone}
773      */
clone()774     public Object clone()
775     {
776         try {
777             return super.clone();
778         } catch (CloneNotSupportedException e) {
779             throw new InternalError(e);
780         }
781     }
782 
783     /**
784      * The null constant as a TimeZone.
785      */
786     static final TimeZone NO_TIMEZONE = null;
787 
788     // =======================privates===============================
789 
790     /**
791      * The string identifier of this {@code TimeZone}.  This is a
792      * programmatic identifier used internally to look up {@code TimeZone}
793      * objects from the system table and also to map them to their localized
794      * display names.  {@code ID} values are unique in the system
795      * table but may not be for dynamically created zones.
796      * @serial
797      */
798     private String           ID;
799     private static volatile TimeZone defaultTimeZone;
800 }
801