1 /*
2 * Copyright (c) 2000, 2013, 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 package sun.util.calendar;
27
28 import java.io.IOException;
29 import java.io.ObjectInputStream;
30 import java.lang.ref.SoftReference;
31 import java.security.AccessController;
32 import java.util.ArrayList;
33 import java.util.Arrays;
34 import java.util.Date;
35 import java.util.List;
36 import java.util.Locale;
37 import java.util.Map;
38 import java.util.Set;
39 import java.util.SimpleTimeZone;
40 import java.util.TimeZone;
41
42 /**
43 * <code>ZoneInfo</code> is an implementation subclass of {@link
44 * java.util.TimeZone TimeZone} that represents GMT offsets and
45 * daylight saving time transitions of a time zone.
46 * <p>
47 * The daylight saving time transitions are described in the {@link
48 * #transitions transitions} table consisting of a chronological
49 * sequence of transitions of GMT offset and/or daylight saving time
50 * changes. Since all transitions are represented in UTC, in theory,
51 * <code>ZoneInfo</code> can be used with any calendar systems except
52 * for the {@link #getOffset(int,int,int,int,int,int) getOffset}
53 * method that takes Gregorian calendar date fields.
54 * <p>
55 * This table covers transitions from 1900 until 2037 (as of version
56 * 1.4), Before 1900, it assumes that there was no daylight saving
57 * time and the <code>getOffset</code> methods always return the
58 * {@link #getRawOffset} value. No Local Mean Time is supported. If a
59 * specified date is beyond the transition table and this time zone is
60 * supposed to observe daylight saving time in 2037, it delegates
61 * operations to a {@link java.util.SimpleTimeZone SimpleTimeZone}
62 * object created using the daylight saving time schedule as of 2037.
63 * <p>
64 * The date items, transitions, GMT offset(s), etc. are read from a database
65 * file. See {@link ZoneInfoFile} for details.
66 * @see java.util.SimpleTimeZone
67 * @since 1.4
68 */
69
70 public class ZoneInfo extends TimeZone {
71
72 private static final int UTC_TIME = 0;
73 private static final int STANDARD_TIME = 1;
74 private static final int WALL_TIME = 2;
75
76 private static final long OFFSET_MASK = 0x0fL;
77 private static final long DST_MASK = 0xf0L;
78 private static final int DST_NSHIFT = 4;
79 // this bit field is reserved for abbreviation support
80 private static final long ABBR_MASK = 0xf00L;
81 private static final int TRANSITION_NSHIFT = 12;
82
83 private static final CalendarSystem gcal = CalendarSystem.getGregorianCalendar();
84
85 /**
86 * The raw GMT offset in milliseconds between this zone and GMT.
87 * Negative offsets are to the west of Greenwich. To obtain local
88 * <em>standard</em> time, add the offset to GMT time.
89 * @serial
90 */
91 private int rawOffset;
92
93 /**
94 * Difference in milliseconds from the original GMT offset in case
95 * the raw offset value has been modified by calling {@link
96 * #setRawOffset}. The initial value is 0.
97 * @serial
98 */
99 private int rawOffsetDiff = 0;
100
101 /**
102 * A CRC32 value of all pairs of transition time (in milliseconds
103 * in <code>long</code>) in local time and its GMT offset (in
104 * seconds in <code>int</code>) in the chronological order. Byte
105 * values of each <code>long</code> and <code>int</code> are taken
106 * in the big endian order (i.e., MSB to LSB).
107 * @serial
108 */
109 private int checksum;
110
111 /**
112 * The amount of time in milliseconds saved during daylight saving
113 * time. If <code>useDaylight</code> is false, this value is 0.
114 * @serial
115 */
116 private int dstSavings;
117
118 /**
119 * This array describes transitions of GMT offsets of this time
120 * zone, including both raw offset changes and daylight saving
121 * time changes.
122 * A long integer consists of four bit fields.
123 * <ul>
124 * <li>The most significant 52-bit field represents transition
125 * time in milliseconds from Gregorian January 1 1970, 00:00:00
126 * GMT.</li>
127 * <li>The next 4-bit field is reserved and must be 0.</li>
128 * <li>The next 4-bit field is an index value to {@link #offsets
129 * offsets[]} for the amount of daylight saving at the
130 * transition. If this value is zero, it means that no daylight
131 * saving, not the index value zero.</li>
132 * <li>The least significant 4-bit field is an index value to
133 * {@link #offsets offsets[]} for <em>total</em> GMT offset at the
134 * transition.</li>
135 * </ul>
136 * If this time zone doesn't observe daylight saving time and has
137 * never changed any GMT offsets in the past, this value is null.
138 * @serial
139 */
140 private long[] transitions;
141
142 /**
143 * This array holds all unique offset values in
144 * milliseconds. Index values to this array are stored in the
145 * transitions array elements.
146 * @serial
147 */
148 private int[] offsets;
149
150 /**
151 * SimpleTimeZone parameter values. It has to have either 8 for
152 * {@link java.util.SimpleTimeZone#SimpleTimeZone(int, String,
153 * int, int , int , int , int , int , int , int , int) the
154 * 11-argument SimpleTimeZone constructor} or 10 for {@link
155 * java.util.SimpleTimeZone#SimpleTimeZone(int, String, int, int,
156 * int , int , int , int , int , int , int, int, int) the
157 * 13-argument SimpleTimeZone constructor} parameters.
158 * @serial
159 */
160 private int[] simpleTimeZoneParams;
161
162 /**
163 * True if the raw GMT offset value would change after the time
164 * zone data has been generated; false, otherwise. The default
165 * value is false.
166 * @serial
167 */
168 private boolean willGMTOffsetChange = false;
169
170 /**
171 * True if the object has been modified after its instantiation.
172 */
173 transient private boolean dirty = false;
174
175 private static final long serialVersionUID = 2653134537216586139L;
176
177 /**
178 * A constructor.
179 */
180 public ZoneInfo() {
181 }
182
183 /**
184 * A Constructor for CustomID.
185 */
186 public ZoneInfo(String ID, int rawOffset) {
187 this(ID, rawOffset, 0, 0, null, null, null, false);
188 }
189
190 /**
191 * Constructs a ZoneInfo instance.
192 *
193 * @param ID time zone name
194 * @param rawOffset GMT offset in milliseconds
195 * @param dstSavings daylight saving value in milliseconds or 0
196 * (zero) if this time zone doesn't observe Daylight Saving Time.
197 * @param checksum CRC32 value with all transitions table entry
198 * values
199 * @param transitions transition table
200 * @param offsets offset value table
201 * @param simpleTimeZoneParams parameter values for constructing
202 * SimpleTimeZone
203 * @param willGMTOffsetChange the value of willGMTOffsetChange
204 */
205 ZoneInfo(String ID,
206 int rawOffset,
207 int dstSavings,
208 int checksum,
209 long[] transitions,
210 int[] offsets,
211 int[] simpleTimeZoneParams,
212 boolean willGMTOffsetChange) {
213 setID(ID);
214 this.rawOffset = rawOffset;
215 this.dstSavings = dstSavings;
216 this.checksum = checksum;
217 this.transitions = transitions;
218 this.offsets = offsets;
219 this.simpleTimeZoneParams = simpleTimeZoneParams;
220 this.willGMTOffsetChange = willGMTOffsetChange;
221 }
222
223 /**
224 * Returns the difference in milliseconds between local time and UTC
225 * of given time, taking into account both the raw offset and the
226 * effect of daylight savings.
227 *
228 * @param date the milliseconds in UTC
229 * @return the milliseconds to add to UTC to get local wall time
230 */
231 public int getOffset(long date) {
232 return getOffsets(date, null, UTC_TIME);
233 }
234
235 public int getOffsets(long utc, int[] offsets) {
236 return getOffsets(utc, offsets, UTC_TIME);
237 }
238
239 public int getOffsetsByStandard(long standard, int[] offsets) {
240 return getOffsets(standard, offsets, STANDARD_TIME);
241 }
242
243 public int getOffsetsByWall(long wall, int[] offsets) {
244 return getOffsets(wall, offsets, WALL_TIME);
245 }
246
247 private int getOffsets(long date, int[] offsets, int type) {
248 // if dst is never observed, there is no transition.
249 if (transitions == null) {
250 int offset = getLastRawOffset();
251 if (offsets != null) {
252 offsets[0] = offset;
253 offsets[1] = 0;
254 }
255 return offset;
256 }
257
258 date -= rawOffsetDiff;
259 int index = getTransitionIndex(date, type);
260
261 // prior to the transition table, returns the raw offset.
262 // FIXME: should support LMT.
263 if (index < 0) {
264 int offset = getLastRawOffset();
265 if (offsets != null) {
266 offsets[0] = offset;
267 offsets[1] = 0;
268 }
269 return offset;
270 }
271
272 if (index < transitions.length) {
273 long val = transitions[index];
274 int offset = this.offsets[(int)(val & OFFSET_MASK)] + rawOffsetDiff;
275 if (offsets != null) {
276 int dst = (int)((val >>> DST_NSHIFT) & 0xfL);
277 int save = (dst == 0) ? 0 : this.offsets[dst];
278 offsets[0] = offset - save;
279 offsets[1] = save;
280 }
281 return offset;
282 }
283
284 // beyond the transitions, delegate to SimpleTimeZone if there
285 // is a rule; otherwise, return rawOffset.
286 SimpleTimeZone tz = getLastRule();
287 if (tz != null) {
288 int rawoffset = tz.getRawOffset();
289 long msec = date;
290 if (type != UTC_TIME) {
291 msec -= rawOffset;
292 }
293 int dstoffset = tz.getOffset(msec) - rawOffset;
294
295 // Check if it's in a standard-to-daylight transition.
296 if (dstoffset > 0 && tz.getOffset(msec - dstoffset) == rawoffset) {
297 dstoffset = 0;
298 }
299
300 if (offsets != null) {
301 offsets[0] = rawoffset;
302 offsets[1] = dstoffset;
303 }
304 return rawoffset + dstoffset;
305 }
306 int offset = getLastRawOffset();
307 if (offsets != null) {
308 offsets[0] = offset;
309 offsets[1] = 0;
310 }
311 return offset;
312 }
313
314 private int getTransitionIndex(long date, int type) {
315 int low = 0;
316 int high = transitions.length - 1;
317
318 while (low <= high) {
319 int mid = (low + high) / 2;
320 long val = transitions[mid];
321 long midVal = val >> TRANSITION_NSHIFT; // sign extended
322 if (type != UTC_TIME) {
323 midVal += offsets[(int)(val & OFFSET_MASK)]; // wall time
324 }
325 if (type == STANDARD_TIME) {
326 int dstIndex = (int)((val >>> DST_NSHIFT) & 0xfL);
327 if (dstIndex != 0) {
328 midVal -= offsets[dstIndex]; // make it standard time
329 }
330 }
331
332 if (midVal < date) {
333 low = mid + 1;
334 } else if (midVal > date) {
335 high = mid - 1;
336 } else {
337 return mid;
338 }
339 }
340
341 // if beyond the transitions, returns that index.
342 if (low >= transitions.length) {
343 return low;
344 }
345 return low - 1;
346 }
347
348 /**
349 * Returns the difference in milliseconds between local time and
350 * UTC, taking into account both the raw offset and the effect of
351 * daylight savings, for the specified date and time. This method
352 * assumes that the start and end month are distinct. This method
353 * assumes a Gregorian calendar for calculations.
354 * <p>
355 * <em>Note: In general, clients should use
356 * {@link Calendar#ZONE_OFFSET Calendar.get(ZONE_OFFSET)} +
357 * {@link Calendar#DST_OFFSET Calendar.get(DST_OFFSET)}
358 * instead of calling this method.</em>
359 *
360 * @param era The era of the given date. The value must be either
361 * GregorianCalendar.AD or GregorianCalendar.BC.
362 * @param year The year in the given date.
363 * @param month The month in the given date. Month is 0-based. e.g.,
364 * 0 for January.
365 * @param day The day-in-month of the given date.
366 * @param dayOfWeek The day-of-week of the given date.
367 * @param millis The milliseconds in day in <em>standard</em> local time.
368 * @return The milliseconds to add to UTC to get local time.
369 */
370 public int getOffset(int era, int year, int month, int day,
371 int dayOfWeek, int milliseconds) {
372 if (milliseconds < 0 || milliseconds >= AbstractCalendar.DAY_IN_MILLIS) {
373 throw new IllegalArgumentException();
374 }
375
376 if (era == java.util.GregorianCalendar.BC) { // BC
377 year = 1 - year;
378 } else if (era != java.util.GregorianCalendar.AD) {
379 throw new IllegalArgumentException();
380 }
381
382 CalendarDate date = gcal.newCalendarDate(null);
383 date.setDate(year, month + 1, day);
384 if (gcal.validate(date) == false) {
385 throw new IllegalArgumentException();
386 }
387
388 // bug-for-bug compatible argument checking
389 if (dayOfWeek < java.util.GregorianCalendar.SUNDAY
390 || dayOfWeek > java.util.GregorianCalendar.SATURDAY) {
391 throw new IllegalArgumentException();
392 }
393
394 if (transitions == null) {
395 return getLastRawOffset();
396 }
397
398 long dateInMillis = gcal.getTime(date) + milliseconds;
399 dateInMillis -= (long) rawOffset; // make it UTC
400 return getOffsets(dateInMillis, null, UTC_TIME);
401 }
402
403 /**
404 * Sets the base time zone offset from GMT. This operation
405 * modifies all the transitions of this ZoneInfo object, including
406 * historical ones, if applicable.
407 *
408 * @param offsetMillis the base time zone offset to GMT.
409 * @see getRawOffset
410 */
411 public synchronized void setRawOffset(int offsetMillis) {
412 if (offsetMillis == rawOffset + rawOffsetDiff) {
413 return;
414 }
415 rawOffsetDiff = offsetMillis - rawOffset;
416 if (lastRule != null) {
417 lastRule.setRawOffset(offsetMillis);
418 }
419 dirty = true;
420 }
421
422 /**
423 * Returns the GMT offset of the current date. This GMT offset
424 * value is not modified during Daylight Saving Time.
425 *
426 * @return the GMT offset value in milliseconds to add to UTC time
427 * to get local standard time
428 */
429 public int getRawOffset() {
430 if (!willGMTOffsetChange) {
431 return rawOffset + rawOffsetDiff;
432 }
433
434 int[] offsets = new int[2];
435 getOffsets(System.currentTimeMillis(), offsets, UTC_TIME);
436 return offsets[0];
437 }
438
439 public boolean isDirty() {
440 return dirty;
441 }
442
443 private int getLastRawOffset() {
444 return rawOffset + rawOffsetDiff;
445 }
446
447 /**
448 * Queries if this time zone uses Daylight Saving Time in the last known rule.
449 */
450 public boolean useDaylightTime() {
451 return (simpleTimeZoneParams != null);
452 }
453
454 @Override
455 public boolean observesDaylightTime() {
456 if (simpleTimeZoneParams != null) {
457 return true;
458 }
459 if (transitions == null) {
460 return false;
461 }
462
463 // Look up the transition table to see if it's in DST right
464 // now or if there's any standard-to-daylight transition at
465 // any future.
466 long utc = System.currentTimeMillis() - rawOffsetDiff;
467 int index = getTransitionIndex(utc, UTC_TIME);
468
469 // before transitions in the transition table
470 if (index < 0) {
471 return false;
472 }
473
474 // the time is in the table range.
475 for (int i = index; i < transitions.length; i++) {
476 if ((transitions[i] & DST_MASK) != 0) {
477 return true;
478 }
479 }
480 // No further DST is observed.
481 return false;
482 }
483
484 /**
485 * Queries if the specified date is in Daylight Saving Time.
486 */
487 public boolean inDaylightTime(Date date) {
488 if (date == null) {
489 throw new NullPointerException();
490 }
491
492 if (transitions == null) {
493 return false;
494 }
495
496 long utc = date.getTime() - rawOffsetDiff;
497 int index = getTransitionIndex(utc, UTC_TIME);
498
499 // before transitions in the transition table
500 if (index < 0) {
501 return false;
502 }
503
504 // the time is in the table range.
505 if (index < transitions.length) {
506 return (transitions[index] & DST_MASK) != 0;
507 }
508
509 // beyond the transition table
510 SimpleTimeZone tz = getLastRule();
511 if (tz != null) {
512 return tz.inDaylightTime(date);
513 }
514 return false;
515 }
516
517 /**
518 * Returns the amount of time in milliseconds that the clock is advanced
519 * during daylight saving time is in effect in its last daylight saving time rule.
520 *
521 * @return the number of milliseconds the time is advanced with respect to
522 * standard time when daylight saving time is in effect.
523 */
524 public int getDSTSavings() {
525 return dstSavings;
526 }
527
528 // /**
529 // * @return the last year in the transition table or -1 if this
530 // * time zone doesn't observe any daylight saving time.
531 // */
532 // public int getMaxTransitionYear() {
533 // if (transitions == null) {
534 // return -1;
535 // }
536 // long val = transitions[transitions.length - 1];
537 // int offset = this.offsets[(int)(val & OFFSET_MASK)] + rawOffsetDiff;
538 // val = (val >> TRANSITION_NSHIFT) + offset;
539 // CalendarDate lastDate = Gregorian.getCalendarDate(val);
540 // return lastDate.getYear();
541 // }
542
543 /**
544 * Returns a string representation of this time zone.
545 * @return the string
546 */
547 public String toString() {
548 return getClass().getName() +
549 "[id=\"" + getID() + "\"" +
550 ",offset=" + getLastRawOffset() +
551 ",dstSavings=" + dstSavings +
552 ",useDaylight=" + useDaylightTime() +
553 ",transitions=" + ((transitions != null) ? transitions.length : 0) +
554 ",lastRule=" + (lastRule == null ? getLastRuleInstance() : lastRule) +
555 "]";
556 }
557
558 /**
559 * Gets all available IDs supported in the Java run-time.
560 *
561 * @return an array of time zone IDs.
562 */
563 public static String[] getAvailableIDs() {
564 return ZoneInfoFile.getZoneIds();
565 }
566
567 /**
568 * Gets all available IDs that have the same value as the
569 * specified raw GMT offset.
570 *
571 * @param rawOffset the GMT offset in milliseconds. This
572 * value should not include any daylight saving time.
573 *
574 * @return an array of time zone IDs.
575 */
576 public static String[] getAvailableIDs(int rawOffset) {
577 return ZoneInfoFile.getZoneIds(rawOffset);
578 }
579
580 /**
581 * Gets the ZoneInfo for the given ID.
582 *
583 * @param ID the ID for a ZoneInfo. See TimeZone for detail.
584 *
585 * @return the specified ZoneInfo object, or null if there is no
586 * time zone of the ID.
587 */
588 public static TimeZone getTimeZone(String ID) {
589 return ZoneInfoFile.getZoneInfo(ID);
590 }
591
592 private transient SimpleTimeZone lastRule;
593
594 /**
595 * Returns a SimpleTimeZone object representing the last GMT
596 * offset and DST schedule or null if this time zone doesn't
597 * observe DST.
598 */
599 private synchronized SimpleTimeZone getLastRule() {
600 if (lastRule == null) {
601 lastRule = getLastRuleInstance();
602 }
603 return lastRule;
604 }
605
606 /**
607 * Returns a SimpleTimeZone object that represents the last
608 * known daylight saving time rules.
609 *
610 * @return a SimpleTimeZone object or null if this time zone
611 * doesn't observe DST.
612 */
613 public SimpleTimeZone getLastRuleInstance() {
614 if (simpleTimeZoneParams == null) {
615 return null;
616 }
617 if (simpleTimeZoneParams.length == 10) {
618 return new SimpleTimeZone(getLastRawOffset(), getID(),
619 simpleTimeZoneParams[0],
620 simpleTimeZoneParams[1],
621 simpleTimeZoneParams[2],
622 simpleTimeZoneParams[3],
623 simpleTimeZoneParams[4],
624 simpleTimeZoneParams[5],
625 simpleTimeZoneParams[6],
626 simpleTimeZoneParams[7],
627 simpleTimeZoneParams[8],
628 simpleTimeZoneParams[9],
629 dstSavings);
630 }
631 return new SimpleTimeZone(getLastRawOffset(), getID(),
632 simpleTimeZoneParams[0],
633 simpleTimeZoneParams[1],
634 simpleTimeZoneParams[2],
635 simpleTimeZoneParams[3],
636 simpleTimeZoneParams[4],
637 simpleTimeZoneParams[5],
638 simpleTimeZoneParams[6],
639 simpleTimeZoneParams[7],
640 dstSavings);
641 }
642
643 /**
644 * Returns a copy of this <code>ZoneInfo</code>.
645 */
646 public Object clone() {
647 ZoneInfo zi = (ZoneInfo) super.clone();
648 zi.lastRule = null;
649 return zi;
650 }
651
652 /**
653 * Returns a hash code value calculated from the GMT offset and
654 * transitions.
655 * @return a hash code of this time zone
656 */
657 public int hashCode() {
658 return getLastRawOffset() ^ checksum;
659 }
660
661 /**
662 * Compares the equity of two ZoneInfo objects.
663 *
664 * @param obj the object to be compared with
665 * @return true if given object is same as this ZoneInfo object,
666 * false otherwise.
667 */
668 public boolean equals(Object obj) {
669 if (this == obj) {
670 return true;
671 }
672 if (!(obj instanceof ZoneInfo)) {
673 return false;
674 }
675 ZoneInfo that = (ZoneInfo) obj;
676 return (getID().equals(that.getID())
677 && (getLastRawOffset() == that.getLastRawOffset())
678 && (checksum == that.checksum));
679 }
680
681 /**
682 * Returns true if this zone has the same raw GMT offset value and
683 * transition table as another zone info. If the specified
684 * TimeZone object is not a ZoneInfo instance, this method returns
685 * true if the specified TimeZone object has the same raw GMT
686 * offset value with no daylight saving time.
687 *
688 * @param other the ZoneInfo object to be compared with
689 * @return true if the given <code>TimeZone</code> has the same
690 * GMT offset and transition information; false, otherwise.
691 */
692 public boolean hasSameRules(TimeZone other) {
693 if (this == other) {
694 return true;
695 }
696 if (other == null) {
697 return false;
698 }
699 if (!(other instanceof ZoneInfo)) {
700 if (getRawOffset() != other.getRawOffset()) {
701 return false;
702 }
703 // if both have the same raw offset and neither observes
704 // DST, they have the same rule.
705 if ((transitions == null)
706 && (useDaylightTime() == false)
707 && (other.useDaylightTime() == false)) {
708 return true;
709 }
710 return false;
711 }
712 if (getLastRawOffset() != ((ZoneInfo)other).getLastRawOffset()) {
713 return false;
714 }
715 return (checksum == ((ZoneInfo)other).checksum);
716 }
717
718 /**
719 * Returns a Map from alias time zone IDs to their standard
720 * time zone IDs.
721 *
722 * @return the Map that holds the mappings from alias time zone IDs
723 * to their standard time zone IDs, or null if
724 * <code>ZoneInfoMappings</code> file is not available.
725 */
726 public static Map<String, String> getAliasTable() {
727 return ZoneInfoFile.getAliasMap();
728 }
729
730 private void readObject(ObjectInputStream stream)
731 throws IOException, ClassNotFoundException {
732 stream.defaultReadObject();
733 // We don't know how this object from 1.4.x or earlier has
734 // been mutated. So it should always be marked as `dirty'.
735 dirty = true;
736 }
737 }