1 /*
2 * Copyright (c) 2012, 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 /*
27 * This file is available under and governed by the GNU General Public
28 * License version 2 only, as published by the Free Software Foundation.
29 * However, the following notice accompanied the original version of this
30 * file:
31 *
32 * Copyright (c) 2009-2012, Stephen Colebourne & Michael Nascimento Santos
33 *
34 * All rights reserved.
35 *
36 * Redistribution and use in source and binary forms, with or without
37 * modification, are permitted provided that the following conditions are met:
38 *
39 * * Redistributions of source code must retain the above copyright notice,
40 * this list of conditions and the following disclaimer.
41 *
42 * * Redistributions in binary form must reproduce the above copyright notice,
43 * this list of conditions and the following disclaimer in the documentation
44 * and/or other materials provided with the distribution.
45 *
46 * * Neither the name of JSR-310 nor the names of its contributors
47 * may be used to endorse or promote products derived from this software
48 * without specific prior written permission.
49 *
50 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
51 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
52 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
53 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
54 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
55 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
56 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
57 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
58 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
59 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
60 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
61 */
62 package java.time.zone;
63
64 import static java.time.temporal.TemporalAdjusters.nextOrSame;
65 import static java.time.temporal.TemporalAdjusters.previousOrSame;
66
67 import java.io.DataInput;
68 import java.io.DataOutput;
69 import java.io.IOException;
70 import java.io.InvalidObjectException;
71 import java.io.ObjectInputStream;
72 import java.io.Serializable;
73 import java.time.DayOfWeek;
74 import java.time.LocalDate;
75 import java.time.LocalDateTime;
76 import java.time.LocalTime;
77 import java.time.Month;
78 import java.time.ZoneOffset;
79 import java.time.chrono.IsoChronology;
80 import java.util.Objects;
81
82 /**
83 * A rule expressing how to create a transition.
84 * <p>
85 * This class allows rules for identifying future transitions to be expressed.
86 * A rule might be written in many forms:
87 * <ul>
88 * <li>the 16th March
89 * <li>the Sunday on or after the 16th March
90 * <li>the Sunday on or before the 16th March
91 * <li>the last Sunday in February
92 * </ul>
93 * These different rule types can be expressed and queried.
94 *
95 * @implSpec
96 * This class is immutable and thread-safe.
97 *
98 * @since 1.8
99 */
100 public final class ZoneOffsetTransitionRule implements Serializable {
101
102 /**
103 * Serialization version.
104 */
105 private static final long serialVersionUID = 6889046316657758795L;
106
107 /**
108 * The month of the month-day of the first day of the cutover week.
109 * The actual date will be adjusted by the dowChange field.
110 */
111 private final Month month;
112 /**
113 * The day-of-month of the month-day of the cutover week.
114 * If positive, it is the start of the week where the cutover can occur.
115 * If negative, it represents the end of the week where cutover can occur.
116 * The value is the number of days from the end of the month, such that
117 * {@code -1} is the last day of the month, {@code -2} is the second
118 * to last day, and so on.
119 */
120 private final byte dom;
121 /**
122 * The cutover day-of-week, null to retain the day-of-month.
123 */
124 private final DayOfWeek dow;
125 /**
126 * The cutover time in the 'before' offset.
127 */
128 private final LocalTime time;
129 /**
130 * Whether the cutover time is midnight at the end of day.
131 */
132 private final boolean timeEndOfDay;
133 /**
134 * The definition of how the local time should be interpreted.
135 */
136 private final TimeDefinition timeDefinition;
137 /**
138 * The standard offset at the cutover.
139 */
140 private final ZoneOffset standardOffset;
141 /**
142 * The offset before the cutover.
143 */
144 private final ZoneOffset offsetBefore;
145 /**
146 * The offset after the cutover.
147 */
148 private final ZoneOffset offsetAfter;
149
150 /**
151 * Obtains an instance defining the yearly rule to create transitions between two offsets.
152 * <p>
153 * Applications should normally obtain an instance from {@link ZoneRules}.
154 * This factory is only intended for use when creating {@link ZoneRules}.
155 *
156 * @param month the month of the month-day of the first day of the cutover week, not null
157 * @param dayOfMonthIndicator the day of the month-day of the cutover week, positive if the week is that
158 * day or later, negative if the week is that day or earlier, counting from the last day of the month,
159 * from -28 to 31 excluding 0
160 * @param dayOfWeek the required day-of-week, null if the month-day should not be changed
161 * @param time the cutover time in the 'before' offset, not null
162 * @param timeEndOfDay whether the time is midnight at the end of day
163 * @param timeDefnition how to interpret the cutover
164 * @param standardOffset the standard offset in force at the cutover, not null
165 * @param offsetBefore the offset before the cutover, not null
166 * @param offsetAfter the offset after the cutover, not null
167 * @return the rule, not null
168 * @throws IllegalArgumentException if the day of month indicator is invalid
169 * @throws IllegalArgumentException if the end of day flag is true when the time is not midnight
170 * @throws IllegalArgumentException if {@code time.getNano()} returns non-zero value
171 */
172 public static ZoneOffsetTransitionRule of(
173 Month month,
174 int dayOfMonthIndicator,
175 DayOfWeek dayOfWeek,
176 LocalTime time,
177 boolean timeEndOfDay,
178 TimeDefinition timeDefnition,
179 ZoneOffset standardOffset,
180 ZoneOffset offsetBefore,
181 ZoneOffset offsetAfter) {
182 Objects.requireNonNull(month, "month");
183 Objects.requireNonNull(time, "time");
184 Objects.requireNonNull(timeDefnition, "timeDefnition");
185 Objects.requireNonNull(standardOffset, "standardOffset");
186 Objects.requireNonNull(offsetBefore, "offsetBefore");
187 Objects.requireNonNull(offsetAfter, "offsetAfter");
188 if (dayOfMonthIndicator < -28 || dayOfMonthIndicator > 31 || dayOfMonthIndicator == 0) {
189 throw new IllegalArgumentException("Day of month indicator must be between -28 and 31 inclusive excluding zero");
190 }
191 if (timeEndOfDay && time.equals(LocalTime.MIDNIGHT) == false) {
192 throw new IllegalArgumentException("Time must be midnight when end of day flag is true");
193 }
194 if (time.getNano() != 0) {
195 throw new IllegalArgumentException("Time's nano-of-second must be zero");
196 }
197 return new ZoneOffsetTransitionRule(month, dayOfMonthIndicator, dayOfWeek, time, timeEndOfDay, timeDefnition, standardOffset, offsetBefore, offsetAfter);
198 }
199
200 /**
201 * Creates an instance defining the yearly rule to create transitions between two offsets.
202 *
203 * @param month the month of the month-day of the first day of the cutover week, not null
204 * @param dayOfMonthIndicator the day of the month-day of the cutover week, positive if the week is that
205 * day or later, negative if the week is that day or earlier, counting from the last day of the month,
206 * from -28 to 31 excluding 0
207 * @param dayOfWeek the required day-of-week, null if the month-day should not be changed
208 * @param time the cutover time in the 'before' offset, not null
209 * @param timeEndOfDay whether the time is midnight at the end of day
210 * @param timeDefnition how to interpret the cutover
211 * @param standardOffset the standard offset in force at the cutover, not null
212 * @param offsetBefore the offset before the cutover, not null
213 * @param offsetAfter the offset after the cutover, not null
214 * @throws IllegalArgumentException if the day of month indicator is invalid
215 * @throws IllegalArgumentException if the end of day flag is true when the time is not midnight
216 */
217 ZoneOffsetTransitionRule(
218 Month month,
219 int dayOfMonthIndicator,
220 DayOfWeek dayOfWeek,
221 LocalTime time,
222 boolean timeEndOfDay,
223 TimeDefinition timeDefnition,
224 ZoneOffset standardOffset,
225 ZoneOffset offsetBefore,
226 ZoneOffset offsetAfter) {
227 this.month = month;
228 this.dom = (byte) dayOfMonthIndicator;
229 this.dow = dayOfWeek;
230 this.time = time;
231 this.timeEndOfDay = timeEndOfDay;
232 this.timeDefinition = timeDefnition;
233 this.standardOffset = standardOffset;
234 this.offsetBefore = offsetBefore;
235 this.offsetAfter = offsetAfter;
236 }
237
238 //-----------------------------------------------------------------------
239 /**
240 * Defend against malicious streams.
241 *
242 * @param s the stream to read
243 * @throws InvalidObjectException always
244 */
245 private void readObject(ObjectInputStream s) throws InvalidObjectException {
246 throw new InvalidObjectException("Deserialization via serialization delegate");
247 }
248
249 /**
250 * Writes the object using a
251 * <a href="../../../serialized-form.html#java.time.zone.Ser">dedicated serialized form</a>.
252 * @serialData
253 * Refer to the serialized form of
254 * <a href="../../../serialized-form.html#java.time.zone.ZoneRules">ZoneRules.writeReplace</a>
255 * for the encoding of epoch seconds and offsets.
256 * <pre style="font-size:1.0em">{@code
257 *
258 * out.writeByte(3); // identifies a ZoneOffsetTransition
259 * final int timeSecs = (timeEndOfDay ? 86400 : time.toSecondOfDay());
260 * final int stdOffset = standardOffset.getTotalSeconds();
261 * final int beforeDiff = offsetBefore.getTotalSeconds() - stdOffset;
262 * final int afterDiff = offsetAfter.getTotalSeconds() - stdOffset;
263 * final int timeByte = (timeSecs % 3600 == 0 ? (timeEndOfDay ? 24 : time.getHour()) : 31);
264 * final int stdOffsetByte = (stdOffset % 900 == 0 ? stdOffset / 900 + 128 : 255);
265 * final int beforeByte = (beforeDiff == 0 || beforeDiff == 1800 || beforeDiff == 3600 ? beforeDiff / 1800 : 3);
266 * final int afterByte = (afterDiff == 0 || afterDiff == 1800 || afterDiff == 3600 ? afterDiff / 1800 : 3);
267 * final int dowByte = (dow == null ? 0 : dow.getValue());
268 * int b = (month.getValue() << 28) + // 4 bits
269 * ((dom + 32) << 22) + // 6 bits
270 * (dowByte << 19) + // 3 bits
271 * (timeByte << 14) + // 5 bits
272 * (timeDefinition.ordinal() << 12) + // 2 bits
273 * (stdOffsetByte << 4) + // 8 bits
274 * (beforeByte << 2) + // 2 bits
275 * afterByte; // 2 bits
276 * out.writeInt(b);
277 * if (timeByte == 31) {
278 * out.writeInt(timeSecs);
279 * }
280 * if (stdOffsetByte == 255) {
281 * out.writeInt(stdOffset);
282 * }
283 * if (beforeByte == 3) {
284 * out.writeInt(offsetBefore.getTotalSeconds());
285 * }
286 * if (afterByte == 3) {
287 * out.writeInt(offsetAfter.getTotalSeconds());
288 * }
289 * }
290 * </pre>
291 *
292 * @return the replacing object, not null
293 */
294 private Object writeReplace() {
295 return new Ser(Ser.ZOTRULE, this);
296 }
297
298 /**
299 * Writes the state to the stream.
300 *
301 * @param out the output stream, not null
302 * @throws IOException if an error occurs
303 */
304 void writeExternal(DataOutput out) throws IOException {
305 final int timeSecs = (timeEndOfDay ? 86400 : time.toSecondOfDay());
306 final int stdOffset = standardOffset.getTotalSeconds();
307 final int beforeDiff = offsetBefore.getTotalSeconds() - stdOffset;
308 final int afterDiff = offsetAfter.getTotalSeconds() - stdOffset;
309 final int timeByte = (timeSecs % 3600 == 0 ? (timeEndOfDay ? 24 : time.getHour()) : 31);
310 final int stdOffsetByte = (stdOffset % 900 == 0 ? stdOffset / 900 + 128 : 255);
311 final int beforeByte = (beforeDiff == 0 || beforeDiff == 1800 || beforeDiff == 3600 ? beforeDiff / 1800 : 3);
312 final int afterByte = (afterDiff == 0 || afterDiff == 1800 || afterDiff == 3600 ? afterDiff / 1800 : 3);
313 final int dowByte = (dow == null ? 0 : dow.getValue());
314 int b = (month.getValue() << 28) + // 4 bits
315 ((dom + 32) << 22) + // 6 bits
316 (dowByte << 19) + // 3 bits
317 (timeByte << 14) + // 5 bits
318 (timeDefinition.ordinal() << 12) + // 2 bits
319 (stdOffsetByte << 4) + // 8 bits
320 (beforeByte << 2) + // 2 bits
321 afterByte; // 2 bits
322 out.writeInt(b);
323 if (timeByte == 31) {
324 out.writeInt(timeSecs);
325 }
326 if (stdOffsetByte == 255) {
327 out.writeInt(stdOffset);
328 }
329 if (beforeByte == 3) {
330 out.writeInt(offsetBefore.getTotalSeconds());
331 }
332 if (afterByte == 3) {
333 out.writeInt(offsetAfter.getTotalSeconds());
334 }
335 }
336
337 /**
338 * Reads the state from the stream.
339 *
340 * @param in the input stream, not null
341 * @return the created object, not null
342 * @throws IOException if an error occurs
343 */
344 static ZoneOffsetTransitionRule readExternal(DataInput in) throws IOException {
345 int data = in.readInt();
346 Month month = Month.of(data >>> 28);
347 int dom = ((data & (63 << 22)) >>> 22) - 32;
348 int dowByte = (data & (7 << 19)) >>> 19;
349 DayOfWeek dow = dowByte == 0 ? null : DayOfWeek.of(dowByte);
350 int timeByte = (data & (31 << 14)) >>> 14;
351 TimeDefinition defn = TimeDefinition.values()[(data & (3 << 12)) >>> 12];
352 int stdByte = (data & (255 << 4)) >>> 4;
353 int beforeByte = (data & (3 << 2)) >>> 2;
354 int afterByte = (data & 3);
355 LocalTime time = (timeByte == 31 ? LocalTime.ofSecondOfDay(in.readInt()) : LocalTime.of(timeByte % 24, 0));
356 ZoneOffset std = (stdByte == 255 ? ZoneOffset.ofTotalSeconds(in.readInt()) : ZoneOffset.ofTotalSeconds((stdByte - 128) * 900));
357 ZoneOffset before = (beforeByte == 3 ? ZoneOffset.ofTotalSeconds(in.readInt()) : ZoneOffset.ofTotalSeconds(std.getTotalSeconds() + beforeByte * 1800));
358 ZoneOffset after = (afterByte == 3 ? ZoneOffset.ofTotalSeconds(in.readInt()) : ZoneOffset.ofTotalSeconds(std.getTotalSeconds() + afterByte * 1800));
359 return ZoneOffsetTransitionRule.of(month, dom, dow, time, timeByte == 24, defn, std, before, after);
360 }
361
362 //-----------------------------------------------------------------------
363 /**
364 * Gets the month of the transition.
365 * <p>
366 * If the rule defines an exact date then the month is the month of that date.
367 * <p>
368 * If the rule defines a week where the transition might occur, then the month
369 * if the month of either the earliest or latest possible date of the cutover.
370 *
371 * @return the month of the transition, not null
372 */
373 public Month getMonth() {
374 return month;
375 }
376
377 /**
378 * Gets the indicator of the day-of-month of the transition.
379 * <p>
380 * If the rule defines an exact date then the day is the month of that date.
381 * <p>
382 * If the rule defines a week where the transition might occur, then the day
383 * defines either the start of the end of the transition week.
384 * <p>
385 * If the value is positive, then it represents a normal day-of-month, and is the
386 * earliest possible date that the transition can be.
387 * The date may refer to 29th February which should be treated as 1st March in non-leap years.
388 * <p>
389 * If the value is negative, then it represents the number of days back from the
390 * end of the month where {@code -1} is the last day of the month.
391 * In this case, the day identified is the latest possible date that the transition can be.
392 *
393 * @return the day-of-month indicator, from -28 to 31 excluding 0
394 */
395 public int getDayOfMonthIndicator() {
396 return dom;
397 }
398
399 /**
400 * Gets the day-of-week of the transition.
401 * <p>
402 * If the rule defines an exact date then this returns null.
403 * <p>
404 * If the rule defines a week where the cutover might occur, then this method
405 * returns the day-of-week that the month-day will be adjusted to.
406 * If the day is positive then the adjustment is later.
407 * If the day is negative then the adjustment is earlier.
408 *
409 * @return the day-of-week that the transition occurs, null if the rule defines an exact date
410 */
411 public DayOfWeek getDayOfWeek() {
412 return dow;
413 }
414
415 /**
416 * Gets the local time of day of the transition which must be checked with
417 * {@link #isMidnightEndOfDay()}.
418 * <p>
419 * The time is converted into an instant using the time definition.
420 *
421 * @return the local time of day of the transition, not null
422 */
423 public LocalTime getLocalTime() {
424 return time;
425 }
426
427 /**
428 * Is the transition local time midnight at the end of day.
429 * <p>
430 * The transition may be represented as occurring at 24:00.
431 *
432 * @return whether a local time of midnight is at the start or end of the day
433 */
434 public boolean isMidnightEndOfDay() {
435 return timeEndOfDay;
436 }
437
438 /**
439 * Gets the time definition, specifying how to convert the time to an instant.
440 * <p>
441 * The local time can be converted to an instant using the standard offset,
442 * the wall offset or UTC.
443 *
444 * @return the time definition, not null
445 */
446 public TimeDefinition getTimeDefinition() {
447 return timeDefinition;
448 }
449
450 /**
451 * Gets the standard offset in force at the transition.
452 *
453 * @return the standard offset, not null
454 */
455 public ZoneOffset getStandardOffset() {
456 return standardOffset;
457 }
458
459 /**
460 * Gets the offset before the transition.
461 *
462 * @return the offset before, not null
463 */
464 public ZoneOffset getOffsetBefore() {
465 return offsetBefore;
466 }
467
468 /**
469 * Gets the offset after the transition.
470 *
471 * @return the offset after, not null
472 */
473 public ZoneOffset getOffsetAfter() {
474 return offsetAfter;
475 }
476
477 //-----------------------------------------------------------------------
478 /**
479 * Creates a transition instance for the specified year.
480 * <p>
481 * Calculations are performed using the ISO-8601 chronology.
482 *
483 * @param year the year to create a transition for, not null
484 * @return the transition instance, not null
485 */
486 public ZoneOffsetTransition createTransition(int year) {
487 LocalDate date;
488 if (dom < 0) {
489 date = LocalDate.of(year, month, month.length(IsoChronology.INSTANCE.isLeapYear(year)) + 1 + dom);
490 if (dow != null) {
491 date = date.with(previousOrSame(dow));
492 }
493 } else {
494 date = LocalDate.of(year, month, dom);
495 if (dow != null) {
496 date = date.with(nextOrSame(dow));
497 }
498 }
499 if (timeEndOfDay) {
500 date = date.plusDays(1);
501 }
502 LocalDateTime localDT = LocalDateTime.of(date, time);
503 LocalDateTime transition = timeDefinition.createDateTime(localDT, standardOffset, offsetBefore);
504 return new ZoneOffsetTransition(transition, offsetBefore, offsetAfter);
505 }
506
507 //-----------------------------------------------------------------------
508 /**
509 * Checks if this object equals another.
510 * <p>
511 * The entire state of the object is compared.
512 *
513 * @param otherRule the other object to compare to, null returns false
514 * @return true if equal
515 */
516 @Override
517 public boolean equals(Object otherRule) {
518 if (otherRule == this) {
519 return true;
520 }
521 if (otherRule instanceof ZoneOffsetTransitionRule) {
522 ZoneOffsetTransitionRule other = (ZoneOffsetTransitionRule) otherRule;
523 return month == other.month && dom == other.dom && dow == other.dow &&
524 timeDefinition == other.timeDefinition &&
525 time.equals(other.time) &&
526 timeEndOfDay == other.timeEndOfDay &&
527 standardOffset.equals(other.standardOffset) &&
528 offsetBefore.equals(other.offsetBefore) &&
529 offsetAfter.equals(other.offsetAfter);
530 }
531 return false;
532 }
533
534 /**
535 * Returns a suitable hash code.
536 *
537 * @return the hash code
538 */
539 @Override
540 public int hashCode() {
541 int hash = ((time.toSecondOfDay() + (timeEndOfDay ? 1 : 0)) << 15) +
542 (month.ordinal() << 11) + ((dom + 32) << 5) +
543 ((dow == null ? 7 : dow.ordinal()) << 2) + (timeDefinition.ordinal());
544 return hash ^ standardOffset.hashCode() ^
545 offsetBefore.hashCode() ^ offsetAfter.hashCode();
546 }
547
548 //-----------------------------------------------------------------------
549 /**
550 * Returns a string describing this object.
551 *
552 * @return a string for debugging, not null
553 */
554 @Override
555 public String toString() {
556 StringBuilder buf = new StringBuilder();
557 buf.append("TransitionRule[")
558 .append(offsetBefore.compareTo(offsetAfter) > 0 ? "Gap " : "Overlap ")
559 .append(offsetBefore).append(" to ").append(offsetAfter).append(", ");
560 if (dow != null) {
561 if (dom == -1) {
562 buf.append(dow.name()).append(" on or before last day of ").append(month.name());
563 } else if (dom < 0) {
564 buf.append(dow.name()).append(" on or before last day minus ").append(-dom - 1).append(" of ").append(month.name());
565 } else {
566 buf.append(dow.name()).append(" on or after ").append(month.name()).append(' ').append(dom);
567 }
568 } else {
569 buf.append(month.name()).append(' ').append(dom);
570 }
571 buf.append(" at ").append(timeEndOfDay ? "24:00" : time.toString())
572 .append(" ").append(timeDefinition)
573 .append(", standard offset ").append(standardOffset)
574 .append(']');
575 return buf.toString();
576 }
577
578 //-----------------------------------------------------------------------
579 /**
580 * A definition of the way a local time can be converted to the actual
581 * transition date-time.
582 * <p>
583 * Time zone rules are expressed in one of three ways:
584 * <ul>
585 * <li>Relative to UTC</li>
586 * <li>Relative to the standard offset in force</li>
587 * <li>Relative to the wall offset (what you would see on a clock on the wall)</li>
588 * </ul>
589 */
590 public static enum TimeDefinition {
591 /** The local date-time is expressed in terms of the UTC offset. */
592 UTC,
593 /** The local date-time is expressed in terms of the wall offset. */
594 WALL,
595 /** The local date-time is expressed in terms of the standard offset. */
596 STANDARD;
597
598 /**
599 * Converts the specified local date-time to the local date-time actually
600 * seen on a wall clock.
601 * <p>
602 * This method converts using the type of this enum.
603 * The output is defined relative to the 'before' offset of the transition.
604 * <p>
605 * The UTC type uses the UTC offset.
606 * The STANDARD type uses the standard offset.
607 * The WALL type returns the input date-time.
608 * The result is intended for use with the wall-offset.
609 *
610 * @param dateTime the local date-time, not null
611 * @param standardOffset the standard offset, not null
612 * @param wallOffset the wall offset, not null
613 * @return the date-time relative to the wall/before offset, not null
614 */
615 public LocalDateTime createDateTime(LocalDateTime dateTime, ZoneOffset standardOffset, ZoneOffset wallOffset) {
616 switch (this) {
617 case UTC: {
618 int difference = wallOffset.getTotalSeconds() - ZoneOffset.UTC.getTotalSeconds();
619 return dateTime.plusSeconds(difference);
620 }
621 case STANDARD: {
622 int difference = wallOffset.getTotalSeconds() - standardOffset.getTotalSeconds();
623 return dateTime.plusSeconds(difference);
624 }
625 default: // WALL
626 return dateTime;
627 }
628 }
629 }
630
631 }