1/* 2 * Copyright (c) 2012, 2015, 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) 2007-2012, 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 */ 62package java.time; 63 64import static java.time.LocalTime.MINUTES_PER_HOUR; 65import static java.time.LocalTime.SECONDS_PER_HOUR; 66import static java.time.LocalTime.SECONDS_PER_MINUTE; 67import static java.time.temporal.ChronoField.OFFSET_SECONDS; 68 69import java.io.DataInput; 70import java.io.DataOutput; 71import java.io.IOException; 72import java.io.InvalidObjectException; 73import java.io.ObjectInputStream; 74import java.io.Serializable; 75import java.time.temporal.ChronoField; 76import java.time.temporal.Temporal; 77import java.time.temporal.TemporalAccessor; 78import java.time.temporal.TemporalAdjuster; 79import java.time.temporal.TemporalField; 80import java.time.temporal.TemporalQueries; 81import java.time.temporal.TemporalQuery; 82import java.time.temporal.UnsupportedTemporalTypeException; 83import java.time.temporal.ValueRange; 84import java.time.zone.ZoneRules; 85import java.util.Objects; 86import java.util.concurrent.ConcurrentHashMap; 87import java.util.concurrent.ConcurrentMap; 88 89// Android-changed: removed ValueBased paragraph. 90/** 91 * A time-zone offset from Greenwich/UTC, such as {@code +02:00}. 92 * <p> 93 * A time-zone offset is the amount of time that a time-zone differs from Greenwich/UTC. 94 * This is usually a fixed number of hours and minutes. 95 * <p> 96 * Different parts of the world have different time-zone offsets. 97 * The rules for how offsets vary by place and time of year are captured in the 98 * {@link ZoneId} class. 99 * <p> 100 * For example, Paris is one hour ahead of Greenwich/UTC in winter and two hours 101 * ahead in summer. The {@code ZoneId} instance for Paris will reference two 102 * {@code ZoneOffset} instances - a {@code +01:00} instance for winter, 103 * and a {@code +02:00} instance for summer. 104 * <p> 105 * In 2008, time-zone offsets around the world extended from -12:00 to +14:00. 106 * To prevent any problems with that range being extended, yet still provide 107 * validation, the range of offsets is restricted to -18:00 to 18:00 inclusive. 108 * <p> 109 * This class is designed for use with the ISO calendar system. 110 * The fields of hours, minutes and seconds make assumptions that are valid for the 111 * standard ISO definitions of those fields. This class may be used with other 112 * calendar systems providing the definition of the time fields matches those 113 * of the ISO calendar system. 114 * <p> 115 * Instances of {@code ZoneOffset} must be compared using {@link #equals}. 116 * Implementations may choose to cache certain common offsets, however 117 * applications must not rely on such caching. 118 * 119 * @implSpec 120 * This class is immutable and thread-safe. 121 * 122 * @since 1.8 123 */ 124public final class ZoneOffset 125 extends ZoneId 126 implements TemporalAccessor, TemporalAdjuster, Comparable<ZoneOffset>, Serializable { 127 128 /** Cache of time-zone offset by offset in seconds. */ 129 private static final ConcurrentMap<Integer, ZoneOffset> SECONDS_CACHE = new ConcurrentHashMap<>(16, 0.75f, 4); 130 /** Cache of time-zone offset by ID. */ 131 private static final ConcurrentMap<String, ZoneOffset> ID_CACHE = new ConcurrentHashMap<>(16, 0.75f, 4); 132 133 /** 134 * The abs maximum seconds. 135 */ 136 private static final int MAX_SECONDS = 18 * SECONDS_PER_HOUR; 137 /** 138 * Serialization version. 139 */ 140 private static final long serialVersionUID = 2357656521762053153L; 141 142 /** 143 * The time-zone offset for UTC, with an ID of 'Z'. 144 */ 145 public static final ZoneOffset UTC = ZoneOffset.ofTotalSeconds(0); 146 /** 147 * Constant for the maximum supported offset. 148 */ 149 public static final ZoneOffset MIN = ZoneOffset.ofTotalSeconds(-MAX_SECONDS); 150 /** 151 * Constant for the maximum supported offset. 152 */ 153 public static final ZoneOffset MAX = ZoneOffset.ofTotalSeconds(MAX_SECONDS); 154 155 /** 156 * The total offset in seconds. 157 */ 158 private final int totalSeconds; 159 /** 160 * The string form of the time-zone offset. 161 */ 162 private final transient String id; 163 164 //----------------------------------------------------------------------- 165 /** 166 * Obtains an instance of {@code ZoneOffset} using the ID. 167 * <p> 168 * This method parses the string ID of a {@code ZoneOffset} to 169 * return an instance. The parsing accepts all the formats generated by 170 * {@link #getId()}, plus some additional formats: 171 * <ul> 172 * <li>{@code Z} - for UTC 173 * <li>{@code +h} 174 * <li>{@code +hh} 175 * <li>{@code +hh:mm} 176 * <li>{@code -hh:mm} 177 * <li>{@code +hhmm} 178 * <li>{@code -hhmm} 179 * <li>{@code +hh:mm:ss} 180 * <li>{@code -hh:mm:ss} 181 * <li>{@code +hhmmss} 182 * <li>{@code -hhmmss} 183 * </ul> 184 * Note that ± means either the plus or minus symbol. 185 * <p> 186 * The ID of the returned offset will be normalized to one of the formats 187 * described by {@link #getId()}. 188 * <p> 189 * The maximum supported range is from +18:00 to -18:00 inclusive. 190 * 191 * @param offsetId the offset ID, not null 192 * @return the zone-offset, not null 193 * @throws DateTimeException if the offset ID is invalid 194 */ 195 @SuppressWarnings("fallthrough") 196 public static ZoneOffset of(String offsetId) { 197 Objects.requireNonNull(offsetId, "offsetId"); 198 // "Z" is always in the cache 199 ZoneOffset offset = ID_CACHE.get(offsetId); 200 if (offset != null) { 201 return offset; 202 } 203 204 // parse - +h, +hh, +hhmm, +hh:mm, +hhmmss, +hh:mm:ss 205 final int hours, minutes, seconds; 206 switch (offsetId.length()) { 207 case 2: 208 offsetId = offsetId.charAt(0) + "0" + offsetId.charAt(1); // fallthru 209 case 3: 210 hours = parseNumber(offsetId, 1, false); 211 minutes = 0; 212 seconds = 0; 213 break; 214 case 5: 215 hours = parseNumber(offsetId, 1, false); 216 minutes = parseNumber(offsetId, 3, false); 217 seconds = 0; 218 break; 219 case 6: 220 hours = parseNumber(offsetId, 1, false); 221 minutes = parseNumber(offsetId, 4, true); 222 seconds = 0; 223 break; 224 case 7: 225 hours = parseNumber(offsetId, 1, false); 226 minutes = parseNumber(offsetId, 3, false); 227 seconds = parseNumber(offsetId, 5, false); 228 break; 229 case 9: 230 hours = parseNumber(offsetId, 1, false); 231 minutes = parseNumber(offsetId, 4, true); 232 seconds = parseNumber(offsetId, 7, true); 233 break; 234 default: 235 throw new DateTimeException("Invalid ID for ZoneOffset, invalid format: " + offsetId); 236 } 237 char first = offsetId.charAt(0); 238 if (first != '+' && first != '-') { 239 throw new DateTimeException("Invalid ID for ZoneOffset, plus/minus not found when expected: " + offsetId); 240 } 241 if (first == '-') { 242 return ofHoursMinutesSeconds(-hours, -minutes, -seconds); 243 } else { 244 return ofHoursMinutesSeconds(hours, minutes, seconds); 245 } 246 } 247 248 /** 249 * Parse a two digit zero-prefixed number. 250 * 251 * @param offsetId the offset ID, not null 252 * @param pos the position to parse, valid 253 * @param precededByColon should this number be prefixed by a precededByColon 254 * @return the parsed number, from 0 to 99 255 */ 256 private static int parseNumber(CharSequence offsetId, int pos, boolean precededByColon) { 257 if (precededByColon && offsetId.charAt(pos - 1) != ':') { 258 throw new DateTimeException("Invalid ID for ZoneOffset, colon not found when expected: " + offsetId); 259 } 260 char ch1 = offsetId.charAt(pos); 261 char ch2 = offsetId.charAt(pos + 1); 262 if (ch1 < '0' || ch1 > '9' || ch2 < '0' || ch2 > '9') { 263 throw new DateTimeException("Invalid ID for ZoneOffset, non numeric characters found: " + offsetId); 264 } 265 return (ch1 - 48) * 10 + (ch2 - 48); 266 } 267 268 //----------------------------------------------------------------------- 269 /** 270 * Obtains an instance of {@code ZoneOffset} using an offset in hours. 271 * 272 * @param hours the time-zone offset in hours, from -18 to +18 273 * @return the zone-offset, not null 274 * @throws DateTimeException if the offset is not in the required range 275 */ 276 public static ZoneOffset ofHours(int hours) { 277 return ofHoursMinutesSeconds(hours, 0, 0); 278 } 279 280 /** 281 * Obtains an instance of {@code ZoneOffset} using an offset in 282 * hours and minutes. 283 * <p> 284 * The sign of the hours and minutes components must match. 285 * Thus, if the hours is negative, the minutes must be negative or zero. 286 * If the hours is zero, the minutes may be positive, negative or zero. 287 * 288 * @param hours the time-zone offset in hours, from -18 to +18 289 * @param minutes the time-zone offset in minutes, from 0 to ±59, sign matches hours 290 * @return the zone-offset, not null 291 * @throws DateTimeException if the offset is not in the required range 292 */ 293 public static ZoneOffset ofHoursMinutes(int hours, int minutes) { 294 return ofHoursMinutesSeconds(hours, minutes, 0); 295 } 296 297 /** 298 * Obtains an instance of {@code ZoneOffset} using an offset in 299 * hours, minutes and seconds. 300 * <p> 301 * The sign of the hours, minutes and seconds components must match. 302 * Thus, if the hours is negative, the minutes and seconds must be negative or zero. 303 * 304 * @param hours the time-zone offset in hours, from -18 to +18 305 * @param minutes the time-zone offset in minutes, from 0 to ±59, sign matches hours and seconds 306 * @param seconds the time-zone offset in seconds, from 0 to ±59, sign matches hours and minutes 307 * @return the zone-offset, not null 308 * @throws DateTimeException if the offset is not in the required range 309 */ 310 public static ZoneOffset ofHoursMinutesSeconds(int hours, int minutes, int seconds) { 311 validate(hours, minutes, seconds); 312 int totalSeconds = totalSeconds(hours, minutes, seconds); 313 return ofTotalSeconds(totalSeconds); 314 } 315 316 //----------------------------------------------------------------------- 317 /** 318 * Obtains an instance of {@code ZoneOffset} from a temporal object. 319 * <p> 320 * This obtains an offset based on the specified temporal. 321 * A {@code TemporalAccessor} represents an arbitrary set of date and time information, 322 * which this factory converts to an instance of {@code ZoneOffset}. 323 * <p> 324 * A {@code TemporalAccessor} represents some form of date and time information. 325 * This factory converts the arbitrary temporal object to an instance of {@code ZoneOffset}. 326 * <p> 327 * The conversion uses the {@link TemporalQueries#offset()} query, which relies 328 * on extracting the {@link ChronoField#OFFSET_SECONDS OFFSET_SECONDS} field. 329 * <p> 330 * This method matches the signature of the functional interface {@link TemporalQuery} 331 * allowing it to be used as a query via method reference, {@code ZoneOffset::from}. 332 * 333 * @param temporal the temporal object to convert, not null 334 * @return the zone-offset, not null 335 * @throws DateTimeException if unable to convert to an {@code ZoneOffset} 336 */ 337 public static ZoneOffset from(TemporalAccessor temporal) { 338 Objects.requireNonNull(temporal, "temporal"); 339 ZoneOffset offset = temporal.query(TemporalQueries.offset()); 340 if (offset == null) { 341 throw new DateTimeException("Unable to obtain ZoneOffset from TemporalAccessor: " + 342 temporal + " of type " + temporal.getClass().getName()); 343 } 344 return offset; 345 } 346 347 //----------------------------------------------------------------------- 348 /** 349 * Validates the offset fields. 350 * 351 * @param hours the time-zone offset in hours, from -18 to +18 352 * @param minutes the time-zone offset in minutes, from 0 to ±59 353 * @param seconds the time-zone offset in seconds, from 0 to ±59 354 * @throws DateTimeException if the offset is not in the required range 355 */ 356 private static void validate(int hours, int minutes, int seconds) { 357 if (hours < -18 || hours > 18) { 358 throw new DateTimeException("Zone offset hours not in valid range: value " + hours + 359 " is not in the range -18 to 18"); 360 } 361 if (hours > 0) { 362 if (minutes < 0 || seconds < 0) { 363 throw new DateTimeException("Zone offset minutes and seconds must be positive because hours is positive"); 364 } 365 } else if (hours < 0) { 366 if (minutes > 0 || seconds > 0) { 367 throw new DateTimeException("Zone offset minutes and seconds must be negative because hours is negative"); 368 } 369 } else if ((minutes > 0 && seconds < 0) || (minutes < 0 && seconds > 0)) { 370 throw new DateTimeException("Zone offset minutes and seconds must have the same sign"); 371 } 372 if (Math.abs(minutes) > 59) { 373 throw new DateTimeException("Zone offset minutes not in valid range: abs(value) " + 374 Math.abs(minutes) + " is not in the range 0 to 59"); 375 } 376 if (Math.abs(seconds) > 59) { 377 throw new DateTimeException("Zone offset seconds not in valid range: abs(value) " + 378 Math.abs(seconds) + " is not in the range 0 to 59"); 379 } 380 if (Math.abs(hours) == 18 && (Math.abs(minutes) > 0 || Math.abs(seconds) > 0)) { 381 throw new DateTimeException("Zone offset not in valid range: -18:00 to +18:00"); 382 } 383 } 384 385 /** 386 * Calculates the total offset in seconds. 387 * 388 * @param hours the time-zone offset in hours, from -18 to +18 389 * @param minutes the time-zone offset in minutes, from 0 to ±59, sign matches hours and seconds 390 * @param seconds the time-zone offset in seconds, from 0 to ±59, sign matches hours and minutes 391 * @return the total in seconds 392 */ 393 private static int totalSeconds(int hours, int minutes, int seconds) { 394 return hours * SECONDS_PER_HOUR + minutes * SECONDS_PER_MINUTE + seconds; 395 } 396 397 //----------------------------------------------------------------------- 398 /** 399 * Obtains an instance of {@code ZoneOffset} specifying the total offset in seconds 400 * <p> 401 * The offset must be in the range {@code -18:00} to {@code +18:00}, which corresponds to -64800 to +64800. 402 * 403 * @param totalSeconds the total time-zone offset in seconds, from -64800 to +64800 404 * @return the ZoneOffset, not null 405 * @throws DateTimeException if the offset is not in the required range 406 */ 407 public static ZoneOffset ofTotalSeconds(int totalSeconds) { 408 if (Math.abs(totalSeconds) > MAX_SECONDS) { 409 throw new DateTimeException("Zone offset not in valid range: -18:00 to +18:00"); 410 } 411 if (totalSeconds % (15 * SECONDS_PER_MINUTE) == 0) { 412 Integer totalSecs = totalSeconds; 413 ZoneOffset result = SECONDS_CACHE.get(totalSecs); 414 if (result == null) { 415 result = new ZoneOffset(totalSeconds); 416 SECONDS_CACHE.putIfAbsent(totalSecs, result); 417 result = SECONDS_CACHE.get(totalSecs); 418 ID_CACHE.putIfAbsent(result.getId(), result); 419 } 420 return result; 421 } else { 422 return new ZoneOffset(totalSeconds); 423 } 424 } 425 426 //----------------------------------------------------------------------- 427 /** 428 * Constructor. 429 * 430 * @param totalSeconds the total time-zone offset in seconds, from -64800 to +64800 431 */ 432 private ZoneOffset(int totalSeconds) { 433 super(); 434 this.totalSeconds = totalSeconds; 435 id = buildId(totalSeconds); 436 } 437 438 private static String buildId(int totalSeconds) { 439 if (totalSeconds == 0) { 440 return "Z"; 441 } else { 442 int absTotalSeconds = Math.abs(totalSeconds); 443 StringBuilder buf = new StringBuilder(); 444 int absHours = absTotalSeconds / SECONDS_PER_HOUR; 445 int absMinutes = (absTotalSeconds / SECONDS_PER_MINUTE) % MINUTES_PER_HOUR; 446 buf.append(totalSeconds < 0 ? "-" : "+") 447 .append(absHours < 10 ? "0" : "").append(absHours) 448 .append(absMinutes < 10 ? ":0" : ":").append(absMinutes); 449 int absSeconds = absTotalSeconds % SECONDS_PER_MINUTE; 450 if (absSeconds != 0) { 451 buf.append(absSeconds < 10 ? ":0" : ":").append(absSeconds); 452 } 453 return buf.toString(); 454 } 455 } 456 457 //----------------------------------------------------------------------- 458 /** 459 * Gets the total zone offset in seconds. 460 * <p> 461 * This is the primary way to access the offset amount. 462 * It returns the total of the hours, minutes and seconds fields as a 463 * single offset that can be added to a time. 464 * 465 * @return the total zone offset amount in seconds 466 */ 467 public int getTotalSeconds() { 468 return totalSeconds; 469 } 470 471 /** 472 * Gets the normalized zone offset ID. 473 * <p> 474 * The ID is minor variation to the standard ISO-8601 formatted string 475 * for the offset. There are three formats: 476 * <ul> 477 * <li>{@code Z} - for UTC (ISO-8601) 478 * <li>{@code +hh:mm} or {@code -hh:mm} - if the seconds are zero (ISO-8601) 479 * <li>{@code +hh:mm:ss} or {@code -hh:mm:ss} - if the seconds are non-zero (not ISO-8601) 480 * </ul> 481 * 482 * @return the zone offset ID, not null 483 */ 484 @Override 485 public String getId() { 486 return id; 487 } 488 489 /** 490 * Gets the associated time-zone rules. 491 * <p> 492 * The rules will always return this offset when queried. 493 * The implementation class is immutable, thread-safe and serializable. 494 * 495 * @return the rules, not null 496 */ 497 @Override 498 public ZoneRules getRules() { 499 return ZoneRules.of(this); 500 } 501 502 //----------------------------------------------------------------------- 503 /** 504 * Checks if the specified field is supported. 505 * <p> 506 * This checks if this offset can be queried for the specified field. 507 * If false, then calling the {@link #range(TemporalField) range} and 508 * {@link #get(TemporalField) get} methods will throw an exception. 509 * <p> 510 * If the field is a {@link ChronoField} then the query is implemented here. 511 * The {@code OFFSET_SECONDS} field returns true. 512 * All other {@code ChronoField} instances will return false. 513 * <p> 514 * If the field is not a {@code ChronoField}, then the result of this method 515 * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)} 516 * passing {@code this} as the argument. 517 * Whether the field is supported is determined by the field. 518 * 519 * @param field the field to check, null returns false 520 * @return true if the field is supported on this offset, false if not 521 */ 522 @Override 523 public boolean isSupported(TemporalField field) { 524 if (field instanceof ChronoField) { 525 return field == OFFSET_SECONDS; 526 } 527 return field != null && field.isSupportedBy(this); 528 } 529 530 /** 531 * Gets the range of valid values for the specified field. 532 * <p> 533 * The range object expresses the minimum and maximum valid values for a field. 534 * This offset is used to enhance the accuracy of the returned range. 535 * If it is not possible to return the range, because the field is not supported 536 * or for some other reason, an exception is thrown. 537 * <p> 538 * If the field is a {@link ChronoField} then the query is implemented here. 539 * The {@link #isSupported(TemporalField) supported fields} will return 540 * appropriate range instances. 541 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. 542 * <p> 543 * If the field is not a {@code ChronoField}, then the result of this method 544 * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)} 545 * passing {@code this} as the argument. 546 * Whether the range can be obtained is determined by the field. 547 * 548 * @param field the field to query the range for, not null 549 * @return the range of valid values for the field, not null 550 * @throws DateTimeException if the range for the field cannot be obtained 551 * @throws UnsupportedTemporalTypeException if the field is not supported 552 */ 553 @Override // override for Javadoc 554 public ValueRange range(TemporalField field) { 555 return TemporalAccessor.super.range(field); 556 } 557 558 /** 559 * Gets the value of the specified field from this offset as an {@code int}. 560 * <p> 561 * This queries this offset for the value of the specified field. 562 * The returned value will always be within the valid range of values for the field. 563 * If it is not possible to return the value, because the field is not supported 564 * or for some other reason, an exception is thrown. 565 * <p> 566 * If the field is a {@link ChronoField} then the query is implemented here. 567 * The {@code OFFSET_SECONDS} field returns the value of the offset. 568 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. 569 * <p> 570 * If the field is not a {@code ChronoField}, then the result of this method 571 * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)} 572 * passing {@code this} as the argument. Whether the value can be obtained, 573 * and what the value represents, is determined by the field. 574 * 575 * @param field the field to get, not null 576 * @return the value for the field 577 * @throws DateTimeException if a value for the field cannot be obtained or 578 * the value is outside the range of valid values for the field 579 * @throws UnsupportedTemporalTypeException if the field is not supported or 580 * the range of values exceeds an {@code int} 581 * @throws ArithmeticException if numeric overflow occurs 582 */ 583 @Override // override for Javadoc and performance 584 public int get(TemporalField field) { 585 if (field == OFFSET_SECONDS) { 586 return totalSeconds; 587 } else if (field instanceof ChronoField) { 588 throw new UnsupportedTemporalTypeException("Unsupported field: " + field); 589 } 590 return range(field).checkValidIntValue(getLong(field), field); 591 } 592 593 /** 594 * Gets the value of the specified field from this offset as a {@code long}. 595 * <p> 596 * This queries this offset for the value of the specified field. 597 * If it is not possible to return the value, because the field is not supported 598 * or for some other reason, an exception is thrown. 599 * <p> 600 * If the field is a {@link ChronoField} then the query is implemented here. 601 * The {@code OFFSET_SECONDS} field returns the value of the offset. 602 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. 603 * <p> 604 * If the field is not a {@code ChronoField}, then the result of this method 605 * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)} 606 * passing {@code this} as the argument. Whether the value can be obtained, 607 * and what the value represents, is determined by the field. 608 * 609 * @param field the field to get, not null 610 * @return the value for the field 611 * @throws DateTimeException if a value for the field cannot be obtained 612 * @throws UnsupportedTemporalTypeException if the field is not supported 613 * @throws ArithmeticException if numeric overflow occurs 614 */ 615 @Override 616 public long getLong(TemporalField field) { 617 if (field == OFFSET_SECONDS) { 618 return totalSeconds; 619 } else if (field instanceof ChronoField) { 620 throw new UnsupportedTemporalTypeException("Unsupported field: " + field); 621 } 622 return field.getFrom(this); 623 } 624 625 //----------------------------------------------------------------------- 626 /** 627 * Queries this offset using the specified query. 628 * <p> 629 * This queries this offset using the specified query strategy object. 630 * The {@code TemporalQuery} object defines the logic to be used to 631 * obtain the result. Read the documentation of the query to understand 632 * what the result of this method will be. 633 * <p> 634 * The result of this method is obtained by invoking the 635 * {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the 636 * specified query passing {@code this} as the argument. 637 * 638 * @param <R> the type of the result 639 * @param query the query to invoke, not null 640 * @return the query result, null may be returned (defined by the query) 641 * @throws DateTimeException if unable to query (defined by the query) 642 * @throws ArithmeticException if numeric overflow occurs (defined by the query) 643 */ 644 @SuppressWarnings("unchecked") 645 @Override 646 public <R> R query(TemporalQuery<R> query) { 647 if (query == TemporalQueries.offset() || query == TemporalQueries.zone()) { 648 return (R) this; 649 } 650 return TemporalAccessor.super.query(query); 651 } 652 653 /** 654 * Adjusts the specified temporal object to have the same offset as this object. 655 * <p> 656 * This returns a temporal object of the same observable type as the input 657 * with the offset changed to be the same as this. 658 * <p> 659 * The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)} 660 * passing {@link ChronoField#OFFSET_SECONDS} as the field. 661 * <p> 662 * In most cases, it is clearer to reverse the calling pattern by using 663 * {@link Temporal#with(TemporalAdjuster)}: 664 * <pre> 665 * // these two lines are equivalent, but the second approach is recommended 666 * temporal = thisOffset.adjustInto(temporal); 667 * temporal = temporal.with(thisOffset); 668 * </pre> 669 * <p> 670 * This instance is immutable and unaffected by this method call. 671 * 672 * @param temporal the target object to be adjusted, not null 673 * @return the adjusted object, not null 674 * @throws DateTimeException if unable to make the adjustment 675 * @throws ArithmeticException if numeric overflow occurs 676 */ 677 @Override 678 public Temporal adjustInto(Temporal temporal) { 679 return temporal.with(OFFSET_SECONDS, totalSeconds); 680 } 681 682 //----------------------------------------------------------------------- 683 /** 684 * Compares this offset to another offset in descending order. 685 * <p> 686 * The offsets are compared in the order that they occur for the same time 687 * of day around the world. Thus, an offset of {@code +10:00} comes before an 688 * offset of {@code +09:00} and so on down to {@code -18:00}. 689 * <p> 690 * The comparison is "consistent with equals", as defined by {@link Comparable}. 691 * 692 * @param other the other date to compare to, not null 693 * @return the comparator value, negative if less, postive if greater 694 * @throws NullPointerException if {@code other} is null 695 */ 696 @Override 697 public int compareTo(ZoneOffset other) { 698 return other.totalSeconds - totalSeconds; 699 } 700 701 //----------------------------------------------------------------------- 702 /** 703 * Checks if this offset is equal to another offset. 704 * <p> 705 * The comparison is based on the amount of the offset in seconds. 706 * This is equivalent to a comparison by ID. 707 * 708 * @param obj the object to check, null returns false 709 * @return true if this is equal to the other offset 710 */ 711 @Override 712 public boolean equals(Object obj) { 713 if (this == obj) { 714 return true; 715 } 716 if (obj instanceof ZoneOffset) { 717 return totalSeconds == ((ZoneOffset) obj).totalSeconds; 718 } 719 return false; 720 } 721 722 /** 723 * A hash code for this offset. 724 * 725 * @return a suitable hash code 726 */ 727 @Override 728 public int hashCode() { 729 return totalSeconds; 730 } 731 732 //----------------------------------------------------------------------- 733 /** 734 * Outputs this offset as a {@code String}, using the normalized ID. 735 * 736 * @return a string representation of this offset, not null 737 */ 738 @Override 739 public String toString() { 740 return id; 741 } 742 743 // ----------------------------------------------------------------------- 744 /** 745 * Writes the object using a 746 * <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>. 747 * @serialData 748 * <pre> 749 * out.writeByte(8); // identifies a ZoneOffset 750 * int offsetByte = totalSeconds % 900 == 0 ? totalSeconds / 900 : 127; 751 * out.writeByte(offsetByte); 752 * if (offsetByte == 127) { 753 * out.writeInt(totalSeconds); 754 * } 755 * </pre> 756 * 757 * @return the instance of {@code Ser}, not null 758 */ 759 private Object writeReplace() { 760 return new Ser(Ser.ZONE_OFFSET_TYPE, this); 761 } 762 763 /** 764 * Defend against malicious streams. 765 * 766 * @param s the stream to read 767 * @throws InvalidObjectException always 768 */ 769 private void readObject(ObjectInputStream s) throws InvalidObjectException { 770 throw new InvalidObjectException("Deserialization via serialization delegate"); 771 } 772 773 @Override 774 void write(DataOutput out) throws IOException { 775 out.writeByte(Ser.ZONE_OFFSET_TYPE); 776 writeExternal(out); 777 } 778 779 void writeExternal(DataOutput out) throws IOException { 780 final int offsetSecs = totalSeconds; 781 int offsetByte = offsetSecs % 900 == 0 ? offsetSecs / 900 : 127; // compress to -72 to +72 782 out.writeByte(offsetByte); 783 if (offsetByte == 127) { 784 out.writeInt(offsetSecs); 785 } 786 } 787 788 static ZoneOffset readExternal(DataInput in) throws IOException { 789 int offsetByte = in.readByte(); 790 return (offsetByte == 127 ? ZoneOffset.ofTotalSeconds(in.readInt()) : ZoneOffset.ofTotalSeconds(offsetByte * 900)); 791 } 792 793} 794