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 */ 62 package java.time; 63 64 import static java.time.temporal.ChronoField.ERA; 65 import static java.time.temporal.ChronoField.YEAR; 66 import static java.time.temporal.ChronoField.YEAR_OF_ERA; 67 import static java.time.temporal.ChronoUnit.CENTURIES; 68 import static java.time.temporal.ChronoUnit.DECADES; 69 import static java.time.temporal.ChronoUnit.ERAS; 70 import static java.time.temporal.ChronoUnit.MILLENNIA; 71 import static java.time.temporal.ChronoUnit.YEARS; 72 73 import java.io.DataInput; 74 import java.io.DataOutput; 75 import java.io.IOException; 76 import java.io.InvalidObjectException; 77 import java.io.ObjectInputStream; 78 import java.io.Serializable; 79 import java.time.chrono.Chronology; 80 import java.time.chrono.IsoChronology; 81 import java.time.format.DateTimeFormatter; 82 import java.time.format.DateTimeFormatterBuilder; 83 import java.time.format.DateTimeParseException; 84 import java.time.format.SignStyle; 85 import java.time.temporal.ChronoField; 86 import java.time.temporal.ChronoUnit; 87 import java.time.temporal.Temporal; 88 import java.time.temporal.TemporalAccessor; 89 import java.time.temporal.TemporalAdjuster; 90 import java.time.temporal.TemporalAmount; 91 import java.time.temporal.TemporalField; 92 import java.time.temporal.TemporalQueries; 93 import java.time.temporal.TemporalQuery; 94 import java.time.temporal.TemporalUnit; 95 import java.time.temporal.UnsupportedTemporalTypeException; 96 import java.time.temporal.ValueRange; 97 import java.util.Objects; 98 99 // Android-changed: removed ValueBased paragraph. 100 /** 101 * A year in the ISO-8601 calendar system, such as {@code 2007}. 102 * <p> 103 * {@code Year} is an immutable date-time object that represents a year. 104 * Any field that can be derived from a year can be obtained. 105 * <p> 106 * <b>Note that years in the ISO chronology only align with years in the 107 * Gregorian-Julian system for modern years. Parts of Russia did not switch to the 108 * modern Gregorian/ISO rules until 1920. 109 * As such, historical years must be treated with caution.</b> 110 * <p> 111 * This class does not store or represent a month, day, time or time-zone. 112 * For example, the value "2007" can be stored in a {@code Year}. 113 * <p> 114 * Years represented by this class follow the ISO-8601 standard and use 115 * the proleptic numbering system. Year 1 is preceded by year 0, then by year -1. 116 * <p> 117 * The ISO-8601 calendar system is the modern civil calendar system used today 118 * in most of the world. It is equivalent to the proleptic Gregorian calendar 119 * system, in which today's rules for leap years are applied for all time. 120 * For most applications written today, the ISO-8601 rules are entirely suitable. 121 * However, any application that makes use of historical dates, and requires them 122 * to be accurate will find the ISO-8601 approach unsuitable. 123 * 124 * @implSpec 125 * This class is immutable and thread-safe. 126 * 127 * @since 1.8 128 */ 129 public final class Year 130 implements Temporal, TemporalAdjuster, Comparable<Year>, Serializable { 131 132 /** 133 * The minimum supported year, '-999,999,999'. 134 */ 135 public static final int MIN_VALUE = -999_999_999; 136 /** 137 * The maximum supported year, '+999,999,999'. 138 */ 139 public static final int MAX_VALUE = 999_999_999; 140 141 /** 142 * Serialization version. 143 */ 144 private static final long serialVersionUID = -23038383694477807L; 145 /** 146 * Parser. 147 */ 148 private static final DateTimeFormatter PARSER = new DateTimeFormatterBuilder() 149 .appendValue(YEAR, 4, 10, SignStyle.EXCEEDS_PAD) 150 .toFormatter(); 151 152 /** 153 * The year being represented. 154 */ 155 private final int year; 156 157 //----------------------------------------------------------------------- 158 /** 159 * Obtains the current year from the system clock in the default time-zone. 160 * <p> 161 * This will query the {@link Clock#systemDefaultZone() system clock} in the default 162 * time-zone to obtain the current year. 163 * <p> 164 * Using this method will prevent the ability to use an alternate clock for testing 165 * because the clock is hard-coded. 166 * 167 * @return the current year using the system clock and default time-zone, not null 168 */ now()169 public static Year now() { 170 return now(Clock.systemDefaultZone()); 171 } 172 173 /** 174 * Obtains the current year from the system clock in the specified time-zone. 175 * <p> 176 * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current year. 177 * Specifying the time-zone avoids dependence on the default time-zone. 178 * <p> 179 * Using this method will prevent the ability to use an alternate clock for testing 180 * because the clock is hard-coded. 181 * 182 * @param zone the zone ID to use, not null 183 * @return the current year using the system clock, not null 184 */ now(ZoneId zone)185 public static Year now(ZoneId zone) { 186 return now(Clock.system(zone)); 187 } 188 189 /** 190 * Obtains the current year from the specified clock. 191 * <p> 192 * This will query the specified clock to obtain the current year. 193 * Using this method allows the use of an alternate clock for testing. 194 * The alternate clock may be introduced using {@link Clock dependency injection}. 195 * 196 * @param clock the clock to use, not null 197 * @return the current year, not null 198 */ now(Clock clock)199 public static Year now(Clock clock) { 200 final LocalDate now = LocalDate.now(clock); // called once 201 return Year.of(now.getYear()); 202 } 203 204 //----------------------------------------------------------------------- 205 /** 206 * Obtains an instance of {@code Year}. 207 * <p> 208 * This method accepts a year value from the proleptic ISO calendar system. 209 * <p> 210 * The year 2AD/CE is represented by 2.<br> 211 * The year 1AD/CE is represented by 1.<br> 212 * The year 1BC/BCE is represented by 0.<br> 213 * The year 2BC/BCE is represented by -1.<br> 214 * 215 * @param isoYear the ISO proleptic year to represent, from {@code MIN_VALUE} to {@code MAX_VALUE} 216 * @return the year, not null 217 * @throws DateTimeException if the field is invalid 218 */ of(int isoYear)219 public static Year of(int isoYear) { 220 YEAR.checkValidValue(isoYear); 221 return new Year(isoYear); 222 } 223 224 //----------------------------------------------------------------------- 225 /** 226 * Obtains an instance of {@code Year} from a temporal object. 227 * <p> 228 * This obtains a year based on the specified temporal. 229 * A {@code TemporalAccessor} represents an arbitrary set of date and time information, 230 * which this factory converts to an instance of {@code Year}. 231 * <p> 232 * The conversion extracts the {@link ChronoField#YEAR year} field. 233 * The extraction is only permitted if the temporal object has an ISO 234 * chronology, or can be converted to a {@code LocalDate}. 235 * <p> 236 * This method matches the signature of the functional interface {@link TemporalQuery} 237 * allowing it to be used as a query via method reference, {@code Year::from}. 238 * 239 * @param temporal the temporal object to convert, not null 240 * @return the year, not null 241 * @throws DateTimeException if unable to convert to a {@code Year} 242 */ from(TemporalAccessor temporal)243 public static Year from(TemporalAccessor temporal) { 244 if (temporal instanceof Year) { 245 return (Year) temporal; 246 } 247 Objects.requireNonNull(temporal, "temporal"); 248 try { 249 if (IsoChronology.INSTANCE.equals(Chronology.from(temporal)) == false) { 250 temporal = LocalDate.from(temporal); 251 } 252 return of(temporal.get(YEAR)); 253 } catch (DateTimeException ex) { 254 throw new DateTimeException("Unable to obtain Year from TemporalAccessor: " + 255 temporal + " of type " + temporal.getClass().getName(), ex); 256 } 257 } 258 259 //----------------------------------------------------------------------- 260 /** 261 * Obtains an instance of {@code Year} from a text string such as {@code 2007}. 262 * <p> 263 * The string must represent a valid year. 264 * Years outside the range 0000 to 9999 must be prefixed by the plus or minus symbol. 265 * 266 * @param text the text to parse such as "2007", not null 267 * @return the parsed year, not null 268 * @throws DateTimeParseException if the text cannot be parsed 269 */ parse(CharSequence text)270 public static Year parse(CharSequence text) { 271 return parse(text, PARSER); 272 } 273 274 /** 275 * Obtains an instance of {@code Year} from a text string using a specific formatter. 276 * <p> 277 * The text is parsed using the formatter, returning a year. 278 * 279 * @param text the text to parse, not null 280 * @param formatter the formatter to use, not null 281 * @return the parsed year, not null 282 * @throws DateTimeParseException if the text cannot be parsed 283 */ parse(CharSequence text, DateTimeFormatter formatter)284 public static Year parse(CharSequence text, DateTimeFormatter formatter) { 285 Objects.requireNonNull(formatter, "formatter"); 286 return formatter.parse(text, Year::from); 287 } 288 289 //------------------------------------------------------------------------- 290 /** 291 * Checks if the year is a leap year, according to the ISO proleptic 292 * calendar system rules. 293 * <p> 294 * This method applies the current rules for leap years across the whole time-line. 295 * In general, a year is a leap year if it is divisible by four without 296 * remainder. However, years divisible by 100, are not leap years, with 297 * the exception of years divisible by 400 which are. 298 * <p> 299 * For example, 1904 is a leap year it is divisible by 4. 300 * 1900 was not a leap year as it is divisible by 100, however 2000 was a 301 * leap year as it is divisible by 400. 302 * <p> 303 * The calculation is proleptic - applying the same rules into the far future and far past. 304 * This is historically inaccurate, but is correct for the ISO-8601 standard. 305 * 306 * @param year the year to check 307 * @return true if the year is leap, false otherwise 308 */ isLeap(long year)309 public static boolean isLeap(long year) { 310 return ((year & 3) == 0) && ((year % 100) != 0 || (year % 400) == 0); 311 } 312 313 //----------------------------------------------------------------------- 314 /** 315 * Constructor. 316 * 317 * @param year the year to represent 318 */ Year(int year)319 private Year(int year) { 320 this.year = year; 321 } 322 323 //----------------------------------------------------------------------- 324 /** 325 * Gets the year value. 326 * <p> 327 * The year returned by this method is proleptic as per {@code get(YEAR)}. 328 * 329 * @return the year, {@code MIN_VALUE} to {@code MAX_VALUE} 330 */ getValue()331 public int getValue() { 332 return year; 333 } 334 335 //----------------------------------------------------------------------- 336 /** 337 * Checks if the specified field is supported. 338 * <p> 339 * This checks if this year can be queried for the specified field. 340 * If false, then calling the {@link #range(TemporalField) range}, 341 * {@link #get(TemporalField) get} and {@link #with(TemporalField, long)} 342 * methods will throw an exception. 343 * <p> 344 * If the field is a {@link ChronoField} then the query is implemented here. 345 * The supported fields are: 346 * <ul> 347 * <li>{@code YEAR_OF_ERA} 348 * <li>{@code YEAR} 349 * <li>{@code ERA} 350 * </ul> 351 * All other {@code ChronoField} instances will return false. 352 * <p> 353 * If the field is not a {@code ChronoField}, then the result of this method 354 * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)} 355 * passing {@code this} as the argument. 356 * Whether the field is supported is determined by the field. 357 * 358 * @param field the field to check, null returns false 359 * @return true if the field is supported on this year, false if not 360 */ 361 @Override isSupported(TemporalField field)362 public boolean isSupported(TemporalField field) { 363 if (field instanceof ChronoField) { 364 return field == YEAR || field == YEAR_OF_ERA || field == ERA; 365 } 366 return field != null && field.isSupportedBy(this); 367 } 368 369 /** 370 * Checks if the specified unit is supported. 371 * <p> 372 * This checks if the specified unit can be added to, or subtracted from, this year. 373 * If false, then calling the {@link #plus(long, TemporalUnit)} and 374 * {@link #minus(long, TemporalUnit) minus} methods will throw an exception. 375 * <p> 376 * If the unit is a {@link ChronoUnit} then the query is implemented here. 377 * The supported units are: 378 * <ul> 379 * <li>{@code YEARS} 380 * <li>{@code DECADES} 381 * <li>{@code CENTURIES} 382 * <li>{@code MILLENNIA} 383 * <li>{@code ERAS} 384 * </ul> 385 * All other {@code ChronoUnit} instances will return false. 386 * <p> 387 * If the unit is not a {@code ChronoUnit}, then the result of this method 388 * is obtained by invoking {@code TemporalUnit.isSupportedBy(Temporal)} 389 * passing {@code this} as the argument. 390 * Whether the unit is supported is determined by the unit. 391 * 392 * @param unit the unit to check, null returns false 393 * @return true if the unit can be added/subtracted, false if not 394 */ 395 @Override isSupported(TemporalUnit unit)396 public boolean isSupported(TemporalUnit unit) { 397 if (unit instanceof ChronoUnit) { 398 return unit == YEARS || unit == DECADES || unit == CENTURIES || unit == MILLENNIA || unit == ERAS; 399 } 400 return unit != null && unit.isSupportedBy(this); 401 } 402 403 //----------------------------------------------------------------------- 404 /** 405 * Gets the range of valid values for the specified field. 406 * <p> 407 * The range object expresses the minimum and maximum valid values for a field. 408 * This year is used to enhance the accuracy of the returned range. 409 * If it is not possible to return the range, because the field is not supported 410 * or for some other reason, an exception is thrown. 411 * <p> 412 * If the field is a {@link ChronoField} then the query is implemented here. 413 * The {@link #isSupported(TemporalField) supported fields} will return 414 * appropriate range instances. 415 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. 416 * <p> 417 * If the field is not a {@code ChronoField}, then the result of this method 418 * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)} 419 * passing {@code this} as the argument. 420 * Whether the range can be obtained is determined by the field. 421 * 422 * @param field the field to query the range for, not null 423 * @return the range of valid values for the field, not null 424 * @throws DateTimeException if the range for the field cannot be obtained 425 * @throws UnsupportedTemporalTypeException if the field is not supported 426 */ 427 @Override range(TemporalField field)428 public ValueRange range(TemporalField field) { 429 if (field == YEAR_OF_ERA) { 430 return (year <= 0 ? ValueRange.of(1, MAX_VALUE + 1) : ValueRange.of(1, MAX_VALUE)); 431 } 432 return Temporal.super.range(field); 433 } 434 435 /** 436 * Gets the value of the specified field from this year as an {@code int}. 437 * <p> 438 * This queries this year for the value of the specified field. 439 * The returned value will always be within the valid range of values for the field. 440 * If it is not possible to return the value, because the field is not supported 441 * or for some other reason, an exception is thrown. 442 * <p> 443 * If the field is a {@link ChronoField} then the query is implemented here. 444 * The {@link #isSupported(TemporalField) supported fields} will return valid 445 * values based on this year. 446 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. 447 * <p> 448 * If the field is not a {@code ChronoField}, then the result of this method 449 * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)} 450 * passing {@code this} as the argument. Whether the value can be obtained, 451 * and what the value represents, is determined by the field. 452 * 453 * @param field the field to get, not null 454 * @return the value for the field 455 * @throws DateTimeException if a value for the field cannot be obtained or 456 * the value is outside the range of valid values for the field 457 * @throws UnsupportedTemporalTypeException if the field is not supported or 458 * the range of values exceeds an {@code int} 459 * @throws ArithmeticException if numeric overflow occurs 460 */ 461 @Override // override for Javadoc get(TemporalField field)462 public int get(TemporalField field) { 463 return range(field).checkValidIntValue(getLong(field), field); 464 } 465 466 /** 467 * Gets the value of the specified field from this year as a {@code long}. 468 * <p> 469 * This queries this year for the value of the specified field. 470 * If it is not possible to return the value, because the field is not supported 471 * or for some other reason, an exception is thrown. 472 * <p> 473 * If the field is a {@link ChronoField} then the query is implemented here. 474 * The {@link #isSupported(TemporalField) supported fields} will return valid 475 * values based on this year. 476 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. 477 * <p> 478 * If the field is not a {@code ChronoField}, then the result of this method 479 * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)} 480 * passing {@code this} as the argument. Whether the value can be obtained, 481 * and what the value represents, is determined by the field. 482 * 483 * @param field the field to get, not null 484 * @return the value for the field 485 * @throws DateTimeException if a value for the field cannot be obtained 486 * @throws UnsupportedTemporalTypeException if the field is not supported 487 * @throws ArithmeticException if numeric overflow occurs 488 */ 489 @Override getLong(TemporalField field)490 public long getLong(TemporalField field) { 491 if (field instanceof ChronoField) { 492 switch ((ChronoField) field) { 493 case YEAR_OF_ERA: return (year < 1 ? 1 - year : year); 494 case YEAR: return year; 495 case ERA: return (year < 1 ? 0 : 1); 496 } 497 throw new UnsupportedTemporalTypeException("Unsupported field: " + field); 498 } 499 return field.getFrom(this); 500 } 501 502 //----------------------------------------------------------------------- 503 /** 504 * Checks if the year is a leap year, according to the ISO proleptic 505 * calendar system rules. 506 * <p> 507 * This method applies the current rules for leap years across the whole time-line. 508 * In general, a year is a leap year if it is divisible by four without 509 * remainder. However, years divisible by 100, are not leap years, with 510 * the exception of years divisible by 400 which are. 511 * <p> 512 * For example, 1904 is a leap year it is divisible by 4. 513 * 1900 was not a leap year as it is divisible by 100, however 2000 was a 514 * leap year as it is divisible by 400. 515 * <p> 516 * The calculation is proleptic - applying the same rules into the far future and far past. 517 * This is historically inaccurate, but is correct for the ISO-8601 standard. 518 * 519 * @return true if the year is leap, false otherwise 520 */ isLeap()521 public boolean isLeap() { 522 return Year.isLeap(year); 523 } 524 525 /** 526 * Checks if the month-day is valid for this year. 527 * <p> 528 * This method checks whether this year and the input month and day form 529 * a valid date. 530 * 531 * @param monthDay the month-day to validate, null returns false 532 * @return true if the month and day are valid for this year 533 */ isValidMonthDay(MonthDay monthDay)534 public boolean isValidMonthDay(MonthDay monthDay) { 535 return monthDay != null && monthDay.isValidYear(year); 536 } 537 538 /** 539 * Gets the length of this year in days. 540 * 541 * @return the length of this year in days, 365 or 366 542 */ length()543 public int length() { 544 return isLeap() ? 366 : 365; 545 } 546 547 //----------------------------------------------------------------------- 548 /** 549 * Returns an adjusted copy of this year. 550 * <p> 551 * This returns a {@code Year}, based on this one, with the year adjusted. 552 * The adjustment takes place using the specified adjuster strategy object. 553 * Read the documentation of the adjuster to understand what adjustment will be made. 554 * <p> 555 * The result of this method is obtained by invoking the 556 * {@link TemporalAdjuster#adjustInto(Temporal)} method on the 557 * specified adjuster passing {@code this} as the argument. 558 * <p> 559 * This instance is immutable and unaffected by this method call. 560 * 561 * @param adjuster the adjuster to use, not null 562 * @return a {@code Year} based on {@code this} with the adjustment made, not null 563 * @throws DateTimeException if the adjustment cannot be made 564 * @throws ArithmeticException if numeric overflow occurs 565 */ 566 @Override with(TemporalAdjuster adjuster)567 public Year with(TemporalAdjuster adjuster) { 568 return (Year) adjuster.adjustInto(this); 569 } 570 571 /** 572 * Returns a copy of this year with the specified field set to a new value. 573 * <p> 574 * This returns a {@code Year}, based on this one, with the value 575 * for the specified field changed. 576 * If it is not possible to set the value, because the field is not supported or for 577 * some other reason, an exception is thrown. 578 * <p> 579 * If the field is a {@link ChronoField} then the adjustment is implemented here. 580 * The supported fields behave as follows: 581 * <ul> 582 * <li>{@code YEAR_OF_ERA} - 583 * Returns a {@code Year} with the specified year-of-era 584 * The era will be unchanged. 585 * <li>{@code YEAR} - 586 * Returns a {@code Year} with the specified year. 587 * This completely replaces the date and is equivalent to {@link #of(int)}. 588 * <li>{@code ERA} - 589 * Returns a {@code Year} with the specified era. 590 * The year-of-era will be unchanged. 591 * </ul> 592 * <p> 593 * In all cases, if the new value is outside the valid range of values for the field 594 * then a {@code DateTimeException} will be thrown. 595 * <p> 596 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. 597 * <p> 598 * If the field is not a {@code ChronoField}, then the result of this method 599 * is obtained by invoking {@code TemporalField.adjustInto(Temporal, long)} 600 * passing {@code this} as the argument. In this case, the field determines 601 * whether and how to adjust the instant. 602 * <p> 603 * This instance is immutable and unaffected by this method call. 604 * 605 * @param field the field to set in the result, not null 606 * @param newValue the new value of the field in the result 607 * @return a {@code Year} based on {@code this} with the specified field set, not null 608 * @throws DateTimeException if the field cannot be set 609 * @throws UnsupportedTemporalTypeException if the field is not supported 610 * @throws ArithmeticException if numeric overflow occurs 611 */ 612 @Override with(TemporalField field, long newValue)613 public Year with(TemporalField field, long newValue) { 614 if (field instanceof ChronoField) { 615 ChronoField f = (ChronoField) field; 616 f.checkValidValue(newValue); 617 switch (f) { 618 case YEAR_OF_ERA: return Year.of((int) (year < 1 ? 1 - newValue : newValue)); 619 case YEAR: return Year.of((int) newValue); 620 case ERA: return (getLong(ERA) == newValue ? this : Year.of(1 - year)); 621 } 622 throw new UnsupportedTemporalTypeException("Unsupported field: " + field); 623 } 624 return field.adjustInto(this, newValue); 625 } 626 627 //----------------------------------------------------------------------- 628 /** 629 * Returns a copy of this year with the specified amount added. 630 * <p> 631 * This returns a {@code Year}, based on this one, with the specified amount added. 632 * The amount is typically {@link Period} but may be any other type implementing 633 * the {@link TemporalAmount} interface. 634 * <p> 635 * The calculation is delegated to the amount object by calling 636 * {@link TemporalAmount#addTo(Temporal)}. The amount implementation is free 637 * to implement the addition in any way it wishes, however it typically 638 * calls back to {@link #plus(long, TemporalUnit)}. Consult the documentation 639 * of the amount implementation to determine if it can be successfully added. 640 * <p> 641 * This instance is immutable and unaffected by this method call. 642 * 643 * @param amountToAdd the amount to add, not null 644 * @return a {@code Year} based on this year with the addition made, not null 645 * @throws DateTimeException if the addition cannot be made 646 * @throws ArithmeticException if numeric overflow occurs 647 */ 648 @Override plus(TemporalAmount amountToAdd)649 public Year plus(TemporalAmount amountToAdd) { 650 return (Year) amountToAdd.addTo(this); 651 } 652 653 /** 654 * Returns a copy of this year with the specified amount added. 655 * <p> 656 * This returns a {@code Year}, based on this one, with the amount 657 * in terms of the unit added. If it is not possible to add the amount, because the 658 * unit is not supported or for some other reason, an exception is thrown. 659 * <p> 660 * If the field is a {@link ChronoUnit} then the addition is implemented here. 661 * The supported fields behave as follows: 662 * <ul> 663 * <li>{@code YEARS} - 664 * Returns a {@code Year} with the specified number of years added. 665 * This is equivalent to {@link #plusYears(long)}. 666 * <li>{@code DECADES} - 667 * Returns a {@code Year} with the specified number of decades added. 668 * This is equivalent to calling {@link #plusYears(long)} with the amount 669 * multiplied by 10. 670 * <li>{@code CENTURIES} - 671 * Returns a {@code Year} with the specified number of centuries added. 672 * This is equivalent to calling {@link #plusYears(long)} with the amount 673 * multiplied by 100. 674 * <li>{@code MILLENNIA} - 675 * Returns a {@code Year} with the specified number of millennia added. 676 * This is equivalent to calling {@link #plusYears(long)} with the amount 677 * multiplied by 1,000. 678 * <li>{@code ERAS} - 679 * Returns a {@code Year} with the specified number of eras added. 680 * Only two eras are supported so the amount must be one, zero or minus one. 681 * If the amount is non-zero then the year is changed such that the year-of-era 682 * is unchanged. 683 * </ul> 684 * <p> 685 * All other {@code ChronoUnit} instances will throw an {@code UnsupportedTemporalTypeException}. 686 * <p> 687 * If the field is not a {@code ChronoUnit}, then the result of this method 688 * is obtained by invoking {@code TemporalUnit.addTo(Temporal, long)} 689 * passing {@code this} as the argument. In this case, the unit determines 690 * whether and how to perform the addition. 691 * <p> 692 * This instance is immutable and unaffected by this method call. 693 * 694 * @param amountToAdd the amount of the unit to add to the result, may be negative 695 * @param unit the unit of the amount to add, not null 696 * @return a {@code Year} based on this year with the specified amount added, not null 697 * @throws DateTimeException if the addition cannot be made 698 * @throws UnsupportedTemporalTypeException if the unit is not supported 699 * @throws ArithmeticException if numeric overflow occurs 700 */ 701 @Override plus(long amountToAdd, TemporalUnit unit)702 public Year plus(long amountToAdd, TemporalUnit unit) { 703 if (unit instanceof ChronoUnit) { 704 switch ((ChronoUnit) unit) { 705 case YEARS: return plusYears(amountToAdd); 706 case DECADES: return plusYears(Math.multiplyExact(amountToAdd, 10)); 707 case CENTURIES: return plusYears(Math.multiplyExact(amountToAdd, 100)); 708 case MILLENNIA: return plusYears(Math.multiplyExact(amountToAdd, 1000)); 709 case ERAS: return with(ERA, Math.addExact(getLong(ERA), amountToAdd)); 710 } 711 throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit); 712 } 713 return unit.addTo(this, amountToAdd); 714 } 715 716 /** 717 * Returns a copy of this {@code Year} with the specified number of years added. 718 * <p> 719 * This instance is immutable and unaffected by this method call. 720 * 721 * @param yearsToAdd the years to add, may be negative 722 * @return a {@code Year} based on this year with the years added, not null 723 * @throws DateTimeException if the result exceeds the supported range 724 */ plusYears(long yearsToAdd)725 public Year plusYears(long yearsToAdd) { 726 if (yearsToAdd == 0) { 727 return this; 728 } 729 return of(YEAR.checkValidIntValue(year + yearsToAdd)); // overflow safe 730 } 731 732 //----------------------------------------------------------------------- 733 /** 734 * Returns a copy of this year with the specified amount subtracted. 735 * <p> 736 * This returns a {@code Year}, based on this one, with the specified amount subtracted. 737 * The amount is typically {@link Period} but may be any other type implementing 738 * the {@link TemporalAmount} interface. 739 * <p> 740 * The calculation is delegated to the amount object by calling 741 * {@link TemporalAmount#subtractFrom(Temporal)}. The amount implementation is free 742 * to implement the subtraction in any way it wishes, however it typically 743 * calls back to {@link #minus(long, TemporalUnit)}. Consult the documentation 744 * of the amount implementation to determine if it can be successfully subtracted. 745 * <p> 746 * This instance is immutable and unaffected by this method call. 747 * 748 * @param amountToSubtract the amount to subtract, not null 749 * @return a {@code Year} based on this year with the subtraction made, not null 750 * @throws DateTimeException if the subtraction cannot be made 751 * @throws ArithmeticException if numeric overflow occurs 752 */ 753 @Override minus(TemporalAmount amountToSubtract)754 public Year minus(TemporalAmount amountToSubtract) { 755 return (Year) amountToSubtract.subtractFrom(this); 756 } 757 758 /** 759 * Returns a copy of this year with the specified amount subtracted. 760 * <p> 761 * This returns a {@code Year}, based on this one, with the amount 762 * in terms of the unit subtracted. If it is not possible to subtract the amount, 763 * because the unit is not supported or for some other reason, an exception is thrown. 764 * <p> 765 * This method is equivalent to {@link #plus(long, TemporalUnit)} with the amount negated. 766 * See that method for a full description of how addition, and thus subtraction, works. 767 * <p> 768 * This instance is immutable and unaffected by this method call. 769 * 770 * @param amountToSubtract the amount of the unit to subtract from the result, may be negative 771 * @param unit the unit of the amount to subtract, not null 772 * @return a {@code Year} based on this year with the specified amount subtracted, not null 773 * @throws DateTimeException if the subtraction cannot be made 774 * @throws UnsupportedTemporalTypeException if the unit is not supported 775 * @throws ArithmeticException if numeric overflow occurs 776 */ 777 @Override minus(long amountToSubtract, TemporalUnit unit)778 public Year minus(long amountToSubtract, TemporalUnit unit) { 779 return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit)); 780 } 781 782 /** 783 * Returns a copy of this {@code Year} with the specified number of years subtracted. 784 * <p> 785 * This instance is immutable and unaffected by this method call. 786 * 787 * @param yearsToSubtract the years to subtract, may be negative 788 * @return a {@code Year} based on this year with the year subtracted, not null 789 * @throws DateTimeException if the result exceeds the supported range 790 */ minusYears(long yearsToSubtract)791 public Year minusYears(long yearsToSubtract) { 792 return (yearsToSubtract == Long.MIN_VALUE ? plusYears(Long.MAX_VALUE).plusYears(1) : plusYears(-yearsToSubtract)); 793 } 794 795 //----------------------------------------------------------------------- 796 /** 797 * Queries this year using the specified query. 798 * <p> 799 * This queries this year using the specified query strategy object. 800 * The {@code TemporalQuery} object defines the logic to be used to 801 * obtain the result. Read the documentation of the query to understand 802 * what the result of this method will be. 803 * <p> 804 * The result of this method is obtained by invoking the 805 * {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the 806 * specified query passing {@code this} as the argument. 807 * 808 * @param <R> the type of the result 809 * @param query the query to invoke, not null 810 * @return the query result, null may be returned (defined by the query) 811 * @throws DateTimeException if unable to query (defined by the query) 812 * @throws ArithmeticException if numeric overflow occurs (defined by the query) 813 */ 814 @SuppressWarnings("unchecked") 815 @Override query(TemporalQuery<R> query)816 public <R> R query(TemporalQuery<R> query) { 817 if (query == TemporalQueries.chronology()) { 818 return (R) IsoChronology.INSTANCE; 819 } else if (query == TemporalQueries.precision()) { 820 return (R) YEARS; 821 } 822 return Temporal.super.query(query); 823 } 824 825 /** 826 * Adjusts the specified temporal object to have this year. 827 * <p> 828 * This returns a temporal object of the same observable type as the input 829 * with the year changed to be the same as this. 830 * <p> 831 * The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)} 832 * passing {@link ChronoField#YEAR} as the field. 833 * If the specified temporal object does not use the ISO calendar system then 834 * a {@code DateTimeException} is thrown. 835 * <p> 836 * In most cases, it is clearer to reverse the calling pattern by using 837 * {@link Temporal#with(TemporalAdjuster)}: 838 * <pre> 839 * // these two lines are equivalent, but the second approach is recommended 840 * temporal = thisYear.adjustInto(temporal); 841 * temporal = temporal.with(thisYear); 842 * </pre> 843 * <p> 844 * This instance is immutable and unaffected by this method call. 845 * 846 * @param temporal the target object to be adjusted, not null 847 * @return the adjusted object, not null 848 * @throws DateTimeException if unable to make the adjustment 849 * @throws ArithmeticException if numeric overflow occurs 850 */ 851 @Override adjustInto(Temporal temporal)852 public Temporal adjustInto(Temporal temporal) { 853 if (Chronology.from(temporal).equals(IsoChronology.INSTANCE) == false) { 854 throw new DateTimeException("Adjustment only supported on ISO date-time"); 855 } 856 return temporal.with(YEAR, year); 857 } 858 859 /** 860 * Calculates the amount of time until another year in terms of the specified unit. 861 * <p> 862 * This calculates the amount of time between two {@code Year} 863 * objects in terms of a single {@code TemporalUnit}. 864 * The start and end points are {@code this} and the specified year. 865 * The result will be negative if the end is before the start. 866 * The {@code Temporal} passed to this method is converted to a 867 * {@code Year} using {@link #from(TemporalAccessor)}. 868 * For example, the amount in decades between two year can be calculated 869 * using {@code startYear.until(endYear, DECADES)}. 870 * <p> 871 * The calculation returns a whole number, representing the number of 872 * complete units between the two years. 873 * For example, the amount in decades between 2012 and 2031 874 * will only be one decade as it is one year short of two decades. 875 * <p> 876 * There are two equivalent ways of using this method. 877 * The first is to invoke this method. 878 * The second is to use {@link TemporalUnit#between(Temporal, Temporal)}: 879 * <pre> 880 * // these two lines are equivalent 881 * amount = start.until(end, YEARS); 882 * amount = YEARS.between(start, end); 883 * </pre> 884 * The choice should be made based on which makes the code more readable. 885 * <p> 886 * The calculation is implemented in this method for {@link ChronoUnit}. 887 * The units {@code YEARS}, {@code DECADES}, {@code CENTURIES}, 888 * {@code MILLENNIA} and {@code ERAS} are supported. 889 * Other {@code ChronoUnit} values will throw an exception. 890 * <p> 891 * If the unit is not a {@code ChronoUnit}, then the result of this method 892 * is obtained by invoking {@code TemporalUnit.between(Temporal, Temporal)} 893 * passing {@code this} as the first argument and the converted input temporal 894 * as the second argument. 895 * <p> 896 * This instance is immutable and unaffected by this method call. 897 * 898 * @param endExclusive the end date, exclusive, which is converted to a {@code Year}, not null 899 * @param unit the unit to measure the amount in, not null 900 * @return the amount of time between this year and the end year 901 * @throws DateTimeException if the amount cannot be calculated, or the end 902 * temporal cannot be converted to a {@code Year} 903 * @throws UnsupportedTemporalTypeException if the unit is not supported 904 * @throws ArithmeticException if numeric overflow occurs 905 */ 906 @Override until(Temporal endExclusive, TemporalUnit unit)907 public long until(Temporal endExclusive, TemporalUnit unit) { 908 Year end = Year.from(endExclusive); 909 if (unit instanceof ChronoUnit) { 910 long yearsUntil = ((long) end.year) - year; // no overflow 911 switch ((ChronoUnit) unit) { 912 case YEARS: return yearsUntil; 913 case DECADES: return yearsUntil / 10; 914 case CENTURIES: return yearsUntil / 100; 915 case MILLENNIA: return yearsUntil / 1000; 916 case ERAS: return end.getLong(ERA) - getLong(ERA); 917 } 918 throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit); 919 } 920 return unit.between(this, end); 921 } 922 923 /** 924 * Formats this year using the specified formatter. 925 * <p> 926 * This year will be passed to the formatter to produce a string. 927 * 928 * @param formatter the formatter to use, not null 929 * @return the formatted year string, not null 930 * @throws DateTimeException if an error occurs during printing 931 */ format(DateTimeFormatter formatter)932 public String format(DateTimeFormatter formatter) { 933 Objects.requireNonNull(formatter, "formatter"); 934 return formatter.format(this); 935 } 936 937 //----------------------------------------------------------------------- 938 /** 939 * Combines this year with a day-of-year to create a {@code LocalDate}. 940 * <p> 941 * This returns a {@code LocalDate} formed from this year and the specified day-of-year. 942 * <p> 943 * The day-of-year value 366 is only valid in a leap year. 944 * 945 * @param dayOfYear the day-of-year to use, from 1 to 365-366 946 * @return the local date formed from this year and the specified date of year, not null 947 * @throws DateTimeException if the day of year is zero or less, 366 or greater or equal 948 * to 366 and this is not a leap year 949 */ atDay(int dayOfYear)950 public LocalDate atDay(int dayOfYear) { 951 return LocalDate.ofYearDay(year, dayOfYear); 952 } 953 954 /** 955 * Combines this year with a month to create a {@code YearMonth}. 956 * <p> 957 * This returns a {@code YearMonth} formed from this year and the specified month. 958 * All possible combinations of year and month are valid. 959 * <p> 960 * This method can be used as part of a chain to produce a date: 961 * <pre> 962 * LocalDate date = year.atMonth(month).atDay(day); 963 * </pre> 964 * 965 * @param month the month-of-year to use, not null 966 * @return the year-month formed from this year and the specified month, not null 967 */ atMonth(Month month)968 public YearMonth atMonth(Month month) { 969 return YearMonth.of(year, month); 970 } 971 972 /** 973 * Combines this year with a month to create a {@code YearMonth}. 974 * <p> 975 * This returns a {@code YearMonth} formed from this year and the specified month. 976 * All possible combinations of year and month are valid. 977 * <p> 978 * This method can be used as part of a chain to produce a date: 979 * <pre> 980 * LocalDate date = year.atMonth(month).atDay(day); 981 * </pre> 982 * 983 * @param month the month-of-year to use, from 1 (January) to 12 (December) 984 * @return the year-month formed from this year and the specified month, not null 985 * @throws DateTimeException if the month is invalid 986 */ atMonth(int month)987 public YearMonth atMonth(int month) { 988 return YearMonth.of(year, month); 989 } 990 991 /** 992 * Combines this year with a month-day to create a {@code LocalDate}. 993 * <p> 994 * This returns a {@code LocalDate} formed from this year and the specified month-day. 995 * <p> 996 * A month-day of February 29th will be adjusted to February 28th in the resulting 997 * date if the year is not a leap year. 998 * 999 * @param monthDay the month-day to use, not null 1000 * @return the local date formed from this year and the specified month-day, not null 1001 */ atMonthDay(MonthDay monthDay)1002 public LocalDate atMonthDay(MonthDay monthDay) { 1003 return monthDay.atYear(year); 1004 } 1005 1006 //----------------------------------------------------------------------- 1007 /** 1008 * Compares this year to another year. 1009 * <p> 1010 * The comparison is based on the value of the year. 1011 * It is "consistent with equals", as defined by {@link Comparable}. 1012 * 1013 * @param other the other year to compare to, not null 1014 * @return the comparator value, negative if less, positive if greater 1015 */ 1016 @Override compareTo(Year other)1017 public int compareTo(Year other) { 1018 return year - other.year; 1019 } 1020 1021 /** 1022 * Checks if this year is after the specified year. 1023 * 1024 * @param other the other year to compare to, not null 1025 * @return true if this is after the specified year 1026 */ isAfter(Year other)1027 public boolean isAfter(Year other) { 1028 return year > other.year; 1029 } 1030 1031 /** 1032 * Checks if this year is before the specified year. 1033 * 1034 * @param other the other year to compare to, not null 1035 * @return true if this point is before the specified year 1036 */ isBefore(Year other)1037 public boolean isBefore(Year other) { 1038 return year < other.year; 1039 } 1040 1041 //----------------------------------------------------------------------- 1042 /** 1043 * Checks if this year is equal to another year. 1044 * <p> 1045 * The comparison is based on the time-line position of the years. 1046 * 1047 * @param obj the object to check, null returns false 1048 * @return true if this is equal to the other year 1049 */ 1050 @Override equals(Object obj)1051 public boolean equals(Object obj) { 1052 if (this == obj) { 1053 return true; 1054 } 1055 if (obj instanceof Year) { 1056 return year == ((Year) obj).year; 1057 } 1058 return false; 1059 } 1060 1061 /** 1062 * A hash code for this year. 1063 * 1064 * @return a suitable hash code 1065 */ 1066 @Override hashCode()1067 public int hashCode() { 1068 return year; 1069 } 1070 1071 //----------------------------------------------------------------------- 1072 /** 1073 * Outputs this year as a {@code String}. 1074 * 1075 * @return a string representation of this year, not null 1076 */ 1077 @Override toString()1078 public String toString() { 1079 return Integer.toString(year); 1080 } 1081 1082 //----------------------------------------------------------------------- 1083 /** 1084 * Writes the object using a 1085 * <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>. 1086 * @serialData 1087 * <pre> 1088 * out.writeByte(11); // identifies a Year 1089 * out.writeInt(year); 1090 * </pre> 1091 * 1092 * @return the instance of {@code Ser}, not null 1093 */ writeReplace()1094 private Object writeReplace() { 1095 return new Ser(Ser.YEAR_TYPE, this); 1096 } 1097 1098 /** 1099 * Defend against malicious streams. 1100 * 1101 * @param s the stream to read 1102 * @throws InvalidObjectException always 1103 */ readObject(ObjectInputStream s)1104 private void readObject(ObjectInputStream s) throws InvalidObjectException { 1105 throw new InvalidObjectException("Deserialization via serialization delegate"); 1106 } 1107 writeExternal(DataOutput out)1108 void writeExternal(DataOutput out) throws IOException { 1109 out.writeInt(year); 1110 } 1111 readExternal(DataInput in)1112 static Year readExternal(DataInput in) throws IOException { 1113 return Year.of(in.readInt()); 1114 } 1115 1116 } 1117