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 /** 100 * A year in the ISO-8601 calendar system, such as {@code 2007}. 101 * <p> 102 * {@code Year} is an immutable date-time object that represents a year. 103 * Any field that can be derived from a year can be obtained. 104 * <p> 105 * <b>Note that years in the ISO chronology only align with years in the 106 * Gregorian-Julian system for modern years. Parts of Russia did not switch to the 107 * modern Gregorian/ISO rules until 1920. 108 * As such, historical years must be treated with caution.</b> 109 * <p> 110 * This class does not store or represent a month, day, time or time-zone. 111 * For example, the value "2007" can be stored in a {@code Year}. 112 * <p> 113 * Years represented by this class follow the ISO-8601 standard and use 114 * the proleptic numbering system. Year 1 is preceded by year 0, then by year -1. 115 * <p> 116 * The ISO-8601 calendar system is the modern civil calendar system used today 117 * in most of the world. It is equivalent to the proleptic Gregorian calendar 118 * system, in which today's rules for leap years are applied for all time. 119 * For most applications written today, the ISO-8601 rules are entirely suitable. 120 * However, any application that makes use of historical dates, and requires them 121 * to be accurate will find the ISO-8601 approach unsuitable. 122 * 123 * <p> 124 * This is a <a href="{@docRoot}/java/lang/doc-files/ValueBased.html">value-based</a> 125 * class; use of identity-sensitive operations (including reference equality 126 * ({@code ==}), identity hash code, or synchronization) on instances of 127 * {@code Year} may have unpredictable results and should be avoided. 128 * The {@code equals} method should be used for comparisons. 129 * 130 * @implSpec 131 * This class is immutable and thread-safe. 132 * 133 * @since 1.8 134 */ 135 public final class Year 136 implements Temporal, TemporalAdjuster, Comparable<Year>, Serializable { 137 138 /** 139 * The minimum supported year, '-999,999,999'. 140 */ 141 public static final int MIN_VALUE = -999_999_999; 142 /** 143 * The maximum supported year, '+999,999,999'. 144 */ 145 public static final int MAX_VALUE = 999_999_999; 146 147 /** 148 * Serialization version. 149 */ 150 private static final long serialVersionUID = -23038383694477807L; 151 /** 152 * Parser. 153 */ 154 private static final DateTimeFormatter PARSER = new DateTimeFormatterBuilder() 155 .appendValue(YEAR, 4, 10, SignStyle.EXCEEDS_PAD) 156 .toFormatter(); 157 158 /** 159 * The year being represented. 160 */ 161 private final int year; 162 163 //----------------------------------------------------------------------- 164 /** 165 * Obtains the current year from the system clock in the default time-zone. 166 * <p> 167 * This will query the {@link Clock#systemDefaultZone() system clock} in the default 168 * time-zone to obtain the current year. 169 * <p> 170 * Using this method will prevent the ability to use an alternate clock for testing 171 * because the clock is hard-coded. 172 * 173 * @return the current year using the system clock and default time-zone, not null 174 */ now()175 public static Year now() { 176 return now(Clock.systemDefaultZone()); 177 } 178 179 /** 180 * Obtains the current year from the system clock in the specified time-zone. 181 * <p> 182 * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current year. 183 * Specifying the time-zone avoids dependence on the default time-zone. 184 * <p> 185 * Using this method will prevent the ability to use an alternate clock for testing 186 * because the clock is hard-coded. 187 * 188 * @param zone the zone ID to use, not null 189 * @return the current year using the system clock, not null 190 */ now(ZoneId zone)191 public static Year now(ZoneId zone) { 192 return now(Clock.system(zone)); 193 } 194 195 /** 196 * Obtains the current year from the specified clock. 197 * <p> 198 * This will query the specified clock to obtain the current year. 199 * Using this method allows the use of an alternate clock for testing. 200 * The alternate clock may be introduced using {@link Clock dependency injection}. 201 * 202 * @param clock the clock to use, not null 203 * @return the current year, not null 204 */ now(Clock clock)205 public static Year now(Clock clock) { 206 final LocalDate now = LocalDate.now(clock); // called once 207 return Year.of(now.getYear()); 208 } 209 210 //----------------------------------------------------------------------- 211 /** 212 * Obtains an instance of {@code Year}. 213 * <p> 214 * This method accepts a year value from the proleptic ISO calendar system. 215 * <p> 216 * The year 2AD/CE is represented by 2.<br> 217 * The year 1AD/CE is represented by 1.<br> 218 * The year 1BC/BCE is represented by 0.<br> 219 * The year 2BC/BCE is represented by -1.<br> 220 * 221 * @param isoYear the ISO proleptic year to represent, from {@code MIN_VALUE} to {@code MAX_VALUE} 222 * @return the year, not null 223 * @throws DateTimeException if the field is invalid 224 */ of(int isoYear)225 public static Year of(int isoYear) { 226 YEAR.checkValidValue(isoYear); 227 return new Year(isoYear); 228 } 229 230 //----------------------------------------------------------------------- 231 /** 232 * Obtains an instance of {@code Year} from a temporal object. 233 * <p> 234 * This obtains a year based on the specified temporal. 235 * A {@code TemporalAccessor} represents an arbitrary set of date and time information, 236 * which this factory converts to an instance of {@code Year}. 237 * <p> 238 * The conversion extracts the {@link ChronoField#YEAR year} field. 239 * The extraction is only permitted if the temporal object has an ISO 240 * chronology, or can be converted to a {@code LocalDate}. 241 * <p> 242 * This method matches the signature of the functional interface {@link TemporalQuery} 243 * allowing it to be used as a query via method reference, {@code Year::from}. 244 * 245 * @param temporal the temporal object to convert, not null 246 * @return the year, not null 247 * @throws DateTimeException if unable to convert to a {@code Year} 248 */ from(TemporalAccessor temporal)249 public static Year from(TemporalAccessor temporal) { 250 if (temporal instanceof Year) { 251 return (Year) temporal; 252 } 253 Objects.requireNonNull(temporal, "temporal"); 254 try { 255 if (IsoChronology.INSTANCE.equals(Chronology.from(temporal)) == false) { 256 temporal = LocalDate.from(temporal); 257 } 258 return of(temporal.get(YEAR)); 259 } catch (DateTimeException ex) { 260 throw new DateTimeException("Unable to obtain Year from TemporalAccessor: " + 261 temporal + " of type " + temporal.getClass().getName(), ex); 262 } 263 } 264 265 //----------------------------------------------------------------------- 266 /** 267 * Obtains an instance of {@code Year} from a text string such as {@code 2007}. 268 * <p> 269 * The string must represent a valid year. 270 * Years outside the range 0000 to 9999 must be prefixed by the plus or minus symbol. 271 * 272 * @param text the text to parse such as "2007", not null 273 * @return the parsed year, not null 274 * @throws DateTimeParseException if the text cannot be parsed 275 */ parse(CharSequence text)276 public static Year parse(CharSequence text) { 277 return parse(text, PARSER); 278 } 279 280 /** 281 * Obtains an instance of {@code Year} from a text string using a specific formatter. 282 * <p> 283 * The text is parsed using the formatter, returning a year. 284 * 285 * @param text the text to parse, not null 286 * @param formatter the formatter to use, not null 287 * @return the parsed year, not null 288 * @throws DateTimeParseException if the text cannot be parsed 289 */ parse(CharSequence text, DateTimeFormatter formatter)290 public static Year parse(CharSequence text, DateTimeFormatter formatter) { 291 Objects.requireNonNull(formatter, "formatter"); 292 return formatter.parse(text, Year::from); 293 } 294 295 //------------------------------------------------------------------------- 296 /** 297 * Checks if the year is a leap year, according to the ISO proleptic 298 * calendar system rules. 299 * <p> 300 * This method applies the current rules for leap years across the whole time-line. 301 * In general, a year is a leap year if it is divisible by four without 302 * remainder. However, years divisible by 100, are not leap years, with 303 * the exception of years divisible by 400 which are. 304 * <p> 305 * For example, 1904 is a leap year it is divisible by 4. 306 * 1900 was not a leap year as it is divisible by 100, however 2000 was a 307 * leap year as it is divisible by 400. 308 * <p> 309 * The calculation is proleptic - applying the same rules into the far future and far past. 310 * This is historically inaccurate, but is correct for the ISO-8601 standard. 311 * 312 * @param year the year to check 313 * @return true if the year is leap, false otherwise 314 */ isLeap(long year)315 public static boolean isLeap(long year) { 316 return ((year & 3) == 0) && ((year % 100) != 0 || (year % 400) == 0); 317 } 318 319 //----------------------------------------------------------------------- 320 /** 321 * Constructor. 322 * 323 * @param year the year to represent 324 */ Year(int year)325 private Year(int year) { 326 this.year = year; 327 } 328 329 //----------------------------------------------------------------------- 330 /** 331 * Gets the year value. 332 * <p> 333 * The year returned by this method is proleptic as per {@code get(YEAR)}. 334 * 335 * @return the year, {@code MIN_VALUE} to {@code MAX_VALUE} 336 */ getValue()337 public int getValue() { 338 return year; 339 } 340 341 //----------------------------------------------------------------------- 342 /** 343 * Checks if the specified field is supported. 344 * <p> 345 * This checks if this year can be queried for the specified field. 346 * If false, then calling the {@link #range(TemporalField) range}, 347 * {@link #get(TemporalField) get} and {@link #with(TemporalField, long)} 348 * methods will throw an exception. 349 * <p> 350 * If the field is a {@link ChronoField} then the query is implemented here. 351 * The supported fields are: 352 * <ul> 353 * <li>{@code YEAR_OF_ERA} 354 * <li>{@code YEAR} 355 * <li>{@code ERA} 356 * </ul> 357 * All other {@code ChronoField} instances will return false. 358 * <p> 359 * If the field is not a {@code ChronoField}, then the result of this method 360 * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)} 361 * passing {@code this} as the argument. 362 * Whether the field is supported is determined by the field. 363 * 364 * @param field the field to check, null returns false 365 * @return true if the field is supported on this year, false if not 366 */ 367 @Override isSupported(TemporalField field)368 public boolean isSupported(TemporalField field) { 369 if (field instanceof ChronoField) { 370 return field == YEAR || field == YEAR_OF_ERA || field == ERA; 371 } 372 return field != null && field.isSupportedBy(this); 373 } 374 375 /** 376 * Checks if the specified unit is supported. 377 * <p> 378 * This checks if the specified unit can be added to, or subtracted from, this year. 379 * If false, then calling the {@link #plus(long, TemporalUnit)} and 380 * {@link #minus(long, TemporalUnit) minus} methods will throw an exception. 381 * <p> 382 * If the unit is a {@link ChronoUnit} then the query is implemented here. 383 * The supported units are: 384 * <ul> 385 * <li>{@code YEARS} 386 * <li>{@code DECADES} 387 * <li>{@code CENTURIES} 388 * <li>{@code MILLENNIA} 389 * <li>{@code ERAS} 390 * </ul> 391 * All other {@code ChronoUnit} instances will return false. 392 * <p> 393 * If the unit is not a {@code ChronoUnit}, then the result of this method 394 * is obtained by invoking {@code TemporalUnit.isSupportedBy(Temporal)} 395 * passing {@code this} as the argument. 396 * Whether the unit is supported is determined by the unit. 397 * 398 * @param unit the unit to check, null returns false 399 * @return true if the unit can be added/subtracted, false if not 400 */ 401 @Override isSupported(TemporalUnit unit)402 public boolean isSupported(TemporalUnit unit) { 403 if (unit instanceof ChronoUnit) { 404 return unit == YEARS || unit == DECADES || unit == CENTURIES || unit == MILLENNIA || unit == ERAS; 405 } 406 return unit != null && unit.isSupportedBy(this); 407 } 408 409 //----------------------------------------------------------------------- 410 /** 411 * Gets the range of valid values for the specified field. 412 * <p> 413 * The range object expresses the minimum and maximum valid values for a field. 414 * This year is used to enhance the accuracy of the returned range. 415 * If it is not possible to return the range, because the field is not supported 416 * or for some other reason, an exception is thrown. 417 * <p> 418 * If the field is a {@link ChronoField} then the query is implemented here. 419 * The {@link #isSupported(TemporalField) supported fields} will return 420 * appropriate range instances. 421 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. 422 * <p> 423 * If the field is not a {@code ChronoField}, then the result of this method 424 * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)} 425 * passing {@code this} as the argument. 426 * Whether the range can be obtained is determined by the field. 427 * 428 * @param field the field to query the range for, not null 429 * @return the range of valid values for the field, not null 430 * @throws DateTimeException if the range for the field cannot be obtained 431 * @throws UnsupportedTemporalTypeException if the field is not supported 432 */ 433 @Override range(TemporalField field)434 public ValueRange range(TemporalField field) { 435 if (field == YEAR_OF_ERA) { 436 return (year <= 0 ? ValueRange.of(1, MAX_VALUE + 1) : ValueRange.of(1, MAX_VALUE)); 437 } 438 return Temporal.super.range(field); 439 } 440 441 /** 442 * Gets the value of the specified field from this year as an {@code int}. 443 * <p> 444 * This queries this year for the value of the specified field. 445 * The returned value will always be within the valid range of values for the field. 446 * If it is not possible to return the value, because the field is not supported 447 * or for some other reason, an exception is thrown. 448 * <p> 449 * If the field is a {@link ChronoField} then the query is implemented here. 450 * The {@link #isSupported(TemporalField) supported fields} will return valid 451 * values based on this year. 452 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. 453 * <p> 454 * If the field is not a {@code ChronoField}, then the result of this method 455 * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)} 456 * passing {@code this} as the argument. Whether the value can be obtained, 457 * and what the value represents, is determined by the field. 458 * 459 * @param field the field to get, not null 460 * @return the value for the field 461 * @throws DateTimeException if a value for the field cannot be obtained or 462 * the value is outside the range of valid values for the field 463 * @throws UnsupportedTemporalTypeException if the field is not supported or 464 * the range of values exceeds an {@code int} 465 * @throws ArithmeticException if numeric overflow occurs 466 */ 467 @Override // override for Javadoc get(TemporalField field)468 public int get(TemporalField field) { 469 return range(field).checkValidIntValue(getLong(field), field); 470 } 471 472 /** 473 * Gets the value of the specified field from this year as a {@code long}. 474 * <p> 475 * This queries this year for the value of the specified field. 476 * If it is not possible to return the value, because the field is not supported 477 * or for some other reason, an exception is thrown. 478 * <p> 479 * If the field is a {@link ChronoField} then the query is implemented here. 480 * The {@link #isSupported(TemporalField) supported fields} will return valid 481 * values based on this year. 482 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. 483 * <p> 484 * If the field is not a {@code ChronoField}, then the result of this method 485 * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)} 486 * passing {@code this} as the argument. Whether the value can be obtained, 487 * and what the value represents, is determined by the field. 488 * 489 * @param field the field to get, not null 490 * @return the value for the field 491 * @throws DateTimeException if a value for the field cannot be obtained 492 * @throws UnsupportedTemporalTypeException if the field is not supported 493 * @throws ArithmeticException if numeric overflow occurs 494 */ 495 @Override getLong(TemporalField field)496 public long getLong(TemporalField field) { 497 if (field instanceof ChronoField) { 498 switch ((ChronoField) field) { 499 case YEAR_OF_ERA: return (year < 1 ? 1 - year : year); 500 case YEAR: return year; 501 case ERA: return (year < 1 ? 0 : 1); 502 } 503 throw new UnsupportedTemporalTypeException("Unsupported field: " + field); 504 } 505 return field.getFrom(this); 506 } 507 508 //----------------------------------------------------------------------- 509 /** 510 * Checks if the year is a leap year, according to the ISO proleptic 511 * calendar system rules. 512 * <p> 513 * This method applies the current rules for leap years across the whole time-line. 514 * In general, a year is a leap year if it is divisible by four without 515 * remainder. However, years divisible by 100, are not leap years, with 516 * the exception of years divisible by 400 which are. 517 * <p> 518 * For example, 1904 is a leap year it is divisible by 4. 519 * 1900 was not a leap year as it is divisible by 100, however 2000 was a 520 * leap year as it is divisible by 400. 521 * <p> 522 * The calculation is proleptic - applying the same rules into the far future and far past. 523 * This is historically inaccurate, but is correct for the ISO-8601 standard. 524 * 525 * @return true if the year is leap, false otherwise 526 */ isLeap()527 public boolean isLeap() { 528 return Year.isLeap(year); 529 } 530 531 /** 532 * Checks if the month-day is valid for this year. 533 * <p> 534 * This method checks whether this year and the input month and day form 535 * a valid date. 536 * 537 * @param monthDay the month-day to validate, null returns false 538 * @return true if the month and day are valid for this year 539 */ isValidMonthDay(MonthDay monthDay)540 public boolean isValidMonthDay(MonthDay monthDay) { 541 return monthDay != null && monthDay.isValidYear(year); 542 } 543 544 /** 545 * Gets the length of this year in days. 546 * 547 * @return the length of this year in days, 365 or 366 548 */ length()549 public int length() { 550 return isLeap() ? 366 : 365; 551 } 552 553 //----------------------------------------------------------------------- 554 /** 555 * Returns an adjusted copy of this year. 556 * <p> 557 * This returns a {@code Year}, based on this one, with the year adjusted. 558 * The adjustment takes place using the specified adjuster strategy object. 559 * Read the documentation of the adjuster to understand what adjustment will be made. 560 * <p> 561 * The result of this method is obtained by invoking the 562 * {@link TemporalAdjuster#adjustInto(Temporal)} method on the 563 * specified adjuster passing {@code this} as the argument. 564 * <p> 565 * This instance is immutable and unaffected by this method call. 566 * 567 * @param adjuster the adjuster to use, not null 568 * @return a {@code Year} based on {@code this} with the adjustment made, not null 569 * @throws DateTimeException if the adjustment cannot be made 570 * @throws ArithmeticException if numeric overflow occurs 571 */ 572 @Override with(TemporalAdjuster adjuster)573 public Year with(TemporalAdjuster adjuster) { 574 return (Year) adjuster.adjustInto(this); 575 } 576 577 /** 578 * Returns a copy of this year with the specified field set to a new value. 579 * <p> 580 * This returns a {@code Year}, based on this one, with the value 581 * for the specified field changed. 582 * If it is not possible to set the value, because the field is not supported or for 583 * some other reason, an exception is thrown. 584 * <p> 585 * If the field is a {@link ChronoField} then the adjustment is implemented here. 586 * The supported fields behave as follows: 587 * <ul> 588 * <li>{@code YEAR_OF_ERA} - 589 * Returns a {@code Year} with the specified year-of-era 590 * The era will be unchanged. 591 * <li>{@code YEAR} - 592 * Returns a {@code Year} with the specified year. 593 * This completely replaces the date and is equivalent to {@link #of(int)}. 594 * <li>{@code ERA} - 595 * Returns a {@code Year} with the specified era. 596 * The year-of-era will be unchanged. 597 * </ul> 598 * <p> 599 * In all cases, if the new value is outside the valid range of values for the field 600 * then a {@code DateTimeException} will be thrown. 601 * <p> 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.adjustInto(Temporal, long)} 606 * passing {@code this} as the argument. In this case, the field determines 607 * whether and how to adjust the instant. 608 * <p> 609 * This instance is immutable and unaffected by this method call. 610 * 611 * @param field the field to set in the result, not null 612 * @param newValue the new value of the field in the result 613 * @return a {@code Year} based on {@code this} with the specified field set, not null 614 * @throws DateTimeException if the field cannot be set 615 * @throws UnsupportedTemporalTypeException if the field is not supported 616 * @throws ArithmeticException if numeric overflow occurs 617 */ 618 @Override with(TemporalField field, long newValue)619 public Year with(TemporalField field, long newValue) { 620 if (field instanceof ChronoField) { 621 ChronoField f = (ChronoField) field; 622 f.checkValidValue(newValue); 623 switch (f) { 624 case YEAR_OF_ERA: return Year.of((int) (year < 1 ? 1 - newValue : newValue)); 625 case YEAR: return Year.of((int) newValue); 626 case ERA: return (getLong(ERA) == newValue ? this : Year.of(1 - year)); 627 } 628 throw new UnsupportedTemporalTypeException("Unsupported field: " + field); 629 } 630 return field.adjustInto(this, newValue); 631 } 632 633 //----------------------------------------------------------------------- 634 /** 635 * Returns a copy of this year with the specified amount added. 636 * <p> 637 * This returns a {@code Year}, based on this one, with the specified amount added. 638 * The amount is typically {@link Period} but may be any other type implementing 639 * the {@link TemporalAmount} interface. 640 * <p> 641 * The calculation is delegated to the amount object by calling 642 * {@link TemporalAmount#addTo(Temporal)}. The amount implementation is free 643 * to implement the addition in any way it wishes, however it typically 644 * calls back to {@link #plus(long, TemporalUnit)}. Consult the documentation 645 * of the amount implementation to determine if it can be successfully added. 646 * <p> 647 * This instance is immutable and unaffected by this method call. 648 * 649 * @param amountToAdd the amount to add, not null 650 * @return a {@code Year} based on this year with the addition made, not null 651 * @throws DateTimeException if the addition cannot be made 652 * @throws ArithmeticException if numeric overflow occurs 653 */ 654 @Override plus(TemporalAmount amountToAdd)655 public Year plus(TemporalAmount amountToAdd) { 656 return (Year) amountToAdd.addTo(this); 657 } 658 659 /** 660 * Returns a copy of this year with the specified amount added. 661 * <p> 662 * This returns a {@code Year}, based on this one, with the amount 663 * in terms of the unit added. If it is not possible to add the amount, because the 664 * unit is not supported or for some other reason, an exception is thrown. 665 * <p> 666 * If the field is a {@link ChronoUnit} then the addition is implemented here. 667 * The supported fields behave as follows: 668 * <ul> 669 * <li>{@code YEARS} - 670 * Returns a {@code Year} with the specified number of years added. 671 * This is equivalent to {@link #plusYears(long)}. 672 * <li>{@code DECADES} - 673 * Returns a {@code Year} with the specified number of decades added. 674 * This is equivalent to calling {@link #plusYears(long)} with the amount 675 * multiplied by 10. 676 * <li>{@code CENTURIES} - 677 * Returns a {@code Year} with the specified number of centuries added. 678 * This is equivalent to calling {@link #plusYears(long)} with the amount 679 * multiplied by 100. 680 * <li>{@code MILLENNIA} - 681 * Returns a {@code Year} with the specified number of millennia added. 682 * This is equivalent to calling {@link #plusYears(long)} with the amount 683 * multiplied by 1,000. 684 * <li>{@code ERAS} - 685 * Returns a {@code Year} with the specified number of eras added. 686 * Only two eras are supported so the amount must be one, zero or minus one. 687 * If the amount is non-zero then the year is changed such that the year-of-era 688 * is unchanged. 689 * </ul> 690 * <p> 691 * All other {@code ChronoUnit} instances will throw an {@code UnsupportedTemporalTypeException}. 692 * <p> 693 * If the field is not a {@code ChronoUnit}, then the result of this method 694 * is obtained by invoking {@code TemporalUnit.addTo(Temporal, long)} 695 * passing {@code this} as the argument. In this case, the unit determines 696 * whether and how to perform the addition. 697 * <p> 698 * This instance is immutable and unaffected by this method call. 699 * 700 * @param amountToAdd the amount of the unit to add to the result, may be negative 701 * @param unit the unit of the amount to add, not null 702 * @return a {@code Year} based on this year with the specified amount added, not null 703 * @throws DateTimeException if the addition cannot be made 704 * @throws UnsupportedTemporalTypeException if the unit is not supported 705 * @throws ArithmeticException if numeric overflow occurs 706 */ 707 @Override plus(long amountToAdd, TemporalUnit unit)708 public Year plus(long amountToAdd, TemporalUnit unit) { 709 if (unit instanceof ChronoUnit) { 710 switch ((ChronoUnit) unit) { 711 case YEARS: return plusYears(amountToAdd); 712 case DECADES: return plusYears(Math.multiplyExact(amountToAdd, 10)); 713 case CENTURIES: return plusYears(Math.multiplyExact(amountToAdd, 100)); 714 case MILLENNIA: return plusYears(Math.multiplyExact(amountToAdd, 1000)); 715 case ERAS: return with(ERA, Math.addExact(getLong(ERA), amountToAdd)); 716 } 717 throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit); 718 } 719 return unit.addTo(this, amountToAdd); 720 } 721 722 /** 723 * Returns a copy of this {@code Year} with the specified number of years added. 724 * <p> 725 * This instance is immutable and unaffected by this method call. 726 * 727 * @param yearsToAdd the years to add, may be negative 728 * @return a {@code Year} based on this year with the years added, not null 729 * @throws DateTimeException if the result exceeds the supported range 730 */ plusYears(long yearsToAdd)731 public Year plusYears(long yearsToAdd) { 732 if (yearsToAdd == 0) { 733 return this; 734 } 735 return of(YEAR.checkValidIntValue(year + yearsToAdd)); // overflow safe 736 } 737 738 //----------------------------------------------------------------------- 739 /** 740 * Returns a copy of this year with the specified amount subtracted. 741 * <p> 742 * This returns a {@code Year}, based on this one, with the specified amount subtracted. 743 * The amount is typically {@link Period} but may be any other type implementing 744 * the {@link TemporalAmount} interface. 745 * <p> 746 * The calculation is delegated to the amount object by calling 747 * {@link TemporalAmount#subtractFrom(Temporal)}. The amount implementation is free 748 * to implement the subtraction in any way it wishes, however it typically 749 * calls back to {@link #minus(long, TemporalUnit)}. Consult the documentation 750 * of the amount implementation to determine if it can be successfully subtracted. 751 * <p> 752 * This instance is immutable and unaffected by this method call. 753 * 754 * @param amountToSubtract the amount to subtract, not null 755 * @return a {@code Year} based on this year with the subtraction made, not null 756 * @throws DateTimeException if the subtraction cannot be made 757 * @throws ArithmeticException if numeric overflow occurs 758 */ 759 @Override minus(TemporalAmount amountToSubtract)760 public Year minus(TemporalAmount amountToSubtract) { 761 return (Year) amountToSubtract.subtractFrom(this); 762 } 763 764 /** 765 * Returns a copy of this year with the specified amount subtracted. 766 * <p> 767 * This returns a {@code Year}, based on this one, with the amount 768 * in terms of the unit subtracted. If it is not possible to subtract the amount, 769 * because the unit is not supported or for some other reason, an exception is thrown. 770 * <p> 771 * This method is equivalent to {@link #plus(long, TemporalUnit)} with the amount negated. 772 * See that method for a full description of how addition, and thus subtraction, works. 773 * <p> 774 * This instance is immutable and unaffected by this method call. 775 * 776 * @param amountToSubtract the amount of the unit to subtract from the result, may be negative 777 * @param unit the unit of the amount to subtract, not null 778 * @return a {@code Year} based on this year with the specified amount subtracted, not null 779 * @throws DateTimeException if the subtraction cannot be made 780 * @throws UnsupportedTemporalTypeException if the unit is not supported 781 * @throws ArithmeticException if numeric overflow occurs 782 */ 783 @Override minus(long amountToSubtract, TemporalUnit unit)784 public Year minus(long amountToSubtract, TemporalUnit unit) { 785 return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit)); 786 } 787 788 /** 789 * Returns a copy of this {@code Year} with the specified number of years subtracted. 790 * <p> 791 * This instance is immutable and unaffected by this method call. 792 * 793 * @param yearsToSubtract the years to subtract, may be negative 794 * @return a {@code Year} based on this year with the year subtracted, not null 795 * @throws DateTimeException if the result exceeds the supported range 796 */ minusYears(long yearsToSubtract)797 public Year minusYears(long yearsToSubtract) { 798 return (yearsToSubtract == Long.MIN_VALUE ? plusYears(Long.MAX_VALUE).plusYears(1) : plusYears(-yearsToSubtract)); 799 } 800 801 //----------------------------------------------------------------------- 802 /** 803 * Queries this year using the specified query. 804 * <p> 805 * This queries this year using the specified query strategy object. 806 * The {@code TemporalQuery} object defines the logic to be used to 807 * obtain the result. Read the documentation of the query to understand 808 * what the result of this method will be. 809 * <p> 810 * The result of this method is obtained by invoking the 811 * {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the 812 * specified query passing {@code this} as the argument. 813 * 814 * @param <R> the type of the result 815 * @param query the query to invoke, not null 816 * @return the query result, null may be returned (defined by the query) 817 * @throws DateTimeException if unable to query (defined by the query) 818 * @throws ArithmeticException if numeric overflow occurs (defined by the query) 819 */ 820 @SuppressWarnings("unchecked") 821 @Override query(TemporalQuery<R> query)822 public <R> R query(TemporalQuery<R> query) { 823 if (query == TemporalQueries.chronology()) { 824 return (R) IsoChronology.INSTANCE; 825 } else if (query == TemporalQueries.precision()) { 826 return (R) YEARS; 827 } 828 return Temporal.super.query(query); 829 } 830 831 /** 832 * Adjusts the specified temporal object to have this year. 833 * <p> 834 * This returns a temporal object of the same observable type as the input 835 * with the year changed to be the same as this. 836 * <p> 837 * The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)} 838 * passing {@link ChronoField#YEAR} as the field. 839 * If the specified temporal object does not use the ISO calendar system then 840 * a {@code DateTimeException} is thrown. 841 * <p> 842 * In most cases, it is clearer to reverse the calling pattern by using 843 * {@link Temporal#with(TemporalAdjuster)}: 844 * <pre> 845 * // these two lines are equivalent, but the second approach is recommended 846 * temporal = thisYear.adjustInto(temporal); 847 * temporal = temporal.with(thisYear); 848 * </pre> 849 * <p> 850 * This instance is immutable and unaffected by this method call. 851 * 852 * @param temporal the target object to be adjusted, not null 853 * @return the adjusted object, not null 854 * @throws DateTimeException if unable to make the adjustment 855 * @throws ArithmeticException if numeric overflow occurs 856 */ 857 @Override adjustInto(Temporal temporal)858 public Temporal adjustInto(Temporal temporal) { 859 if (Chronology.from(temporal).equals(IsoChronology.INSTANCE) == false) { 860 throw new DateTimeException("Adjustment only supported on ISO date-time"); 861 } 862 return temporal.with(YEAR, year); 863 } 864 865 /** 866 * Calculates the amount of time until another year in terms of the specified unit. 867 * <p> 868 * This calculates the amount of time between two {@code Year} 869 * objects in terms of a single {@code TemporalUnit}. 870 * The start and end points are {@code this} and the specified year. 871 * The result will be negative if the end is before the start. 872 * The {@code Temporal} passed to this method is converted to a 873 * {@code Year} using {@link #from(TemporalAccessor)}. 874 * For example, the amount in decades between two year can be calculated 875 * using {@code startYear.until(endYear, DECADES)}. 876 * <p> 877 * The calculation returns a whole number, representing the number of 878 * complete units between the two years. 879 * For example, the amount in decades between 2012 and 2031 880 * will only be one decade as it is one year short of two decades. 881 * <p> 882 * There are two equivalent ways of using this method. 883 * The first is to invoke this method. 884 * The second is to use {@link TemporalUnit#between(Temporal, Temporal)}: 885 * <pre> 886 * // these two lines are equivalent 887 * amount = start.until(end, YEARS); 888 * amount = YEARS.between(start, end); 889 * </pre> 890 * The choice should be made based on which makes the code more readable. 891 * <p> 892 * The calculation is implemented in this method for {@link ChronoUnit}. 893 * The units {@code YEARS}, {@code DECADES}, {@code CENTURIES}, 894 * {@code MILLENNIA} and {@code ERAS} are supported. 895 * Other {@code ChronoUnit} values will throw an exception. 896 * <p> 897 * If the unit is not a {@code ChronoUnit}, then the result of this method 898 * is obtained by invoking {@code TemporalUnit.between(Temporal, Temporal)} 899 * passing {@code this} as the first argument and the converted input temporal 900 * as the second argument. 901 * <p> 902 * This instance is immutable and unaffected by this method call. 903 * 904 * @param endExclusive the end date, exclusive, which is converted to a {@code Year}, not null 905 * @param unit the unit to measure the amount in, not null 906 * @return the amount of time between this year and the end year 907 * @throws DateTimeException if the amount cannot be calculated, or the end 908 * temporal cannot be converted to a {@code Year} 909 * @throws UnsupportedTemporalTypeException if the unit is not supported 910 * @throws ArithmeticException if numeric overflow occurs 911 */ 912 @Override until(Temporal endExclusive, TemporalUnit unit)913 public long until(Temporal endExclusive, TemporalUnit unit) { 914 Year end = Year.from(endExclusive); 915 if (unit instanceof ChronoUnit) { 916 long yearsUntil = ((long) end.year) - year; // no overflow 917 switch ((ChronoUnit) unit) { 918 case YEARS: return yearsUntil; 919 case DECADES: return yearsUntil / 10; 920 case CENTURIES: return yearsUntil / 100; 921 case MILLENNIA: return yearsUntil / 1000; 922 case ERAS: return end.getLong(ERA) - getLong(ERA); 923 } 924 throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit); 925 } 926 return unit.between(this, end); 927 } 928 929 /** 930 * Formats this year using the specified formatter. 931 * <p> 932 * This year will be passed to the formatter to produce a string. 933 * 934 * @param formatter the formatter to use, not null 935 * @return the formatted year string, not null 936 * @throws DateTimeException if an error occurs during printing 937 */ format(DateTimeFormatter formatter)938 public String format(DateTimeFormatter formatter) { 939 Objects.requireNonNull(formatter, "formatter"); 940 return formatter.format(this); 941 } 942 943 //----------------------------------------------------------------------- 944 /** 945 * Combines this year with a day-of-year to create a {@code LocalDate}. 946 * <p> 947 * This returns a {@code LocalDate} formed from this year and the specified day-of-year. 948 * <p> 949 * The day-of-year value 366 is only valid in a leap year. 950 * 951 * @param dayOfYear the day-of-year to use, from 1 to 365-366 952 * @return the local date formed from this year and the specified date of year, not null 953 * @throws DateTimeException if the day of year is zero or less, 366 or greater or equal 954 * to 366 and this is not a leap year 955 */ atDay(int dayOfYear)956 public LocalDate atDay(int dayOfYear) { 957 return LocalDate.ofYearDay(year, dayOfYear); 958 } 959 960 /** 961 * Combines this year with a month to create a {@code YearMonth}. 962 * <p> 963 * This returns a {@code YearMonth} formed from this year and the specified month. 964 * All possible combinations of year and month are valid. 965 * <p> 966 * This method can be used as part of a chain to produce a date: 967 * <pre> 968 * LocalDate date = year.atMonth(month).atDay(day); 969 * </pre> 970 * 971 * @param month the month-of-year to use, not null 972 * @return the year-month formed from this year and the specified month, not null 973 */ atMonth(Month month)974 public YearMonth atMonth(Month month) { 975 return YearMonth.of(year, month); 976 } 977 978 /** 979 * Combines this year with a month to create a {@code YearMonth}. 980 * <p> 981 * This returns a {@code YearMonth} formed from this year and the specified month. 982 * All possible combinations of year and month are valid. 983 * <p> 984 * This method can be used as part of a chain to produce a date: 985 * <pre> 986 * LocalDate date = year.atMonth(month).atDay(day); 987 * </pre> 988 * 989 * @param month the month-of-year to use, from 1 (January) to 12 (December) 990 * @return the year-month formed from this year and the specified month, not null 991 * @throws DateTimeException if the month is invalid 992 */ atMonth(int month)993 public YearMonth atMonth(int month) { 994 return YearMonth.of(year, month); 995 } 996 997 /** 998 * Combines this year with a month-day to create a {@code LocalDate}. 999 * <p> 1000 * This returns a {@code LocalDate} formed from this year and the specified month-day. 1001 * <p> 1002 * A month-day of February 29th will be adjusted to February 28th in the resulting 1003 * date if the year is not a leap year. 1004 * 1005 * @param monthDay the month-day to use, not null 1006 * @return the local date formed from this year and the specified month-day, not null 1007 */ atMonthDay(MonthDay monthDay)1008 public LocalDate atMonthDay(MonthDay monthDay) { 1009 return monthDay.atYear(year); 1010 } 1011 1012 //----------------------------------------------------------------------- 1013 /** 1014 * Compares this year to another year. 1015 * <p> 1016 * The comparison is based on the value of the year. 1017 * It is "consistent with equals", as defined by {@link Comparable}. 1018 * 1019 * @param other the other year to compare to, not null 1020 * @return the comparator value, negative if less, positive if greater 1021 */ 1022 @Override compareTo(Year other)1023 public int compareTo(Year other) { 1024 return year - other.year; 1025 } 1026 1027 /** 1028 * Checks if this year is after the specified year. 1029 * 1030 * @param other the other year to compare to, not null 1031 * @return true if this is after the specified year 1032 */ isAfter(Year other)1033 public boolean isAfter(Year other) { 1034 return year > other.year; 1035 } 1036 1037 /** 1038 * Checks if this year is before the specified year. 1039 * 1040 * @param other the other year to compare to, not null 1041 * @return true if this point is before the specified year 1042 */ isBefore(Year other)1043 public boolean isBefore(Year other) { 1044 return year < other.year; 1045 } 1046 1047 //----------------------------------------------------------------------- 1048 /** 1049 * Checks if this year is equal to another year. 1050 * <p> 1051 * The comparison is based on the time-line position of the years. 1052 * 1053 * @param obj the object to check, null returns false 1054 * @return true if this is equal to the other year 1055 */ 1056 @Override equals(Object obj)1057 public boolean equals(Object obj) { 1058 if (this == obj) { 1059 return true; 1060 } 1061 if (obj instanceof Year) { 1062 return year == ((Year) obj).year; 1063 } 1064 return false; 1065 } 1066 1067 /** 1068 * A hash code for this year. 1069 * 1070 * @return a suitable hash code 1071 */ 1072 @Override hashCode()1073 public int hashCode() { 1074 return year; 1075 } 1076 1077 //----------------------------------------------------------------------- 1078 /** 1079 * Outputs this year as a {@code String}. 1080 * 1081 * @return a string representation of this year, not null 1082 */ 1083 @Override toString()1084 public String toString() { 1085 return Integer.toString(year); 1086 } 1087 1088 //----------------------------------------------------------------------- 1089 /** 1090 * Writes the object using a 1091 * <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>. 1092 * @serialData 1093 * <pre> 1094 * out.writeByte(11); // identifies a Year 1095 * out.writeInt(year); 1096 * </pre> 1097 * 1098 * @return the instance of {@code Ser}, not null 1099 */ writeReplace()1100 private Object writeReplace() { 1101 return new Ser(Ser.YEAR_TYPE, this); 1102 } 1103 1104 /** 1105 * Defend against malicious streams. 1106 * 1107 * @param s the stream to read 1108 * @throws InvalidObjectException always 1109 */ readObject(ObjectInputStream s)1110 private void readObject(ObjectInputStream s) throws InvalidObjectException { 1111 throw new InvalidObjectException("Deserialization via serialization delegate"); 1112 } 1113 writeExternal(DataOutput out)1114 void writeExternal(DataOutput out) throws IOException { 1115 out.writeInt(year); 1116 } 1117 readExternal(DataInput in)1118 static Year readExternal(DataInput in) throws IOException { 1119 return Year.of(in.readInt()); 1120 } 1121 1122 } 1123