1/* 2 * Copyright (c) 2012, 2016, 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) 2008-2012, Stephen Colebourne & Michael Nascimento Santos 33 * 34 * All rights reserved. 35 * 36 * Redistribution and use in source and binary forms, with or without 37 * modification, are permitted provided that the following conditions are met: 38 * 39 * * Redistributions of source code must retain the above copyright notice, 40 * this list of conditions and the following disclaimer. 41 * 42 * * Redistributions in binary form must reproduce the above copyright notice, 43 * this list of conditions and the following disclaimer in the documentation 44 * and/or other materials provided with the distribution. 45 * 46 * * Neither the name of JSR-310 nor the names of its contributors 47 * may be used to endorse or promote products derived from this software 48 * without specific prior written permission. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 51 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 52 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 53 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 54 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 55 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 56 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 57 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 58 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 59 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 60 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 61 */ 62package java.time; 63 64import static java.time.temporal.ChronoUnit.DAYS; 65import static java.time.temporal.ChronoUnit.MONTHS; 66import static java.time.temporal.ChronoUnit.YEARS; 67 68import java.io.DataInput; 69import java.io.DataOutput; 70import java.io.IOException; 71import java.io.InvalidObjectException; 72import java.io.ObjectInputStream; 73import java.io.Serializable; 74import java.time.chrono.ChronoLocalDate; 75import java.time.chrono.ChronoPeriod; 76import java.time.chrono.Chronology; 77import java.time.chrono.IsoChronology; 78import java.time.format.DateTimeParseException; 79import java.time.temporal.ChronoUnit; 80import java.time.temporal.Temporal; 81import java.time.temporal.TemporalAccessor; 82import java.time.temporal.TemporalAmount; 83import java.time.temporal.TemporalQueries; 84import java.time.temporal.TemporalUnit; 85import java.time.temporal.UnsupportedTemporalTypeException; 86import java.util.List; 87import java.util.Objects; 88import java.util.regex.Matcher; 89import java.util.regex.Pattern; 90 91/** 92 * A date-based amount of time in the ISO-8601 calendar system, 93 * such as '2 years, 3 months and 4 days'. 94 * <p> 95 * This class models a quantity or amount of time in terms of years, months and days. 96 * See {@link Duration} for the time-based equivalent to this class. 97 * <p> 98 * Durations and periods differ in their treatment of daylight savings time 99 * when added to {@link ZonedDateTime}. A {@code Duration} will add an exact 100 * number of seconds, thus a duration of one day is always exactly 24 hours. 101 * By contrast, a {@code Period} will add a conceptual day, trying to maintain 102 * the local time. 103 * <p> 104 * For example, consider adding a period of one day and a duration of one day to 105 * 18:00 on the evening before a daylight savings gap. The {@code Period} will add 106 * the conceptual day and result in a {@code ZonedDateTime} at 18:00 the following day. 107 * By contrast, the {@code Duration} will add exactly 24 hours, resulting in a 108 * {@code ZonedDateTime} at 19:00 the following day (assuming a one hour DST gap). 109 * <p> 110 * The supported units of a period are {@link ChronoUnit#YEARS YEARS}, 111 * {@link ChronoUnit#MONTHS MONTHS} and {@link ChronoUnit#DAYS DAYS}. 112 * All three fields are always present, but may be set to zero. 113 * <p> 114 * The ISO-8601 calendar system is the modern civil calendar system used today 115 * in most of the world. It is equivalent to the proleptic Gregorian calendar 116 * system, in which today's rules for leap years are applied for all time. 117 * <p> 118 * The period is modeled as a directed amount of time, meaning that individual parts of the 119 * period may be negative. 120 * 121 * <p> 122 * This is a <a href="{@docRoot}/java/lang/doc-files/ValueBased.html">value-based</a> 123 * class; use of identity-sensitive operations (including reference equality 124 * ({@code ==}), identity hash code, or synchronization) on instances of 125 * {@code Period} may have unpredictable results and should be avoided. 126 * The {@code equals} method should be used for comparisons. 127 * 128 * @implSpec 129 * This class is immutable and thread-safe. 130 * 131 * @since 1.8 132 */ 133public final class Period 134 implements ChronoPeriod, Serializable { 135 136 /** 137 * A constant for a period of zero. 138 */ 139 public static final Period ZERO = new Period(0, 0, 0); 140 /** 141 * Serialization version. 142 */ 143 private static final long serialVersionUID = -3587258372562876L; 144 /** 145 * The pattern for parsing. 146 */ 147 private static final Pattern PATTERN = 148 Pattern.compile("([-+]?)P(?:([-+]?[0-9]+)Y)?(?:([-+]?[0-9]+)M)?(?:([-+]?[0-9]+)W)?(?:([-+]?[0-9]+)D)?", Pattern.CASE_INSENSITIVE); 149 150 /** 151 * The set of supported units. 152 */ 153 private static final List<TemporalUnit> SUPPORTED_UNITS = List.of(YEARS, MONTHS, DAYS); 154 155 /** 156 * The number of years. 157 */ 158 private final int years; 159 /** 160 * The number of months. 161 */ 162 private final int months; 163 /** 164 * The number of days. 165 */ 166 private final int days; 167 168 //----------------------------------------------------------------------- 169 /** 170 * Obtains a {@code Period} representing a number of years. 171 * <p> 172 * The resulting period will have the specified years. 173 * The months and days units will be zero. 174 * 175 * @param years the number of years, positive or negative 176 * @return the period of years, not null 177 */ 178 public static Period ofYears(int years) { 179 return create(years, 0, 0); 180 } 181 182 /** 183 * Obtains a {@code Period} representing a number of months. 184 * <p> 185 * The resulting period will have the specified months. 186 * The years and days units will be zero. 187 * 188 * @param months the number of months, positive or negative 189 * @return the period of months, not null 190 */ 191 public static Period ofMonths(int months) { 192 return create(0, months, 0); 193 } 194 195 /** 196 * Obtains a {@code Period} representing a number of weeks. 197 * <p> 198 * The resulting period will be day-based, with the amount of days 199 * equal to the number of weeks multiplied by 7. 200 * The years and months units will be zero. 201 * 202 * @param weeks the number of weeks, positive or negative 203 * @return the period, with the input weeks converted to days, not null 204 */ 205 public static Period ofWeeks(int weeks) { 206 return create(0, 0, Math.multiplyExact(weeks, 7)); 207 } 208 209 /** 210 * Obtains a {@code Period} representing a number of days. 211 * <p> 212 * The resulting period will have the specified days. 213 * The years and months units will be zero. 214 * 215 * @param days the number of days, positive or negative 216 * @return the period of days, not null 217 */ 218 public static Period ofDays(int days) { 219 return create(0, 0, days); 220 } 221 222 //----------------------------------------------------------------------- 223 /** 224 * Obtains a {@code Period} representing a number of years, months and days. 225 * <p> 226 * This creates an instance based on years, months and days. 227 * 228 * @param years the amount of years, may be negative 229 * @param months the amount of months, may be negative 230 * @param days the amount of days, may be negative 231 * @return the period of years, months and days, not null 232 */ 233 public static Period of(int years, int months, int days) { 234 return create(years, months, days); 235 } 236 237 //----------------------------------------------------------------------- 238 /** 239 * Obtains an instance of {@code Period} from a temporal amount. 240 * <p> 241 * This obtains a period based on the specified amount. 242 * A {@code TemporalAmount} represents an amount of time, which may be 243 * date-based or time-based, which this factory extracts to a {@code Period}. 244 * <p> 245 * The conversion loops around the set of units from the amount and uses 246 * the {@link ChronoUnit#YEARS YEARS}, {@link ChronoUnit#MONTHS MONTHS} 247 * and {@link ChronoUnit#DAYS DAYS} units to create a period. 248 * If any other units are found then an exception is thrown. 249 * <p> 250 * If the amount is a {@code ChronoPeriod} then it must use the ISO chronology. 251 * 252 * @param amount the temporal amount to convert, not null 253 * @return the equivalent period, not null 254 * @throws DateTimeException if unable to convert to a {@code Period} 255 * @throws ArithmeticException if the amount of years, months or days exceeds an int 256 */ 257 public static Period from(TemporalAmount amount) { 258 if (amount instanceof Period) { 259 return (Period) amount; 260 } 261 if (amount instanceof ChronoPeriod) { 262 if (IsoChronology.INSTANCE.equals(((ChronoPeriod) amount).getChronology()) == false) { 263 throw new DateTimeException("Period requires ISO chronology: " + amount); 264 } 265 } 266 Objects.requireNonNull(amount, "amount"); 267 int years = 0; 268 int months = 0; 269 int days = 0; 270 for (TemporalUnit unit : amount.getUnits()) { 271 long unitAmount = amount.get(unit); 272 if (unit == ChronoUnit.YEARS) { 273 years = Math.toIntExact(unitAmount); 274 } else if (unit == ChronoUnit.MONTHS) { 275 months = Math.toIntExact(unitAmount); 276 } else if (unit == ChronoUnit.DAYS) { 277 days = Math.toIntExact(unitAmount); 278 } else { 279 throw new DateTimeException("Unit must be Years, Months or Days, but was " + unit); 280 } 281 } 282 return create(years, months, days); 283 } 284 285 //----------------------------------------------------------------------- 286 /** 287 * Obtains a {@code Period} from a text string such as {@code PnYnMnD}. 288 * <p> 289 * This will parse the string produced by {@code toString()} which is 290 * based on the ISO-8601 period formats {@code PnYnMnD} and {@code PnW}. 291 * <p> 292 * The string starts with an optional sign, denoted by the ASCII negative 293 * or positive symbol. If negative, the whole period is negated. 294 * The ASCII letter "P" is next in upper or lower case. 295 * There are then four sections, each consisting of a number and a suffix. 296 * At least one of the four sections must be present. 297 * The sections have suffixes in ASCII of "Y", "M", "W" and "D" for 298 * years, months, weeks and days, accepted in upper or lower case. 299 * The suffixes must occur in order. 300 * The number part of each section must consist of ASCII digits. 301 * The number may be prefixed by the ASCII negative or positive symbol. 302 * The number must parse to an {@code int}. 303 * <p> 304 * The leading plus/minus sign, and negative values for other units are 305 * not part of the ISO-8601 standard. In addition, ISO-8601 does not 306 * permit mixing between the {@code PnYnMnD} and {@code PnW} formats. 307 * Any week-based input is multiplied by 7 and treated as a number of days. 308 * <p> 309 * For example, the following are valid inputs: 310 * <pre> 311 * "P2Y" -- Period.ofYears(2) 312 * "P3M" -- Period.ofMonths(3) 313 * "P4W" -- Period.ofWeeks(4) 314 * "P5D" -- Period.ofDays(5) 315 * "P1Y2M3D" -- Period.of(1, 2, 3) 316 * "P1Y2M3W4D" -- Period.of(1, 2, 25) 317 * "P-1Y2M" -- Period.of(-1, 2, 0) 318 * "-P1Y2M" -- Period.of(-1, -2, 0) 319 * </pre> 320 * 321 * @param text the text to parse, not null 322 * @return the parsed period, not null 323 * @throws DateTimeParseException if the text cannot be parsed to a period 324 */ 325 public static Period parse(CharSequence text) { 326 Objects.requireNonNull(text, "text"); 327 Matcher matcher = PATTERN.matcher(text); 328 if (matcher.matches()) { 329 int negate = (charMatch(text, matcher.start(1), matcher.end(1), '-') ? -1 : 1); 330 int yearStart = matcher.start(2), yearEnd = matcher.end(2); 331 int monthStart = matcher.start(3), monthEnd = matcher.end(3); 332 int weekStart = matcher.start(4), weekEnd = matcher.end(4); 333 int dayStart = matcher.start(5), dayEnd = matcher.end(5); 334 if (yearStart >= 0 || monthStart >= 0 || weekStart >= 0 || dayStart >= 0) { 335 try { 336 int years = parseNumber(text, yearStart, yearEnd, negate); 337 int months = parseNumber(text, monthStart, monthEnd, negate); 338 int weeks = parseNumber(text, weekStart, weekEnd, negate); 339 int days = parseNumber(text, dayStart, dayEnd, negate); 340 days = Math.addExact(days, Math.multiplyExact(weeks, 7)); 341 return create(years, months, days); 342 } catch (NumberFormatException ex) { 343 throw new DateTimeParseException("Text cannot be parsed to a Period", text, 0, ex); 344 } 345 } 346 } 347 throw new DateTimeParseException("Text cannot be parsed to a Period", text, 0); 348 } 349 350 private static boolean charMatch(CharSequence text, int start, int end, char c) { 351 return (start >= 0 && end == start + 1 && text.charAt(start) == c); 352 } 353 354 private static int parseNumber(CharSequence text, int start, int end, int negate) { 355 if (start < 0 || end < 0) { 356 return 0; 357 } 358 int val = Integer.parseInt(text, start, end, 10); 359 try { 360 return Math.multiplyExact(val, negate); 361 } catch (ArithmeticException ex) { 362 throw new DateTimeParseException("Text cannot be parsed to a Period", text, 0, ex); 363 } 364 } 365 366 //----------------------------------------------------------------------- 367 /** 368 * Obtains a {@code Period} consisting of the number of years, months, 369 * and days between two dates. 370 * <p> 371 * The start date is included, but the end date is not. 372 * The period is calculated by removing complete months, then calculating 373 * the remaining number of days, adjusting to ensure that both have the same sign. 374 * The number of months is then split into years and months based on a 12 month year. 375 * A month is considered if the end day-of-month is greater than or equal to the start day-of-month. 376 * For example, from {@code 2010-01-15} to {@code 2011-03-18} is one year, two months and three days. 377 * <p> 378 * The result of this method can be a negative period if the end is before the start. 379 * The negative sign will be the same in each of year, month and day. 380 * 381 * @param startDateInclusive the start date, inclusive, not null 382 * @param endDateExclusive the end date, exclusive, not null 383 * @return the period between this date and the end date, not null 384 * @see ChronoLocalDate#until(ChronoLocalDate) 385 */ 386 public static Period between(LocalDate startDateInclusive, LocalDate endDateExclusive) { 387 return startDateInclusive.until(endDateExclusive); 388 } 389 390 //----------------------------------------------------------------------- 391 /** 392 * Creates an instance. 393 * 394 * @param years the amount 395 * @param months the amount 396 * @param days the amount 397 */ 398 private static Period create(int years, int months, int days) { 399 if ((years | months | days) == 0) { 400 return ZERO; 401 } 402 return new Period(years, months, days); 403 } 404 405 /** 406 * Constructor. 407 * 408 * @param years the amount 409 * @param months the amount 410 * @param days the amount 411 */ 412 private Period(int years, int months, int days) { 413 this.years = years; 414 this.months = months; 415 this.days = days; 416 } 417 418 //----------------------------------------------------------------------- 419 /** 420 * Gets the value of the requested unit. 421 * <p> 422 * This returns a value for each of the three supported units, 423 * {@link ChronoUnit#YEARS YEARS}, {@link ChronoUnit#MONTHS MONTHS} and 424 * {@link ChronoUnit#DAYS DAYS}. 425 * All other units throw an exception. 426 * 427 * @param unit the {@code TemporalUnit} for which to return the value 428 * @return the long value of the unit 429 * @throws DateTimeException if the unit is not supported 430 * @throws UnsupportedTemporalTypeException if the unit is not supported 431 */ 432 @Override 433 public long get(TemporalUnit unit) { 434 if (unit == ChronoUnit.YEARS) { 435 return getYears(); 436 } else if (unit == ChronoUnit.MONTHS) { 437 return getMonths(); 438 } else if (unit == ChronoUnit.DAYS) { 439 return getDays(); 440 } else { 441 throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit); 442 } 443 } 444 445 /** 446 * Gets the set of units supported by this period. 447 * <p> 448 * The supported units are {@link ChronoUnit#YEARS YEARS}, 449 * {@link ChronoUnit#MONTHS MONTHS} and {@link ChronoUnit#DAYS DAYS}. 450 * They are returned in the order years, months, days. 451 * <p> 452 * This set can be used in conjunction with {@link #get(TemporalUnit)} 453 * to access the entire state of the period. 454 * 455 * @return a list containing the years, months and days units, not null 456 */ 457 @Override 458 public List<TemporalUnit> getUnits() { 459 return SUPPORTED_UNITS; 460 } 461 462 /** 463 * Gets the chronology of this period, which is the ISO calendar system. 464 * <p> 465 * The {@code Chronology} represents the calendar system in use. 466 * The ISO-8601 calendar system is the modern civil calendar system used today 467 * in most of the world. It is equivalent to the proleptic Gregorian calendar 468 * system, in which today's rules for leap years are applied for all time. 469 * 470 * @return the ISO chronology, not null 471 */ 472 @Override 473 public IsoChronology getChronology() { 474 return IsoChronology.INSTANCE; 475 } 476 477 //----------------------------------------------------------------------- 478 /** 479 * Checks if all three units of this period are zero. 480 * <p> 481 * A zero period has the value zero for the years, months and days units. 482 * 483 * @return true if this period is zero-length 484 */ 485 public boolean isZero() { 486 return (this == ZERO); 487 } 488 489 /** 490 * Checks if any of the three units of this period are negative. 491 * <p> 492 * This checks whether the years, months or days units are less than zero. 493 * 494 * @return true if any unit of this period is negative 495 */ 496 public boolean isNegative() { 497 return years < 0 || months < 0 || days < 0; 498 } 499 500 //----------------------------------------------------------------------- 501 /** 502 * Gets the amount of years of this period. 503 * <p> 504 * This returns the years unit. 505 * <p> 506 * The months unit is not automatically normalized with the years unit. 507 * This means that a period of "15 months" is different to a period 508 * of "1 year and 3 months". 509 * 510 * @return the amount of years of this period, may be negative 511 */ 512 public int getYears() { 513 return years; 514 } 515 516 /** 517 * Gets the amount of months of this period. 518 * <p> 519 * This returns the months unit. 520 * <p> 521 * The months unit is not automatically normalized with the years unit. 522 * This means that a period of "15 months" is different to a period 523 * of "1 year and 3 months". 524 * 525 * @return the amount of months of this period, may be negative 526 */ 527 public int getMonths() { 528 return months; 529 } 530 531 /** 532 * Gets the amount of days of this period. 533 * <p> 534 * This returns the days unit. 535 * 536 * @return the amount of days of this period, may be negative 537 */ 538 public int getDays() { 539 return days; 540 } 541 542 //----------------------------------------------------------------------- 543 /** 544 * Returns a copy of this period with the specified amount of years. 545 * <p> 546 * This sets the amount of the years unit in a copy of this period. 547 * The months and days units are unaffected. 548 * <p> 549 * The months unit is not automatically normalized with the years unit. 550 * This means that a period of "15 months" is different to a period 551 * of "1 year and 3 months". 552 * <p> 553 * This instance is immutable and unaffected by this method call. 554 * 555 * @param years the years to represent, may be negative 556 * @return a {@code Period} based on this period with the requested years, not null 557 */ 558 public Period withYears(int years) { 559 if (years == this.years) { 560 return this; 561 } 562 return create(years, months, days); 563 } 564 565 /** 566 * Returns a copy of this period with the specified amount of months. 567 * <p> 568 * This sets the amount of the months unit in a copy of this period. 569 * The years and days units are unaffected. 570 * <p> 571 * The months unit is not automatically normalized with the years unit. 572 * This means that a period of "15 months" is different to a period 573 * of "1 year and 3 months". 574 * <p> 575 * This instance is immutable and unaffected by this method call. 576 * 577 * @param months the months to represent, may be negative 578 * @return a {@code Period} based on this period with the requested months, not null 579 */ 580 public Period withMonths(int months) { 581 if (months == this.months) { 582 return this; 583 } 584 return create(years, months, days); 585 } 586 587 /** 588 * Returns a copy of this period with the specified amount of days. 589 * <p> 590 * This sets the amount of the days unit in a copy of this period. 591 * The years and months units are unaffected. 592 * <p> 593 * This instance is immutable and unaffected by this method call. 594 * 595 * @param days the days to represent, may be negative 596 * @return a {@code Period} based on this period with the requested days, not null 597 */ 598 public Period withDays(int days) { 599 if (days == this.days) { 600 return this; 601 } 602 return create(years, months, days); 603 } 604 605 //----------------------------------------------------------------------- 606 /** 607 * Returns a copy of this period with the specified period added. 608 * <p> 609 * This operates separately on the years, months and days. 610 * No normalization is performed. 611 * <p> 612 * For example, "1 year, 6 months and 3 days" plus "2 years, 2 months and 2 days" 613 * returns "3 years, 8 months and 5 days". 614 * <p> 615 * The specified amount is typically an instance of {@code Period}. 616 * Other types are interpreted using {@link Period#from(TemporalAmount)}. 617 * <p> 618 * This instance is immutable and unaffected by this method call. 619 * 620 * @param amountToAdd the amount to add, not null 621 * @return a {@code Period} based on this period with the requested period added, not null 622 * @throws DateTimeException if the specified amount has a non-ISO chronology or 623 * contains an invalid unit 624 * @throws ArithmeticException if numeric overflow occurs 625 */ 626 public Period plus(TemporalAmount amountToAdd) { 627 Period isoAmount = Period.from(amountToAdd); 628 return create( 629 Math.addExact(years, isoAmount.years), 630 Math.addExact(months, isoAmount.months), 631 Math.addExact(days, isoAmount.days)); 632 } 633 634 /** 635 * Returns a copy of this period with the specified years added. 636 * <p> 637 * This adds the amount to the years unit in a copy of this period. 638 * The months and days units are unaffected. 639 * For example, "1 year, 6 months and 3 days" plus 2 years returns "3 years, 6 months and 3 days". 640 * <p> 641 * This instance is immutable and unaffected by this method call. 642 * 643 * @param yearsToAdd the years to add, positive or negative 644 * @return a {@code Period} based on this period with the specified years added, not null 645 * @throws ArithmeticException if numeric overflow occurs 646 */ 647 public Period plusYears(long yearsToAdd) { 648 if (yearsToAdd == 0) { 649 return this; 650 } 651 return create(Math.toIntExact(Math.addExact(years, yearsToAdd)), months, days); 652 } 653 654 /** 655 * Returns a copy of this period with the specified months added. 656 * <p> 657 * This adds the amount to the months unit in a copy of this period. 658 * The years and days units are unaffected. 659 * For example, "1 year, 6 months and 3 days" plus 2 months returns "1 year, 8 months and 3 days". 660 * <p> 661 * This instance is immutable and unaffected by this method call. 662 * 663 * @param monthsToAdd the months to add, positive or negative 664 * @return a {@code Period} based on this period with the specified months added, not null 665 * @throws ArithmeticException if numeric overflow occurs 666 */ 667 public Period plusMonths(long monthsToAdd) { 668 if (monthsToAdd == 0) { 669 return this; 670 } 671 return create(years, Math.toIntExact(Math.addExact(months, monthsToAdd)), days); 672 } 673 674 /** 675 * Returns a copy of this period with the specified days added. 676 * <p> 677 * This adds the amount to the days unit in a copy of this period. 678 * The years and months units are unaffected. 679 * For example, "1 year, 6 months and 3 days" plus 2 days returns "1 year, 6 months and 5 days". 680 * <p> 681 * This instance is immutable and unaffected by this method call. 682 * 683 * @param daysToAdd the days to add, positive or negative 684 * @return a {@code Period} based on this period with the specified days added, not null 685 * @throws ArithmeticException if numeric overflow occurs 686 */ 687 public Period plusDays(long daysToAdd) { 688 if (daysToAdd == 0) { 689 return this; 690 } 691 return create(years, months, Math.toIntExact(Math.addExact(days, daysToAdd))); 692 } 693 694 //----------------------------------------------------------------------- 695 /** 696 * Returns a copy of this period with the specified period subtracted. 697 * <p> 698 * This operates separately on the years, months and days. 699 * No normalization is performed. 700 * <p> 701 * For example, "1 year, 6 months and 3 days" minus "2 years, 2 months and 2 days" 702 * returns "-1 years, 4 months and 1 day". 703 * <p> 704 * The specified amount is typically an instance of {@code Period}. 705 * Other types are interpreted using {@link Period#from(TemporalAmount)}. 706 * <p> 707 * This instance is immutable and unaffected by this method call. 708 * 709 * @param amountToSubtract the amount to subtract, not null 710 * @return a {@code Period} based on this period with the requested period subtracted, not null 711 * @throws DateTimeException if the specified amount has a non-ISO chronology or 712 * contains an invalid unit 713 * @throws ArithmeticException if numeric overflow occurs 714 */ 715 public Period minus(TemporalAmount amountToSubtract) { 716 Period isoAmount = Period.from(amountToSubtract); 717 return create( 718 Math.subtractExact(years, isoAmount.years), 719 Math.subtractExact(months, isoAmount.months), 720 Math.subtractExact(days, isoAmount.days)); 721 } 722 723 /** 724 * Returns a copy of this period with the specified years subtracted. 725 * <p> 726 * This subtracts the amount from the years unit in a copy of this period. 727 * The months and days units are unaffected. 728 * For example, "1 year, 6 months and 3 days" minus 2 years returns "-1 years, 6 months and 3 days". 729 * <p> 730 * This instance is immutable and unaffected by this method call. 731 * 732 * @param yearsToSubtract the years to subtract, positive or negative 733 * @return a {@code Period} based on this period with the specified years subtracted, not null 734 * @throws ArithmeticException if numeric overflow occurs 735 */ 736 public Period minusYears(long yearsToSubtract) { 737 return (yearsToSubtract == Long.MIN_VALUE ? plusYears(Long.MAX_VALUE).plusYears(1) : plusYears(-yearsToSubtract)); 738 } 739 740 /** 741 * Returns a copy of this period with the specified months subtracted. 742 * <p> 743 * This subtracts the amount from the months unit in a copy of this period. 744 * The years and days units are unaffected. 745 * For example, "1 year, 6 months and 3 days" minus 2 months returns "1 year, 4 months and 3 days". 746 * <p> 747 * This instance is immutable and unaffected by this method call. 748 * 749 * @param monthsToSubtract the years to subtract, positive or negative 750 * @return a {@code Period} based on this period with the specified months subtracted, not null 751 * @throws ArithmeticException if numeric overflow occurs 752 */ 753 public Period minusMonths(long monthsToSubtract) { 754 return (monthsToSubtract == Long.MIN_VALUE ? plusMonths(Long.MAX_VALUE).plusMonths(1) : plusMonths(-monthsToSubtract)); 755 } 756 757 /** 758 * Returns a copy of this period with the specified days subtracted. 759 * <p> 760 * This subtracts the amount from the days unit in a copy of this period. 761 * The years and months units are unaffected. 762 * For example, "1 year, 6 months and 3 days" minus 2 days returns "1 year, 6 months and 1 day". 763 * <p> 764 * This instance is immutable and unaffected by this method call. 765 * 766 * @param daysToSubtract the months to subtract, positive or negative 767 * @return a {@code Period} based on this period with the specified days subtracted, not null 768 * @throws ArithmeticException if numeric overflow occurs 769 */ 770 public Period minusDays(long daysToSubtract) { 771 return (daysToSubtract == Long.MIN_VALUE ? plusDays(Long.MAX_VALUE).plusDays(1) : plusDays(-daysToSubtract)); 772 } 773 774 //----------------------------------------------------------------------- 775 /** 776 * Returns a new instance with each element in this period multiplied 777 * by the specified scalar. 778 * <p> 779 * This returns a period with each of the years, months and days units 780 * individually multiplied. 781 * For example, a period of "2 years, -3 months and 4 days" multiplied by 782 * 3 will return "6 years, -9 months and 12 days". 783 * No normalization is performed. 784 * 785 * @param scalar the scalar to multiply by, not null 786 * @return a {@code Period} based on this period with the amounts multiplied by the scalar, not null 787 * @throws ArithmeticException if numeric overflow occurs 788 */ 789 public Period multipliedBy(int scalar) { 790 if (this == ZERO || scalar == 1) { 791 return this; 792 } 793 return create( 794 Math.multiplyExact(years, scalar), 795 Math.multiplyExact(months, scalar), 796 Math.multiplyExact(days, scalar)); 797 } 798 799 /** 800 * Returns a new instance with each amount in this period negated. 801 * <p> 802 * This returns a period with each of the years, months and days units 803 * individually negated. 804 * For example, a period of "2 years, -3 months and 4 days" will be 805 * negated to "-2 years, 3 months and -4 days". 806 * No normalization is performed. 807 * 808 * @return a {@code Period} based on this period with the amounts negated, not null 809 * @throws ArithmeticException if numeric overflow occurs, which only happens if 810 * one of the units has the value {@code Long.MIN_VALUE} 811 */ 812 public Period negated() { 813 return multipliedBy(-1); 814 } 815 816 //----------------------------------------------------------------------- 817 /** 818 * Returns a copy of this period with the years and months normalized. 819 * <p> 820 * This normalizes the years and months units, leaving the days unit unchanged. 821 * The months unit is adjusted to have an absolute value less than 12, 822 * with the years unit being adjusted to compensate. For example, a period of 823 * "1 Year and 15 months" will be normalized to "2 years and 3 months". 824 * <p> 825 * The sign of the years and months units will be the same after normalization. 826 * For example, a period of "1 year and -25 months" will be normalized to 827 * "-1 year and -1 month". 828 * <p> 829 * This instance is immutable and unaffected by this method call. 830 * 831 * @return a {@code Period} based on this period with excess months normalized to years, not null 832 * @throws ArithmeticException if numeric overflow occurs 833 */ 834 public Period normalized() { 835 long totalMonths = toTotalMonths(); 836 long splitYears = totalMonths / 12; 837 int splitMonths = (int) (totalMonths % 12); // no overflow 838 if (splitYears == years && splitMonths == months) { 839 return this; 840 } 841 return create(Math.toIntExact(splitYears), splitMonths, days); 842 } 843 844 /** 845 * Gets the total number of months in this period. 846 * <p> 847 * This returns the total number of months in the period by multiplying the 848 * number of years by 12 and adding the number of months. 849 * <p> 850 * This instance is immutable and unaffected by this method call. 851 * 852 * @return the total number of months in the period, may be negative 853 */ 854 public long toTotalMonths() { 855 return years * 12L + months; // no overflow 856 } 857 858 //------------------------------------------------------------------------- 859 /** 860 * Adds this period to the specified temporal object. 861 * <p> 862 * This returns a temporal object of the same observable type as the input 863 * with this period added. 864 * If the temporal has a chronology, it must be the ISO chronology. 865 * <p> 866 * In most cases, it is clearer to reverse the calling pattern by using 867 * {@link Temporal#plus(TemporalAmount)}. 868 * <pre> 869 * // these two lines are equivalent, but the second approach is recommended 870 * dateTime = thisPeriod.addTo(dateTime); 871 * dateTime = dateTime.plus(thisPeriod); 872 * </pre> 873 * <p> 874 * The calculation operates as follows. 875 * First, the chronology of the temporal is checked to ensure it is ISO chronology or null. 876 * Second, if the months are zero, the years are added if non-zero, otherwise 877 * the combination of years and months is added if non-zero. 878 * Finally, any days are added. 879 * <p> 880 * This approach ensures that a partial period can be added to a partial date. 881 * For example, a period of years and/or months can be added to a {@code YearMonth}, 882 * but a period including days cannot. 883 * The approach also adds years and months together when necessary, which ensures 884 * correct behaviour at the end of the month. 885 * <p> 886 * This instance is immutable and unaffected by this method call. 887 * 888 * @param temporal the temporal object to adjust, not null 889 * @return an object of the same type with the adjustment made, not null 890 * @throws DateTimeException if unable to add 891 * @throws ArithmeticException if numeric overflow occurs 892 */ 893 @Override 894 public Temporal addTo(Temporal temporal) { 895 validateChrono(temporal); 896 if (months == 0) { 897 if (years != 0) { 898 temporal = temporal.plus(years, YEARS); 899 } 900 } else { 901 long totalMonths = toTotalMonths(); 902 if (totalMonths != 0) { 903 temporal = temporal.plus(totalMonths, MONTHS); 904 } 905 } 906 if (days != 0) { 907 temporal = temporal.plus(days, DAYS); 908 } 909 return temporal; 910 } 911 912 /** 913 * Subtracts this period from the specified temporal object. 914 * <p> 915 * This returns a temporal object of the same observable type as the input 916 * with this period subtracted. 917 * If the temporal has a chronology, it must be the ISO chronology. 918 * <p> 919 * In most cases, it is clearer to reverse the calling pattern by using 920 * {@link Temporal#minus(TemporalAmount)}. 921 * <pre> 922 * // these two lines are equivalent, but the second approach is recommended 923 * dateTime = thisPeriod.subtractFrom(dateTime); 924 * dateTime = dateTime.minus(thisPeriod); 925 * </pre> 926 * <p> 927 * The calculation operates as follows. 928 * First, the chronology of the temporal is checked to ensure it is ISO chronology or null. 929 * Second, if the months are zero, the years are subtracted if non-zero, otherwise 930 * the combination of years and months is subtracted if non-zero. 931 * Finally, any days are subtracted. 932 * <p> 933 * This approach ensures that a partial period can be subtracted from a partial date. 934 * For example, a period of years and/or months can be subtracted from a {@code YearMonth}, 935 * but a period including days cannot. 936 * The approach also subtracts years and months together when necessary, which ensures 937 * correct behaviour at the end of the month. 938 * <p> 939 * This instance is immutable and unaffected by this method call. 940 * 941 * @param temporal the temporal object to adjust, not null 942 * @return an object of the same type with the adjustment made, not null 943 * @throws DateTimeException if unable to subtract 944 * @throws ArithmeticException if numeric overflow occurs 945 */ 946 @Override 947 public Temporal subtractFrom(Temporal temporal) { 948 validateChrono(temporal); 949 if (months == 0) { 950 if (years != 0) { 951 temporal = temporal.minus(years, YEARS); 952 } 953 } else { 954 long totalMonths = toTotalMonths(); 955 if (totalMonths != 0) { 956 temporal = temporal.minus(totalMonths, MONTHS); 957 } 958 } 959 if (days != 0) { 960 temporal = temporal.minus(days, DAYS); 961 } 962 return temporal; 963 } 964 965 /** 966 * Validates that the temporal has the correct chronology. 967 */ 968 private void validateChrono(TemporalAccessor temporal) { 969 Objects.requireNonNull(temporal, "temporal"); 970 Chronology temporalChrono = temporal.query(TemporalQueries.chronology()); 971 if (temporalChrono != null && IsoChronology.INSTANCE.equals(temporalChrono) == false) { 972 throw new DateTimeException("Chronology mismatch, expected: ISO, actual: " + temporalChrono.getId()); 973 } 974 } 975 976 //----------------------------------------------------------------------- 977 /** 978 * Checks if this period is equal to another period. 979 * <p> 980 * The comparison is based on the type {@code Period} and each of the three amounts. 981 * To be equal, the years, months and days units must be individually equal. 982 * Note that this means that a period of "15 Months" is not equal to a period 983 * of "1 Year and 3 Months". 984 * 985 * @param obj the object to check, null returns false 986 * @return true if this is equal to the other period 987 */ 988 @Override 989 public boolean equals(Object obj) { 990 if (this == obj) { 991 return true; 992 } 993 if (obj instanceof Period) { 994 Period other = (Period) obj; 995 return years == other.years && 996 months == other.months && 997 days == other.days; 998 } 999 return false; 1000 } 1001 1002 /** 1003 * A hash code for this period. 1004 * 1005 * @return a suitable hash code 1006 */ 1007 @Override 1008 public int hashCode() { 1009 return years + Integer.rotateLeft(months, 8) + Integer.rotateLeft(days, 16); 1010 } 1011 1012 //----------------------------------------------------------------------- 1013 /** 1014 * Outputs this period as a {@code String}, such as {@code P6Y3M1D}. 1015 * <p> 1016 * The output will be in the ISO-8601 period format. 1017 * A zero period will be represented as zero days, 'P0D'. 1018 * 1019 * @return a string representation of this period, not null 1020 */ 1021 @Override 1022 public String toString() { 1023 if (this == ZERO) { 1024 return "P0D"; 1025 } else { 1026 StringBuilder buf = new StringBuilder(); 1027 buf.append('P'); 1028 if (years != 0) { 1029 buf.append(years).append('Y'); 1030 } 1031 if (months != 0) { 1032 buf.append(months).append('M'); 1033 } 1034 if (days != 0) { 1035 buf.append(days).append('D'); 1036 } 1037 return buf.toString(); 1038 } 1039 } 1040 1041 //----------------------------------------------------------------------- 1042 /** 1043 * Writes the object using a 1044 * <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>. 1045 * @serialData 1046 * <pre> 1047 * out.writeByte(14); // identifies a Period 1048 * out.writeInt(years); 1049 * out.writeInt(months); 1050 * out.writeInt(days); 1051 * </pre> 1052 * 1053 * @return the instance of {@code Ser}, not null 1054 */ 1055 private Object writeReplace() { 1056 return new Ser(Ser.PERIOD_TYPE, this); 1057 } 1058 1059 /** 1060 * Defend against malicious streams. 1061 * 1062 * @param s the stream to read 1063 * @throws java.io.InvalidObjectException always 1064 */ 1065 private void readObject(ObjectInputStream s) throws InvalidObjectException { 1066 throw new InvalidObjectException("Deserialization via serialization delegate"); 1067 } 1068 1069 void writeExternal(DataOutput out) throws IOException { 1070 out.writeInt(years); 1071 out.writeInt(months); 1072 out.writeInt(days); 1073 } 1074 1075 static Period readExternal(DataInput in) throws IOException { 1076 int years = in.readInt(); 1077 int months = in.readInt(); 1078 int days = in.readInt(); 1079 return Period.of(years, months, days); 1080 } 1081 1082} 1083