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) 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 */ 62 package java.time; 63 64 import static java.time.temporal.ChronoUnit.DAYS; 65 import static java.time.temporal.ChronoUnit.MONTHS; 66 import static java.time.temporal.ChronoUnit.YEARS; 67 68 import java.io.DataInput; 69 import java.io.DataOutput; 70 import java.io.IOException; 71 import java.io.InvalidObjectException; 72 import java.io.ObjectInputStream; 73 import java.io.Serializable; 74 import java.time.chrono.ChronoLocalDate; 75 import java.time.chrono.ChronoPeriod; 76 import java.time.chrono.Chronology; 77 import java.time.chrono.IsoChronology; 78 import java.time.format.DateTimeParseException; 79 import java.time.temporal.ChronoUnit; 80 import java.time.temporal.Temporal; 81 import java.time.temporal.TemporalAccessor; 82 import java.time.temporal.TemporalAmount; 83 import java.time.temporal.TemporalQueries; 84 import java.time.temporal.TemporalUnit; 85 import java.time.temporal.UnsupportedTemporalTypeException; 86 import java.util.Arrays; 87 import java.util.Collections; 88 import java.util.List; 89 import java.util.Objects; 90 import java.util.regex.Matcher; 91 import java.util.regex.Pattern; 92 93 /** 94 * A date-based amount of time in the ISO-8601 calendar system, 95 * such as '2 years, 3 months and 4 days'. 96 * <p> 97 * This class models a quantity or amount of time in terms of years, months and days. 98 * See {@link Duration} for the time-based equivalent to this class. 99 * <p> 100 * Durations and periods differ in their treatment of daylight savings time 101 * when added to {@link ZonedDateTime}. A {@code Duration} will add an exact 102 * number of seconds, thus a duration of one day is always exactly 24 hours. 103 * By contrast, a {@code Period} will add a conceptual day, trying to maintain 104 * the local time. 105 * <p> 106 * For example, consider adding a period of one day and a duration of one day to 107 * 18:00 on the evening before a daylight savings gap. The {@code Period} will add 108 * the conceptual day and result in a {@code ZonedDateTime} at 18:00 the following day. 109 * By contrast, the {@code Duration} will add exactly 24 hours, resulting in a 110 * {@code ZonedDateTime} at 19:00 the following day (assuming a one hour DST gap). 111 * <p> 112 * The supported units of a period are {@link ChronoUnit#YEARS YEARS}, 113 * {@link ChronoUnit#MONTHS MONTHS} and {@link ChronoUnit#DAYS DAYS}. 114 * All three fields are always present, but may be set to zero. 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 * <p> 120 * The period is modeled as a directed amount of time, meaning that individual parts of the 121 * period may be negative. 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 Period} 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 Period 136 implements ChronoPeriod, Serializable { 137 138 /** 139 * A constant for a period of zero. 140 */ 141 public static final Period ZERO = new Period(0, 0, 0); 142 /** 143 * Serialization version. 144 */ 145 private static final long serialVersionUID = -3587258372562876L; 146 /** 147 * The pattern for parsing. 148 */ 149 private static final Pattern PATTERN = 150 Pattern.compile("([-+]?)P(?:([-+]?[0-9]+)Y)?(?:([-+]?[0-9]+)M)?(?:([-+]?[0-9]+)W)?(?:([-+]?[0-9]+)D)?", Pattern.CASE_INSENSITIVE); 151 152 /** 153 * The set of supported units. 154 */ 155 private static final List<TemporalUnit> SUPPORTED_UNITS = 156 Collections.unmodifiableList(Arrays.<TemporalUnit>asList(YEARS, MONTHS, DAYS)); 157 158 /** 159 * The number of years. 160 */ 161 private final int years; 162 /** 163 * The number of months. 164 */ 165 private final int months; 166 /** 167 * The number of days. 168 */ 169 private final int days; 170 171 //----------------------------------------------------------------------- 172 /** 173 * Obtains a {@code Period} representing a number of years. 174 * <p> 175 * The resulting period will have the specified years. 176 * The months and days units will be zero. 177 * 178 * @param years the number of years, positive or negative 179 * @return the period of years, not null 180 */ ofYears(int years)181 public static Period ofYears(int years) { 182 return create(years, 0, 0); 183 } 184 185 /** 186 * Obtains a {@code Period} representing a number of months. 187 * <p> 188 * The resulting period will have the specified months. 189 * The years and days units will be zero. 190 * 191 * @param months the number of months, positive or negative 192 * @return the period of months, not null 193 */ ofMonths(int months)194 public static Period ofMonths(int months) { 195 return create(0, months, 0); 196 } 197 198 /** 199 * Obtains a {@code Period} representing a number of weeks. 200 * <p> 201 * The resulting period will be day-based, with the amount of days 202 * equal to the number of weeks multiplied by 7. 203 * The years and months units will be zero. 204 * 205 * @param weeks the number of weeks, positive or negative 206 * @return the period, with the input weeks converted to days, not null 207 */ ofWeeks(int weeks)208 public static Period ofWeeks(int weeks) { 209 return create(0, 0, Math.multiplyExact(weeks, 7)); 210 } 211 212 /** 213 * Obtains a {@code Period} representing a number of days. 214 * <p> 215 * The resulting period will have the specified days. 216 * The years and months units will be zero. 217 * 218 * @param days the number of days, positive or negative 219 * @return the period of days, not null 220 */ ofDays(int days)221 public static Period ofDays(int days) { 222 return create(0, 0, days); 223 } 224 225 //----------------------------------------------------------------------- 226 /** 227 * Obtains a {@code Period} representing a number of years, months and days. 228 * <p> 229 * This creates an instance based on years, months and days. 230 * 231 * @param years the amount of years, may be negative 232 * @param months the amount of months, may be negative 233 * @param days the amount of days, may be negative 234 * @return the period of years, months and days, not null 235 */ of(int years, int months, int days)236 public static Period of(int years, int months, int days) { 237 return create(years, months, days); 238 } 239 240 //----------------------------------------------------------------------- 241 /** 242 * Obtains an instance of {@code Period} from a temporal amount. 243 * <p> 244 * This obtains a period based on the specified amount. 245 * A {@code TemporalAmount} represents an amount of time, which may be 246 * date-based or time-based, which this factory extracts to a {@code Period}. 247 * <p> 248 * The conversion loops around the set of units from the amount and uses 249 * the {@link ChronoUnit#YEARS YEARS}, {@link ChronoUnit#MONTHS MONTHS} 250 * and {@link ChronoUnit#DAYS DAYS} units to create a period. 251 * If any other units are found then an exception is thrown. 252 * <p> 253 * If the amount is a {@code ChronoPeriod} then it must use the ISO chronology. 254 * 255 * @param amount the temporal amount to convert, not null 256 * @return the equivalent period, not null 257 * @throws DateTimeException if unable to convert to a {@code Period} 258 * @throws ArithmeticException if the amount of years, months or days exceeds an int 259 */ from(TemporalAmount amount)260 public static Period from(TemporalAmount amount) { 261 if (amount instanceof Period) { 262 return (Period) amount; 263 } 264 if (amount instanceof ChronoPeriod) { 265 if (IsoChronology.INSTANCE.equals(((ChronoPeriod) amount).getChronology()) == false) { 266 throw new DateTimeException("Period requires ISO chronology: " + amount); 267 } 268 } 269 Objects.requireNonNull(amount, "amount"); 270 int years = 0; 271 int months = 0; 272 int days = 0; 273 for (TemporalUnit unit : amount.getUnits()) { 274 long unitAmount = amount.get(unit); 275 if (unit == ChronoUnit.YEARS) { 276 years = Math.toIntExact(unitAmount); 277 } else if (unit == ChronoUnit.MONTHS) { 278 months = Math.toIntExact(unitAmount); 279 } else if (unit == ChronoUnit.DAYS) { 280 days = Math.toIntExact(unitAmount); 281 } else { 282 throw new DateTimeException("Unit must be Years, Months or Days, but was " + unit); 283 } 284 } 285 return create(years, months, days); 286 } 287 288 //----------------------------------------------------------------------- 289 /** 290 * Obtains a {@code Period} from a text string such as {@code PnYnMnD}. 291 * <p> 292 * This will parse the string produced by {@code toString()} which is 293 * based on the ISO-8601 period formats {@code PnYnMnD} and {@code PnW}. 294 * <p> 295 * The string starts with an optional sign, denoted by the ASCII negative 296 * or positive symbol. If negative, the whole period is negated. 297 * The ASCII letter "P" is next in upper or lower case. 298 * There are then four sections, each consisting of a number and a suffix. 299 * At least one of the four sections must be present. 300 * The sections have suffixes in ASCII of "Y", "M", "W" and "D" for 301 * years, months, weeks and days, accepted in upper or lower case. 302 * The suffixes must occur in order. 303 * The number part of each section must consist of ASCII digits. 304 * The number may be prefixed by the ASCII negative or positive symbol. 305 * The number must parse to an {@code int}. 306 * <p> 307 * The leading plus/minus sign, and negative values for other units are 308 * not part of the ISO-8601 standard. In addition, ISO-8601 does not 309 * permit mixing between the {@code PnYnMnD} and {@code PnW} formats. 310 * Any week-based input is multiplied by 7 and treated as a number of days. 311 * <p> 312 * For example, the following are valid inputs: 313 * <pre> 314 * "P2Y" -- Period.ofYears(2) 315 * "P3M" -- Period.ofMonths(3) 316 * "P4W" -- Period.ofWeeks(4) 317 * "P5D" -- Period.ofDays(5) 318 * "P1Y2M3D" -- Period.of(1, 2, 3) 319 * "P1Y2M3W4D" -- Period.of(1, 2, 25) 320 * "P-1Y2M" -- Period.of(-1, 2, 0) 321 * "-P1Y2M" -- Period.of(-1, -2, 0) 322 * </pre> 323 * 324 * @param text the text to parse, not null 325 * @return the parsed period, not null 326 * @throws DateTimeParseException if the text cannot be parsed to a period 327 */ parse(CharSequence text)328 public static Period parse(CharSequence text) { 329 Objects.requireNonNull(text, "text"); 330 Matcher matcher = PATTERN.matcher(text); 331 if (matcher.matches()) { 332 int negate = ("-".equals(matcher.group(1)) ? -1 : 1); 333 String yearMatch = matcher.group(2); 334 String monthMatch = matcher.group(3); 335 String weekMatch = matcher.group(4); 336 String dayMatch = matcher.group(5); 337 if (yearMatch != null || monthMatch != null || dayMatch != null || weekMatch != null) { 338 try { 339 int years = parseNumber(text, yearMatch, negate); 340 int months = parseNumber(text, monthMatch, negate); 341 int weeks = parseNumber(text, weekMatch, negate); 342 int days = parseNumber(text, dayMatch, negate); 343 days = Math.addExact(days, Math.multiplyExact(weeks, 7)); 344 return create(years, months, days); 345 } catch (NumberFormatException ex) { 346 throw new DateTimeParseException("Text cannot be parsed to a Period", text, 0, ex); 347 } 348 } 349 } 350 throw new DateTimeParseException("Text cannot be parsed to a Period", text, 0); 351 } 352 parseNumber(CharSequence text, String str, int negate)353 private static int parseNumber(CharSequence text, String str, int negate) { 354 if (str == null) { 355 return 0; 356 } 357 int val = Integer.parseInt(str); 358 try { 359 return Math.multiplyExact(val, negate); 360 } catch (ArithmeticException ex) { 361 throw new DateTimeParseException("Text cannot be parsed to a Period", text, 0, ex); 362 } 363 } 364 365 //----------------------------------------------------------------------- 366 /** 367 * Obtains a {@code Period} consisting of the number of years, months, 368 * and days between two dates. 369 * <p> 370 * The start date is included, but the end date is not. 371 * The period is calculated by removing complete months, then calculating 372 * the remaining number of days, adjusting to ensure that both have the same sign. 373 * The number of months is then split into years and months based on a 12 month year. 374 * A month is considered if the end day-of-month is greater than or equal to the start day-of-month. 375 * For example, from {@code 2010-01-15} to {@code 2011-03-18} is one year, two months and three days. 376 * <p> 377 * The result of this method can be a negative period if the end is before the start. 378 * The negative sign will be the same in each of year, month and day. 379 * 380 * @param startDateInclusive the start date, inclusive, not null 381 * @param endDateExclusive the end date, exclusive, not null 382 * @return the period between this date and the end date, not null 383 * @see ChronoLocalDate#until(ChronoLocalDate) 384 */ between(LocalDate startDateInclusive, LocalDate endDateExclusive)385 public static Period between(LocalDate startDateInclusive, LocalDate endDateExclusive) { 386 return startDateInclusive.until(endDateExclusive); 387 } 388 389 //----------------------------------------------------------------------- 390 /** 391 * Creates an instance. 392 * 393 * @param years the amount 394 * @param months the amount 395 * @param days the amount 396 */ create(int years, int months, int days)397 private static Period create(int years, int months, int days) { 398 if ((years | months | days) == 0) { 399 return ZERO; 400 } 401 return new Period(years, months, days); 402 } 403 404 /** 405 * Constructor. 406 * 407 * @param years the amount 408 * @param months the amount 409 * @param days the amount 410 */ Period(int years, int months, int days)411 private Period(int years, int months, int days) { 412 this.years = years; 413 this.months = months; 414 this.days = days; 415 } 416 417 //----------------------------------------------------------------------- 418 /** 419 * Gets the value of the requested unit. 420 * <p> 421 * This returns a value for each of the three supported units, 422 * {@link ChronoUnit#YEARS YEARS}, {@link ChronoUnit#MONTHS MONTHS} and 423 * {@link ChronoUnit#DAYS DAYS}. 424 * All other units throw an exception. 425 * 426 * @param unit the {@code TemporalUnit} for which to return the value 427 * @return the long value of the unit 428 * @throws DateTimeException if the unit is not supported 429 * @throws UnsupportedTemporalTypeException if the unit is not supported 430 */ 431 @Override get(TemporalUnit unit)432 public long get(TemporalUnit unit) { 433 if (unit == ChronoUnit.YEARS) { 434 return getYears(); 435 } else if (unit == ChronoUnit.MONTHS) { 436 return getMonths(); 437 } else if (unit == ChronoUnit.DAYS) { 438 return getDays(); 439 } else { 440 throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit); 441 } 442 } 443 444 /** 445 * Gets the set of units supported by this period. 446 * <p> 447 * The supported units are {@link ChronoUnit#YEARS YEARS}, 448 * {@link ChronoUnit#MONTHS MONTHS} and {@link ChronoUnit#DAYS DAYS}. 449 * They are returned in the order years, months, days. 450 * <p> 451 * This set can be used in conjunction with {@link #get(TemporalUnit)} 452 * to access the entire state of the period. 453 * 454 * @return a list containing the years, months and days units, not null 455 */ 456 @Override getUnits()457 public List<TemporalUnit> getUnits() { 458 return SUPPORTED_UNITS; 459 } 460 461 /** 462 * Gets the chronology of this period, which is the ISO calendar system. 463 * <p> 464 * The {@code Chronology} represents the calendar system in use. 465 * The ISO-8601 calendar system is the modern civil calendar system used today 466 * in most of the world. It is equivalent to the proleptic Gregorian calendar 467 * system, in which today's rules for leap years are applied for all time. 468 * 469 * @return the ISO chronology, not null 470 */ 471 @Override getChronology()472 public IsoChronology getChronology() { 473 return IsoChronology.INSTANCE; 474 } 475 476 //----------------------------------------------------------------------- 477 /** 478 * Checks if all three units of this period are zero. 479 * <p> 480 * A zero period has the value zero for the years, months and days units. 481 * 482 * @return true if this period is zero-length 483 */ isZero()484 public boolean isZero() { 485 return (this == ZERO); 486 } 487 488 /** 489 * Checks if any of the three units of this period are negative. 490 * <p> 491 * This checks whether the years, months or days units are less than zero. 492 * 493 * @return true if any unit of this period is negative 494 */ isNegative()495 public boolean isNegative() { 496 return years < 0 || months < 0 || days < 0; 497 } 498 499 //----------------------------------------------------------------------- 500 /** 501 * Gets the amount of years of this period. 502 * <p> 503 * This returns the years unit. 504 * <p> 505 * The months unit is not automatically normalized with the years unit. 506 * This means that a period of "15 months" is different to a period 507 * of "1 year and 3 months". 508 * 509 * @return the amount of years of this period, may be negative 510 */ getYears()511 public int getYears() { 512 return years; 513 } 514 515 /** 516 * Gets the amount of months of this period. 517 * <p> 518 * This returns the months unit. 519 * <p> 520 * The months unit is not automatically normalized with the years unit. 521 * This means that a period of "15 months" is different to a period 522 * of "1 year and 3 months". 523 * 524 * @return the amount of months of this period, may be negative 525 */ getMonths()526 public int getMonths() { 527 return months; 528 } 529 530 /** 531 * Gets the amount of days of this period. 532 * <p> 533 * This returns the days unit. 534 * 535 * @return the amount of days of this period, may be negative 536 */ getDays()537 public int getDays() { 538 return days; 539 } 540 541 //----------------------------------------------------------------------- 542 /** 543 * Returns a copy of this period with the specified amount of years. 544 * <p> 545 * This sets the amount of the years unit in a copy of this period. 546 * The months and days units are unaffected. 547 * <p> 548 * The months unit is not automatically normalized with the years unit. 549 * This means that a period of "15 months" is different to a period 550 * of "1 year and 3 months". 551 * <p> 552 * This instance is immutable and unaffected by this method call. 553 * 554 * @param years the years to represent, may be negative 555 * @return a {@code Period} based on this period with the requested years, not null 556 */ withYears(int years)557 public Period withYears(int years) { 558 if (years == this.years) { 559 return this; 560 } 561 return create(years, months, days); 562 } 563 564 /** 565 * Returns a copy of this period with the specified amount of months. 566 * <p> 567 * This sets the amount of the months unit in a copy of this period. 568 * The years and days units are unaffected. 569 * <p> 570 * The months unit is not automatically normalized with the years unit. 571 * This means that a period of "15 months" is different to a period 572 * of "1 year and 3 months". 573 * <p> 574 * This instance is immutable and unaffected by this method call. 575 * 576 * @param months the months to represent, may be negative 577 * @return a {@code Period} based on this period with the requested months, not null 578 */ withMonths(int months)579 public Period withMonths(int months) { 580 if (months == this.months) { 581 return this; 582 } 583 return create(years, months, days); 584 } 585 586 /** 587 * Returns a copy of this period with the specified amount of days. 588 * <p> 589 * This sets the amount of the days unit in a copy of this period. 590 * The years and months units are unaffected. 591 * <p> 592 * This instance is immutable and unaffected by this method call. 593 * 594 * @param days the days to represent, may be negative 595 * @return a {@code Period} based on this period with the requested days, not null 596 */ withDays(int days)597 public Period withDays(int days) { 598 if (days == this.days) { 599 return this; 600 } 601 return create(years, months, days); 602 } 603 604 //----------------------------------------------------------------------- 605 /** 606 * Returns a copy of this period with the specified period added. 607 * <p> 608 * This operates separately on the years, months and days. 609 * No normalization is performed. 610 * <p> 611 * For example, "1 year, 6 months and 3 days" plus "2 years, 2 months and 2 days" 612 * returns "3 years, 8 months and 5 days". 613 * <p> 614 * The specified amount is typically an instance of {@code Period}. 615 * Other types are interpreted using {@link Period#from(TemporalAmount)}. 616 * <p> 617 * This instance is immutable and unaffected by this method call. 618 * 619 * @param amountToAdd the amount to add, not null 620 * @return a {@code Period} based on this period with the requested period added, not null 621 * @throws DateTimeException if the specified amount has a non-ISO chronology or 622 * contains an invalid unit 623 * @throws ArithmeticException if numeric overflow occurs 624 */ plus(TemporalAmount amountToAdd)625 public Period plus(TemporalAmount amountToAdd) { 626 Period isoAmount = Period.from(amountToAdd); 627 return create( 628 Math.addExact(years, isoAmount.years), 629 Math.addExact(months, isoAmount.months), 630 Math.addExact(days, isoAmount.days)); 631 } 632 633 /** 634 * Returns a copy of this period with the specified years added. 635 * <p> 636 * This adds the amount to the years unit in a copy of this period. 637 * The months and days units are unaffected. 638 * For example, "1 year, 6 months and 3 days" plus 2 years returns "3 years, 6 months and 3 days". 639 * <p> 640 * This instance is immutable and unaffected by this method call. 641 * 642 * @param yearsToAdd the years to add, positive or negative 643 * @return a {@code Period} based on this period with the specified years added, not null 644 * @throws ArithmeticException if numeric overflow occurs 645 */ plusYears(long yearsToAdd)646 public Period plusYears(long yearsToAdd) { 647 if (yearsToAdd == 0) { 648 return this; 649 } 650 return create(Math.toIntExact(Math.addExact(years, yearsToAdd)), months, days); 651 } 652 653 /** 654 * Returns a copy of this period with the specified months added. 655 * <p> 656 * This adds the amount to the months unit in a copy of this period. 657 * The years and days units are unaffected. 658 * For example, "1 year, 6 months and 3 days" plus 2 months returns "1 year, 8 months and 3 days". 659 * <p> 660 * This instance is immutable and unaffected by this method call. 661 * 662 * @param monthsToAdd the months to add, positive or negative 663 * @return a {@code Period} based on this period with the specified months added, not null 664 * @throws ArithmeticException if numeric overflow occurs 665 */ plusMonths(long monthsToAdd)666 public Period plusMonths(long monthsToAdd) { 667 if (monthsToAdd == 0) { 668 return this; 669 } 670 return create(years, Math.toIntExact(Math.addExact(months, monthsToAdd)), days); 671 } 672 673 /** 674 * Returns a copy of this period with the specified days added. 675 * <p> 676 * This adds the amount to the days unit in a copy of this period. 677 * The years and months units are unaffected. 678 * For example, "1 year, 6 months and 3 days" plus 2 days returns "1 year, 6 months and 5 days". 679 * <p> 680 * This instance is immutable and unaffected by this method call. 681 * 682 * @param daysToAdd the days to add, positive or negative 683 * @return a {@code Period} based on this period with the specified days added, not null 684 * @throws ArithmeticException if numeric overflow occurs 685 */ plusDays(long daysToAdd)686 public Period plusDays(long daysToAdd) { 687 if (daysToAdd == 0) { 688 return this; 689 } 690 return create(years, months, Math.toIntExact(Math.addExact(days, daysToAdd))); 691 } 692 693 //----------------------------------------------------------------------- 694 /** 695 * Returns a copy of this period with the specified period subtracted. 696 * <p> 697 * This operates separately on the years, months and days. 698 * No normalization is performed. 699 * <p> 700 * For example, "1 year, 6 months and 3 days" minus "2 years, 2 months and 2 days" 701 * returns "-1 years, 4 months and 1 day". 702 * <p> 703 * The specified amount is typically an instance of {@code Period}. 704 * Other types are interpreted using {@link Period#from(TemporalAmount)}. 705 * <p> 706 * This instance is immutable and unaffected by this method call. 707 * 708 * @param amountToSubtract the amount to subtract, not null 709 * @return a {@code Period} based on this period with the requested period subtracted, not null 710 * @throws DateTimeException if the specified amount has a non-ISO chronology or 711 * contains an invalid unit 712 * @throws ArithmeticException if numeric overflow occurs 713 */ minus(TemporalAmount amountToSubtract)714 public Period minus(TemporalAmount amountToSubtract) { 715 Period isoAmount = Period.from(amountToSubtract); 716 return create( 717 Math.subtractExact(years, isoAmount.years), 718 Math.subtractExact(months, isoAmount.months), 719 Math.subtractExact(days, isoAmount.days)); 720 } 721 722 /** 723 * Returns a copy of this period with the specified years subtracted. 724 * <p> 725 * This subtracts the amount from the years unit in a copy of this period. 726 * The months and days units are unaffected. 727 * For example, "1 year, 6 months and 3 days" minus 2 years returns "-1 years, 6 months and 3 days". 728 * <p> 729 * This instance is immutable and unaffected by this method call. 730 * 731 * @param yearsToSubtract the years to subtract, positive or negative 732 * @return a {@code Period} based on this period with the specified years subtracted, not null 733 * @throws ArithmeticException if numeric overflow occurs 734 */ minusYears(long yearsToSubtract)735 public Period minusYears(long yearsToSubtract) { 736 return (yearsToSubtract == Long.MIN_VALUE ? plusYears(Long.MAX_VALUE).plusYears(1) : plusYears(-yearsToSubtract)); 737 } 738 739 /** 740 * Returns a copy of this period with the specified months subtracted. 741 * <p> 742 * This subtracts the amount from the months unit in a copy of this period. 743 * The years and days units are unaffected. 744 * For example, "1 year, 6 months and 3 days" minus 2 months returns "1 year, 4 months and 3 days". 745 * <p> 746 * This instance is immutable and unaffected by this method call. 747 * 748 * @param monthsToSubtract the years to subtract, positive or negative 749 * @return a {@code Period} based on this period with the specified months subtracted, not null 750 * @throws ArithmeticException if numeric overflow occurs 751 */ minusMonths(long monthsToSubtract)752 public Period minusMonths(long monthsToSubtract) { 753 return (monthsToSubtract == Long.MIN_VALUE ? plusMonths(Long.MAX_VALUE).plusMonths(1) : plusMonths(-monthsToSubtract)); 754 } 755 756 /** 757 * Returns a copy of this period with the specified days subtracted. 758 * <p> 759 * This subtracts the amount from the days unit in a copy of this period. 760 * The years and months units are unaffected. 761 * For example, "1 year, 6 months and 3 days" minus 2 days returns "1 year, 6 months and 1 day". 762 * <p> 763 * This instance is immutable and unaffected by this method call. 764 * 765 * @param daysToSubtract the months to subtract, positive or negative 766 * @return a {@code Period} based on this period with the specified days subtracted, not null 767 * @throws ArithmeticException if numeric overflow occurs 768 */ minusDays(long daysToSubtract)769 public Period minusDays(long daysToSubtract) { 770 return (daysToSubtract == Long.MIN_VALUE ? plusDays(Long.MAX_VALUE).plusDays(1) : plusDays(-daysToSubtract)); 771 } 772 773 //----------------------------------------------------------------------- 774 /** 775 * Returns a new instance with each element in this period multiplied 776 * by the specified scalar. 777 * <p> 778 * This returns a period with each of the years, months and days units 779 * individually multiplied. 780 * For example, a period of "2 years, -3 months and 4 days" multiplied by 781 * 3 will return "6 years, -9 months and 12 days". 782 * No normalization is performed. 783 * 784 * @param scalar the scalar to multiply by, not null 785 * @return a {@code Period} based on this period with the amounts multiplied by the scalar, not null 786 * @throws ArithmeticException if numeric overflow occurs 787 */ multipliedBy(int scalar)788 public Period multipliedBy(int scalar) { 789 if (this == ZERO || scalar == 1) { 790 return this; 791 } 792 return create( 793 Math.multiplyExact(years, scalar), 794 Math.multiplyExact(months, scalar), 795 Math.multiplyExact(days, scalar)); 796 } 797 798 /** 799 * Returns a new instance with each amount in this period negated. 800 * <p> 801 * This returns a period with each of the years, months and days units 802 * individually negated. 803 * For example, a period of "2 years, -3 months and 4 days" will be 804 * negated to "-2 years, 3 months and -4 days". 805 * No normalization is performed. 806 * 807 * @return a {@code Period} based on this period with the amounts negated, not null 808 * @throws ArithmeticException if numeric overflow occurs, which only happens if 809 * one of the units has the value {@code Long.MIN_VALUE} 810 */ negated()811 public Period negated() { 812 return multipliedBy(-1); 813 } 814 815 //----------------------------------------------------------------------- 816 /** 817 * Returns a copy of this period with the years and months normalized. 818 * <p> 819 * This normalizes the years and months units, leaving the days unit unchanged. 820 * The months unit is adjusted to have an absolute value less than 11, 821 * with the years unit being adjusted to compensate. For example, a period of 822 * "1 Year and 15 months" will be normalized to "2 years and 3 months". 823 * <p> 824 * The sign of the years and months units will be the same after normalization. 825 * For example, a period of "1 year and -25 months" will be normalized to 826 * "-1 year and -1 month". 827 * <p> 828 * This instance is immutable and unaffected by this method call. 829 * 830 * @return a {@code Period} based on this period with excess months normalized to years, not null 831 * @throws ArithmeticException if numeric overflow occurs 832 */ normalized()833 public Period normalized() { 834 long totalMonths = toTotalMonths(); 835 long splitYears = totalMonths / 12; 836 int splitMonths = (int) (totalMonths % 12); // no overflow 837 if (splitYears == years && splitMonths == months) { 838 return this; 839 } 840 return create(Math.toIntExact(splitYears), splitMonths, days); 841 } 842 843 /** 844 * Gets the total number of months in this period. 845 * <p> 846 * This returns the total number of months in the period by multiplying the 847 * number of years by 12 and adding the number of months. 848 * <p> 849 * This instance is immutable and unaffected by this method call. 850 * 851 * @return the total number of months in the period, may be negative 852 */ toTotalMonths()853 public long toTotalMonths() { 854 return years * 12L + months; // no overflow 855 } 856 857 //------------------------------------------------------------------------- 858 /** 859 * Adds this period to the specified temporal object. 860 * <p> 861 * This returns a temporal object of the same observable type as the input 862 * with this period added. 863 * If the temporal has a chronology, it must be the ISO chronology. 864 * <p> 865 * In most cases, it is clearer to reverse the calling pattern by using 866 * {@link Temporal#plus(TemporalAmount)}. 867 * <pre> 868 * // these two lines are equivalent, but the second approach is recommended 869 * dateTime = thisPeriod.addTo(dateTime); 870 * dateTime = dateTime.plus(thisPeriod); 871 * </pre> 872 * <p> 873 * The calculation operates as follows. 874 * First, the chronology of the temporal is checked to ensure it is ISO chronology or null. 875 * Second, if the months are zero, the years are added if non-zero, otherwise 876 * the combination of years and months is added if non-zero. 877 * Finally, any days are added. 878 * <p> 879 * This approach ensures that a partial period can be added to a partial date. 880 * For example, a period of years and/or months can be added to a {@code YearMonth}, 881 * but a period including days cannot. 882 * The approach also adds years and months together when necessary, which ensures 883 * correct behaviour at the end of the month. 884 * <p> 885 * This instance is immutable and unaffected by this method call. 886 * 887 * @param temporal the temporal object to adjust, not null 888 * @return an object of the same type with the adjustment made, not null 889 * @throws DateTimeException if unable to add 890 * @throws ArithmeticException if numeric overflow occurs 891 */ 892 @Override addTo(Temporal temporal)893 public Temporal addTo(Temporal temporal) { 894 validateChrono(temporal); 895 if (months == 0) { 896 if (years != 0) { 897 temporal = temporal.plus(years, YEARS); 898 } 899 } else { 900 long totalMonths = toTotalMonths(); 901 if (totalMonths != 0) { 902 temporal = temporal.plus(totalMonths, MONTHS); 903 } 904 } 905 if (days != 0) { 906 temporal = temporal.plus(days, DAYS); 907 } 908 return temporal; 909 } 910 911 /** 912 * Subtracts this period from the specified temporal object. 913 * <p> 914 * This returns a temporal object of the same observable type as the input 915 * with this period subtracted. 916 * If the temporal has a chronology, it must be the ISO chronology. 917 * <p> 918 * In most cases, it is clearer to reverse the calling pattern by using 919 * {@link Temporal#minus(TemporalAmount)}. 920 * <pre> 921 * // these two lines are equivalent, but the second approach is recommended 922 * dateTime = thisPeriod.subtractFrom(dateTime); 923 * dateTime = dateTime.minus(thisPeriod); 924 * </pre> 925 * <p> 926 * The calculation operates as follows. 927 * First, the chronology of the temporal is checked to ensure it is ISO chronology or null. 928 * Second, if the months are zero, the years are subtracted if non-zero, otherwise 929 * the combination of years and months is subtracted if non-zero. 930 * Finally, any days are subtracted. 931 * <p> 932 * This approach ensures that a partial period can be subtracted from a partial date. 933 * For example, a period of years and/or months can be subtracted from a {@code YearMonth}, 934 * but a period including days cannot. 935 * The approach also subtracts years and months together when necessary, which ensures 936 * correct behaviour at the end of the month. 937 * <p> 938 * This instance is immutable and unaffected by this method call. 939 * 940 * @param temporal the temporal object to adjust, not null 941 * @return an object of the same type with the adjustment made, not null 942 * @throws DateTimeException if unable to subtract 943 * @throws ArithmeticException if numeric overflow occurs 944 */ 945 @Override subtractFrom(Temporal temporal)946 public Temporal subtractFrom(Temporal temporal) { 947 validateChrono(temporal); 948 if (months == 0) { 949 if (years != 0) { 950 temporal = temporal.minus(years, YEARS); 951 } 952 } else { 953 long totalMonths = toTotalMonths(); 954 if (totalMonths != 0) { 955 temporal = temporal.minus(totalMonths, MONTHS); 956 } 957 } 958 if (days != 0) { 959 temporal = temporal.minus(days, DAYS); 960 } 961 return temporal; 962 } 963 964 /** 965 * Validates that the temporal has the correct chronology. 966 */ validateChrono(TemporalAccessor temporal)967 private void validateChrono(TemporalAccessor temporal) { 968 Objects.requireNonNull(temporal, "temporal"); 969 Chronology temporalChrono = temporal.query(TemporalQueries.chronology()); 970 if (temporalChrono != null && IsoChronology.INSTANCE.equals(temporalChrono) == false) { 971 throw new DateTimeException("Chronology mismatch, expected: ISO, actual: " + temporalChrono.getId()); 972 } 973 } 974 975 //----------------------------------------------------------------------- 976 /** 977 * Checks if this period is equal to another period. 978 * <p> 979 * The comparison is based on the type {@code Period} and each of the three amounts. 980 * To be equal, the years, months and days units must be individually equal. 981 * Note that this means that a period of "15 Months" is not equal to a period 982 * of "1 Year and 3 Months". 983 * 984 * @param obj the object to check, null returns false 985 * @return true if this is equal to the other period 986 */ 987 @Override equals(Object obj)988 public boolean equals(Object obj) { 989 if (this == obj) { 990 return true; 991 } 992 if (obj instanceof Period) { 993 Period other = (Period) obj; 994 return years == other.years && 995 months == other.months && 996 days == other.days; 997 } 998 return false; 999 } 1000 1001 /** 1002 * A hash code for this period. 1003 * 1004 * @return a suitable hash code 1005 */ 1006 @Override hashCode()1007 public int hashCode() { 1008 return years + Integer.rotateLeft(months, 8) + Integer.rotateLeft(days, 16); 1009 } 1010 1011 //----------------------------------------------------------------------- 1012 /** 1013 * Outputs this period as a {@code String}, such as {@code P6Y3M1D}. 1014 * <p> 1015 * The output will be in the ISO-8601 period format. 1016 * A zero period will be represented as zero days, 'P0D'. 1017 * 1018 * @return a string representation of this period, not null 1019 */ 1020 @Override toString()1021 public String toString() { 1022 if (this == ZERO) { 1023 return "P0D"; 1024 } else { 1025 StringBuilder buf = new StringBuilder(); 1026 buf.append('P'); 1027 if (years != 0) { 1028 buf.append(years).append('Y'); 1029 } 1030 if (months != 0) { 1031 buf.append(months).append('M'); 1032 } 1033 if (days != 0) { 1034 buf.append(days).append('D'); 1035 } 1036 return buf.toString(); 1037 } 1038 } 1039 1040 //----------------------------------------------------------------------- 1041 /** 1042 * Writes the object using a 1043 * <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>. 1044 * @serialData 1045 * <pre> 1046 * out.writeByte(14); // identifies a Period 1047 * out.writeInt(years); 1048 * out.writeInt(months); 1049 * out.writeInt(days); 1050 * </pre> 1051 * 1052 * @return the instance of {@code Ser}, not null 1053 */ writeReplace()1054 private Object writeReplace() { 1055 return new Ser(Ser.PERIOD_TYPE, this); 1056 } 1057 1058 /** 1059 * Defend against malicious streams. 1060 * 1061 * @param s the stream to read 1062 * @throws java.io.InvalidObjectException always 1063 */ readObject(ObjectInputStream s)1064 private void readObject(ObjectInputStream s) throws InvalidObjectException { 1065 throw new InvalidObjectException("Deserialization via serialization delegate"); 1066 } 1067 writeExternal(DataOutput out)1068 void writeExternal(DataOutput out) throws IOException { 1069 out.writeInt(years); 1070 out.writeInt(months); 1071 out.writeInt(days); 1072 } 1073 readExternal(DataInput in)1074 static Period readExternal(DataInput in) throws IOException { 1075 int years = in.readInt(); 1076 int months = in.readInt(); 1077 int days = in.readInt(); 1078 return Period.of(years, months, days); 1079 } 1080 1081 } 1082