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) 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.chrono; 63 64 import java.time.Clock; 65 import java.time.DateTimeException; 66 import java.time.Instant; 67 import java.time.LocalDate; 68 import java.time.LocalTime; 69 import java.time.ZoneId; 70 import java.time.ZoneOffset; 71 import java.time.format.DateTimeFormatterBuilder; 72 import java.time.format.ResolverStyle; 73 import java.time.format.TextStyle; 74 import java.time.temporal.ChronoField; 75 import java.time.temporal.TemporalAccessor; 76 import java.time.temporal.TemporalField; 77 import java.time.temporal.TemporalQueries; 78 import java.time.temporal.TemporalQuery; 79 import java.time.temporal.UnsupportedTemporalTypeException; 80 import java.time.temporal.ValueRange; 81 import java.util.List; 82 import java.util.Locale; 83 import java.util.Map; 84 import java.util.Objects; 85 import java.util.Set; 86 87 /** 88 * A calendar system, used to organize and identify dates. 89 * <p> 90 * The main date and time API is built on the ISO calendar system. 91 * The chronology operates behind the scenes to represent the general concept of a calendar system. 92 * For example, the Japanese, Minguo, Thai Buddhist and others. 93 * <p> 94 * Most other calendar systems also operate on the shared concepts of year, month and day, 95 * linked to the cycles of the Earth around the Sun, and the Moon around the Earth. 96 * These shared concepts are defined by {@link ChronoField} and are available 97 * for use by any {@code Chronology} implementation: 98 * <pre> 99 * LocalDate isoDate = ... 100 * ThaiBuddhistDate thaiDate = ... 101 * int isoYear = isoDate.get(ChronoField.YEAR); 102 * int thaiYear = thaiDate.get(ChronoField.YEAR); 103 * </pre> 104 * As shown, although the date objects are in different calendar systems, represented by different 105 * {@code Chronology} instances, both can be queried using the same constant on {@code ChronoField}. 106 * For a full discussion of the implications of this, see {@link ChronoLocalDate}. 107 * In general, the advice is to use the known ISO-based {@code LocalDate}, rather than 108 * {@code ChronoLocalDate}. 109 * <p> 110 * While a {@code Chronology} object typically uses {@code ChronoField} and is based on 111 * an era, year-of-era, month-of-year, day-of-month model of a date, this is not required. 112 * A {@code Chronology} instance may represent a totally different kind of calendar system, 113 * such as the Mayan. 114 * <p> 115 * In practical terms, the {@code Chronology} instance also acts as a factory. 116 * The {@link #of(String)} method allows an instance to be looked up by identifier, 117 * while the {@link #ofLocale(Locale)} method allows lookup by locale. 118 * <p> 119 * The {@code Chronology} instance provides a set of methods to create {@code ChronoLocalDate} instances. 120 * The date classes are used to manipulate specific dates. 121 * <ul> 122 * <li> {@link #dateNow() dateNow()} 123 * <li> {@link #dateNow(Clock) dateNow(clock)} 124 * <li> {@link #dateNow(ZoneId) dateNow(zone)} 125 * <li> {@link #date(int, int, int) date(yearProleptic, month, day)} 126 * <li> {@link #date(Era, int, int, int) date(era, yearOfEra, month, day)} 127 * <li> {@link #dateYearDay(int, int) dateYearDay(yearProleptic, dayOfYear)} 128 * <li> {@link #dateYearDay(Era, int, int) dateYearDay(era, yearOfEra, dayOfYear)} 129 * <li> {@link #date(TemporalAccessor) date(TemporalAccessor)} 130 * </ul> 131 * 132 * <h3 id="addcalendars">Adding New Calendars</h3> 133 * The set of available chronologies can be extended by applications. 134 * Adding a new calendar system requires the writing of an implementation of 135 * {@code Chronology}, {@code ChronoLocalDate} and {@code Era}. 136 * The majority of the logic specific to the calendar system will be in the 137 * {@code ChronoLocalDate} implementation. 138 * The {@code Chronology} implementation acts as a factory. 139 * <p> 140 * To permit the discovery of additional chronologies, the {@link java.util.ServiceLoader ServiceLoader} 141 * is used. A file must be added to the {@code META-INF/services} directory with the 142 * name 'java.time.chrono.Chronology' listing the implementation classes. 143 * See the ServiceLoader for more details on service loading. 144 * For lookup by id or calendarType, the system provided calendars are found 145 * first followed by application provided calendars. 146 * <p> 147 * Each chronology must define a chronology ID that is unique within the system. 148 * If the chronology represents a calendar system defined by the 149 * CLDR specification then the calendar type is the concatenation of the 150 * CLDR type and, if applicable, the CLDR variant, 151 * 152 * @implSpec 153 * This interface must be implemented with care to ensure other classes operate correctly. 154 * All implementations that can be instantiated must be final, immutable and thread-safe. 155 * Subclasses should be Serializable wherever possible. 156 * 157 * @since 1.8 158 */ 159 public interface Chronology extends Comparable<Chronology> { 160 161 /** 162 * Obtains an instance of {@code Chronology} from a temporal object. 163 * <p> 164 * This obtains a chronology based on the specified temporal. 165 * A {@code TemporalAccessor} represents an arbitrary set of date and time information, 166 * which this factory converts to an instance of {@code Chronology}. 167 * <p> 168 * The conversion will obtain the chronology using {@link TemporalQueries#chronology()}. 169 * If the specified temporal object does not have a chronology, {@link IsoChronology} is returned. 170 * <p> 171 * This method matches the signature of the functional interface {@link TemporalQuery} 172 * allowing it to be used as a query via method reference, {@code Chronology::from}. 173 * 174 * @param temporal the temporal to convert, not null 175 * @return the chronology, not null 176 * @throws DateTimeException if unable to convert to an {@code Chronology} 177 */ 178 static Chronology from(TemporalAccessor temporal) { 179 Objects.requireNonNull(temporal, "temporal"); 180 Chronology obj = temporal.query(TemporalQueries.chronology()); 181 return Objects.requireNonNullElse(obj, IsoChronology.INSTANCE); 182 } 183 184 //----------------------------------------------------------------------- 185 /** 186 * Obtains an instance of {@code Chronology} from a locale. 187 * <p> 188 * This returns a {@code Chronology} based on the specified locale, 189 * typically returning {@code IsoChronology}. Other calendar systems 190 * are only returned if they are explicitly selected within the locale. 191 * <p> 192 * The {@link Locale} class provide access to a range of information useful 193 * for localizing an application. This includes the language and region, 194 * such as "en-GB" for English as used in Great Britain. 195 * <p> 196 * The {@code Locale} class also supports an extension mechanism that 197 * can be used to identify a calendar system. The mechanism is a form 198 * of key-value pairs, where the calendar system has the key "ca". 199 * For example, the locale "en-JP-u-ca-japanese" represents the English 200 * language as used in Japan with the Japanese calendar system. 201 * <p> 202 * This method finds the desired calendar system by in a manner equivalent 203 * to passing "ca" to {@link Locale#getUnicodeLocaleType(String)}. 204 * If the "ca" key is not present, then {@code IsoChronology} is returned. 205 * <p> 206 * Note that the behavior of this method differs from the older 207 * {@link java.util.Calendar#getInstance(Locale)} method. 208 * If that method receives a locale of "th_TH" it will return {@code BuddhistCalendar}. 209 * By contrast, this method will return {@code IsoChronology}. 210 * Passing the locale "th-TH-u-ca-buddhist" into either method will 211 * result in the Thai Buddhist calendar system and is therefore the 212 * recommended approach going forward for Thai calendar system localization. 213 * <p> 214 * A similar, but simpler, situation occurs for the Japanese calendar system. 215 * The locale "jp_JP_JP" has previously been used to access the calendar. 216 * However, unlike the Thai locale, "ja_JP_JP" is automatically converted by 217 * {@code Locale} to the modern and recommended form of "ja-JP-u-ca-japanese". 218 * Thus, there is no difference in behavior between this method and 219 * {@code Calendar#getInstance(Locale)}. 220 * 221 * @param locale the locale to use to obtain the calendar system, not null 222 * @return the calendar system associated with the locale, not null 223 * @throws DateTimeException if the locale-specified calendar cannot be found 224 */ 225 static Chronology ofLocale(Locale locale) { 226 return AbstractChronology.ofLocale(locale); 227 } 228 229 //----------------------------------------------------------------------- 230 /** 231 * Obtains an instance of {@code Chronology} from a chronology ID or 232 * calendar system type. 233 * <p> 234 * This returns a chronology based on either the ID or the type. 235 * The {@link #getId() chronology ID} uniquely identifies the chronology. 236 * The {@link #getCalendarType() calendar system type} is defined by the 237 * CLDR specification. 238 * <p> 239 * The chronology may be a system chronology or a chronology 240 * provided by the application via ServiceLoader configuration. 241 * <p> 242 * Since some calendars can be customized, the ID or type typically refers 243 * to the default customization. For example, the Gregorian calendar can have multiple 244 * cutover dates from the Julian, but the lookup only provides the default cutover date. 245 * 246 * @param id the chronology ID or calendar system type, not null 247 * @return the chronology with the identifier requested, not null 248 * @throws DateTimeException if the chronology cannot be found 249 */ 250 static Chronology of(String id) { 251 return AbstractChronology.of(id); 252 } 253 254 /** 255 * Returns the available chronologies. 256 * <p> 257 * Each returned {@code Chronology} is available for use in the system. 258 * The set of chronologies includes the system chronologies and 259 * any chronologies provided by the application via ServiceLoader 260 * configuration. 261 * 262 * @return the independent, modifiable set of the available chronology IDs, not null 263 */ 264 static Set<Chronology> getAvailableChronologies() { 265 return AbstractChronology.getAvailableChronologies(); 266 } 267 268 //----------------------------------------------------------------------- 269 /** 270 * Gets the ID of the chronology. 271 * <p> 272 * The ID uniquely identifies the {@code Chronology}. 273 * It can be used to lookup the {@code Chronology} using {@link #of(String)}. 274 * 275 * @return the chronology ID, not null 276 * @see #getCalendarType() 277 */ 278 String getId(); 279 280 /** 281 * Gets the calendar type of the calendar system. 282 * <p> 283 * The calendar type is an identifier defined by the CLDR and 284 * <em>Unicode Locale Data Markup Language (LDML)</em> specifications 285 * to uniquely identification a calendar. 286 * The {@code getCalendarType} is the concatenation of the CLDR calendar type 287 * and the variant, if applicable, is appended separated by "-". 288 * The calendar type is used to lookup the {@code Chronology} using {@link #of(String)}. 289 * 290 * @return the calendar system type, null if the calendar is not defined by CLDR/LDML 291 * @see #getId() 292 */ 293 String getCalendarType(); 294 295 //----------------------------------------------------------------------- 296 /** 297 * Obtains a local date in this chronology from the era, year-of-era, 298 * month-of-year and day-of-month fields. 299 * 300 * @implSpec 301 * The default implementation combines the era and year-of-era into a proleptic 302 * year before calling {@link #date(int, int, int)}. 303 * 304 * @param era the era of the correct type for the chronology, not null 305 * @param yearOfEra the chronology year-of-era 306 * @param month the chronology month-of-year 307 * @param dayOfMonth the chronology day-of-month 308 * @return the local date in this chronology, not null 309 * @throws DateTimeException if unable to create the date 310 * @throws ClassCastException if the {@code era} is not of the correct type for the chronology 311 */ 312 default ChronoLocalDate date(Era era, int yearOfEra, int month, int dayOfMonth) { 313 return date(prolepticYear(era, yearOfEra), month, dayOfMonth); 314 } 315 316 /** 317 * Obtains a local date in this chronology from the proleptic-year, 318 * month-of-year and day-of-month fields. 319 * 320 * @param prolepticYear the chronology proleptic-year 321 * @param month the chronology month-of-year 322 * @param dayOfMonth the chronology day-of-month 323 * @return the local date in this chronology, not null 324 * @throws DateTimeException if unable to create the date 325 */ 326 ChronoLocalDate date(int prolepticYear, int month, int dayOfMonth); 327 328 /** 329 * Obtains a local date in this chronology from the era, year-of-era and 330 * day-of-year fields. 331 * 332 * @implSpec 333 * The default implementation combines the era and year-of-era into a proleptic 334 * year before calling {@link #dateYearDay(int, int)}. 335 * 336 * @param era the era of the correct type for the chronology, not null 337 * @param yearOfEra the chronology year-of-era 338 * @param dayOfYear the chronology day-of-year 339 * @return the local date in this chronology, not null 340 * @throws DateTimeException if unable to create the date 341 * @throws ClassCastException if the {@code era} is not of the correct type for the chronology 342 */ 343 default ChronoLocalDate dateYearDay(Era era, int yearOfEra, int dayOfYear) { 344 return dateYearDay(prolepticYear(era, yearOfEra), dayOfYear); 345 } 346 347 /** 348 * Obtains a local date in this chronology from the proleptic-year and 349 * day-of-year fields. 350 * 351 * @param prolepticYear the chronology proleptic-year 352 * @param dayOfYear the chronology day-of-year 353 * @return the local date in this chronology, not null 354 * @throws DateTimeException if unable to create the date 355 */ 356 ChronoLocalDate dateYearDay(int prolepticYear, int dayOfYear); 357 358 /** 359 * Obtains a local date in this chronology from the epoch-day. 360 * <p> 361 * The definition of {@link ChronoField#EPOCH_DAY EPOCH_DAY} is the same 362 * for all calendar systems, thus it can be used for conversion. 363 * 364 * @param epochDay the epoch day 365 * @return the local date in this chronology, not null 366 * @throws DateTimeException if unable to create the date 367 */ 368 ChronoLocalDate dateEpochDay(long epochDay); 369 370 //----------------------------------------------------------------------- 371 /** 372 * Obtains the current local date in this chronology from the system clock in the default time-zone. 373 * <p> 374 * This will query the {@link Clock#systemDefaultZone() system clock} in the default 375 * time-zone to obtain the current date. 376 * <p> 377 * Using this method will prevent the ability to use an alternate clock for testing 378 * because the clock is hard-coded. 379 * 380 * @implSpec 381 * The default implementation invokes {@link #dateNow(Clock)}. 382 * 383 * @return the current local date using the system clock and default time-zone, not null 384 * @throws DateTimeException if unable to create the date 385 */ 386 default ChronoLocalDate dateNow() { 387 return dateNow(Clock.systemDefaultZone()); 388 } 389 390 /** 391 * Obtains the current local date in this chronology from the system clock in the specified time-zone. 392 * <p> 393 * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current date. 394 * Specifying the time-zone avoids dependence on the default time-zone. 395 * <p> 396 * Using this method will prevent the ability to use an alternate clock for testing 397 * because the clock is hard-coded. 398 * 399 * @implSpec 400 * The default implementation invokes {@link #dateNow(Clock)}. 401 * 402 * @param zone the zone ID to use, not null 403 * @return the current local date using the system clock, not null 404 * @throws DateTimeException if unable to create the date 405 */ 406 default ChronoLocalDate dateNow(ZoneId zone) { 407 return dateNow(Clock.system(zone)); 408 } 409 410 /** 411 * Obtains the current local date in this chronology from the specified clock. 412 * <p> 413 * This will query the specified clock to obtain the current date - today. 414 * Using this method allows the use of an alternate clock for testing. 415 * The alternate clock may be introduced using {@link Clock dependency injection}. 416 * 417 * @implSpec 418 * The default implementation invokes {@link #date(TemporalAccessor)}. 419 * 420 * @param clock the clock to use, not null 421 * @return the current local date, not null 422 * @throws DateTimeException if unable to create the date 423 */ 424 default ChronoLocalDate dateNow(Clock clock) { 425 Objects.requireNonNull(clock, "clock"); 426 return date(LocalDate.now(clock)); 427 } 428 429 //----------------------------------------------------------------------- 430 /** 431 * Obtains a local date in this chronology from another temporal object. 432 * <p> 433 * This obtains a date in this chronology based on the specified temporal. 434 * A {@code TemporalAccessor} represents an arbitrary set of date and time information, 435 * which this factory converts to an instance of {@code ChronoLocalDate}. 436 * <p> 437 * The conversion typically uses the {@link ChronoField#EPOCH_DAY EPOCH_DAY} 438 * field, which is standardized across calendar systems. 439 * <p> 440 * This method matches the signature of the functional interface {@link TemporalQuery} 441 * allowing it to be used as a query via method reference, {@code aChronology::date}. 442 * 443 * @param temporal the temporal object to convert, not null 444 * @return the local date in this chronology, not null 445 * @throws DateTimeException if unable to create the date 446 * @see ChronoLocalDate#from(TemporalAccessor) 447 */ 448 ChronoLocalDate date(TemporalAccessor temporal); 449 450 /** 451 * Obtains a local date-time in this chronology from another temporal object. 452 * <p> 453 * This obtains a date-time in this chronology based on the specified temporal. 454 * A {@code TemporalAccessor} represents an arbitrary set of date and time information, 455 * which this factory converts to an instance of {@code ChronoLocalDateTime}. 456 * <p> 457 * The conversion extracts and combines the {@code ChronoLocalDate} and the 458 * {@code LocalTime} from the temporal object. 459 * Implementations are permitted to perform optimizations such as accessing 460 * those fields that are equivalent to the relevant objects. 461 * The result uses this chronology. 462 * <p> 463 * This method matches the signature of the functional interface {@link TemporalQuery} 464 * allowing it to be used as a query via method reference, {@code aChronology::localDateTime}. 465 * 466 * @param temporal the temporal object to convert, not null 467 * @return the local date-time in this chronology, not null 468 * @throws DateTimeException if unable to create the date-time 469 * @see ChronoLocalDateTime#from(TemporalAccessor) 470 */ 471 default ChronoLocalDateTime<? extends ChronoLocalDate> localDateTime(TemporalAccessor temporal) { 472 try { 473 return date(temporal).atTime(LocalTime.from(temporal)); 474 } catch (DateTimeException ex) { 475 throw new DateTimeException("Unable to obtain ChronoLocalDateTime from TemporalAccessor: " + temporal.getClass(), ex); 476 } 477 } 478 479 /** 480 * Obtains a {@code ChronoZonedDateTime} in this chronology from another temporal object. 481 * <p> 482 * This obtains a zoned date-time in this chronology based on the specified temporal. 483 * A {@code TemporalAccessor} represents an arbitrary set of date and time information, 484 * which this factory converts to an instance of {@code ChronoZonedDateTime}. 485 * <p> 486 * The conversion will first obtain a {@code ZoneId} from the temporal object, 487 * falling back to a {@code ZoneOffset} if necessary. It will then try to obtain 488 * an {@code Instant}, falling back to a {@code ChronoLocalDateTime} if necessary. 489 * The result will be either the combination of {@code ZoneId} or {@code ZoneOffset} 490 * with {@code Instant} or {@code ChronoLocalDateTime}. 491 * Implementations are permitted to perform optimizations such as accessing 492 * those fields that are equivalent to the relevant objects. 493 * The result uses this chronology. 494 * <p> 495 * This method matches the signature of the functional interface {@link TemporalQuery} 496 * allowing it to be used as a query via method reference, {@code aChronology::zonedDateTime}. 497 * 498 * @param temporal the temporal object to convert, not null 499 * @return the zoned date-time in this chronology, not null 500 * @throws DateTimeException if unable to create the date-time 501 * @see ChronoZonedDateTime#from(TemporalAccessor) 502 */ 503 default ChronoZonedDateTime<? extends ChronoLocalDate> zonedDateTime(TemporalAccessor temporal) { 504 try { 505 ZoneId zone = ZoneId.from(temporal); 506 try { 507 Instant instant = Instant.from(temporal); 508 return zonedDateTime(instant, zone); 509 510 } catch (DateTimeException ex1) { 511 ChronoLocalDateTimeImpl<?> cldt = ChronoLocalDateTimeImpl.ensureValid(this, localDateTime(temporal)); 512 return ChronoZonedDateTimeImpl.ofBest(cldt, zone, null); 513 } 514 } catch (DateTimeException ex) { 515 throw new DateTimeException("Unable to obtain ChronoZonedDateTime from TemporalAccessor: " + temporal.getClass(), ex); 516 } 517 } 518 519 /** 520 * Obtains a {@code ChronoZonedDateTime} in this chronology from an {@code Instant}. 521 * <p> 522 * This obtains a zoned date-time with the same instant as that specified. 523 * 524 * @param instant the instant to create the date-time from, not null 525 * @param zone the time-zone, not null 526 * @return the zoned date-time, not null 527 * @throws DateTimeException if the result exceeds the supported range 528 */ 529 default ChronoZonedDateTime<? extends ChronoLocalDate> zonedDateTime(Instant instant, ZoneId zone) { 530 return ChronoZonedDateTimeImpl.ofInstant(this, instant, zone); 531 } 532 533 //----------------------------------------------------------------------- 534 /** 535 * Checks if the specified year is a leap year. 536 * <p> 537 * A leap-year is a year of a longer length than normal. 538 * The exact meaning is determined by the chronology according to the following constraints. 539 * <ul> 540 * <li>a leap-year must imply a year-length longer than a non leap-year. 541 * <li>a chronology that does not support the concept of a year must return false. 542 * <li>the correct result must be returned for all years within the 543 * valid range of years for the chronology. 544 * </ul> 545 * <p> 546 * Outside the range of valid years an implementation is free to return 547 * either a best guess or false. 548 * An implementation must not throw an exception, even if the year is 549 * outside the range of valid years. 550 * 551 * @param prolepticYear the proleptic-year to check, not validated for range 552 * @return true if the year is a leap year 553 */ 554 boolean isLeapYear(long prolepticYear); 555 556 /** 557 * Calculates the proleptic-year given the era and year-of-era. 558 * <p> 559 * This combines the era and year-of-era into the single proleptic-year field. 560 * <p> 561 * If the chronology makes active use of eras, such as {@code JapaneseChronology} 562 * then the year-of-era will be validated against the era. 563 * For other chronologies, validation is optional. 564 * 565 * @param era the era of the correct type for the chronology, not null 566 * @param yearOfEra the chronology year-of-era 567 * @return the proleptic-year 568 * @throws DateTimeException if unable to convert to a proleptic-year, 569 * such as if the year is invalid for the era 570 * @throws ClassCastException if the {@code era} is not of the correct type for the chronology 571 */ 572 int prolepticYear(Era era, int yearOfEra); 573 574 /** 575 * Creates the chronology era object from the numeric value. 576 * <p> 577 * The era is, conceptually, the largest division of the time-line. 578 * Most calendar systems have a single epoch dividing the time-line into two eras. 579 * However, some have multiple eras, such as one for the reign of each leader. 580 * The exact meaning is determined by the chronology according to the following constraints. 581 * <p> 582 * The era in use at 1970-01-01 must have the value 1. 583 * Later eras must have sequentially higher values. 584 * Earlier eras must have sequentially lower values. 585 * Each chronology must refer to an enum or similar singleton to provide the era values. 586 * <p> 587 * This method returns the singleton era of the correct type for the specified era value. 588 * 589 * @param eraValue the era value 590 * @return the calendar system era, not null 591 * @throws DateTimeException if unable to create the era 592 */ 593 Era eraOf(int eraValue); 594 595 /** 596 * Gets the list of eras for the chronology. 597 * <p> 598 * Most calendar systems have an era, within which the year has meaning. 599 * If the calendar system does not support the concept of eras, an empty 600 * list must be returned. 601 * 602 * @return the list of eras for the chronology, may be immutable, not null 603 */ 604 List<Era> eras(); 605 606 //----------------------------------------------------------------------- 607 /** 608 * Gets the range of valid values for the specified field. 609 * <p> 610 * All fields can be expressed as a {@code long} integer. 611 * This method returns an object that describes the valid range for that value. 612 * <p> 613 * Note that the result only describes the minimum and maximum valid values 614 * and it is important not to read too much into them. For example, there 615 * could be values within the range that are invalid for the field. 616 * <p> 617 * This method will return a result whether or not the chronology supports the field. 618 * 619 * @param field the field to get the range for, not null 620 * @return the range of valid values for the field, not null 621 * @throws DateTimeException if the range for the field cannot be obtained 622 */ 623 ValueRange range(ChronoField field); 624 625 //----------------------------------------------------------------------- 626 /** 627 * Gets the textual representation of this chronology. 628 * <p> 629 * This returns the textual name used to identify the chronology, 630 * suitable for presentation to the user. 631 * The parameters control the style of the returned text and the locale. 632 * 633 * @implSpec 634 * The default implementation behaves as though the formatter was used to 635 * format the chronology textual name. 636 * 637 * @param style the style of the text required, not null 638 * @param locale the locale to use, not null 639 * @return the text value of the chronology, not null 640 */ 641 default String getDisplayName(TextStyle style, Locale locale) { 642 TemporalAccessor temporal = new TemporalAccessor() { 643 @Override 644 public boolean isSupported(TemporalField field) { 645 return false; 646 } 647 @Override 648 public long getLong(TemporalField field) { 649 throw new UnsupportedTemporalTypeException("Unsupported field: " + field); 650 } 651 @SuppressWarnings("unchecked") 652 @Override 653 public <R> R query(TemporalQuery<R> query) { 654 if (query == TemporalQueries.chronology()) { 655 return (R) Chronology.this; 656 } 657 return TemporalAccessor.super.query(query); 658 } 659 }; 660 return new DateTimeFormatterBuilder().appendChronologyText(style).toFormatter(locale).format(temporal); 661 } 662 663 //----------------------------------------------------------------------- 664 /** 665 * Resolves parsed {@code ChronoField} values into a date during parsing. 666 * <p> 667 * Most {@code TemporalField} implementations are resolved using the 668 * resolve method on the field. By contrast, the {@code ChronoField} class 669 * defines fields that only have meaning relative to the chronology. 670 * As such, {@code ChronoField} date fields are resolved here in the 671 * context of a specific chronology. 672 * <p> 673 * The default implementation, which explains typical resolve behaviour, 674 * is provided in {@link AbstractChronology}. 675 * 676 * @param fieldValues the map of fields to values, which can be updated, not null 677 * @param resolverStyle the requested type of resolve, not null 678 * @return the resolved date, null if insufficient information to create a date 679 * @throws DateTimeException if the date cannot be resolved, typically 680 * because of a conflict in the input data 681 */ 682 ChronoLocalDate resolveDate(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle); 683 684 //----------------------------------------------------------------------- 685 /** 686 * Obtains a period for this chronology based on years, months and days. 687 * <p> 688 * This returns a period tied to this chronology using the specified 689 * years, months and days. All supplied chronologies use periods 690 * based on years, months and days, however the {@code ChronoPeriod} API 691 * allows the period to be represented using other units. 692 * 693 * @implSpec 694 * The default implementation returns an implementation class suitable 695 * for most calendar systems. It is based solely on the three units. 696 * Normalization, addition and subtraction derive the number of months 697 * in a year from the {@link #range(ChronoField)}. If the number of 698 * months within a year is fixed, then the calculation approach for 699 * addition, subtraction and normalization is slightly different. 700 * <p> 701 * If implementing an unusual calendar system that is not based on 702 * years, months and days, or where you want direct control, then 703 * the {@code ChronoPeriod} interface must be directly implemented. 704 * <p> 705 * The returned period is immutable and thread-safe. 706 * 707 * @param years the number of years, may be negative 708 * @param months the number of years, may be negative 709 * @param days the number of years, may be negative 710 * @return the period in terms of this chronology, not null 711 */ 712 default ChronoPeriod period(int years, int months, int days) { 713 return new ChronoPeriodImpl(this, years, months, days); 714 } 715 716 //--------------------------------------------------------------------- 717 718 /** 719 * Gets the number of seconds from the epoch of 1970-01-01T00:00:00Z. 720 * <p> 721 * The number of seconds is calculated using the proleptic-year, 722 * month, day-of-month, hour, minute, second, and zoneOffset. 723 * 724 * @param prolepticYear the chronology proleptic-year 725 * @param month the chronology month-of-year 726 * @param dayOfMonth the chronology day-of-month 727 * @param hour the hour-of-day, from 0 to 23 728 * @param minute the minute-of-hour, from 0 to 59 729 * @param second the second-of-minute, from 0 to 59 730 * @param zoneOffset the zone offset, not null 731 * @return the number of seconds relative to 1970-01-01T00:00:00Z, may be negative 732 * @since 9 733 */ 734 public default long epochSecond(int prolepticYear, int month, int dayOfMonth, 735 int hour, int minute, int second, ZoneOffset zoneOffset) { 736 Objects.requireNonNull(zoneOffset, "zoneOffset"); 737 long daysInSec = Math.multiplyExact(date(prolepticYear, month, dayOfMonth).toEpochDay(), 86400); 738 long timeinSec = (hour * 60 + minute) * 60 + second; 739 return Math.addExact(daysInSec, timeinSec - zoneOffset.getTotalSeconds()); 740 } 741 742 /** 743 * Gets the number of seconds from the epoch of 1970-01-01T00:00:00Z. 744 * <p> 745 * The number of seconds is calculated using the era, year-of-era, 746 * month, day-of-month, hour, minute, second, and zoneOffset. 747 * 748 * @param era the era of the correct type for the chronology, not null 749 * @param yearOfEra the chronology year-of-era 750 * @param month the chronology month-of-year 751 * @param dayOfMonth the chronology day-of-month 752 * @param hour the hour-of-day, from 0 to 23 753 * @param minute the minute-of-hour, from 0 to 59 754 * @param second the second-of-minute, from 0 to 59 755 * @param zoneOffset the zone offset, not null 756 * @return the number of seconds relative to 1970-01-01T00:00:00Z, may be negative 757 * @since 9 758 */ 759 public default long epochSecond(Era era, int yearOfEra, int month, int dayOfMonth, 760 int hour, int minute, int second, ZoneOffset zoneOffset) { 761 Objects.requireNonNull(era, "era"); 762 return epochSecond(prolepticYear(era, yearOfEra), month, dayOfMonth, hour, minute, second, zoneOffset); 763 } 764 //----------------------------------------------------------------------- 765 /** 766 * Compares this chronology to another chronology. 767 * <p> 768 * The comparison order first by the chronology ID string, then by any 769 * additional information specific to the subclass. 770 * It is "consistent with equals", as defined by {@link Comparable}. 771 * 772 * @param other the other chronology to compare to, not null 773 * @return the comparator value, negative if less, positive if greater 774 */ 775 @Override 776 int compareTo(Chronology other); 777 778 /** 779 * Checks if this chronology is equal to another chronology. 780 * <p> 781 * The comparison is based on the entire state of the object. 782 * 783 * @param obj the object to check, null returns false 784 * @return true if this is equal to the other chronology 785 */ 786 @Override 787 boolean equals(Object obj); 788 789 /** 790 * A hash code for this chronology. 791 * <p> 792 * The hash code should be based on the entire state of the object. 793 * 794 * @return a suitable hash code 795 */ 796 @Override 797 int hashCode(); 798 799 //----------------------------------------------------------------------- 800 /** 801 * Outputs this chronology as a {@code String}. 802 * <p> 803 * The format should include the entire state of the object. 804 * 805 * @return a string representation of this chronology, not null 806 */ 807 @Override 808 String toString(); 809 810 }