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
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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).
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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 static java.time.temporal.ChronoField.HOUR_OF_DAY;
65 import static java.time.temporal.ChronoField.MINUTE_OF_HOUR;
66 import static java.time.temporal.ChronoField.SECOND_OF_MINUTE;
67
68 import java.time.Clock;
69 import java.time.DateTimeException;
70 import java.time.Instant;
71 import java.time.LocalDate;
72 import java.time.LocalTime;
73 import java.time.ZoneId;
74 import java.time.ZoneOffset;
75 import java.time.format.DateTimeFormatterBuilder;
76 import java.time.format.ResolverStyle;
77 import java.time.format.TextStyle;
78 import java.time.temporal.ChronoField;
79 import java.time.temporal.TemporalAccessor;
80 import java.time.temporal.TemporalField;
81 import java.time.temporal.TemporalQueries;
82 import java.time.temporal.TemporalQuery;
83 import java.time.temporal.UnsupportedTemporalTypeException;
84 import java.time.temporal.ValueRange;
85 import java.util.List;
86 import java.util.Locale;
87 import java.util.Map;
88 import java.util.Objects;
89 import java.util.Set;
90
91 /**
92 * A calendar system, used to organize and identify dates.
93 * <p>
94 * The main date and time API is built on the ISO calendar system.
95 * The chronology operates behind the scenes to represent the general concept of a calendar system.
96 * For example, the Japanese, Minguo, Thai Buddhist and others.
97 * <p>
98 * Most other calendar systems also operate on the shared concepts of year, month and day,
99 * linked to the cycles of the Earth around the Sun, and the Moon around the Earth.
100 * These shared concepts are defined by {@link ChronoField} and are available
101 * for use by any {@code Chronology} implementation:
102 * <pre>
103 * LocalDate isoDate = ...
104 * ThaiBuddhistDate thaiDate = ...
105 * int isoYear = isoDate.get(ChronoField.YEAR);
106 * int thaiYear = thaiDate.get(ChronoField.YEAR);
107 * </pre>
108 * As shown, although the date objects are in different calendar systems, represented by different
109 * {@code Chronology} instances, both can be queried using the same constant on {@code ChronoField}.
110 * For a full discussion of the implications of this, see {@link ChronoLocalDate}.
111 * In general, the advice is to use the known ISO-based {@code LocalDate}, rather than
112 * {@code ChronoLocalDate}.
113 * <p>
114 * While a {@code Chronology} object typically uses {@code ChronoField} and is based on
115 * an era, year-of-era, month-of-year, day-of-month model of a date, this is not required.
116 * A {@code Chronology} instance may represent a totally different kind of calendar system,
117 * such as the Mayan.
118 * <p>
119 * In practical terms, the {@code Chronology} instance also acts as a factory.
120 * The {@link #of(String)} method allows an instance to be looked up by identifier,
121 * while the {@link #ofLocale(Locale)} method allows lookup by locale.
122 * <p>
123 * The {@code Chronology} instance provides a set of methods to create {@code ChronoLocalDate} instances.
124 * The date classes are used to manipulate specific dates.
125 * <ul>
126 * <li> {@link #dateNow() dateNow()}
127 * <li> {@link #dateNow(Clock) dateNow(clock)}
128 * <li> {@link #dateNow(ZoneId) dateNow(zone)}
129 * <li> {@link #date(int, int, int) date(yearProleptic, month, day)}
130 * <li> {@link #date(Era, int, int, int) date(era, yearOfEra, month, day)}
131 * <li> {@link #dateYearDay(int, int) dateYearDay(yearProleptic, dayOfYear)}
132 * <li> {@link #dateYearDay(Era, int, int) dateYearDay(era, yearOfEra, dayOfYear)}
133 * <li> {@link #date(TemporalAccessor) date(TemporalAccessor)}
134 * </ul>
135 *
136 * <h3 id="addcalendars">Adding New Calendars</h3>
137 * The set of available chronologies can be extended by applications.
138 * Adding a new calendar system requires the writing of an implementation of
139 * {@code Chronology}, {@code ChronoLocalDate} and {@code Era}.
140 * The majority of the logic specific to the calendar system will be in the
141 * {@code ChronoLocalDate} implementation.
142 * The {@code Chronology} implementation acts as a factory.
143 * <p>
144 * To permit the discovery of additional chronologies, the {@link java.util.ServiceLoader ServiceLoader}
145 * is used. A file must be added to the {@code META-INF/services} directory with the
146 * name 'java.time.chrono.Chronology' listing the implementation classes.
147 * See the ServiceLoader for more details on service loading.
148 * For lookup by id or calendarType, the system provided calendars are found
149 * first followed by application provided calendars.
150 * <p>
151 * Each chronology must define a chronology ID that is unique within the system.
152 * If the chronology represents a calendar system defined by the
153 * CLDR specification then the calendar type is the concatenation of the
154 * CLDR type and, if applicable, the CLDR variant.
155 *
156 * @implSpec
157 * This interface must be implemented with care to ensure other classes operate correctly.
158 * All implementations that can be instantiated must be final, immutable and thread-safe.
159 * Subclasses should be Serializable wherever possible.
160 *
161 * @since 1.8
162 */
163 public interface Chronology extends Comparable<Chronology> {
164
165 /**
166 * Obtains an instance of {@code Chronology} from a temporal object.
167 * <p>
168 * This obtains a chronology based on the specified temporal.
169 * A {@code TemporalAccessor} represents an arbitrary set of date and time information,
170 * which this factory converts to an instance of {@code Chronology}.
171 * <p>
172 * The conversion will obtain the chronology using {@link TemporalQueries#chronology()}.
173 * If the specified temporal object does not have a chronology, {@link IsoChronology} is returned.
174 * <p>
175 * This method matches the signature of the functional interface {@link TemporalQuery}
176 * allowing it to be used as a query via method reference, {@code Chronology::from}.
177 *
178 * @param temporal the temporal to convert, not null
179 * @return the chronology, not null
180 * @throws DateTimeException if unable to convert to a {@code Chronology}
181 */
182 static Chronology from(TemporalAccessor temporal) {
183 Objects.requireNonNull(temporal, "temporal");
184 Chronology obj = temporal.query(TemporalQueries.chronology());
185 return Objects.requireNonNullElse(obj, IsoChronology.INSTANCE);
186 }
187
188 //-----------------------------------------------------------------------
189 /**
190 * Obtains an instance of {@code Chronology} from a locale.
191 * <p>
192 * This returns a {@code Chronology} based on the specified locale,
193 * typically returning {@code IsoChronology}. Other calendar systems
194 * are only returned if they are explicitly selected within the locale.
195 * <p>
196 * The {@link Locale} class provide access to a range of information useful
197 * for localizing an application. This includes the language and region,
198 * such as "en-GB" for English as used in Great Britain.
199 * <p>
200 * The {@code Locale} class also supports an extension mechanism that
201 * can be used to identify a calendar system. The mechanism is a form
202 * of key-value pairs, where the calendar system has the key "ca".
203 * For example, the locale "en-JP-u-ca-japanese" represents the English
204 * language as used in Japan with the Japanese calendar system.
205 * <p>
206 * This method finds the desired calendar system in a manner equivalent
207 * to passing "ca" to {@link Locale#getUnicodeLocaleType(String)}.
208 * If the "ca" key is not present, then {@code IsoChronology} is returned.
209 * <p>
210 * Note that the behavior of this method differs from the older
211 * {@link java.util.Calendar#getInstance(Locale)} method.
212 * If that method receives a locale of "th_TH" it will return {@code BuddhistCalendar}.
213 * By contrast, this method will return {@code IsoChronology}.
214 * Passing the locale "th-TH-u-ca-buddhist" into either method will
215 * result in the Thai Buddhist calendar system and is therefore the
216 * recommended approach going forward for Thai calendar system localization.
217 * <p>
218 * A similar, but simpler, situation occurs for the Japanese calendar system.
219 * The locale "jp_JP_JP" has previously been used to access the calendar.
220 * However, unlike the Thai locale, "ja_JP_JP" is automatically converted by
221 * {@code Locale} to the modern and recommended form of "ja-JP-u-ca-japanese".
222 * Thus, there is no difference in behavior between this method and
223 * {@code Calendar#getInstance(Locale)}.
224 *
225 * @param locale the locale to use to obtain the calendar system, not null
226 * @return the calendar system associated with the locale, not null
227 * @throws DateTimeException if the locale-specified calendar cannot be found
228 */
229 static Chronology ofLocale(Locale locale) {
230 return AbstractChronology.ofLocale(locale);
231 }
232
233 //-----------------------------------------------------------------------
234 /**
235 * Obtains an instance of {@code Chronology} from a chronology ID or
236 * calendar system type.
237 * <p>
238 * This returns a chronology based on either the ID or the type.
239 * The {@link #getId() chronology ID} uniquely identifies the chronology.
240 * The {@link #getCalendarType() calendar system type} is defined by the
241 * CLDR specification.
242 * <p>
243 * The chronology may be a system chronology or a chronology
244 * provided by the application via ServiceLoader configuration.
245 * <p>
246 * Since some calendars can be customized, the ID or type typically refers
247 * to the default customization. For example, the Gregorian calendar can have multiple
248 * cutover dates from the Julian, but the lookup only provides the default cutover date.
249 *
250 * @param id the chronology ID or calendar system type, not null
251 * @return the chronology with the identifier requested, not null
252 * @throws DateTimeException if the chronology cannot be found
253 */
254 static Chronology of(String id) {
255 return AbstractChronology.of(id);
256 }
257
258 /**
259 * Returns the available chronologies.
260 * <p>
261 * Each returned {@code Chronology} is available for use in the system.
262 * The set of chronologies includes the system chronologies and
263 * any chronologies provided by the application via ServiceLoader
264 * configuration.
265 *
266 * @return the independent, modifiable set of the available chronology IDs, not null
267 */
268 static Set<Chronology> getAvailableChronologies() {
269 return AbstractChronology.getAvailableChronologies();
270 }
271
272 //-----------------------------------------------------------------------
273 /**
274 * Gets the ID of the chronology.
275 * <p>
276 * The ID uniquely identifies the {@code Chronology}.
277 * It can be used to lookup the {@code Chronology} using {@link #of(String)}.
278 *
279 * @return the chronology ID, not null
280 * @see #getCalendarType()
281 */
282 String getId();
283
284 /**
285 * Gets the calendar type of the calendar system.
286 * <p>
287 * The calendar type is an identifier defined by the CLDR and
288 * <em>Unicode Locale Data Markup Language (LDML)</em> specifications
289 * to uniquely identify a calendar.
290 * The {@code getCalendarType} is the concatenation of the CLDR calendar type
291 * and the variant, if applicable, is appended separated by "-".
292 * The calendar type is used to lookup the {@code Chronology} using {@link #of(String)}.
293 *
294 * @return the calendar system type, null if the calendar is not defined by CLDR/LDML
295 * @see #getId()
296 */
297 String getCalendarType();
298
299 //-----------------------------------------------------------------------
300 /**
301 * Obtains a local date in this chronology from the era, year-of-era,
302 * month-of-year and day-of-month fields.
303 *
304 * @implSpec
305 * The default implementation combines the era and year-of-era into a proleptic
306 * year before calling {@link #date(int, int, int)}.
307 *
308 * @param era the era of the correct type for the chronology, not null
309 * @param yearOfEra the chronology year-of-era
310 * @param month the chronology month-of-year
311 * @param dayOfMonth the chronology day-of-month
312 * @return the local date in this chronology, not null
313 * @throws DateTimeException if unable to create the date
314 * @throws ClassCastException if the {@code era} is not of the correct type for the chronology
315 */
316 default ChronoLocalDate date(Era era, int yearOfEra, int month, int dayOfMonth) {
317 return date(prolepticYear(era, yearOfEra), month, dayOfMonth);
318 }
319
320 /**
321 * Obtains a local date in this chronology from the proleptic-year,
322 * month-of-year and day-of-month fields.
323 *
324 * @param prolepticYear the chronology proleptic-year
325 * @param month the chronology month-of-year
326 * @param dayOfMonth the chronology day-of-month
327 * @return the local date in this chronology, not null
328 * @throws DateTimeException if unable to create the date
329 */
330 ChronoLocalDate date(int prolepticYear, int month, int dayOfMonth);
331
332 /**
333 * Obtains a local date in this chronology from the era, year-of-era and
334 * day-of-year fields.
335 *
336 * @implSpec
337 * The default implementation combines the era and year-of-era into a proleptic
338 * year before calling {@link #dateYearDay(int, int)}.
339 *
340 * @param era the era of the correct type for the chronology, not null
341 * @param yearOfEra the chronology year-of-era
342 * @param dayOfYear the chronology day-of-year
343 * @return the local date in this chronology, not null
344 * @throws DateTimeException if unable to create the date
345 * @throws ClassCastException if the {@code era} is not of the correct type for the chronology
346 */
347 default ChronoLocalDate dateYearDay(Era era, int yearOfEra, int dayOfYear) {
348 return dateYearDay(prolepticYear(era, yearOfEra), dayOfYear);
349 }
350
351 /**
352 * Obtains a local date in this chronology from the proleptic-year and
353 * day-of-year fields.
354 *
355 * @param prolepticYear the chronology proleptic-year
356 * @param dayOfYear the chronology day-of-year
357 * @return the local date in this chronology, not null
358 * @throws DateTimeException if unable to create the date
359 */
360 ChronoLocalDate dateYearDay(int prolepticYear, int dayOfYear);
361
362 /**
363 * Obtains a local date in this chronology from the epoch-day.
364 * <p>
365 * The definition of {@link ChronoField#EPOCH_DAY EPOCH_DAY} is the same
366 * for all calendar systems, thus it can be used for conversion.
367 *
368 * @param epochDay the epoch day
369 * @return the local date in this chronology, not null
370 * @throws DateTimeException if unable to create the date
371 */
372 ChronoLocalDate dateEpochDay(long epochDay);
373
374 //-----------------------------------------------------------------------
375 /**
376 * Obtains the current local date in this chronology from the system clock in the default time-zone.
377 * <p>
378 * This will query the {@link Clock#systemDefaultZone() system clock} in the default
379 * time-zone to obtain the current date.
380 * <p>
381 * Using this method will prevent the ability to use an alternate clock for testing
382 * because the clock is hard-coded.
383 *
384 * @implSpec
385 * The default implementation invokes {@link #dateNow(Clock)}.
386 *
387 * @return the current local date using the system clock and default time-zone, not null
388 * @throws DateTimeException if unable to create the date
389 */
390 default ChronoLocalDate dateNow() {
391 return dateNow(Clock.systemDefaultZone());
392 }
393
394 /**
395 * Obtains the current local date in this chronology from the system clock in the specified time-zone.
396 * <p>
397 * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current date.
398 * Specifying the time-zone avoids dependence on the default time-zone.
399 * <p>
400 * Using this method will prevent the ability to use an alternate clock for testing
401 * because the clock is hard-coded.
402 *
403 * @implSpec
404 * The default implementation invokes {@link #dateNow(Clock)}.
405 *
406 * @param zone the zone ID to use, not null
407 * @return the current local date using the system clock, not null
408 * @throws DateTimeException if unable to create the date
409 */
410 default ChronoLocalDate dateNow(ZoneId zone) {
411 return dateNow(Clock.system(zone));
412 }
413
414 /**
415 * Obtains the current local date in this chronology from the specified clock.
416 * <p>
417 * This will query the specified clock to obtain the current date - today.
418 * Using this method allows the use of an alternate clock for testing.
419 * The alternate clock may be introduced using {@link Clock dependency injection}.
420 *
421 * @implSpec
422 * The default implementation invokes {@link #date(TemporalAccessor)}.
423 *
424 * @param clock the clock to use, not null
425 * @return the current local date, not null
426 * @throws DateTimeException if unable to create the date
427 */
428 default ChronoLocalDate dateNow(Clock clock) {
429 Objects.requireNonNull(clock, "clock");
430 return date(LocalDate.now(clock));
431 }
432
433 //-----------------------------------------------------------------------
434 /**
435 * Obtains a local date in this chronology from another temporal object.
436 * <p>
437 * This obtains a date in this chronology based on the specified temporal.
438 * A {@code TemporalAccessor} represents an arbitrary set of date and time information,
439 * which this factory converts to an instance of {@code ChronoLocalDate}.
440 * <p>
441 * The conversion typically uses the {@link ChronoField#EPOCH_DAY EPOCH_DAY}
442 * field, which is standardized across calendar systems.
443 * <p>
444 * This method matches the signature of the functional interface {@link TemporalQuery}
445 * allowing it to be used as a query via method reference, {@code aChronology::date}.
446 *
447 * @param temporal the temporal object to convert, not null
448 * @return the local date in this chronology, not null
449 * @throws DateTimeException if unable to create the date
450 * @see ChronoLocalDate#from(TemporalAccessor)
451 */
452 ChronoLocalDate date(TemporalAccessor temporal);
453
454 /**
455 * Obtains a local date-time in this chronology from another temporal object.
456 * <p>
457 * This obtains a date-time in this chronology based on the specified temporal.
458 * A {@code TemporalAccessor} represents an arbitrary set of date and time information,
459 * which this factory converts to an instance of {@code ChronoLocalDateTime}.
460 * <p>
461 * The conversion extracts and combines the {@code ChronoLocalDate} and the
462 * {@code LocalTime} from the temporal object.
463 * Implementations are permitted to perform optimizations such as accessing
464 * those fields that are equivalent to the relevant objects.
465 * The result uses this chronology.
466 * <p>
467 * This method matches the signature of the functional interface {@link TemporalQuery}
468 * allowing it to be used as a query via method reference, {@code aChronology::localDateTime}.
469 *
470 * @param temporal the temporal object to convert, not null
471 * @return the local date-time in this chronology, not null
472 * @throws DateTimeException if unable to create the date-time
473 * @see ChronoLocalDateTime#from(TemporalAccessor)
474 */
475 default ChronoLocalDateTime<? extends ChronoLocalDate> localDateTime(TemporalAccessor temporal) {
476 try {
477 return date(temporal).atTime(LocalTime.from(temporal));
478 } catch (DateTimeException ex) {
479 throw new DateTimeException("Unable to obtain ChronoLocalDateTime from TemporalAccessor: " + temporal.getClass(), ex);
480 }
481 }
482
483 /**
484 * Obtains a {@code ChronoZonedDateTime} in this chronology from another temporal object.
485 * <p>
486 * This obtains a zoned date-time in this chronology based on the specified temporal.
487 * A {@code TemporalAccessor} represents an arbitrary set of date and time information,
488 * which this factory converts to an instance of {@code ChronoZonedDateTime}.
489 * <p>
490 * The conversion will first obtain a {@code ZoneId} from the temporal object,
491 * falling back to a {@code ZoneOffset} if necessary. It will then try to obtain
492 * an {@code Instant}, falling back to a {@code ChronoLocalDateTime} if necessary.
493 * The result will be either the combination of {@code ZoneId} or {@code ZoneOffset}
494 * with {@code Instant} or {@code ChronoLocalDateTime}.
495 * Implementations are permitted to perform optimizations such as accessing
496 * those fields that are equivalent to the relevant objects.
497 * The result uses this chronology.
498 * <p>
499 * This method matches the signature of the functional interface {@link TemporalQuery}
500 * allowing it to be used as a query via method reference, {@code aChronology::zonedDateTime}.
501 *
502 * @param temporal the temporal object to convert, not null
503 * @return the zoned date-time in this chronology, not null
504 * @throws DateTimeException if unable to create the date-time
505 * @see ChronoZonedDateTime#from(TemporalAccessor)
506 */
507 default ChronoZonedDateTime<? extends ChronoLocalDate> zonedDateTime(TemporalAccessor temporal) {
508 try {
509 ZoneId zone = ZoneId.from(temporal);
510 try {
511 Instant instant = Instant.from(temporal);
512 return zonedDateTime(instant, zone);
513
514 } catch (DateTimeException ex1) {
515 ChronoLocalDateTimeImpl<?> cldt = ChronoLocalDateTimeImpl.ensureValid(this, localDateTime(temporal));
516 return ChronoZonedDateTimeImpl.ofBest(cldt, zone, null);
517 }
518 } catch (DateTimeException ex) {
519 throw new DateTimeException("Unable to obtain ChronoZonedDateTime from TemporalAccessor: " + temporal.getClass(), ex);
520 }
521 }
522
523 /**
524 * Obtains a {@code ChronoZonedDateTime} in this chronology from an {@code Instant}.
525 * <p>
526 * This obtains a zoned date-time with the same instant as that specified.
527 *
528 * @param instant the instant to create the date-time from, not null
529 * @param zone the time-zone, not null
530 * @return the zoned date-time, not null
531 * @throws DateTimeException if the result exceeds the supported range
532 */
533 default ChronoZonedDateTime<? extends ChronoLocalDate> zonedDateTime(Instant instant, ZoneId zone) {
534 return ChronoZonedDateTimeImpl.ofInstant(this, instant, zone);
535 }
536
537 //-----------------------------------------------------------------------
538 /**
539 * Checks if the specified year is a leap year.
540 * <p>
541 * A leap-year is a year of a longer length than normal.
542 * The exact meaning is determined by the chronology according to the following constraints.
543 * <ul>
544 * <li>a leap-year must imply a year-length longer than a non leap-year.
545 * <li>a chronology that does not support the concept of a year must return false.
546 * <li>the correct result must be returned for all years within the
547 * valid range of years for the chronology.
548 * </ul>
549 * <p>
550 * Outside the range of valid years an implementation is free to return
551 * either a best guess or false.
552 * An implementation must not throw an exception, even if the year is
553 * outside the range of valid years.
554 *
555 * @param prolepticYear the proleptic-year to check, not validated for range
556 * @return true if the year is a leap year
557 */
558 boolean isLeapYear(long prolepticYear);
559
560 /**
561 * Calculates the proleptic-year given the era and year-of-era.
562 * <p>
563 * This combines the era and year-of-era into the single proleptic-year field.
564 * <p>
565 * If the chronology makes active use of eras, such as {@code JapaneseChronology}
566 * then the year-of-era will be validated against the era.
567 * For other chronologies, validation is optional.
568 *
569 * @param era the era of the correct type for the chronology, not null
570 * @param yearOfEra the chronology year-of-era
571 * @return the proleptic-year
572 * @throws DateTimeException if unable to convert to a proleptic-year,
573 * such as if the year is invalid for the era
574 * @throws ClassCastException if the {@code era} is not of the correct type for the chronology
575 */
576 int prolepticYear(Era era, int yearOfEra);
577
578 /**
579 * Creates the chronology era object from the numeric value.
580 * <p>
581 * The era is, conceptually, the largest division of the time-line.
582 * Most calendar systems have a single epoch dividing the time-line into two eras.
583 * However, some have multiple eras, such as one for the reign of each leader.
584 * The exact meaning is determined by the chronology according to the following constraints.
585 * <p>
586 * The era in use at 1970-01-01 must have the value 1.
587 * Later eras must have sequentially higher values.
588 * Earlier eras must have sequentially lower values.
589 * Each chronology must refer to an enum or similar singleton to provide the era values.
590 * <p>
591 * This method returns the singleton era of the correct type for the specified era value.
592 *
593 * @param eraValue the era value
594 * @return the calendar system era, not null
595 * @throws DateTimeException if unable to create the era
596 */
597 Era eraOf(int eraValue);
598
599 /**
600 * Gets the list of eras for the chronology.
601 * <p>
602 * Most calendar systems have an era, within which the year has meaning.
603 * If the calendar system does not support the concept of eras, an empty
604 * list must be returned.
605 *
606 * @return the list of eras for the chronology, may be immutable, not null
607 */
608 List<Era> eras();
609
610 //-----------------------------------------------------------------------
611 /**
612 * Gets the range of valid values for the specified field.
613 * <p>
614 * All fields can be expressed as a {@code long} integer.
615 * This method returns an object that describes the valid range for that value.
616 * <p>
617 * Note that the result only describes the minimum and maximum valid values
618 * and it is important not to read too much into them. For example, there
619 * could be values within the range that are invalid for the field.
620 * <p>
621 * This method will return a result whether or not the chronology supports the field.
622 *
623 * @param field the field to get the range for, not null
624 * @return the range of valid values for the field, not null
625 * @throws DateTimeException if the range for the field cannot be obtained
626 */
627 ValueRange range(ChronoField field);
628
629 //-----------------------------------------------------------------------
630 /**
631 * Gets the textual representation of this chronology.
632 * <p>
633 * This returns the textual name used to identify the chronology,
634 * suitable for presentation to the user.
635 * The parameters control the style of the returned text and the locale.
636 *
637 * @implSpec
638 * The default implementation behaves as though the formatter was used to
639 * format the chronology textual name.
640 *
641 * @param style the style of the text required, not null
642 * @param locale the locale to use, not null
643 * @return the text value of the chronology, not null
644 */
645 default String getDisplayName(TextStyle style, Locale locale) {
646 TemporalAccessor temporal = new TemporalAccessor() {
647 @Override
648 public boolean isSupported(TemporalField field) {
649 return false;
650 }
651 @Override
652 public long getLong(TemporalField field) {
653 throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
654 }
655 @SuppressWarnings("unchecked")
656 @Override
657 public <R> R query(TemporalQuery<R> query) {
658 if (query == TemporalQueries.chronology()) {
659 return (R) Chronology.this;
660 }
661 return TemporalAccessor.super.query(query);
662 }
663 };
664 return new DateTimeFormatterBuilder().appendChronologyText(style).toFormatter(locale).format(temporal);
665 }
666
667 //-----------------------------------------------------------------------
668 /**
669 * Resolves parsed {@code ChronoField} values into a date during parsing.
670 * <p>
671 * Most {@code TemporalField} implementations are resolved using the
672 * resolve method on the field. By contrast, the {@code ChronoField} class
673 * defines fields that only have meaning relative to the chronology.
674 * As such, {@code ChronoField} date fields are resolved here in the
675 * context of a specific chronology.
676 * <p>
677 * The default implementation, which explains typical resolve behaviour,
678 * is provided in {@link AbstractChronology}.
679 *
680 * @param fieldValues the map of fields to values, which can be updated, not null
681 * @param resolverStyle the requested type of resolve, not null
682 * @return the resolved date, null if insufficient information to create a date
683 * @throws DateTimeException if the date cannot be resolved, typically
684 * because of a conflict in the input data
685 */
686 ChronoLocalDate resolveDate(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle);
687
688 //-----------------------------------------------------------------------
689 /**
690 * Obtains a period for this chronology based on years, months and days.
691 * <p>
692 * This returns a period tied to this chronology using the specified
693 * years, months and days. All supplied chronologies use periods
694 * based on years, months and days, however the {@code ChronoPeriod} API
695 * allows the period to be represented using other units.
696 *
697 * @implSpec
698 * The default implementation returns an implementation class suitable
699 * for most calendar systems. It is based solely on the three units.
700 * Normalization, addition and subtraction derive the number of months
701 * in a year from the {@link #range(ChronoField)}. If the number of
702 * months within a year is fixed, then the calculation approach for
703 * addition, subtraction and normalization is slightly different.
704 * <p>
705 * If implementing an unusual calendar system that is not based on
706 * years, months and days, or where you want direct control, then
707 * the {@code ChronoPeriod} interface must be directly implemented.
708 * <p>
709 * The returned period is immutable and thread-safe.
710 *
711 * @param years the number of years, may be negative
712 * @param months the number of years, may be negative
713 * @param days the number of years, may be negative
714 * @return the period in terms of this chronology, not null
715 */
716 default ChronoPeriod period(int years, int months, int days) {
717 return new ChronoPeriodImpl(this, years, months, days);
718 }
719
720 //---------------------------------------------------------------------
721
722 /**
723 * Gets the number of seconds from the epoch of 1970-01-01T00:00:00Z.
724 * <p>
725 * The number of seconds is calculated using the proleptic-year,
726 * month, day-of-month, hour, minute, second, and zoneOffset.
727 *
728 * @param prolepticYear the chronology proleptic-year
729 * @param month the chronology month-of-year
730 * @param dayOfMonth the chronology day-of-month
731 * @param hour the hour-of-day, from 0 to 23
732 * @param minute the minute-of-hour, from 0 to 59
733 * @param second the second-of-minute, from 0 to 59
734 * @param zoneOffset the zone offset, not null
735 * @return the number of seconds relative to 1970-01-01T00:00:00Z, may be negative
736 * @throws DateTimeException if any of the values are out of range
737 * @since 9
738 */
739 public default long epochSecond(int prolepticYear, int month, int dayOfMonth,
740 int hour, int minute, int second, ZoneOffset zoneOffset) {
741 Objects.requireNonNull(zoneOffset, "zoneOffset");
742 HOUR_OF_DAY.checkValidValue(hour);
743 MINUTE_OF_HOUR.checkValidValue(minute);
744 SECOND_OF_MINUTE.checkValidValue(second);
745 long daysInSec = Math.multiplyExact(date(prolepticYear, month, dayOfMonth).toEpochDay(), 86400);
746 long timeinSec = (hour * 60 + minute) * 60 + second;
747 return Math.addExact(daysInSec, timeinSec - zoneOffset.getTotalSeconds());
748 }
749
750 /**
751 * Gets the number of seconds from the epoch of 1970-01-01T00:00:00Z.
752 * <p>
753 * The number of seconds is calculated using the era, year-of-era,
754 * month, day-of-month, hour, minute, second, and zoneOffset.
755 *
756 * @param era the era of the correct type for the chronology, not null
757 * @param yearOfEra the chronology year-of-era
758 * @param month the chronology month-of-year
759 * @param dayOfMonth the chronology day-of-month
760 * @param hour the hour-of-day, from 0 to 23
761 * @param minute the minute-of-hour, from 0 to 59
762 * @param second the second-of-minute, from 0 to 59
763 * @param zoneOffset the zone offset, not null
764 * @return the number of seconds relative to 1970-01-01T00:00:00Z, may be negative
765 * @throws DateTimeException if any of the values are out of range
766 * @since 9
767 */
768 public default long epochSecond(Era era, int yearOfEra, int month, int dayOfMonth,
769 int hour, int minute, int second, ZoneOffset zoneOffset) {
770 Objects.requireNonNull(era, "era");
771 return epochSecond(prolepticYear(era, yearOfEra), month, dayOfMonth, hour, minute, second, zoneOffset);
772 }
773 //-----------------------------------------------------------------------
774 /**
775 * Compares this chronology to another chronology.
776 * <p>
777 * The comparison order first by the chronology ID string, then by any
778 * additional information specific to the subclass.
779 * It is "consistent with equals", as defined by {@link Comparable}.
780 *
781 * @param other the other chronology to compare to, not null
782 * @return the comparator value, negative if less, positive if greater
783 */
784 @Override
785 int compareTo(Chronology other);
786
787 /**
788 * Checks if this chronology is equal to another chronology.
789 * <p>
790 * The comparison is based on the entire state of the object.
791 *
792 * @param obj the object to check, null returns false
793 * @return true if this is equal to the other chronology
794 */
795 @Override
796 boolean equals(Object obj);
797
798 /**
799 * A hash code for this chronology.
800 * <p>
801 * The hash code should be based on the entire state of the object.
802 *
803 * @return a suitable hash code
804 */
805 @Override
806 int hashCode();
807
808 //-----------------------------------------------------------------------
809 /**
810 * Outputs this chronology as a {@code String}.
811 * <p>
812 * The format should include the entire state of the object.
813 *
814 * @return a string representation of this chronology, not null
815 */
816 @Override
817 String toString();
818
819 }