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1 /*
2  * Copyright (c) 2012, 2020, 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  * Copyright (c) 2012, Stephen Colebourne & Michael Nascimento Santos
28  *
29  * All rights reserved.
30  *
31  * Redistribution and use in source and binary forms, with or without
32  * modification, are permitted provided that the following conditions are met:
33  *
34  *  * Redistributions of source code must retain the above copyright notice,
35  *    this list of conditions and the following disclaimer.
36  *
37  *  * Redistributions in binary form must reproduce the above copyright notice,
38  *    this list of conditions and the following disclaimer in the documentation
39  *    and/or other materials provided with the distribution.
40  *
41  *  * Neither the name of JSR-310 nor the names of its contributors
42  *    may be used to endorse or promote products derived from this software
43  *    without specific prior written permission.
44  *
45  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
46  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
47  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
48  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
49  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
50  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
51  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
52  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
53  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
54  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
55  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
56  */
57 package java.time.temporal;
58 
59 import android.icu.text.DateTimePatternGenerator;
60 import android.icu.util.ULocale;
61 import java.time.DayOfWeek;
62 import java.time.Instant;
63 import java.time.Year;
64 import java.time.ZoneOffset;
65 import java.time.chrono.ChronoLocalDate;
66 import java.time.chrono.Chronology;
67 import java.util.Locale;
68 import java.util.Objects;
69 
70 import static java.time.temporal.ChronoUnit.DAYS;
71 import static java.time.temporal.ChronoUnit.ERAS;
72 import static java.time.temporal.ChronoUnit.FOREVER;
73 import static java.time.temporal.ChronoUnit.HALF_DAYS;
74 import static java.time.temporal.ChronoUnit.HOURS;
75 import static java.time.temporal.ChronoUnit.MICROS;
76 import static java.time.temporal.ChronoUnit.MILLIS;
77 import static java.time.temporal.ChronoUnit.MINUTES;
78 import static java.time.temporal.ChronoUnit.MONTHS;
79 import static java.time.temporal.ChronoUnit.NANOS;
80 import static java.time.temporal.ChronoUnit.SECONDS;
81 import static java.time.temporal.ChronoUnit.WEEKS;
82 import static java.time.temporal.ChronoUnit.YEARS;
83 
84 import java.time.DayOfWeek;
85 import java.time.Instant;
86 import java.time.Year;
87 import java.time.ZoneOffset;
88 import java.time.chrono.ChronoLocalDate;
89 import java.time.chrono.Chronology;
90 import java.util.Locale;
91 import java.util.Objects;
92 import java.util.ResourceBundle;
93 import sun.util.locale.provider.CalendarDataUtility;
94 
95 /**
96  * A standard set of fields.
97  * <p>
98  * This set of fields provide field-based access to manipulate a date, time or date-time.
99  * The standard set of fields can be extended by implementing {@link TemporalField}.
100  * <p>
101  * These fields are intended to be applicable in multiple calendar systems.
102  * For example, most non-ISO calendar systems define dates as a year, month and day,
103  * just with slightly different rules.
104  * The documentation of each field explains how it operates.
105  *
106  * @implSpec
107  * This is a final, immutable and thread-safe enum.
108  *
109  * @since 1.8
110  */
111 public enum ChronoField implements TemporalField {
112 
113     /**
114      * The nano-of-second.
115      * <p>
116      * This counts the nanosecond within the second, from 0 to 999,999,999.
117      * This field has the same meaning for all calendar systems.
118      * <p>
119      * This field is used to represent the nano-of-second handling any fraction of the second.
120      * Implementations of {@code TemporalAccessor} should provide a value for this field if
121      * they can return a value for {@link #SECOND_OF_MINUTE}, {@link #SECOND_OF_DAY} or
122      * {@link #INSTANT_SECONDS} filling unknown precision with zero.
123      * <p>
124      * When this field is used for setting a value, it should set as much precision as the
125      * object stores, using integer division to remove excess precision.
126      * For example, if the {@code TemporalAccessor} stores time to millisecond precision,
127      * then the nano-of-second must be divided by 1,000,000 before replacing the milli-of-second.
128      * <p>
129      * When parsing this field it behaves equivalent to the following:
130      * The value is validated in strict and smart mode but not in lenient mode.
131      * The field is resolved in combination with {@code MILLI_OF_SECOND} and {@code MICRO_OF_SECOND}.
132      */
133     NANO_OF_SECOND("NanoOfSecond", NANOS, SECONDS, ValueRange.of(0, 999_999_999)),
134     /**
135      * The nano-of-day.
136      * <p>
137      * This counts the nanosecond within the day, from 0 to (24 * 60 * 60 * 1,000,000,000) - 1.
138      * This field has the same meaning for all calendar systems.
139      * <p>
140      * This field is used to represent the nano-of-day handling any fraction of the second.
141      * Implementations of {@code TemporalAccessor} should provide a value for this field if
142      * they can return a value for {@link #SECOND_OF_DAY} filling unknown precision with zero.
143      * <p>
144      * When parsing this field it behaves equivalent to the following:
145      * The value is validated in strict and smart mode but not in lenient mode.
146      * The value is split to form {@code NANO_OF_SECOND}, {@code SECOND_OF_MINUTE},
147      * {@code MINUTE_OF_HOUR} and {@code HOUR_OF_DAY} fields.
148      */
149     NANO_OF_DAY("NanoOfDay", NANOS, DAYS, ValueRange.of(0, 86400L * 1000_000_000L - 1)),
150     /**
151      * The micro-of-second.
152      * <p>
153      * This counts the microsecond within the second, from 0 to 999,999.
154      * This field has the same meaning for all calendar systems.
155      * <p>
156      * This field is used to represent the micro-of-second handling any fraction of the second.
157      * Implementations of {@code TemporalAccessor} should provide a value for this field if
158      * they can return a value for {@link #SECOND_OF_MINUTE}, {@link #SECOND_OF_DAY} or
159      * {@link #INSTANT_SECONDS} filling unknown precision with zero.
160      * <p>
161      * When this field is used for setting a value, it should behave in the same way as
162      * setting {@link #NANO_OF_SECOND} with the value multiplied by 1,000.
163      * <p>
164      * When parsing this field it behaves equivalent to the following:
165      * The value is validated in strict and smart mode but not in lenient mode.
166      * The field is resolved in combination with {@code MILLI_OF_SECOND} to produce
167      * {@code NANO_OF_SECOND}.
168      */
169     MICRO_OF_SECOND("MicroOfSecond", MICROS, SECONDS, ValueRange.of(0, 999_999)),
170     /**
171      * The micro-of-day.
172      * <p>
173      * This counts the microsecond within the day, from 0 to (24 * 60 * 60 * 1,000,000) - 1.
174      * This field has the same meaning for all calendar systems.
175      * <p>
176      * This field is used to represent the micro-of-day handling any fraction of the second.
177      * Implementations of {@code TemporalAccessor} should provide a value for this field if
178      * they can return a value for {@link #SECOND_OF_DAY} filling unknown precision with zero.
179      * <p>
180      * When this field is used for setting a value, it should behave in the same way as
181      * setting {@link #NANO_OF_DAY} with the value multiplied by 1,000.
182      * <p>
183      * When parsing this field it behaves equivalent to the following:
184      * The value is validated in strict and smart mode but not in lenient mode.
185      * The value is split to form {@code MICRO_OF_SECOND}, {@code SECOND_OF_MINUTE},
186      * {@code MINUTE_OF_HOUR} and {@code HOUR_OF_DAY} fields.
187      */
188     MICRO_OF_DAY("MicroOfDay", MICROS, DAYS, ValueRange.of(0, 86400L * 1000_000L - 1)),
189     /**
190      * The milli-of-second.
191      * <p>
192      * This counts the millisecond within the second, from 0 to 999.
193      * This field has the same meaning for all calendar systems.
194      * <p>
195      * This field is used to represent the milli-of-second handling any fraction of the second.
196      * Implementations of {@code TemporalAccessor} should provide a value for this field if
197      * they can return a value for {@link #SECOND_OF_MINUTE}, {@link #SECOND_OF_DAY} or
198      * {@link #INSTANT_SECONDS} filling unknown precision with zero.
199      * <p>
200      * When this field is used for setting a value, it should behave in the same way as
201      * setting {@link #NANO_OF_SECOND} with the value multiplied by 1,000,000.
202      * <p>
203      * When parsing this field it behaves equivalent to the following:
204      * The value is validated in strict and smart mode but not in lenient mode.
205      * The field is resolved in combination with {@code MICRO_OF_SECOND} to produce
206      * {@code NANO_OF_SECOND}.
207      */
208     MILLI_OF_SECOND("MilliOfSecond", MILLIS, SECONDS, ValueRange.of(0, 999)),
209     /**
210      * The milli-of-day.
211      * <p>
212      * This counts the millisecond within the day, from 0 to (24 * 60 * 60 * 1,000) - 1.
213      * This field has the same meaning for all calendar systems.
214      * <p>
215      * This field is used to represent the milli-of-day handling any fraction of the second.
216      * Implementations of {@code TemporalAccessor} should provide a value for this field if
217      * they can return a value for {@link #SECOND_OF_DAY} filling unknown precision with zero.
218      * <p>
219      * When this field is used for setting a value, it should behave in the same way as
220      * setting {@link #NANO_OF_DAY} with the value multiplied by 1,000,000.
221      * <p>
222      * When parsing this field it behaves equivalent to the following:
223      * The value is validated in strict and smart mode but not in lenient mode.
224      * The value is split to form {@code MILLI_OF_SECOND}, {@code SECOND_OF_MINUTE},
225      * {@code MINUTE_OF_HOUR} and {@code HOUR_OF_DAY} fields.
226      */
227     MILLI_OF_DAY("MilliOfDay", MILLIS, DAYS, ValueRange.of(0, 86400L * 1000L - 1)),
228     /**
229      * The second-of-minute.
230      * <p>
231      * This counts the second within the minute, from 0 to 59.
232      * This field has the same meaning for all calendar systems.
233      * <p>
234      * When parsing this field it behaves equivalent to the following:
235      * The value is validated in strict and smart mode but not in lenient mode.
236      */
237     SECOND_OF_MINUTE("SecondOfMinute", SECONDS, MINUTES, ValueRange.of(0, 59), "second"),
238     /**
239      * The second-of-day.
240      * <p>
241      * This counts the second within the day, from 0 to (24 * 60 * 60) - 1.
242      * This field has the same meaning for all calendar systems.
243      * <p>
244      * When parsing this field it behaves equivalent to the following:
245      * The value is validated in strict and smart mode but not in lenient mode.
246      * The value is split to form {@code SECOND_OF_MINUTE}, {@code MINUTE_OF_HOUR}
247      * and {@code HOUR_OF_DAY} fields.
248      */
249     SECOND_OF_DAY("SecondOfDay", SECONDS, DAYS, ValueRange.of(0, 86400L - 1)),
250     /**
251      * The minute-of-hour.
252      * <p>
253      * This counts the minute within the hour, from 0 to 59.
254      * This field has the same meaning for all calendar systems.
255      * <p>
256      * When parsing this field it behaves equivalent to the following:
257      * The value is validated in strict and smart mode but not in lenient mode.
258      */
259     MINUTE_OF_HOUR("MinuteOfHour", MINUTES, HOURS, ValueRange.of(0, 59), "minute"),
260     /**
261      * The minute-of-day.
262      * <p>
263      * This counts the minute within the day, from 0 to (24 * 60) - 1.
264      * This field has the same meaning for all calendar systems.
265      * <p>
266      * When parsing this field it behaves equivalent to the following:
267      * The value is validated in strict and smart mode but not in lenient mode.
268      * The value is split to form {@code MINUTE_OF_HOUR} and {@code HOUR_OF_DAY} fields.
269      */
270     MINUTE_OF_DAY("MinuteOfDay", MINUTES, DAYS, ValueRange.of(0, (24 * 60) - 1)),
271     /**
272      * The hour-of-am-pm.
273      * <p>
274      * This counts the hour within the AM/PM, from 0 to 11.
275      * This is the hour that would be observed on a standard 12-hour digital clock.
276      * This field has the same meaning for all calendar systems.
277      * <p>
278      * When parsing this field it behaves equivalent to the following:
279      * The value is validated from 0 to 11 in strict and smart mode.
280      * In lenient mode the value is not validated. It is combined with
281      * {@code AMPM_OF_DAY} to form {@code HOUR_OF_DAY} by multiplying
282      * the {@code AMPM_OF_DAY} value by 12.
283      * <p>
284      * See {@link #CLOCK_HOUR_OF_AMPM} for the related field that counts hours from 1 to 12.
285      */
286     HOUR_OF_AMPM("HourOfAmPm", HOURS, HALF_DAYS, ValueRange.of(0, 11)),
287     /**
288      * The clock-hour-of-am-pm.
289      * <p>
290      * This counts the hour within the AM/PM, from 1 to 12.
291      * This is the hour that would be observed on a standard 12-hour analog wall clock.
292      * This field has the same meaning for all calendar systems.
293      * <p>
294      * When parsing this field it behaves equivalent to the following:
295      * The value is validated from 1 to 12 in strict mode and from
296      * 0 to 12 in smart mode. In lenient mode the value is not validated.
297      * The field is converted to an {@code HOUR_OF_AMPM} with the same value,
298      * unless the value is 12, in which case it is converted to 0.
299      * <p>
300      * See {@link #HOUR_OF_AMPM} for the related field that counts hours from 0 to 11.
301      */
302     CLOCK_HOUR_OF_AMPM("ClockHourOfAmPm", HOURS, HALF_DAYS, ValueRange.of(1, 12)),
303     /**
304      * The hour-of-day.
305      * <p>
306      * This counts the hour within the day, from 0 to 23.
307      * This is the hour that would be observed on a standard 24-hour digital clock.
308      * This field has the same meaning for all calendar systems.
309      * <p>
310      * When parsing this field it behaves equivalent to the following:
311      * The value is validated in strict and smart mode but not in lenient mode.
312      * The field is combined with {@code MINUTE_OF_HOUR}, {@code SECOND_OF_MINUTE} and
313      * {@code NANO_OF_SECOND} to produce a {@code LocalTime}.
314      * In lenient mode, any excess days are added to the parsed date, or
315      * made available via {@link java.time.format.DateTimeFormatter#parsedExcessDays()}.
316      * <p>
317      * See {@link #CLOCK_HOUR_OF_DAY} for the related field that counts hours from 1 to 24.
318      */
319     HOUR_OF_DAY("HourOfDay", HOURS, DAYS, ValueRange.of(0, 23), "hour"),
320     /**
321      * The clock-hour-of-day.
322      * <p>
323      * This counts the hour within the day, from 1 to 24.
324      * This is the hour that would be observed on a 24-hour analog wall clock.
325      * This field has the same meaning for all calendar systems.
326      * <p>
327      * When parsing this field it behaves equivalent to the following:
328      * The value is validated from 1 to 24 in strict mode and from
329      * 0 to 24 in smart mode. In lenient mode the value is not validated.
330      * The field is converted to an {@code HOUR_OF_DAY} with the same value,
331      * unless the value is 24, in which case it is converted to 0.
332      * <p>
333      * See {@link #HOUR_OF_DAY} for the related field that counts hours from 0 to 23.
334      */
335     CLOCK_HOUR_OF_DAY("ClockHourOfDay", HOURS, DAYS, ValueRange.of(1, 24)),
336     /**
337      * The am-pm-of-day.
338      * <p>
339      * This counts the AM/PM within the day, from 0 (AM) to 1 (PM).
340      * This field has the same meaning for all calendar systems.
341      * <p>
342      * When parsing this field it behaves equivalent to the following:
343      * The value is validated from 0 to 1 in strict and smart mode.
344      * In lenient mode the value is not validated. It is combined with
345      * {@code HOUR_OF_AMPM} (if not present, it defaults to '6') to form
346      * {@code HOUR_OF_DAY} by multiplying the {@code AMPM_OF_DAY} value
347      * by 12.
348      */
349     AMPM_OF_DAY("AmPmOfDay", HALF_DAYS, DAYS, ValueRange.of(0, 1), "dayperiod"),
350     /**
351      * The day-of-week, such as Tuesday.
352      * <p>
353      * This represents the standard concept of the day of the week.
354      * In the default ISO calendar system, this has values from Monday (1) to Sunday (7).
355      * The {@link DayOfWeek} class can be used to interpret the result.
356      * <p>
357      * Most non-ISO calendar systems also define a seven day week that aligns with ISO.
358      * Those calendar systems must also use the same numbering system, from Monday (1) to
359      * Sunday (7), which allows {@code DayOfWeek} to be used.
360      * <p>
361      * Calendar systems that do not have a standard seven day week should implement this field
362      * if they have a similar concept of named or numbered days within a period similar
363      * to a week. It is recommended that the numbering starts from 1.
364      */
365     DAY_OF_WEEK("DayOfWeek", DAYS, WEEKS, ValueRange.of(1, 7), "weekday"),
366     /**
367      * The aligned day-of-week within a month.
368      * <p>
369      * This represents concept of the count of days within the period of a week
370      * where the weeks are aligned to the start of the month.
371      * This field is typically used with {@link #ALIGNED_WEEK_OF_MONTH}.
372      * <p>
373      * For example, in a calendar systems with a seven day week, the first aligned-week-of-month
374      * starts on day-of-month 1, the second aligned-week starts on day-of-month 8, and so on.
375      * Within each of these aligned-weeks, the days are numbered from 1 to 7 and returned
376      * as the value of this field.
377      * As such, day-of-month 1 to 7 will have aligned-day-of-week values from 1 to 7.
378      * And day-of-month 8 to 14 will repeat this with aligned-day-of-week values from 1 to 7.
379      * <p>
380      * Calendar systems that do not have a seven day week should typically implement this
381      * field in the same way, but using the alternate week length.
382      */
383     ALIGNED_DAY_OF_WEEK_IN_MONTH("AlignedDayOfWeekInMonth", DAYS, WEEKS, ValueRange.of(1, 7)),
384     /**
385      * The aligned day-of-week within a year.
386      * <p>
387      * This represents concept of the count of days within the period of a week
388      * where the weeks are aligned to the start of the year.
389      * This field is typically used with {@link #ALIGNED_WEEK_OF_YEAR}.
390      * <p>
391      * For example, in a calendar systems with a seven day week, the first aligned-week-of-year
392      * starts on day-of-year 1, the second aligned-week starts on day-of-year 8, and so on.
393      * Within each of these aligned-weeks, the days are numbered from 1 to 7 and returned
394      * as the value of this field.
395      * As such, day-of-year 1 to 7 will have aligned-day-of-week values from 1 to 7.
396      * And day-of-year 8 to 14 will repeat this with aligned-day-of-week values from 1 to 7.
397      * <p>
398      * Calendar systems that do not have a seven day week should typically implement this
399      * field in the same way, but using the alternate week length.
400      */
401     ALIGNED_DAY_OF_WEEK_IN_YEAR("AlignedDayOfWeekInYear", DAYS, WEEKS, ValueRange.of(1, 7)),
402     /**
403      * The day-of-month.
404      * <p>
405      * This represents the concept of the day within the month.
406      * In the default ISO calendar system, this has values from 1 to 31 in most months.
407      * April, June, September, November have days from 1 to 30, while February has days
408      * from 1 to 28, or 29 in a leap year.
409      * <p>
410      * Non-ISO calendar systems should implement this field using the most recognized
411      * day-of-month values for users of the calendar system.
412      * Normally, this is a count of days from 1 to the length of the month.
413      */
414     DAY_OF_MONTH("DayOfMonth", DAYS, MONTHS, ValueRange.of(1, 28, 31), "day"),
415     /**
416      * The day-of-year.
417      * <p>
418      * This represents the concept of the day within the year.
419      * In the default ISO calendar system, this has values from 1 to 365 in standard
420      * years and 1 to 366 in leap years.
421      * <p>
422      * Non-ISO calendar systems should implement this field using the most recognized
423      * day-of-year values for users of the calendar system.
424      * Normally, this is a count of days from 1 to the length of the year.
425      * <p>
426      * Note that a non-ISO calendar system may have year numbering system that changes
427      * at a different point to the natural reset in the month numbering. An example
428      * of this is the Japanese calendar system where a change of era, which resets
429      * the year number to 1, can happen on any date. The era and year reset also cause
430      * the day-of-year to be reset to 1, but not the month-of-year or day-of-month.
431      */
432     DAY_OF_YEAR("DayOfYear", DAYS, YEARS, ValueRange.of(1, 365, 366)),
433     /**
434      * The epoch-day, based on the Java epoch of 1970-01-01 (ISO).
435      * <p>
436      * This field is the sequential count of days where 1970-01-01 (ISO) is zero.
437      * Note that this uses the <i>local</i> time-line, ignoring offset and time-zone.
438      * <p>
439      * This field is strictly defined to have the same meaning in all calendar systems.
440      * This is necessary to ensure interoperation between calendars.
441      * <p>
442      * Range of EpochDay is between (LocalDate.MIN.toEpochDay(), LocalDate.MAX.toEpochDay())
443      * both inclusive.
444      */
445     EPOCH_DAY("EpochDay", DAYS, FOREVER, ValueRange.of(-365243219162L, 365241780471L)),
446     /**
447      * The aligned week within a month.
448      * <p>
449      * This represents concept of the count of weeks within the period of a month
450      * where the weeks are aligned to the start of the month.
451      * This field is typically used with {@link #ALIGNED_DAY_OF_WEEK_IN_MONTH}.
452      * <p>
453      * For example, in a calendar systems with a seven day week, the first aligned-week-of-month
454      * starts on day-of-month 1, the second aligned-week starts on day-of-month 8, and so on.
455      * Thus, day-of-month values 1 to 7 are in aligned-week 1, while day-of-month values
456      * 8 to 14 are in aligned-week 2, and so on.
457      * <p>
458      * Calendar systems that do not have a seven day week should typically implement this
459      * field in the same way, but using the alternate week length.
460      */
461     ALIGNED_WEEK_OF_MONTH("AlignedWeekOfMonth", WEEKS, MONTHS, ValueRange.of(1, 4, 5)),
462     /**
463      * The aligned week within a year.
464      * <p>
465      * This represents concept of the count of weeks within the period of a year
466      * where the weeks are aligned to the start of the year.
467      * This field is typically used with {@link #ALIGNED_DAY_OF_WEEK_IN_YEAR}.
468      * <p>
469      * For example, in a calendar systems with a seven day week, the first aligned-week-of-year
470      * starts on day-of-year 1, the second aligned-week starts on day-of-year 8, and so on.
471      * Thus, day-of-year values 1 to 7 are in aligned-week 1, while day-of-year values
472      * 8 to 14 are in aligned-week 2, and so on.
473      * <p>
474      * Calendar systems that do not have a seven day week should typically implement this
475      * field in the same way, but using the alternate week length.
476      */
477     ALIGNED_WEEK_OF_YEAR("AlignedWeekOfYear", WEEKS, YEARS, ValueRange.of(1, 53)),
478     /**
479      * The month-of-year, such as March.
480      * <p>
481      * This represents the concept of the month within the year.
482      * In the default ISO calendar system, this has values from January (1) to December (12).
483      * <p>
484      * Non-ISO calendar systems should implement this field using the most recognized
485      * month-of-year values for users of the calendar system.
486      * Normally, this is a count of months starting from 1.
487      */
488     MONTH_OF_YEAR("MonthOfYear", MONTHS, YEARS, ValueRange.of(1, 12), "month"),
489     /**
490      * The proleptic-month based, counting months sequentially from year 0.
491      * <p>
492      * This field is the sequential count of months where the first month
493      * in proleptic-year zero has the value zero.
494      * Later months have increasingly larger values.
495      * Earlier months have increasingly small values.
496      * There are no gaps or breaks in the sequence of months.
497      * Note that this uses the <i>local</i> time-line, ignoring offset and time-zone.
498      * <p>
499      * In the default ISO calendar system, June 2012 would have the value
500      * {@code (2012 * 12 + 6 - 1)}. This field is primarily for internal use.
501      * <p>
502      * Non-ISO calendar systems must implement this field as per the definition above.
503      * It is just a simple zero-based count of elapsed months from the start of proleptic-year 0.
504      * All calendar systems with a full proleptic-year definition will have a year zero.
505      * If the calendar system has a minimum year that excludes year zero, then one must
506      * be extrapolated in order for this method to be defined.
507      */
508     PROLEPTIC_MONTH("ProlepticMonth", MONTHS, FOREVER, ValueRange.of(Year.MIN_VALUE * 12L, Year.MAX_VALUE * 12L + 11)),
509     /**
510      * The year within the era.
511      * <p>
512      * This represents the concept of the year within the era.
513      * This field is typically used with {@link #ERA}.
514      * <p>
515      * The standard mental model for a date is based on three concepts - year, month and day.
516      * These map onto the {@code YEAR}, {@code MONTH_OF_YEAR} and {@code DAY_OF_MONTH} fields.
517      * Note that there is no reference to eras.
518      * The full model for a date requires four concepts - era, year, month and day. These map onto
519      * the {@code ERA}, {@code YEAR_OF_ERA}, {@code MONTH_OF_YEAR} and {@code DAY_OF_MONTH} fields.
520      * Whether this field or {@code YEAR} is used depends on which mental model is being used.
521      * See {@link ChronoLocalDate} for more discussion on this topic.
522      * <p>
523      * In the default ISO calendar system, there are two eras defined, 'BCE' and 'CE'.
524      * The era 'CE' is the one currently in use and year-of-era runs from 1 to the maximum value.
525      * The era 'BCE' is the previous era, and the year-of-era runs backwards.
526      * <p>
527      * For example, subtracting a year each time yield the following:<br>
528      * - year-proleptic 2  = 'CE' year-of-era 2<br>
529      * - year-proleptic 1  = 'CE' year-of-era 1<br>
530      * - year-proleptic 0  = 'BCE' year-of-era 1<br>
531      * - year-proleptic -1 = 'BCE' year-of-era 2<br>
532      * <p>
533      * Note that the ISO-8601 standard does not actually define eras.
534      * Note also that the ISO eras do not align with the well-known AD/BC eras due to the
535      * change between the Julian and Gregorian calendar systems.
536      * <p>
537      * Non-ISO calendar systems should implement this field using the most recognized
538      * year-of-era value for users of the calendar system.
539      * Since most calendar systems have only two eras, the year-of-era numbering approach
540      * will typically be the same as that used by the ISO calendar system.
541      * The year-of-era value should typically always be positive, however this is not required.
542      */
543     YEAR_OF_ERA("YearOfEra", YEARS, FOREVER, ValueRange.of(1, Year.MAX_VALUE, Year.MAX_VALUE + 1)),
544     /**
545      * The proleptic year, such as 2012.
546      * <p>
547      * This represents the concept of the year, counting sequentially and using negative numbers.
548      * The proleptic year is not interpreted in terms of the era.
549      * See {@link #YEAR_OF_ERA} for an example showing the mapping from proleptic year to year-of-era.
550      * <p>
551      * The standard mental model for a date is based on three concepts - year, month and day.
552      * These map onto the {@code YEAR}, {@code MONTH_OF_YEAR} and {@code DAY_OF_MONTH} fields.
553      * Note that there is no reference to eras.
554      * The full model for a date requires four concepts - era, year, month and day. These map onto
555      * the {@code ERA}, {@code YEAR_OF_ERA}, {@code MONTH_OF_YEAR} and {@code DAY_OF_MONTH} fields.
556      * Whether this field or {@code YEAR_OF_ERA} is used depends on which mental model is being used.
557      * See {@link ChronoLocalDate} for more discussion on this topic.
558      * <p>
559      * Non-ISO calendar systems should implement this field as follows.
560      * If the calendar system has only two eras, before and after a fixed date, then the
561      * proleptic-year value must be the same as the year-of-era value for the later era,
562      * and increasingly negative for the earlier era.
563      * If the calendar system has more than two eras, then the proleptic-year value may be
564      * defined with any appropriate value, although defining it to be the same as ISO may be
565      * the best option.
566      */
567     YEAR("Year", YEARS, FOREVER, ValueRange.of(Year.MIN_VALUE, Year.MAX_VALUE), "year"),
568     /**
569      * The era.
570      * <p>
571      * This represents the concept of the era, which is the largest division of the time-line.
572      * This field is typically used with {@link #YEAR_OF_ERA}.
573      * <p>
574      * In the default ISO calendar system, there are two eras defined, 'BCE' and 'CE'.
575      * The era 'CE' is the one currently in use and year-of-era runs from 1 to the maximum value.
576      * The era 'BCE' is the previous era, and the year-of-era runs backwards.
577      * See {@link #YEAR_OF_ERA} for a full example.
578      * <p>
579      * Non-ISO calendar systems should implement this field to define eras.
580      * The value of the era that was active on 1970-01-01 (ISO) must be assigned the value 1.
581      * Earlier eras must have sequentially smaller values.
582      * Later eras must have sequentially larger values,
583      */
584     ERA("Era", ERAS, FOREVER, ValueRange.of(0, 1), "era"),
585     /**
586      * The instant epoch-seconds.
587      * <p>
588      * This represents the concept of the sequential count of seconds where
589      * 1970-01-01T00:00Z (ISO) is zero.
590      * This field may be used with {@link #NANO_OF_SECOND} to represent the fraction of the second.
591      * <p>
592      * An {@link Instant} represents an instantaneous point on the time-line.
593      * On their own, an instant has insufficient information to allow a local date-time to be obtained.
594      * Only when paired with an offset or time-zone can the local date or time be calculated.
595      * <p>
596      * This field is strictly defined to have the same meaning in all calendar systems.
597      * This is necessary to ensure interoperation between calendars.
598      */
599     INSTANT_SECONDS("InstantSeconds", SECONDS, FOREVER, ValueRange.of(Long.MIN_VALUE, Long.MAX_VALUE)),
600     /**
601      * The offset from UTC/Greenwich.
602      * <p>
603      * This represents the concept of the offset in seconds of local time from UTC/Greenwich.
604      * <p>
605      * A {@link ZoneOffset} represents the period of time that local time differs from UTC/Greenwich.
606      * This is usually a fixed number of hours and minutes.
607      * It is equivalent to the {@link ZoneOffset#getTotalSeconds() total amount} of the offset in seconds.
608      * For example, during the winter Paris has an offset of {@code +01:00}, which is 3600 seconds.
609      * <p>
610      * This field is strictly defined to have the same meaning in all calendar systems.
611      * This is necessary to ensure interoperation between calendars.
612      */
613     OFFSET_SECONDS("OffsetSeconds", SECONDS, FOREVER, ValueRange.of(-18 * 3600, 18 * 3600));
614 
615     private final String name;
616     private final TemporalUnit baseUnit;
617     private final TemporalUnit rangeUnit;
618     private final ValueRange range;
619     private final String displayNameKey;
620 
ChronoField(String name, TemporalUnit baseUnit, TemporalUnit rangeUnit, ValueRange range)621     private ChronoField(String name, TemporalUnit baseUnit, TemporalUnit rangeUnit, ValueRange range) {
622         this.name = name;
623         this.baseUnit = baseUnit;
624         this.rangeUnit = rangeUnit;
625         this.range = range;
626         this.displayNameKey = null;
627     }
628 
ChronoField(String name, TemporalUnit baseUnit, TemporalUnit rangeUnit, ValueRange range, String displayNameKey)629     private ChronoField(String name, TemporalUnit baseUnit, TemporalUnit rangeUnit,
630             ValueRange range, String displayNameKey) {
631         this.name = name;
632         this.baseUnit = baseUnit;
633         this.rangeUnit = rangeUnit;
634         this.range = range;
635         this.displayNameKey = displayNameKey;
636     }
637 
638     @Override
getDisplayName(Locale locale)639     public String getDisplayName(Locale locale) {
640         Objects.requireNonNull(locale, "locale");
641         if (displayNameKey == null) {
642             return name;
643         }
644 
645         // BEGIN Android-changed: use ICU names.
646         /*
647         LocaleResources lr = LocaleProviderAdapter.getResourceBundleBased()
648                                     .getLocaleResources(
649                                         CalendarDataUtility
650                                             .findRegionOverride(locale));
651         ResourceBundle rb = lr.getJavaTimeFormatData();
652         String key = "field." + displayNameKey;
653         return rb.containsKey(key) ? rb.getString(key) : name;
654          */
655         DateTimePatternGenerator generator = DateTimePatternGenerator
656                 .getInstance(ULocale.forLocale(locale));
657         String icuName = generator.getAppendItemName(getIcuFieldNumber(this));
658         return icuName != null && !icuName.isEmpty() ? icuName : name;
659     }
660 
661     /**
662      * @return the field id according to {@link DateTimePatternGenerator} for the field.
663      */
getIcuFieldNumber(ChronoField field)664     private static int getIcuFieldNumber(ChronoField field) {
665         switch (field) {
666             case SECOND_OF_MINUTE:
667                 return DateTimePatternGenerator.SECOND;
668             case MINUTE_OF_HOUR:
669                 return DateTimePatternGenerator.MINUTE;
670             case HOUR_OF_DAY:
671                 return DateTimePatternGenerator.HOUR;
672             case AMPM_OF_DAY:
673                 return DateTimePatternGenerator.DAYPERIOD;
674             case DAY_OF_WEEK:
675                 return DateTimePatternGenerator.WEEKDAY;
676             case DAY_OF_MONTH:
677                 return DateTimePatternGenerator.DAY;
678             case MONTH_OF_YEAR:
679                 return DateTimePatternGenerator.MONTH;
680             case YEAR:
681                 return DateTimePatternGenerator.YEAR;
682             case ERA:
683                 return DateTimePatternGenerator.ERA;
684             default:
685                 throw new IllegalArgumentException("Unexpected ChronoField " + field.name());
686         }
687         // END Android-changed: use ICU names.
688     }
689 
690     @Override
getBaseUnit()691     public TemporalUnit getBaseUnit() {
692         return baseUnit;
693     }
694 
695     @Override
getRangeUnit()696     public TemporalUnit getRangeUnit() {
697         return rangeUnit;
698     }
699 
700     /**
701      * Gets the range of valid values for the field.
702      * <p>
703      * All fields can be expressed as a {@code long} integer.
704      * This method returns an object that describes the valid range for that value.
705      * <p>
706      * This method returns the range of the field in the ISO-8601 calendar system.
707      * This range may be incorrect for other calendar systems.
708      * Use {@link Chronology#range(ChronoField)} to access the correct range
709      * for a different calendar system.
710      * <p>
711      * Note that the result only describes the minimum and maximum valid values
712      * and it is important not to read too much into them. For example, there
713      * could be values within the range that are invalid for the field.
714      *
715      * @return the range of valid values for the field, not null
716      */
717     @Override
range()718     public ValueRange range() {
719         return range;
720     }
721 
722     //-----------------------------------------------------------------------
723     /**
724      * Checks if this field represents a component of a date.
725      * <p>
726      * Fields from day-of-week to era are date-based.
727      *
728      * @return true if it is a component of a date
729      */
730     @Override
isDateBased()731     public boolean isDateBased() {
732         return ordinal() >= DAY_OF_WEEK.ordinal() && ordinal() <= ERA.ordinal();
733     }
734 
735     /**
736      * Checks if this field represents a component of a time.
737      * <p>
738      * Fields from nano-of-second to am-pm-of-day are time-based.
739      *
740      * @return true if it is a component of a time
741      */
742     @Override
isTimeBased()743     public boolean isTimeBased() {
744         return ordinal() < DAY_OF_WEEK.ordinal();
745     }
746 
747     //-----------------------------------------------------------------------
748     /**
749      * Checks that the specified value is valid for this field.
750      * <p>
751      * This validates that the value is within the outer range of valid values
752      * returned by {@link #range()}.
753      * <p>
754      * This method checks against the range of the field in the ISO-8601 calendar system.
755      * This range may be incorrect for other calendar systems.
756      * Use {@link Chronology#range(ChronoField)} to access the correct range
757      * for a different calendar system.
758      *
759      * @param value  the value to check
760      * @return the value that was passed in
761      */
checkValidValue(long value)762     public long checkValidValue(long value) {
763         return range().checkValidValue(value, this);
764     }
765 
766     /**
767      * Checks that the specified value is valid and fits in an {@code int}.
768      * <p>
769      * This validates that the value is within the outer range of valid values
770      * returned by {@link #range()}.
771      * It also checks that all valid values are within the bounds of an {@code int}.
772      * <p>
773      * This method checks against the range of the field in the ISO-8601 calendar system.
774      * This range may be incorrect for other calendar systems.
775      * Use {@link Chronology#range(ChronoField)} to access the correct range
776      * for a different calendar system.
777      *
778      * @param value  the value to check
779      * @return the value that was passed in
780      */
checkValidIntValue(long value)781     public int checkValidIntValue(long value) {
782         return range().checkValidIntValue(value, this);
783     }
784 
785     //-----------------------------------------------------------------------
786     @Override
isSupportedBy(TemporalAccessor temporal)787     public boolean isSupportedBy(TemporalAccessor temporal) {
788         return temporal.isSupported(this);
789     }
790 
791     @Override
rangeRefinedBy(TemporalAccessor temporal)792     public ValueRange rangeRefinedBy(TemporalAccessor temporal) {
793         return temporal.range(this);
794     }
795 
796     @Override
getFrom(TemporalAccessor temporal)797     public long getFrom(TemporalAccessor temporal) {
798         return temporal.getLong(this);
799     }
800 
801     @SuppressWarnings("unchecked")
802     @Override
adjustInto(R temporal, long newValue)803     public <R extends Temporal> R adjustInto(R temporal, long newValue) {
804         return (R) temporal.with(this, newValue);
805     }
806 
807     //-----------------------------------------------------------------------
808     @Override
toString()809     public String toString() {
810         return name;
811     }
812 
813 }
814