src/share/classes/java/time/temporal/ChronoField.java

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  59 import static java.time.temporal.ChronoUnit.DAYS;
  60 import static java.time.temporal.ChronoUnit.ERAS;
  61 import static java.time.temporal.ChronoUnit.FOREVER;
  62 import static java.time.temporal.ChronoUnit.HALF_DAYS;
  63 import static java.time.temporal.ChronoUnit.HOURS;
  64 import static java.time.temporal.ChronoUnit.MICROS;
  65 import static java.time.temporal.ChronoUnit.MILLIS;
  66 import static java.time.temporal.ChronoUnit.MINUTES;
  67 import static java.time.temporal.ChronoUnit.MONTHS;
  68 import static java.time.temporal.ChronoUnit.NANOS;
  69 import static java.time.temporal.ChronoUnit.SECONDS;
  70 import static java.time.temporal.ChronoUnit.WEEKS;
  71 import static java.time.temporal.ChronoUnit.YEARS;
  72 
  73 import java.time.DayOfWeek;
  74 import java.time.Instant;
  75 import java.time.Year;
  76 import java.time.ZoneOffset;
  77 import java.time.chrono.ChronoLocalDate;
  78 import java.time.chrono.Chronology;





  79 
  80 /**
  81  * A standard set of fields.
  82  * <p>
  83  * This set of fields provide field-based access to manipulate a date, time or date-time.
  84  * The standard set of fields can be extended by implementing {@link TemporalField}.
  85  * <p>
  86  * These fields are intended to be applicable in multiple calendar systems.
  87  * For example, most non-ISO calendar systems define dates as a year, month and day,
  88  * just with slightly different rules.
  89  * The documentation of each field explains how it operates.
  90  *
  91  * <h3>Specification for implementors</h3>
  92  * This is a final, immutable and thread-safe enum.
  93  *
  94  * @since 1.8
  95  */
  96 public enum ChronoField implements TemporalField {
  97 
  98     /**


 170     /**
 171      * The milli-of-day.
 172      * <p>
 173      * This counts the millisecond within the day, from 0 to (24 * 60 * 60 * 1,000) - 1.
 174      * This field has the same meaning for all calendar systems.
 175      * <p>
 176      * This field is used to represent the milli-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 1,000,000.
 182      */
 183     MILLI_OF_DAY("MilliOfDay", MILLIS, DAYS, ValueRange.of(0, 86400L * 1000L - 1)),
 184     /**
 185      * The second-of-minute.
 186      * <p>
 187      * This counts the second within the minute, from 0 to 59.
 188      * This field has the same meaning for all calendar systems.
 189      */
 190     SECOND_OF_MINUTE("SecondOfMinute", SECONDS, MINUTES, ValueRange.of(0, 59)),
 191     /**
 192      * The second-of-day.
 193      * <p>
 194      * This counts the second within the day, from 0 to (24 * 60 * 60) - 1.
 195      * This field has the same meaning for all calendar systems.
 196      */
 197     SECOND_OF_DAY("SecondOfDay", SECONDS, DAYS, ValueRange.of(0, 86400L - 1)),
 198     /**
 199      * The minute-of-hour.
 200      * <p>
 201      * This counts the minute within the hour, from 0 to 59.
 202      * This field has the same meaning for all calendar systems.
 203      */
 204     MINUTE_OF_HOUR("MinuteOfHour", MINUTES, HOURS, ValueRange.of(0, 59)),
 205     /**
 206      * The minute-of-day.
 207      * <p>
 208      * This counts the minute within the day, from 0 to (24 * 60) - 1.
 209      * This field has the same meaning for all calendar systems.
 210      */
 211     MINUTE_OF_DAY("MinuteOfDay", MINUTES, DAYS, ValueRange.of(0, (24 * 60) - 1)),
 212     /**
 213      * The hour-of-am-pm.
 214      * <p>
 215      * This counts the hour within the AM/PM, from 0 to 11.
 216      * This is the hour that would be observed on a standard 12-hour digital clock.
 217      * This field has the same meaning for all calendar systems.
 218      */
 219     HOUR_OF_AMPM("HourOfAmPm", HOURS, HALF_DAYS, ValueRange.of(0, 11)),
 220     /**
 221      * The clock-hour-of-am-pm.
 222      * <p>
 223      * This counts the hour within the AM/PM, from 1 to 12.
 224      * This is the hour that would be observed on a standard 12-hour analog wall clock.
 225      * This field has the same meaning for all calendar systems.
 226      */
 227     CLOCK_HOUR_OF_AMPM("ClockHourOfAmPm", HOURS, HALF_DAYS, ValueRange.of(1, 12)),
 228     /**
 229      * The hour-of-day.
 230      * <p>
 231      * This counts the hour within the day, from 0 to 23.
 232      * This is the hour that would be observed on a standard 24-hour digital clock.
 233      * This field has the same meaning for all calendar systems.
 234      */
 235     HOUR_OF_DAY("HourOfDay", HOURS, DAYS, ValueRange.of(0, 23)),
 236     /**
 237      * The clock-hour-of-day.
 238      * <p>
 239      * This counts the hour within the AM/PM, from 1 to 24.
 240      * This is the hour that would be observed on a 24-hour analog wall clock.
 241      * This field has the same meaning for all calendar systems.
 242      */
 243     CLOCK_HOUR_OF_DAY("ClockHourOfDay", HOURS, DAYS, ValueRange.of(1, 24)),
 244     /**
 245      * The am-pm-of-day.
 246      * <p>
 247      * This counts the AM/PM within the day, from 0 (AM) to 1 (PM).
 248      * This field has the same meaning for all calendar systems.
 249      */
 250     AMPM_OF_DAY("AmPmOfDay", HALF_DAYS, DAYS, ValueRange.of(0, 1)),
 251     /**
 252      * The day-of-week, such as Tuesday.
 253      * <p>
 254      * This represents the standard concept of the day of the week.
 255      * In the default ISO calendar system, this has values from Monday (1) to Sunday (7).
 256      * The {@link DayOfWeek} class can be used to interpret the result.
 257      * <p>
 258      * Most non-ISO calendar systems also define a seven day week that aligns with ISO.
 259      * Those calendar systems must also use the same numbering system, from Monday (1) to
 260      * Sunday (7), which allows {@code DayOfWeek} to be used.
 261      * <p>
 262      * Calendar systems that do not have a standard seven day week should implement this field
 263      * if they have a similar concept of named or numbered days within a period similar
 264      * to a week. It is recommended that the numbering starts from 1.
 265      */
 266     DAY_OF_WEEK("DayOfWeek", DAYS, WEEKS, ValueRange.of(1, 7)),
 267     /**
 268      * The aligned day-of-week within a month.
 269      * <p>
 270      * This represents concept of the count of days within the period of a week
 271      * where the weeks are aligned to the start of the month.
 272      * This field is typically used with {@link #ALIGNED_WEEK_OF_MONTH}.
 273      * <p>
 274      * For example, in a calendar systems with a seven day week, the first aligned-week-of-month
 275      * starts on day-of-month 1, the second aligned-week starts on day-of-month 8, and so on.
 276      * Within each of these aligned-weeks, the days are numbered from 1 to 7 and returned
 277      * as the value of this field.
 278      * As such, day-of-month 1 to 7 will have aligned-day-of-week values from 1 to 7.
 279      * And day-of-month 8 to 14 will repeat this with aligned-day-of-week values from 1 to 7.
 280      * <p>
 281      * Calendar systems that do not have a seven day week should typically implement this
 282      * field in the same way, but using the alternate week length.
 283      */
 284     ALIGNED_DAY_OF_WEEK_IN_MONTH("AlignedDayOfWeekInMonth", DAYS, WEEKS, ValueRange.of(1, 7)),
 285     /**
 286      * The aligned day-of-week within a year.


 295      * as the value of this field.
 296      * As such, day-of-year 1 to 7 will have aligned-day-of-week values from 1 to 7.
 297      * And day-of-year 8 to 14 will repeat this with aligned-day-of-week values from 1 to 7.
 298      * <p>
 299      * Calendar systems that do not have a seven day week should typically implement this
 300      * field in the same way, but using the alternate week length.
 301      */
 302     ALIGNED_DAY_OF_WEEK_IN_YEAR("AlignedDayOfWeekInYear", DAYS, WEEKS, ValueRange.of(1, 7)),
 303     /**
 304      * The day-of-month.
 305      * <p>
 306      * This represents the concept of the day within the month.
 307      * In the default ISO calendar system, this has values from 1 to 31 in most months.
 308      * April, June, September, November have days from 1 to 30, while February has days
 309      * from 1 to 28, or 29 in a leap year.
 310      * <p>
 311      * Non-ISO calendar systems should implement this field using the most recognized
 312      * day-of-month values for users of the calendar system.
 313      * Normally, this is a count of days from 1 to the length of the month.
 314      */
 315     DAY_OF_MONTH("DayOfMonth", DAYS, MONTHS, ValueRange.of(1, 28, 31)),
 316     /**
 317      * The day-of-year.
 318      * <p>
 319      * This represents the concept of the day within the year.
 320      * In the default ISO calendar system, this has values from 1 to 365 in standard
 321      * years and 1 to 366 in leap years.
 322      * <p>
 323      * Non-ISO calendar systems should implement this field using the most recognized
 324      * day-of-year values for users of the calendar system.
 325      * Normally, this is a count of days from 1 to the length of the year.
 326      */
 327     DAY_OF_YEAR("DayOfYear", DAYS, YEARS, ValueRange.of(1, 365, 366)),
 328     /**
 329      * The epoch-day, based on the Java epoch of 1970-01-01 (ISO).
 330      * <p>
 331      * This field is the sequential count of days where 1970-01-01 (ISO) is zero.
 332      * Note that this uses the <i>local</i> time-line, ignoring offset and time-zone.
 333      * <p>
 334      * This field is strictly defined to have the same meaning in all calendar systems.
 335      * This is necessary to ensure interoperation between calendars.


 360      * <p>
 361      * For example, in a calendar systems with a seven day week, the first aligned-week-of-year
 362      * starts on day-of-year 1, the second aligned-week starts on day-of-year 8, and so on.
 363      * Thus, day-of-year values 1 to 7 are in aligned-week 1, while day-of-year values
 364      * 8 to 14 are in aligned-week 2, and so on.
 365      * <p>
 366      * Calendar systems that do not have a seven day week should typically implement this
 367      * field in the same way, but using the alternate week length.
 368      */
 369     ALIGNED_WEEK_OF_YEAR("AlignedWeekOfYear", WEEKS, YEARS, ValueRange.of(1, 53)),
 370     /**
 371      * The month-of-year, such as March.
 372      * <p>
 373      * This represents the concept of the month within the year.
 374      * In the default ISO calendar system, this has values from January (1) to December (12).
 375      * <p>
 376      * Non-ISO calendar systems should implement this field using the most recognized
 377      * month-of-year values for users of the calendar system.
 378      * Normally, this is a count of months starting from 1.
 379      */
 380     MONTH_OF_YEAR("MonthOfYear", MONTHS, YEARS, ValueRange.of(1, 12)),
 381     /**
 382      * The epoch-month based on the Java epoch of 1970-01-01.
 383      * <p>
 384      * This field is the sequential count of months where January 1970 (ISO) is zero.




 385      * Note that this uses the <i>local</i> time-line, ignoring offset and time-zone.
 386      * <p>
 387      * Non-ISO calendar systems should also implement this field to represent a sequential
 388      * count of months. It is recommended to define zero as the month of 1970-01-01 (ISO).






 389      */
 390     EPOCH_MONTH("EpochMonth", MONTHS, FOREVER, ValueRange.of((Year.MIN_VALUE - 1970L) * 12, (Year.MAX_VALUE - 1970L) * 12L - 1L)),
 391     /**
 392      * The year within the era.
 393      * <p>
 394      * This represents the concept of the year within the era.
 395      * This field is typically used with {@link #ERA}.
 396      * <p>
 397      * The standard mental model for a date is based on three concepts - year, month and day.
 398      * These map onto the {@code YEAR}, {@code MONTH_OF_YEAR} and {@code DAY_OF_MONTH} fields.
 399      * Note that there is no reference to eras.
 400      * The full model for a date requires four concepts - era, year, month and day. These map onto
 401      * the {@code ERA}, {@code YEAR_OF_ERA}, {@code MONTH_OF_YEAR} and {@code DAY_OF_MONTH} fields.
 402      * Whether this field or {@code YEAR} is used depends on which mental model is being used.
 403      * See {@link ChronoLocalDate} for more discussion on this topic.
 404      * <p>
 405      * In the default ISO calendar system, there are two eras defined, 'BCE' and 'CE'.
 406      * The era 'CE' is the one currently in use and year-of-era runs from 1 to the maximum value.
 407      * The era 'BCE' is the previous era, and the year-of-era runs backwards.
 408      * <p>
 409      * For example, subtracting a year each time yield the following:<br>
 410      * - year-proleptic 2  = 'CE' year-of-era 2<br>


 429      * This represents the concept of the year, counting sequentially and using negative numbers.
 430      * The proleptic year is not interpreted in terms of the era.
 431      * See {@link #YEAR_OF_ERA} for an example showing the mapping from proleptic year to year-of-era.
 432      * <p>
 433      * The standard mental model for a date is based on three concepts - year, month and day.
 434      * These map onto the {@code YEAR}, {@code MONTH_OF_YEAR} and {@code DAY_OF_MONTH} fields.
 435      * Note that there is no reference to eras.
 436      * The full model for a date requires four concepts - era, year, month and day. These map onto
 437      * the {@code ERA}, {@code YEAR_OF_ERA}, {@code MONTH_OF_YEAR} and {@code DAY_OF_MONTH} fields.
 438      * Whether this field or {@code YEAR_OF_ERA} is used depends on which mental model is being used.
 439      * See {@link ChronoLocalDate} for more discussion on this topic.
 440      * <p>
 441      * Non-ISO calendar systems should implement this field as follows.
 442      * If the calendar system has only two eras, before and after a fixed date, then the
 443      * proleptic-year value must be the same as the year-of-era value for the later era,
 444      * and increasingly negative for the earlier era.
 445      * If the calendar system has more than two eras, then the proleptic-year value may be
 446      * defined with any appropriate value, although defining it to be the same as ISO may be
 447      * the best option.
 448      */
 449     YEAR("Year", YEARS, FOREVER, ValueRange.of(Year.MIN_VALUE, Year.MAX_VALUE)),
 450     /**
 451      * The era.
 452      * <p>
 453      * This represents the concept of the era, which is the largest division of the time-line.
 454      * This field is typically used with {@link #YEAR_OF_ERA}.
 455      * <p>
 456      * In the default ISO calendar system, there are two eras defined, 'BCE' and 'CE'.
 457      * The era 'CE' is the one currently in use and year-of-era runs from 1 to the maximum value.
 458      * The era 'BCE' is the previous era, and the year-of-era runs backwards.
 459      * See {@link #YEAR_OF_ERA} for a full example.
 460      * <p>
 461      * Non-ISO calendar systems should implement this field to define eras.
 462      * The value of the era that was active on 1970-01-01 (ISO) must be assigned the value 1.
 463      * Earlier eras must have sequentially smaller values.
 464      * Later eras must have sequentially larger values,
 465      */
 466     ERA("Era", ERAS, FOREVER, ValueRange.of(0, 1)),
 467     /**
 468      * The instant epoch-seconds.
 469      * <p>
 470      * This represents the concept of the sequential count of seconds where
 471      * 1970-01-01T00:00Z (ISO) is zero.
 472      * This field may be used with {@link #NANO_OF_DAY} to represent the fraction of the day.
 473      * <p>
 474      * An {@link Instant} represents an instantaneous point on the time-line.
 475      * On their own they have no elements which allow a local date-time to be obtained.
 476      * Only when paired with an offset or time-zone can the local date or time be found.
 477      * This field allows the seconds part of the instant to be queried.
 478      * <p>
 479      * This field is strictly defined to have the same meaning in all calendar systems.
 480      * This is necessary to ensure interoperation between calendars.
 481      */
 482     INSTANT_SECONDS("InstantSeconds", SECONDS, FOREVER, ValueRange.of(Long.MIN_VALUE, Long.MAX_VALUE)),
 483     /**
 484      * The offset from UTC/Greenwich.
 485      * <p>
 486      * This represents the concept of the offset in seconds of local time from UTC/Greenwich.
 487      * <p>
 488      * A {@link ZoneOffset} represents the period of time that local time differs from UTC/Greenwich.
 489      * This is usually a fixed number of hours and minutes.
 490      * It is equivalent to the {@link ZoneOffset#getTotalSeconds() total amount} of the offset in seconds.
 491      * For example, during the winter Paris has an offset of {@code +01:00}, which is 3600 seconds.
 492      * <p>
 493      * This field is strictly defined to have the same meaning in all calendar systems.
 494      * This is necessary to ensure interoperation between calendars.
 495      */
 496     OFFSET_SECONDS("OffsetSeconds", SECONDS, FOREVER, ValueRange.of(-18 * 3600, 18 * 3600));
 497 
 498     private final String name;
 499     private final TemporalUnit baseUnit;
 500     private final TemporalUnit rangeUnit;
 501     private final ValueRange range;

 502 
 503     private ChronoField(String name, TemporalUnit baseUnit, TemporalUnit rangeUnit, ValueRange range) {
 504         this.name = name;
 505         this.baseUnit = baseUnit;
 506         this.rangeUnit = rangeUnit;
 507         this.range = range;










 508     }
 509 
 510     //-----------------------------------------------------------------------
 511     @Override
 512     public String getName() {
 513         return name;
 514     }
 515 
 516     @Override














 517     public TemporalUnit getBaseUnit() {
 518         return baseUnit;
 519     }
 520 
 521     @Override
 522     public TemporalUnit getRangeUnit() {
 523         return rangeUnit;
 524     }
 525 
 526     /**
 527      * Gets the range of valid values for the field.
 528      * <p>
 529      * All fields can be expressed as a {@code long} integer.
 530      * This method returns an object that describes the valid range for that value.
 531      * <p>
 532      * This method returns the range of the field in the ISO-8601 calendar system.
 533      * This range may be incorrect for other calendar systems.
 534      * Use {@link Chronology#range(ChronoField)} to access the correct range
 535      * for a different calendar system.
 536      * <p>
 537      * Note that the result only describes the minimum and maximum valid values
 538      * and it is important not to read too much into them. For example, there
 539      * could be values within the range that are invalid for the field.
 540      *
 541      * @return the range of valid values for the field, not null
 542      */
 543     @Override
 544     public ValueRange range() {
 545         return range;
 546     }
 547 
 548     //-----------------------------------------------------------------------
 549     /**
 550      * Checks if this field represents a component of a date.


 551      *
 552      * @return true if it is a component of a date
 553      */
 554     public boolean isDateField() {

 555         return ordinal() >= DAY_OF_WEEK.ordinal() && ordinal() <= ERA.ordinal();
 556     }
 557 
 558     /**
 559      * Checks if this field represents a component of a time.


 560      *
 561      * @return true if it is a component of a time
 562      */
 563     public boolean isTimeField() {

 564         return ordinal() < DAY_OF_WEEK.ordinal();
 565     }
 566 
 567     //-----------------------------------------------------------------------
 568     /**
 569      * Checks that the specified value is valid for this field.
 570      * <p>
 571      * This validates that the value is within the outer range of valid values
 572      * returned by {@link #range()}.
 573      * <p>
 574      * This method checks against the range of the field in the ISO-8601 calendar system.
 575      * This range may be incorrect for other calendar systems.
 576      * Use {@link Chronology#range(ChronoField)} to access the correct range
 577      * for a different calendar system.
 578      *
 579      * @param value  the value to check
 580      * @return the value that was passed in
 581      */
 582     public long checkValidValue(long value) {
 583         return range().checkValidValue(value, this);




  59 import static java.time.temporal.ChronoUnit.DAYS;
  60 import static java.time.temporal.ChronoUnit.ERAS;
  61 import static java.time.temporal.ChronoUnit.FOREVER;
  62 import static java.time.temporal.ChronoUnit.HALF_DAYS;
  63 import static java.time.temporal.ChronoUnit.HOURS;
  64 import static java.time.temporal.ChronoUnit.MICROS;
  65 import static java.time.temporal.ChronoUnit.MILLIS;
  66 import static java.time.temporal.ChronoUnit.MINUTES;
  67 import static java.time.temporal.ChronoUnit.MONTHS;
  68 import static java.time.temporal.ChronoUnit.NANOS;
  69 import static java.time.temporal.ChronoUnit.SECONDS;
  70 import static java.time.temporal.ChronoUnit.WEEKS;
  71 import static java.time.temporal.ChronoUnit.YEARS;
  72 
  73 import java.time.DayOfWeek;
  74 import java.time.Instant;
  75 import java.time.Year;
  76 import java.time.ZoneOffset;
  77 import java.time.chrono.ChronoLocalDate;
  78 import java.time.chrono.Chronology;
  79 import java.util.Locale;
  80 import java.util.Objects;
  81 import java.util.ResourceBundle;
  82 import sun.util.locale.provider.LocaleProviderAdapter;
  83 import sun.util.locale.provider.LocaleResources;
  84 
  85 /**
  86  * A standard set of fields.
  87  * <p>
  88  * This set of fields provide field-based access to manipulate a date, time or date-time.
  89  * The standard set of fields can be extended by implementing {@link TemporalField}.
  90  * <p>
  91  * These fields are intended to be applicable in multiple calendar systems.
  92  * For example, most non-ISO calendar systems define dates as a year, month and day,
  93  * just with slightly different rules.
  94  * The documentation of each field explains how it operates.
  95  *
  96  * <h3>Specification for implementors</h3>
  97  * This is a final, immutable and thread-safe enum.
  98  *
  99  * @since 1.8
 100  */
 101 public enum ChronoField implements TemporalField {
 102 
 103     /**


 175     /**
 176      * The milli-of-day.
 177      * <p>
 178      * This counts the millisecond within the day, from 0 to (24 * 60 * 60 * 1,000) - 1.
 179      * This field has the same meaning for all calendar systems.
 180      * <p>
 181      * This field is used to represent the milli-of-day handling any fraction of the second.
 182      * Implementations of {@code TemporalAccessor} should provide a value for this field if
 183      * they can return a value for {@link #SECOND_OF_DAY} filling unknown precision with zero.
 184      * <p>
 185      * When this field is used for setting a value, it should behave in the same way as
 186      * setting {@link #NANO_OF_DAY} with the value multiplied by 1,000,000.
 187      */
 188     MILLI_OF_DAY("MilliOfDay", MILLIS, DAYS, ValueRange.of(0, 86400L * 1000L - 1)),
 189     /**
 190      * The second-of-minute.
 191      * <p>
 192      * This counts the second within the minute, from 0 to 59.
 193      * This field has the same meaning for all calendar systems.
 194      */
 195     SECOND_OF_MINUTE("SecondOfMinute", SECONDS, MINUTES, ValueRange.of(0, 59), "second"),
 196     /**
 197      * The second-of-day.
 198      * <p>
 199      * This counts the second within the day, from 0 to (24 * 60 * 60) - 1.
 200      * This field has the same meaning for all calendar systems.
 201      */
 202     SECOND_OF_DAY("SecondOfDay", SECONDS, DAYS, ValueRange.of(0, 86400L - 1)),
 203     /**
 204      * The minute-of-hour.
 205      * <p>
 206      * This counts the minute within the hour, from 0 to 59.
 207      * This field has the same meaning for all calendar systems.
 208      */
 209     MINUTE_OF_HOUR("MinuteOfHour", MINUTES, HOURS, ValueRange.of(0, 59), "minute"),
 210     /**
 211      * The minute-of-day.
 212      * <p>
 213      * This counts the minute within the day, from 0 to (24 * 60) - 1.
 214      * This field has the same meaning for all calendar systems.
 215      */
 216     MINUTE_OF_DAY("MinuteOfDay", MINUTES, DAYS, ValueRange.of(0, (24 * 60) - 1)),
 217     /**
 218      * The hour-of-am-pm.
 219      * <p>
 220      * This counts the hour within the AM/PM, from 0 to 11.
 221      * This is the hour that would be observed on a standard 12-hour digital clock.
 222      * This field has the same meaning for all calendar systems.
 223      */
 224     HOUR_OF_AMPM("HourOfAmPm", HOURS, HALF_DAYS, ValueRange.of(0, 11)),
 225     /**
 226      * The clock-hour-of-am-pm.
 227      * <p>
 228      * This counts the hour within the AM/PM, from 1 to 12.
 229      * This is the hour that would be observed on a standard 12-hour analog wall clock.
 230      * This field has the same meaning for all calendar systems.
 231      */
 232     CLOCK_HOUR_OF_AMPM("ClockHourOfAmPm", HOURS, HALF_DAYS, ValueRange.of(1, 12)),
 233     /**
 234      * The hour-of-day.
 235      * <p>
 236      * This counts the hour within the day, from 0 to 23.
 237      * This is the hour that would be observed on a standard 24-hour digital clock.
 238      * This field has the same meaning for all calendar systems.
 239      */
 240     HOUR_OF_DAY("HourOfDay", HOURS, DAYS, ValueRange.of(0, 23), "hour"),
 241     /**
 242      * The clock-hour-of-day.
 243      * <p>
 244      * This counts the hour within the AM/PM, from 1 to 24.
 245      * This is the hour that would be observed on a 24-hour analog wall clock.
 246      * This field has the same meaning for all calendar systems.
 247      */
 248     CLOCK_HOUR_OF_DAY("ClockHourOfDay", HOURS, DAYS, ValueRange.of(1, 24)),
 249     /**
 250      * The am-pm-of-day.
 251      * <p>
 252      * This counts the AM/PM within the day, from 0 (AM) to 1 (PM).
 253      * This field has the same meaning for all calendar systems.
 254      */
 255     AMPM_OF_DAY("AmPmOfDay", HALF_DAYS, DAYS, ValueRange.of(0, 1), "dayperiod"),
 256     /**
 257      * The day-of-week, such as Tuesday.
 258      * <p>
 259      * This represents the standard concept of the day of the week.
 260      * In the default ISO calendar system, this has values from Monday (1) to Sunday (7).
 261      * The {@link DayOfWeek} class can be used to interpret the result.
 262      * <p>
 263      * Most non-ISO calendar systems also define a seven day week that aligns with ISO.
 264      * Those calendar systems must also use the same numbering system, from Monday (1) to
 265      * Sunday (7), which allows {@code DayOfWeek} to be used.
 266      * <p>
 267      * Calendar systems that do not have a standard seven day week should implement this field
 268      * if they have a similar concept of named or numbered days within a period similar
 269      * to a week. It is recommended that the numbering starts from 1.
 270      */
 271     DAY_OF_WEEK("DayOfWeek", DAYS, WEEKS, ValueRange.of(1, 7), "weekday"),
 272     /**
 273      * The aligned day-of-week within a month.
 274      * <p>
 275      * This represents concept of the count of days within the period of a week
 276      * where the weeks are aligned to the start of the month.
 277      * This field is typically used with {@link #ALIGNED_WEEK_OF_MONTH}.
 278      * <p>
 279      * For example, in a calendar systems with a seven day week, the first aligned-week-of-month
 280      * starts on day-of-month 1, the second aligned-week starts on day-of-month 8, and so on.
 281      * Within each of these aligned-weeks, the days are numbered from 1 to 7 and returned
 282      * as the value of this field.
 283      * As such, day-of-month 1 to 7 will have aligned-day-of-week values from 1 to 7.
 284      * And day-of-month 8 to 14 will repeat this with aligned-day-of-week values from 1 to 7.
 285      * <p>
 286      * Calendar systems that do not have a seven day week should typically implement this
 287      * field in the same way, but using the alternate week length.
 288      */
 289     ALIGNED_DAY_OF_WEEK_IN_MONTH("AlignedDayOfWeekInMonth", DAYS, WEEKS, ValueRange.of(1, 7)),
 290     /**
 291      * The aligned day-of-week within a year.


 300      * as the value of this field.
 301      * As such, day-of-year 1 to 7 will have aligned-day-of-week values from 1 to 7.
 302      * And day-of-year 8 to 14 will repeat this with aligned-day-of-week values from 1 to 7.
 303      * <p>
 304      * Calendar systems that do not have a seven day week should typically implement this
 305      * field in the same way, but using the alternate week length.
 306      */
 307     ALIGNED_DAY_OF_WEEK_IN_YEAR("AlignedDayOfWeekInYear", DAYS, WEEKS, ValueRange.of(1, 7)),
 308     /**
 309      * The day-of-month.
 310      * <p>
 311      * This represents the concept of the day within the month.
 312      * In the default ISO calendar system, this has values from 1 to 31 in most months.
 313      * April, June, September, November have days from 1 to 30, while February has days
 314      * from 1 to 28, or 29 in a leap year.
 315      * <p>
 316      * Non-ISO calendar systems should implement this field using the most recognized
 317      * day-of-month values for users of the calendar system.
 318      * Normally, this is a count of days from 1 to the length of the month.
 319      */
 320     DAY_OF_MONTH("DayOfMonth", DAYS, MONTHS, ValueRange.of(1, 28, 31), "day"),
 321     /**
 322      * The day-of-year.
 323      * <p>
 324      * This represents the concept of the day within the year.
 325      * In the default ISO calendar system, this has values from 1 to 365 in standard
 326      * years and 1 to 366 in leap years.
 327      * <p>
 328      * Non-ISO calendar systems should implement this field using the most recognized
 329      * day-of-year values for users of the calendar system.
 330      * Normally, this is a count of days from 1 to the length of the year.
 331      */
 332     DAY_OF_YEAR("DayOfYear", DAYS, YEARS, ValueRange.of(1, 365, 366)),
 333     /**
 334      * The epoch-day, based on the Java epoch of 1970-01-01 (ISO).
 335      * <p>
 336      * This field is the sequential count of days where 1970-01-01 (ISO) is zero.
 337      * Note that this uses the <i>local</i> time-line, ignoring offset and time-zone.
 338      * <p>
 339      * This field is strictly defined to have the same meaning in all calendar systems.
 340      * This is necessary to ensure interoperation between calendars.


 365      * <p>
 366      * For example, in a calendar systems with a seven day week, the first aligned-week-of-year
 367      * starts on day-of-year 1, the second aligned-week starts on day-of-year 8, and so on.
 368      * Thus, day-of-year values 1 to 7 are in aligned-week 1, while day-of-year values
 369      * 8 to 14 are in aligned-week 2, and so on.
 370      * <p>
 371      * Calendar systems that do not have a seven day week should typically implement this
 372      * field in the same way, but using the alternate week length.
 373      */
 374     ALIGNED_WEEK_OF_YEAR("AlignedWeekOfYear", WEEKS, YEARS, ValueRange.of(1, 53)),
 375     /**
 376      * The month-of-year, such as March.
 377      * <p>
 378      * This represents the concept of the month within the year.
 379      * In the default ISO calendar system, this has values from January (1) to December (12).
 380      * <p>
 381      * Non-ISO calendar systems should implement this field using the most recognized
 382      * month-of-year values for users of the calendar system.
 383      * Normally, this is a count of months starting from 1.
 384      */
 385     MONTH_OF_YEAR("MonthOfYear", MONTHS, YEARS, ValueRange.of(1, 12), "month"),
 386     /**
 387      * The proleptic-month based, counting months sequentially from year 0.
 388      * <p>
 389      * This field is the sequential count of months where the first month
 390      * in proleptic-year zero has the value zero.
 391      * Later months have increasingly larger values.
 392      * Earlier months have increasingly small values.
 393      * There are no gaps or breaks in the sequence of months.
 394      * Note that this uses the <i>local</i> time-line, ignoring offset and time-zone.
 395      * <p>
 396      * In the default ISO calendar system, June 2012 would have the value
 397      * {@code (2012 * 12 + 6 - 1)}. This field is primarily for internal use.
 398      * <p>
 399      * Non-ISO calendar systems must implement this field as per the definition above.
 400      * It is just a simple zero-based count of elapsed months from the start of proleptic-year 0.
 401      * All calendar systems with a full proleptic-year definition will have a year zero.
 402      * If the calendar system has a minimum year that excludes year zero, then one must
 403      * be extrapolated in order for this method to be defined.
 404      */
 405     PROLEPTIC_MONTH("ProlepticMonth", MONTHS, FOREVER, ValueRange.of(Year.MIN_VALUE * 12L, Year.MAX_VALUE * 12L + 11)),
 406     /**
 407      * The year within the era.
 408      * <p>
 409      * This represents the concept of the year within the era.
 410      * This field is typically used with {@link #ERA}.
 411      * <p>
 412      * The standard mental model for a date is based on three concepts - year, month and day.
 413      * These map onto the {@code YEAR}, {@code MONTH_OF_YEAR} and {@code DAY_OF_MONTH} fields.
 414      * Note that there is no reference to eras.
 415      * The full model for a date requires four concepts - era, year, month and day. These map onto
 416      * the {@code ERA}, {@code YEAR_OF_ERA}, {@code MONTH_OF_YEAR} and {@code DAY_OF_MONTH} fields.
 417      * Whether this field or {@code YEAR} is used depends on which mental model is being used.
 418      * See {@link ChronoLocalDate} for more discussion on this topic.
 419      * <p>
 420      * In the default ISO calendar system, there are two eras defined, 'BCE' and 'CE'.
 421      * The era 'CE' is the one currently in use and year-of-era runs from 1 to the maximum value.
 422      * The era 'BCE' is the previous era, and the year-of-era runs backwards.
 423      * <p>
 424      * For example, subtracting a year each time yield the following:<br>
 425      * - year-proleptic 2  = 'CE' year-of-era 2<br>


 444      * This represents the concept of the year, counting sequentially and using negative numbers.
 445      * The proleptic year is not interpreted in terms of the era.
 446      * See {@link #YEAR_OF_ERA} for an example showing the mapping from proleptic year to year-of-era.
 447      * <p>
 448      * The standard mental model for a date is based on three concepts - year, month and day.
 449      * These map onto the {@code YEAR}, {@code MONTH_OF_YEAR} and {@code DAY_OF_MONTH} fields.
 450      * Note that there is no reference to eras.
 451      * The full model for a date requires four concepts - era, year, month and day. These map onto
 452      * the {@code ERA}, {@code YEAR_OF_ERA}, {@code MONTH_OF_YEAR} and {@code DAY_OF_MONTH} fields.
 453      * Whether this field or {@code YEAR_OF_ERA} is used depends on which mental model is being used.
 454      * See {@link ChronoLocalDate} for more discussion on this topic.
 455      * <p>
 456      * Non-ISO calendar systems should implement this field as follows.
 457      * If the calendar system has only two eras, before and after a fixed date, then the
 458      * proleptic-year value must be the same as the year-of-era value for the later era,
 459      * and increasingly negative for the earlier era.
 460      * If the calendar system has more than two eras, then the proleptic-year value may be
 461      * defined with any appropriate value, although defining it to be the same as ISO may be
 462      * the best option.
 463      */
 464     YEAR("Year", YEARS, FOREVER, ValueRange.of(Year.MIN_VALUE, Year.MAX_VALUE), "year"),
 465     /**
 466      * The era.
 467      * <p>
 468      * This represents the concept of the era, which is the largest division of the time-line.
 469      * This field is typically used with {@link #YEAR_OF_ERA}.
 470      * <p>
 471      * In the default ISO calendar system, there are two eras defined, 'BCE' and 'CE'.
 472      * The era 'CE' is the one currently in use and year-of-era runs from 1 to the maximum value.
 473      * The era 'BCE' is the previous era, and the year-of-era runs backwards.
 474      * See {@link #YEAR_OF_ERA} for a full example.
 475      * <p>
 476      * Non-ISO calendar systems should implement this field to define eras.
 477      * The value of the era that was active on 1970-01-01 (ISO) must be assigned the value 1.
 478      * Earlier eras must have sequentially smaller values.
 479      * Later eras must have sequentially larger values,
 480      */
 481     ERA("Era", ERAS, FOREVER, ValueRange.of(0, 1), "era"),
 482     /**
 483      * The instant epoch-seconds.
 484      * <p>
 485      * This represents the concept of the sequential count of seconds where
 486      * 1970-01-01T00:00Z (ISO) is zero.
 487      * This field may be used with {@link #NANO_OF_DAY} to represent the fraction of the day.
 488      * <p>
 489      * An {@link Instant} represents an instantaneous point on the time-line.
 490      * On their own they have no elements which allow a local date-time to be obtained.
 491      * Only when paired with an offset or time-zone can the local date or time be found.
 492      * This field allows the seconds part of the instant to be queried.
 493      * <p>
 494      * This field is strictly defined to have the same meaning in all calendar systems.
 495      * This is necessary to ensure interoperation between calendars.
 496      */
 497     INSTANT_SECONDS("InstantSeconds", SECONDS, FOREVER, ValueRange.of(Long.MIN_VALUE, Long.MAX_VALUE)),
 498     /**
 499      * The offset from UTC/Greenwich.
 500      * <p>
 501      * This represents the concept of the offset in seconds of local time from UTC/Greenwich.
 502      * <p>
 503      * A {@link ZoneOffset} represents the period of time that local time differs from UTC/Greenwich.
 504      * This is usually a fixed number of hours and minutes.
 505      * It is equivalent to the {@link ZoneOffset#getTotalSeconds() total amount} of the offset in seconds.
 506      * For example, during the winter Paris has an offset of {@code +01:00}, which is 3600 seconds.
 507      * <p>
 508      * This field is strictly defined to have the same meaning in all calendar systems.
 509      * This is necessary to ensure interoperation between calendars.
 510      */
 511     OFFSET_SECONDS("OffsetSeconds", SECONDS, FOREVER, ValueRange.of(-18 * 3600, 18 * 3600));
 512 
 513     private final String name;
 514     private final TemporalUnit baseUnit;
 515     private final TemporalUnit rangeUnit;
 516     private final ValueRange range;
 517     private final String displayNameKey;
 518 
 519     private ChronoField(String name, TemporalUnit baseUnit, TemporalUnit rangeUnit, ValueRange range) {
 520         this.name = name;
 521         this.baseUnit = baseUnit;
 522         this.rangeUnit = rangeUnit;
 523         this.range = range;
 524         this.displayNameKey = null;
 525     }
 526 
 527     private ChronoField(String name, TemporalUnit baseUnit, TemporalUnit rangeUnit,
 528             ValueRange range, String displayNameKey) {
 529         this.name = name;
 530         this.baseUnit = baseUnit;
 531         this.rangeUnit = rangeUnit;
 532         this.range = range;
 533         this.displayNameKey = displayNameKey;
 534     }
 535 
 536     //-----------------------------------------------------------------------
 537     @Override
 538     public String getName() {
 539         return name;
 540     }
 541 
 542     @Override
 543     public String getDisplayName(Locale locale) {
 544         Objects.requireNonNull(locale, "locale");
 545         if (displayNameKey == null) {
 546             return getName();
 547         }
 548 
 549         LocaleResources lr = LocaleProviderAdapter.getResourceBundleBased()
 550                                     .getLocaleResources(locale);
 551         ResourceBundle rb = lr.getJavaTimeFormatData();
 552         String key = "field." + displayNameKey;
 553         return rb.containsKey(key) ? rb.getString(key) : getName();
 554     }
 555 
 556     @Override
 557     public TemporalUnit getBaseUnit() {
 558         return baseUnit;
 559     }
 560 
 561     @Override
 562     public TemporalUnit getRangeUnit() {
 563         return rangeUnit;
 564     }
 565 
 566     /**
 567      * Gets the range of valid values for the field.
 568      * <p>
 569      * All fields can be expressed as a {@code long} integer.
 570      * This method returns an object that describes the valid range for that value.
 571      * <p>
 572      * This method returns the range of the field in the ISO-8601 calendar system.
 573      * This range may be incorrect for other calendar systems.
 574      * Use {@link Chronology#range(ChronoField)} to access the correct range
 575      * for a different calendar system.
 576      * <p>
 577      * Note that the result only describes the minimum and maximum valid values
 578      * and it is important not to read too much into them. For example, there
 579      * could be values within the range that are invalid for the field.
 580      *
 581      * @return the range of valid values for the field, not null
 582      */
 583     @Override
 584     public ValueRange range() {
 585         return range;
 586     }
 587 
 588     //-----------------------------------------------------------------------
 589     /**
 590      * Checks if this field represents a component of a date.
 591      * <p>
 592      * Fields from day-of-week to era are date-based.
 593      *
 594      * @return true if it is a component of a date
 595      */
 596     @Override
 597     public boolean isDateBased() {
 598         return ordinal() >= DAY_OF_WEEK.ordinal() && ordinal() <= ERA.ordinal();
 599     }
 600 
 601     /**
 602      * Checks if this field represents a component of a time.
 603      * <p>
 604      * Fields from nano-of-second to am-pm-of-day are time-based.
 605      *
 606      * @return true if it is a component of a time
 607      */
 608     @Override
 609     public boolean isTimeBased() {
 610         return ordinal() < DAY_OF_WEEK.ordinal();
 611     }
 612 
 613     //-----------------------------------------------------------------------
 614     /**
 615      * Checks that the specified value is valid for this field.
 616      * <p>
 617      * This validates that the value is within the outer range of valid values
 618      * returned by {@link #range()}.
 619      * <p>
 620      * This method checks against the range of the field in the ISO-8601 calendar system.
 621      * This range may be incorrect for other calendar systems.
 622      * Use {@link Chronology#range(ChronoField)} to access the correct range
 623      * for a different calendar system.
 624      *
 625      * @param value  the value to check
 626      * @return the value that was passed in
 627      */
 628     public long checkValidValue(long value) {
 629         return range().checkValidValue(value, this);