* This set of units provide unit-based access to manipulate a date, time or date-time. * The standard set of units can be extended by implementing {@link TemporalUnit}. *
* These units are intended to be applicable in multiple calendar systems. * For example, most non-ISO calendar systems define units of years, months and days, * just with slightly different rules. * The documentation of each unit explains how it operates. * * @implSpec * This is a final, immutable and thread-safe enum. * * @since 1.8 */ public enum ChronoUnit implements TemporalUnit { /** * Unit that represents the concept of a nanosecond, the smallest supported unit of time. * For the ISO calendar system, it is equal to the 1,000,000,000th part of the second unit. */ NANOS("Nanos", Duration.ofNanos(1)), /** * Unit that represents the concept of a microsecond. * For the ISO calendar system, it is equal to the 1,000,000th part of the second unit. */ MICROS("Micros", Duration.ofNanos(1000)), /** * Unit that represents the concept of a millisecond. * For the ISO calendar system, it is equal to the 1000th part of the second unit. */ MILLIS("Millis", Duration.ofNanos(1000_000)), /** * Unit that represents the concept of a second. * For the ISO calendar system, it is equal to the second in the SI system * of units, except around a leap-second. */ SECONDS("Seconds", Duration.ofSeconds(1)), /** * Unit that represents the concept of a minute. * For the ISO calendar system, it is equal to 60 seconds. */ MINUTES("Minutes", Duration.ofSeconds(60)), /** * Unit that represents the concept of an hour. * For the ISO calendar system, it is equal to 60 minutes. */ HOURS("Hours", Duration.ofSeconds(3600)), /** * Unit that represents the concept of half a day, as used in AM/PM. * For the ISO calendar system, it is equal to 12 hours. */ HALF_DAYS("HalfDays", Duration.ofSeconds(43200)), /** * Unit that represents the concept of a day. * For the ISO calendar system, it is the standard day from midnight to midnight. * The estimated duration of a day is {@code 24 Hours}. *
* When used with other calendar systems it must correspond to the day defined by * the rising and setting of the Sun on Earth. It is not required that days begin * at midnight - when converting between calendar systems, the date should be * equivalent at midday. */ DAYS("Days", Duration.ofSeconds(86400)), /** * Unit that represents the concept of a week. * For the ISO calendar system, it is equal to 7 days. *
* When used with other calendar systems it must correspond to an integral number of days. */ WEEKS("Weeks", Duration.ofSeconds(7 * 86400L)), /** * Unit that represents the concept of a month. * For the ISO calendar system, the length of the month varies by month-of-year. * The estimated duration of a month is one twelfth of {@code 365.2425 Days}. *
* When used with other calendar systems it must correspond to an integral number of days. */ MONTHS("Months", Duration.ofSeconds(31556952L / 12)), /** * Unit that represents the concept of a year. * For the ISO calendar system, it is equal to 12 months. * The estimated duration of a year is {@code 365.2425 Days}. *
* When used with other calendar systems it must correspond to an integral number of days * or months roughly equal to a year defined by the passage of the Earth around the Sun. */ YEARS("Years", Duration.ofSeconds(31556952L)), /** * Unit that represents the concept of a decade. * For the ISO calendar system, it is equal to 10 years. *
* When used with other calendar systems it must correspond to an integral number of days * and is normally an integral number of years. */ DECADES("Decades", Duration.ofSeconds(31556952L * 10L)), /** * Unit that represents the concept of a century. * For the ISO calendar system, it is equal to 100 years. *
* When used with other calendar systems it must correspond to an integral number of days * and is normally an integral number of years. */ CENTURIES("Centuries", Duration.ofSeconds(31556952L * 100L)), /** * Unit that represents the concept of a millennium. * For the ISO calendar system, it is equal to 1000 years. *
* When used with other calendar systems it must correspond to an integral number of days * and is normally an integral number of years. */ MILLENNIA("Millennia", Duration.ofSeconds(31556952L * 1000L)), /** * Unit that represents the concept of an era. * The ISO calendar system doesn't have eras thus it is impossible to add * an era to a date or date-time. * The estimated duration of the era is artificially defined as {@code 1,000,000,000 Years}. *
* When used with other calendar systems there are no restrictions on the unit. */ ERAS("Eras", Duration.ofSeconds(31556952L * 1000_000_000L)), /** * Artificial unit that represents the concept of forever. * This is primarily used with {@link TemporalField} to represent unbounded fields * such as the year or era. * The estimated duration of the era is artificially defined as the largest duration * supported by {@code Duration}. */ FOREVER("Forever", Duration.ofSeconds(Long.MAX_VALUE, 999_999_999)); private final String name; private final Duration duration; private ChronoUnit(String name, Duration estimatedDuration) { this.name = name; this.duration = estimatedDuration; } //----------------------------------------------------------------------- /** * Gets the estimated duration of this unit in the ISO calendar system. *
* All of the units in this class have an estimated duration. * Days vary due to daylight saving time, while months have different lengths. * * @return the estimated duration of this unit, not null */ @Override public Duration getDuration() { return duration; } /** * Checks if the duration of the unit is an estimate. *
* All time units in this class are considered to be accurate, while all date * units in this class are considered to be estimated. *
* This definition ignores leap seconds, but considers that Days vary due to * daylight saving time and months have different lengths. * * @return true if the duration is estimated, false if accurate */ @Override public boolean isDurationEstimated() { return this.compareTo(DAYS) >= 0; } //----------------------------------------------------------------------- /** * Checks if this unit is a date unit. *
* All units from days to eras inclusive are date-based. * Time-based units and {@code FOREVER} return false. * * @return true if a date unit, false if a time unit */ @Override public boolean isDateBased() { return this.compareTo(DAYS) >= 0 && this != FOREVER; } /** * Checks if this unit is a time unit. *
* All units from nanos to half-days inclusive are time-based.
* Date-based units and {@code FOREVER} return false.
*
* @return true if a time unit, false if a date unit
*/
@Override
public boolean isTimeBased() {
return this.compareTo(DAYS) < 0;
}
//-----------------------------------------------------------------------
@Override
public boolean isSupportedBy(Temporal temporal) {
return temporal.isSupported(this);
}
@SuppressWarnings("unchecked")
@Override
public