Java Module java.base Package java.time.temporal Enum ChronoUnit（JDK11）

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java.lang.Object
- java.lang.Enum<ChronoUnit>
- - java.time.temporal.ChronoUnit

All Implemented Interfaces:

Serializable, Comparable<ChronoUnit>, TemporalUnit
```
public enum ChronoUnit
extends Enum<ChronoUnit>
implements TemporalUnit
```
A standard set of date periods units.
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 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.

Implementation Requirements:

This is a final, immutable and thread-safe enum.

Since:

1.8

Enum Constant Summary

Enum Constants
Enum Constant	Description
`CENTURIES`	Unit that represents the concept of a century.
`DAYS`	Unit that represents the concept of a day.
`DECADES`	Unit that represents the concept of a decade.
`ERAS`	Unit that represents the concept of an era.
`FOREVER`	Artificial unit that represents the concept of forever.
`HALF_DAYS`	Unit that represents the concept of half a day, as used in AM/PM.
`HOURS`	Unit that represents the concept of an hour.
`MICROS`	Unit that represents the concept of a microsecond.
`MILLENNIA`	Unit that represents the concept of a millennium.
`MILLIS`	Unit that represents the concept of a millisecond.
`MINUTES`	Unit that represents the concept of a minute.
`MONTHS`	Unit that represents the concept of a month.
`NANOS`	Unit that represents the concept of a nanosecond, the smallest supported unit of time.
`SECONDS`	Unit that represents the concept of a second.
`WEEKS`	Unit that represents the concept of a week.
`YEARS`	Unit that represents the concept of a year.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`Duration`	`getDuration()`	Gets the estimated duration of this unit in the ISO calendar system.
`boolean`	`isDateBased()`	Checks if this unit is a date unit.
`boolean`	`isDurationEstimated()`	Checks if the duration of the unit is an estimate.
`boolean`	`isTimeBased()`	Checks if this unit is a time unit.
`static ChronoUnit`	`valueOf(String name)`	Returns the enum constant of this type with the specified name.
`static ChronoUnit[]`	`values()`	Returns an array containing the constants of this enum type, in the order they are declared.

Methods declared in class java.lang.Enum
clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods declared in class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait

Methods declared in interface java.time.temporal.TemporalUnit
addTo, between, isSupportedBy, toString

- Enum Constant Detail
  - NANOS
```
public static final ChronoUnit NANOS
```
    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.
  - MICROS
```
public static final ChronoUnit MICROS
```
    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.
  - MILLIS
```
public static final ChronoUnit MILLIS
```
    Unit that represents the concept of a millisecond. For the ISO calendar system, it is equal to the 1000th part of the second unit.
  - SECONDS
```
public static final ChronoUnit SECONDS
```
    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.
  - MINUTES
```
public static final ChronoUnit MINUTES
```
    Unit that represents the concept of a minute. For the ISO calendar system, it is equal to 60 seconds.
  - HOURS
```
public static final ChronoUnit HOURS
```
    Unit that represents the concept of an hour. For the ISO calendar system, it is equal to 60 minutes.
  - HALF_DAYS
```
public static final ChronoUnit HALF_DAYS
```
    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.
  - DAYS
```
public static final ChronoUnit DAYS
```
    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 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.
  - WEEKS
```
public static final ChronoUnit WEEKS
```
    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.
  - MONTHS
```
public static final ChronoUnit MONTHS
```
    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 365.2425 Days.
    When used with other calendar systems it must correspond to an integral number of days.
  - YEARS
```
public static final ChronoUnit YEARS
```
    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 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.
  - DECADES
```
public static final ChronoUnit DECADES
```
    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.
  - CENTURIES
```
public static final ChronoUnit CENTURIES
```
    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.
  - MILLENNIA
```
public static final ChronoUnit MILLENNIA
```
    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.
  - ERAS
```
public static final ChronoUnit ERAS
```
    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 1,000,000,000 Years.
    When used with other calendar systems there are no restrictions on the unit.
  - FOREVER
```
public static final ChronoUnit FOREVER
```
    Artificial unit that represents the concept of forever. This is primarily used with TemporalField to represent unbounded fields such as the year or era. The estimated duration of this unit is artificially defined as the largest duration supported by Duration.
- Method Detail
  - values
```
public static ChronoUnit[] values()
```
    Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:
    for (ChronoUnit c : ChronoUnit.values()) System.out.println(c);
    Returns:
    
    an array containing the constants of this enum type, in the order they are declared
  - valueOf
```
public static ChronoUnit valueOf(String name)
```
    Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
    
    Parameters:
    
    name - the name of the enum constant to be returned.
    
    Returns:
    
    the enum constant with the specified name
    
    Throws:
    
    IllegalArgumentException - if this enum type has no constant with the specified name
    
    NullPointerException - if the argument is null
  - getDuration
```
public Duration getDuration()
```
    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.
    
    Specified by:
    
    getDuration in interface TemporalUnit
    
    Returns:
    
    the estimated duration of this unit, not null
  - isDurationEstimated
```
public boolean isDurationEstimated()
```
    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.
    
    Specified by:
    
    isDurationEstimated in interface TemporalUnit
    
    Returns:
    
    true if the duration is estimated, false if accurate
  - isDateBased
```
public boolean isDateBased()
```
    Checks if this unit is a date unit.
    All units from days to eras inclusive are date-based. Time-based units and FOREVER return false.
    
    Specified by:
    
    isDateBased in interface TemporalUnit
    
    Returns:
    
    true if a date unit, false if a time unit
  - isTimeBased
```
public boolean isTimeBased()
```
    Checks if this unit is a time unit.
    All units from nanos to half-days inclusive are time-based. Date-based units and FOREVER return false.
    
    Specified by:
    
    isTimeBased in interface TemporalUnit
    
    Returns:
    
    true if a time unit, false if a date unit

Java Module java.base Package java.time.temporal Enum ChronoUnit（JDK11）

Enum ChronoUnit

Enum Constant Summary

Method Summary

Methods declared in class java.lang.Enum

Methods declared in class java.lang.Object

Methods declared in interface java.time.temporal.TemporalUnit

Enum Constant Detail

NANOS

MICROS

MILLIS

SECONDS

MINUTES

HOURS

HALF_DAYS

DAYS

WEEKS

MONTHS

YEARS

DECADES

CENTURIES

MILLENNIA

ERAS

FOREVER

Method Detail

values

valueOf

getDuration

isDurationEstimated

isDateBased

isTimeBased