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ChronoUnit

public final enum ChronoUnit
extends Enum<ChronoUnit> implements TemporalUnit

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


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.

Summary

Enum values

ChronoUnit  CENTURIES

Unit that represents the concept of a century. 

ChronoUnit  DAYS

Unit that represents the concept of a day. 

ChronoUnit  DECADES

Unit that represents the concept of a decade. 

ChronoUnit  ERAS

Unit that represents the concept of an era. 

ChronoUnit  FOREVER

Artificial unit that represents the concept of forever. 

ChronoUnit  HALF_DAYS

Unit that represents the concept of half a day, as used in AM/PM. 

ChronoUnit  HOURS

Unit that represents the concept of an hour. 

ChronoUnit  MICROS

Unit that represents the concept of a microsecond. 

ChronoUnit  MILLENNIA

Unit that represents the concept of a millennium. 

ChronoUnit  MILLIS

Unit that represents the concept of a millisecond. 

ChronoUnit  MINUTES

Unit that represents the concept of a minute. 

ChronoUnit  MONTHS

Unit that represents the concept of a month. 

ChronoUnit  NANOS

Unit that represents the concept of a nanosecond, the smallest supported unit of time. 

ChronoUnit  SECONDS

Unit that represents the concept of a second. 

ChronoUnit  WEEKS

Unit that represents the concept of a week. 

ChronoUnit  YEARS

Unit that represents the concept of a year. 

Public methods

<R extends Temporal> R addTo(R temporal, long amount)

Returns a copy of the specified temporal object with the specified period added.

long between(Temporal temporal1Inclusive, Temporal temporal2Exclusive)

Calculates the amount of time between two temporal objects.

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 isSupportedBy(Temporal temporal)

Checks if this unit is supported by the specified temporal object.

boolean isTimeBased()

Checks if this unit is a time unit.

String toString()

Returns the name of this enum constant, as contained in the declaration.

static ChronoUnit valueOf(String name)
static final ChronoUnit[] values()

Inherited methods

Enum values

CENTURIES

added in API level 26
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.

DAYS

added in API level 26
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.

DECADES

added in API level 26
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.

ERAS

added in API level 26
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

added in API level 26
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 the era is artificially defined as the largest duration supported by Duration.

HALF_DAYS

added in API level 26
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.

HOURS

added in API level 26
public static final ChronoUnit HOURS

Unit that represents the concept of an hour. For the ISO calendar system, it is equal to 60 minutes.

MICROS

added in API level 26
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.

MILLENNIA

added in API level 26
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.

MILLIS

added in API level 26
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.

MINUTES

added in API level 26
public static final ChronoUnit MINUTES

Unit that represents the concept of a minute. For the ISO calendar system, it is equal to 60 seconds.

MONTHS

added in API level 26
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.

NANOS

added in API level 26
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.

SECONDS

added in API level 26
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.

WEEKS

added in API level 26
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.

YEARS

added in API level 26
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.

Public methods

addTo

added in API level 26
public R addTo (R temporal, 
                long amount)

Returns a copy of the specified temporal object with the specified period added.

The period added is a multiple of this unit. For example, this method could be used to add "3 days" to a date by calling this method on the instance representing "days", passing the date and the period "3". The period to be added may be negative, which is equivalent to subtraction.

There are two equivalent ways of using this method. The first is to invoke this method directly. The second is to use Temporal.plus(long, TemporalUnit):

   // these two lines are equivalent, but the second approach is recommended
   temporal = thisUnit.addTo(temporal);
   temporal = temporal.plus(thisUnit);
 
It is recommended to use the second approach, plus(TemporalUnit), as it is a lot clearer to read in code.

Implementations should perform any queries or calculations using the units available in ChronoUnit or the fields available in ChronoField. If the unit is not supported an UnsupportedTemporalTypeException must be thrown.

Implementations must not alter the specified temporal object. Instead, an adjusted copy of the original must be returned. This provides equivalent, safe behavior for immutable and mutable implementations.

Parameters
temporal R: the temporal object to adjust, not null

amount long: the amount of this unit to add, positive or negative

Returns
R the adjusted temporal object, not null

between

added in API level 26
public long between (Temporal temporal1Inclusive, 
                Temporal temporal2Exclusive)

Calculates the amount of time between two temporal objects.

This calculates the amount in terms of this unit. The start and end points are supplied as temporal objects and must be of compatible types. The implementation will convert the second type to be an instance of the first type before the calculating the amount. The result will be negative if the end is before the start. For example, the amount in hours between two temporal objects can be calculated using HOURS.between(startTime, endTime).

The calculation returns a whole number, representing the number of complete units between the two temporals. For example, the amount in hours between the times 11:30 and 13:29 will only be one hour as it is one minute short of two hours.

There are two equivalent ways of using this method. The first is to invoke this method directly. The second is to use Temporal.until(Temporal, TemporalUnit):

   // these two lines are equivalent
   between = thisUnit.between(start, end);
   between = start.until(end, thisUnit);
 
The choice should be made based on which makes the code more readable.

For example, this method allows the number of days between two dates to be calculated:

  long daysBetween = DAYS.between(start, end);
  // or alternatively
  long daysBetween = start.until(end, DAYS);
 

Implementations should perform any queries or calculations using the units available in ChronoUnit or the fields available in ChronoField. If the unit is not supported an UnsupportedTemporalTypeException must be thrown. Implementations must not alter the specified temporal objects.

Parameters
temporal1Inclusive Temporal: the base temporal object, not null

temporal2Exclusive Temporal: the other temporal object, exclusive, not null

Returns
long the amount of time between temporal1Inclusive and temporal2Exclusive in terms of this unit; positive if temporal2Exclusive is later than temporal1Inclusive, negative if earlier

getDuration

added in API level 26
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.

Returns
Duration the estimated duration of this unit, not null

isDateBased

added in API level 26
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.

Returns
boolean true if a date unit, false if a time unit

isDurationEstimated

added in API level 26
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.

Returns
boolean true if the duration is estimated, false if accurate

isSupportedBy

added in API level 26
public boolean isSupportedBy (Temporal temporal)

Checks if this unit is supported by the specified temporal object.

This checks that the implementing date-time can add/subtract this unit. This can be used to avoid throwing an exception.

This default implementation derives the value using Temporal.plus(long, TemporalUnit).

Parameters
temporal Temporal: the temporal object to check, not null

Returns
boolean true if the unit is supported

isTimeBased

added in API level 26
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.

Returns
boolean true if a time unit, false if a date unit

toString

added in API level 26
public String toString ()

Returns the name of this enum constant, as contained in the declaration. This method may be overridden, though it typically isn't necessary or desirable. An enum type should override this method when a more "programmer-friendly" string form exists.

Returns
String the name of this enum constant

valueOf

added in API level 26
public static ChronoUnit valueOf (String name)

Parameters
name String

Returns
ChronoUnit

values

added in API level 26
public static final ChronoUnit[] values ()

Returns
ChronoUnit[]