Enum ChronoUnit
- java.lang.Object
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- java.lang.Enum<ChronoUnit>
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- org.threeten.bp.temporal.ChronoUnit
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- 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.
Specification for implementors
This is a final, immutable and thread-safe enum.
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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.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description <R extends Temporal>
RaddTo(R dateTime, long periodToAdd)
Returns a copy of the specified temporal object with the specified period added.long
between(Temporal temporal1, Temporal temporal2)
Calculates the period in terms of this unit between two temporal objects of the same type.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()
Outputs this unit as aString
using the name.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.
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Enum Constant Detail
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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 is24 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.
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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.
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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 of365.2425 Days
.When used with other calendar systems it must correspond to an integral number of days.
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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 is365.2425 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.
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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.
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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.
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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.
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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 as1,000,000,000 Years
.When used with other calendar systems there are no restrictions on the unit.
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FOREVER
public static final ChronoUnit FOREVER
Artificial unit that represents the concept of forever. This is primarily used withTemporalField
to represent unbounded fields such as the year or era. The estimated duration of the era is artificially defined as the largest duration supported byDuration
.
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Method Detail
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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
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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 nameNullPointerException
- if the argument is null
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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 interfaceTemporalUnit
- Returns:
- the estimated duration of this unit, not null
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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 interfaceTemporalUnit
- Returns:
- true if the duration is estimated, false if accurate
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isDateBased
public boolean isDateBased()
Checks if this unit is a date unit.- Specified by:
isDateBased
in interfaceTemporalUnit
- Returns:
- true if a date unit, false if a time unit
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isTimeBased
public boolean isTimeBased()
Checks if this unit is a time unit.- Specified by:
isTimeBased
in interfaceTemporalUnit
- Returns:
- true if a time unit, false if a date unit
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isSupportedBy
public boolean isSupportedBy(Temporal temporal)
Description copied from interface:TemporalUnit
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.
- Specified by:
isSupportedBy
in interfaceTemporalUnit
- Parameters:
temporal
- the temporal object to check, not null- Returns:
- true if the unit is supported
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addTo
public <R extends Temporal> R addTo(R dateTime, long periodToAdd)
Description copied from interface:TemporalUnit
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.doPlus(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 inChronoField
. If the field is not supported aDateTimeException
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.
- Specified by:
addTo
in interfaceTemporalUnit
- Type Parameters:
R
- the type of the Temporal object- Parameters:
dateTime
- the temporal object to adjust, not nullperiodToAdd
- the period of this unit to add, positive or negative- Returns:
- the adjusted temporal object, not null
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between
public long between(Temporal temporal1, Temporal temporal2)
Description copied from interface:TemporalUnit
Calculates the period in terms of this unit between two temporal objects of the same type.This calculates the period between two temporals in terms of this unit. The start and end points are supplied as temporal objects and must be of the same type. The result will be negative if the end is before the start. For example, the period 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 period in hours between the times 11:30 and 13:29 will only b 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 inChronoUnit
or the fields available inChronoField
. If the unit is not supported a DateTimeException must be thrown. Implementations must not alter the specified temporal objects.- Specified by:
between
in interfaceTemporalUnit
- Parameters:
temporal1
- the base temporal object, not nulltemporal2
- the other temporal object, not null- Returns:
- the period between temporal1 and temporal2 in terms of this unit; positive if temporal2 is later than temporal1, negative if earlier
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toString
public String toString()
Description copied from interface:TemporalUnit
Outputs this unit as aString
using the name.- Specified by:
toString
in interfaceTemporalUnit
- Overrides:
toString
in classEnum<ChronoUnit>
- Returns:
- the name of this unit, not null
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