Package net.time4j

Enum Class SI

java.lang.Object

java.lang.Enum<SI>

net.time4j.SI

All Implemented Interfaces:

Serializable, Comparable<SI>, java.lang.constant.Constable, ChronoUnit

public enum SI
extends Enum<SI>
implements ChronoUnit

Defines the SI-second as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.

SI-seconds were first officially defined in 1967 so that any reference before that date are meaningless. Time4J supports SI-seconds first with the start of UTC epoch 1972-01-01 because especially the class Moment stores everything before 1972 in mean solar seconds.

Author:

Meno Hochschild

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Enum

Enum.EnumDesc<E extends Enum<E>>

Enum Constant Summary

Enum Constants

Enum Constant	Description
NANOSECONDS
SECONDS

Method Summary

Modifier and Type	Method	Description
long	between(Moment start, Moment end)	Calculates the time distance between given time points in SI-units.
double	getLength()	Defines the typical length of this time unit in seconds without taking into account anomalies like timezone effects or leap seconds.
boolean	isCalendrical()	Queries if this time unit is calendrical respective is at least as long as a calendar day.
static SI	valueOf(String name)	Returns the enum constant of this class with the specified name.
static SI[]	values()	Returns an array containing the constants of this enum class, in the order they are declared.

Methods inherited from class java.lang.Enum

compareTo, describeConstable, equals, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Details

SECONDS

public static final SI SECONDS

NANOSECONDS

public static final SI NANOSECONDS

Method Details

values

public static SI[] values()

Returns an array containing the constants of this enum class, in the order they are declared.

Returns:

an array containing the constants of this enum class, in the order they are declared

valueOf

public static SI valueOf(String name)

Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (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 class has no constant with the specified name

NullPointerException - if the argument is null

between

public long between(Moment start,
 Moment end)

Calculates the time distance between given time points in SI-units.

Parameters:

start - start time point

end - end time point

Returns:

count of SI-units between start and end

Throws:

UnsupportedOperationException - if any time point is before 1972

getLength

public double getLength()

Description copied from interface: ChronoUnit

Defines the typical length of this time unit in seconds without taking into account anomalies like timezone effects or leap seconds.

Important note: This method can only yield an estimated value and is not intended to assist in calculations of durations, but only in sorting of units.

Specified by:

getLength in interface ChronoUnit

Returns:

estimated decimal value in seconds

isCalendrical

public boolean isCalendrical()

Description copied from interface: ChronoUnit

Queries if this time unit is calendrical respective is at least as long as a calendar day.

Implementation note: The method must be consistent with the typical length of the unit. The expression Double.compare(unit.getLength(), 86400.0) >= 0 is equivalent to unit.isCalendrical().

Specified by:

isCalendrical in interface ChronoUnit

Returns:

true if at least as long as a day else false