Class TAIInstant
- java.lang.Object
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- javax.time.TAIInstant
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- All Implemented Interfaces:
Serializable
,Comparable<TAIInstant>
public final class TAIInstant extends Object implements Comparable<TAIInstant>, Serializable
An instantaneous point on the time-line measured in the TAI time-scale.Most of the Time Framework for Java works on the assumption that the time-line is simple, there are no leap-seconds and there are always 24 * 60 * 60 seconds in a day. Sadly, the real-life time-line is not this simple.
This class is an alternative representation based on the TAI time-scale. This scale is defined using atomic clocks and has proceeded in a continuous uninterrupted manner since its epoch of
1958-01-01T00:00:00(TAI)
.As there are no leap seconds, or other discontinuities, in TAI, this time-scale would make an excellent timestamp. While there are, at the time of writing, few easy ways to obtain an accurate TAI instant, it is relatively easy to obtain a GPS instant. GPS and TAI differ by the fixed amount of 19 seconds.
The duration between two points on the TAI time-scale is calculated solely using this class. Do not use the
between
method onDuration
as that will lose information. Instead usedurationUntil(TAIInstant)
on this class.It is intended that most applications will use the
Instant
class which uses the UTC-SLS mapping from UTC to guarantee 86400 seconds per day. Specialist applications with access to an accurate time-source may find this class useful.TAIInstant is immutable and thread-safe.
- Author:
- Stephen Colebourne
- See Also:
- Serialized Form
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description int
compareTo(TAIInstant otherInstant)
Compares this instant to another based on the time-line.Duration
durationUntil(TAIInstant taiInstant)
Returns the duration between this instant and the specified instant.boolean
equals(Object otherInstant)
Checks if this instant is equal to the specifiedTAIInstant
.int
getNanoOfSecond()
Gets the number of nanoseconds, later along the time-line, from the start of the second.long
getTAISeconds()
Gets the number of seconds from the TAI epoch of 1958-01-01T00:00:00(TAI).int
hashCode()
Returns a hash code for this instant.TAIInstant
minus(Duration duration)
Returns a copy of this instant with the specified duration subtracted.static TAIInstant
of(Instant instant)
Obtains an instance ofTAIInstant
from anInstant
using the system default leap second rules.static TAIInstant
of(UTCInstant instant)
Obtains an instance ofTAIInstant
from aUTCInstant
.static TAIInstant
ofTAISeconds(long taiSeconds, long nanoAdjustment)
Obtains an instance ofTAIInstant
from the number of seconds from the TAI epoch of 1958-01-01T00:00:00(TAI) with a nanosecond fraction of second.static TAIInstant
parse(String text)
Obtains an instance ofTAIInstant
from a text string.TAIInstant
plus(Duration duration)
Returns a copy of this instant with the specified duration added.Instant
toInstant()
Converts this instant to anInstant
using the system default leap second rules.String
toString()
A string representation of this instant.UTCInstant
toUTCInstant()
Converts this instant to aUTCInstant
using the system default leap second rules.
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Method Detail
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ofTAISeconds
public static TAIInstant ofTAISeconds(long taiSeconds, long nanoAdjustment)
Obtains an instance ofTAIInstant
from the number of seconds from the TAI epoch of 1958-01-01T00:00:00(TAI) with a nanosecond fraction of second.This method allows an arbitrary number of nanoseconds to be passed in. The factory will alter the values of the second and nanosecond in order to ensure that the stored nanosecond is in the range 0 to 999,999,999. For example, the following will result in the exactly the same instant:
TAIInstant.ofSeconds(3, 1); TAIInstant.ofSeconds(4, -999999999); TAIInstant.ofSeconds(2, 1000000001);
- Parameters:
taiSeconds
- the number of seconds from the epoch of 1958-01-01T00:00:00(TAI)nanoAdjustment
- the nanosecond adjustment to the number of seconds, positive or negative- Returns:
- the TAI instant, never null
- Throws:
IllegalArgumentException
- if nanoOfSecond is out of range
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of
public static TAIInstant of(Instant instant)
Obtains an instance ofTAIInstant
from anInstant
using the system default leap second rules.Converting a UTC-SLS instant to a TAI instant requires leap second rules. This method uses the latest available system rules. The conversion first maps from UTC-SLS to UTC, then converts to TAI.
Conversion from an
Instant
will not be completely accurate near a leap second in accordance with UTC-SLS.- Parameters:
instant
- the instant to convert, not null- Returns:
- the TAI instant, never null
- Throws:
ArithmeticException
- if the calculation exceeds the supported range
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of
public static TAIInstant of(UTCInstant instant)
Obtains an instance ofTAIInstant
from aUTCInstant
.Converting a UTC instant to a TAI instant requires leap second rules. This method uses the rules held in within the UTC instant.
Conversion from a
UTCInstant
will be entirely accurate. The resulting TAI instant will not reference the leap second rules, so converting back to a UTC instant may result in a different UTC instant.- Parameters:
instant
- the instant to convert, not null- Returns:
- the TAI instant, never null
- Throws:
ArithmeticException
- if the calculation exceeds the supported range
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parse
public static TAIInstant parse(String text)
Obtains an instance ofTAIInstant
from a text string.The following format is accepted in ASCII:
{seconds}.{nanosOfSecond}s(TAI)
toString
format.- Parameters:
text
- the text to parse such as '12345.123456789s(TAI)', not null- Returns:
- the parsed instant, never null
- Throws:
CalendricalException
- if the text cannot be parsed
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getTAISeconds
public long getTAISeconds()
Gets the number of seconds from the TAI epoch of 1958-01-01T00:00:00(TAI).The TAI second count is a simple incrementing count of seconds where second 0 is 1958-01-01T00:00:00(TAI). The nanosecond part of the day is returned by
getNanosOfSecond
.- Returns:
- the seconds from the epoch of 1958-01-01T00:00:00(TAI)
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getNanoOfSecond
public int getNanoOfSecond()
Gets the number of nanoseconds, later along the time-line, from the start of the second.The nanosecond-of-second value measures the total number of nanoseconds from the second returned by
getTAISeconds
.- Returns:
- the nanoseconds within the second, from 0 to 999,999,999
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plus
public TAIInstant plus(Duration duration)
Returns a copy of this instant with the specified duration added.The duration is added using simple addition of the seconds and nanoseconds in the duration to the seconds and nanoseconds of this instant. As a result, the duration is treated as being measured in TAI compatible seconds for the purpose of this method.
This instance is immutable and unaffected by this method call.
- Parameters:
duration
- the duration to add, not null- Returns:
- a
TAIInstant
based on this instant with the duration added, never null - Throws:
ArithmeticException
- if the calculation exceeds the supported range
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minus
public TAIInstant minus(Duration duration)
Returns a copy of this instant with the specified duration subtracted.The duration is subtracted using simple subtraction of the seconds and nanoseconds in the duration from the seconds and nanoseconds of this instant. As a result, the duration is treated as being measured in TAI compatible seconds for the purpose of this method.
This instance is immutable and unaffected by this method call.
- Parameters:
duration
- the duration to subtract, not null- Returns:
- a
TAIInstant
based on this instant with the duration subtracted, never null - Throws:
ArithmeticException
- if the calculation exceeds the supported range
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durationUntil
public Duration durationUntil(TAIInstant taiInstant)
Returns the duration between this instant and the specified instant.This calculates the duration between this instant and another based on the TAI time-scale. Adding the duration to this instant using
plus(javax.time.Duration)
will always result in an instant equal to the specified instant.- Parameters:
taiInstant
- the instant to calculate the duration until, not null- Returns:
- the duration until the specified instant, may be negative, never null
- Throws:
ArithmeticException
- if the calculation exceeds the supported range
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toUTCInstant
public UTCInstant toUTCInstant()
Converts this instant to aUTCInstant
using the system default leap second rules.This method converts this instant from the TAI to the UTC time-scale using the system default leap-second rules. This conversion does not lose information and the UTC instant may safely be converted back to a
TAIInstant
.- Returns:
- a
UTCInstant
representing the same instant using the system leap second rules, never null
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toInstant
public Instant toInstant()
Converts this instant to anInstant
using the system default leap second rules.This method converts this instant from the TAI to the UTC-SLS time-scale using the system default leap-second rules to convert to UTC. This conversion will lose information around a leap second in accordance with UTC-SLS. Converting back to a
TAIInstant
may result in a slightly different instant.- Returns:
- an
Instant
representing the best approximation of this instant, never null
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compareTo
public int compareTo(TAIInstant otherInstant)
Compares this instant to another based on the time-line.- Specified by:
compareTo
in interfaceComparable<TAIInstant>
- Parameters:
otherInstant
- the other instant to compare to, not null- Returns:
- the comparator value, negative if less, positive if greater
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equals
public boolean equals(Object otherInstant)
Checks if this instant is equal to the specifiedTAIInstant
.
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hashCode
public int hashCode()
Returns a hash code for this instant.
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toString
public String toString()
A string representation of this instant.The string is formatted as
{seconds).(nanosOfSecond}s(TAI)
. At least one second digit will be present. The nanoseconds will always be nine digits.
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