UTCInstant (time-api 0.6.4 API)

java.lang.Object
- javax.time.UTCInstant

All Implemented Interfaces:

Serializable, Comparable<UTCInstant>
```
public final class UTCInstant
extends Object
implements Comparable<UTCInstant>, Serializable
```
An instantaneous point on the time-line measured in the UTC time-scale, handling leap seconds.
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. However, the Earth's rotation is not straightforward, and a solar day does not match this definition.
This class is an alternative representation based on the UTC time-scale which includes leap-seconds. Leap-seconds are additional seconds that are inserted into the year-month-day-hour-minute-second time-line in order to keep UTC in line with the solar day. When a leap second occurs, an accurate clock will show the time 23:59:60 just before midnight.
Leap-seconds are announced in advance, typically at least six months. The UTCRules class models which dates have leap-seconds. Alternative implementations of the rules may be supplied.
The default rules implementation fixes the start point of UTC as 1972. This date was chosen as UTC was more complex before 1972.
The duration between two points on the UTC time-scale is calculated solely using this class. Do not use the between method on Duration as that will lose information. Instead use durationUntil(UTCInstant) 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.
Time-scale

The length of the solar day is the standard way that humans measure time. As the Earth's rotation changes, the length of the day varies. In general, a solar day is slightly longer than 86400 seconds. The actual length is not predictable and can only be determined by measurement. The UT1 time-scale captures these measurements.
The UTC time-scale is a standard approach to bundle up all the additional fractions of a second from UT1 into whole seconds, known as leap-seconds. A leap-second may be added or removed depending on the Earth's rotational changes. If it is removed, then the relevant date will have no time of 23:59:59. If it is added, then the relevant date will have an extra second of 23:59:60.
The modern UTC time-scale was introduced in 1972, introducing the concept of whole leap-seconds. Between 1958 and 1972, the definition of UTC was complex, with minor sub-second leaps and alterations to the length of seconds. The default rules only implement UTC from 1972. Prior to that date, the default rules fix the UTC-TAI offset at 10 seconds. While not historically accurate, it is a simple, easy definition, suitable for this library.
The standard Java epoch of 1970-01-01 is prior to the introduction of whole leap-seconds into UTC in 1972. As such, the Time Framework for Java needs to define what the 1970 epoch actually means. The chosen definition follows the UTC definition given above, such that 1970-01-01 is 10 seconds offset from TAI.
UTCInstant is immutable and thread-safe.

Author:

Stephen Colebourne

See Also:

Serialized Form

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`int`	`compareTo(UTCInstant otherInstant)` Compares this instant to another based on the time-line, then the name of the rules.
`Duration`	`durationUntil(UTCInstant utcInstant)` Returns the duration between this instant and the specified instant.
`boolean`	`equals(Object otherInstant)` Checks if this instant is equal to the specified `UTCInstant`.
`long`	`getModifiedJulianDays()` Gets the Modified Julian Day (MJD).
`long`	`getNanoOfDay()` Gets the number of nanoseconds, later along the time-line, from the start of the Modified Julian Day.
`UTCRules`	`getRules()` Gets the leap second rules defining when leap seconds occur.
`int`	`hashCode()` Returns a hash code for this instant.
`boolean`	`isLeapSecond()` Checks if the instant is within a leap second.
`UTCInstant`	`minus(Duration duration)` Returns a copy of this instant with the specified duration subtracted.
`static UTCInstant`	`of(Instant instant)` Obtains an instance of `UTCInstant` from a provider of instants using the system default leap second rules.
`static UTCInstant`	`of(Instant instant, UTCRules rules)` Obtains an instance of `UTCInstant` from a provider of instants using the specified leap second rules.
`static UTCInstant`	`of(TAIInstant taiInstant)` Obtains an instance of `UTCInstant` from a TAI instant using the system default leap second rules.
`static UTCInstant`	`of(TAIInstant taiInstant, UTCRules rules)` Obtains an instance of `UTCInstant` from a TAI instant using the specified leap second rules.
`static UTCInstant`	`ofModifiedJulianDays(long mjDay, long nanoOfDay)` Obtains an instance of `UTCInstant` from a Modified Julian Day with a nanosecond fraction of second using the system default leap second rules.
`static UTCInstant`	`ofModifiedJulianDays(long mjDay, long nanoOfDay, UTCRules rules)` Obtains an instance of `UTCInstant` from a Modified Julian Day with a nanosecond fraction of second using the specified leap second rules.
`UTCInstant`	`plus(Duration duration)` Returns a copy of this instant with the specified duration added.
`Instant`	`toInstant()` Converts this instant to an `Instant` using the system default leap second rules.
`String`	`toString()` A string representation of this instant.
`TAIInstant`	`toTAIInstant()` Converts this instant to a `TAIInstant` using the stored leap second rules.

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Method Detail
  - ofModifiedJulianDays
```
public static UTCInstant ofModifiedJulianDays(long mjDay,
                                              long nanoOfDay)
```
    Obtains an instance of UTCInstant from a Modified Julian Day with a nanosecond fraction of second using the system default leap second rules.
    This factory creates an instance of a UTC instant. The nanosecond of day value includes any leap second and has a valid range from 0 to 86,400,000,000,000 - 1 on days other than leap-second-days and other lengths on leap-second-days.
    The nanosecond value must be positive even for negative values of Modified Julian Days. One nanosecond before Modified Julian Day zero will be -1 days and the maximum nanosecond value.
    
    Parameters:
    
    mjDay - the date as a Modified Julian Day (number of days from the epoch of 1858-11-17)
    
    nanoOfDay - the nanoseconds within the day, including leap seconds
    
    Returns:
    
    the UTC instant, never null
    
    Throws:
    
    IllegalArgumentException - if nanoOfDay is out of range
  - ofModifiedJulianDays
```
public static UTCInstant ofModifiedJulianDays(long mjDay,
                                              long nanoOfDay,
                                              UTCRules rules)
```
    Obtains an instance of UTCInstant from a Modified Julian Day with a nanosecond fraction of second using the specified leap second rules.
    This factory creates an instance of a UTC instant. The nanosecond of day value includes any leap second and has a valid range from 0 to 86,400,000,000,000 - 1 on days other than leap-second-days and other lengths on leap-second-days.
    The nanosecond value must be positive even for negative values of Modified Julian Days. One nanosecond before Modified Julian Day zero will be -1 days and the maximum nanosecond value.
    
    Parameters:
    
    mjDay - the date as a Modified Julian Day (number of days from the epoch of 1858-11-17)
    
    nanoOfDay - the nanoseconds within the day, including leap seconds
    
    Returns:
    
    the UTC instant, never null
    
    Throws:
    
    IllegalArgumentException - if nanoOfDay is out of range
  - of
```
public static UTCInstant of(Instant instant)
```
    Obtains an instance of UTCInstant from a provider of instants using the system default leap second rules.
    This method converts from the UTC-SLS to the UTC time-scale using the system default leap-second rules. This conversion will lose information around a leap second in accordance with UTC-SLS. Converting back to an Instant may result in a slightly different instant.
    
    Parameters:
    
    instant - the instant to convert, not null
    
    Returns:
    
    the UTC instant, never null
  - of
```
public static UTCInstant of(Instant instant,
                            UTCRules rules)
```
    Obtains an instance of UTCInstant from a provider of instants using the specified leap second rules.
    This method converts from the UTC-SLS to the UTC time-scale using the specified leap-second rules. This conversion will lose information around a leap second in accordance with UTC-SLS. Converting back to an Instant may result in a slightly different instant.
    
    Parameters:
    
    instant - the instant to convert, not null
    
    rules - the leap second rules, not null
    
    Returns:
    
    the UTC instant, never null
  - of
```
public static UTCInstant of(TAIInstant taiInstant)
```
    Obtains an instance of UTCInstant from a TAI instant using the system default leap second rules.
    This method converts 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.
    
    Parameters:
    
    taiInstant - the TAI instant to convert, not null
    
    Returns:
    
    the UTC instant, never null
  - of
```
public static UTCInstant of(TAIInstant taiInstant,
                            UTCRules rules)
```
    Obtains an instance of UTCInstant from a TAI instant using the specified leap second rules.
    This method converts from the TAI to the UTC time-scale using the specified leap-second rules. This conversion does not lose information and the UTC instant may safely be converted back to a TAIInstant.
    
    Parameters:
    
    taiInstant - the TAI instant to convert, not null
    
    rules - the leap second rules, not null
    
    Returns:
    
    the UTC instant, never null
  - getRules
```
public UTCRules getRules()
```
    Gets the leap second rules defining when leap seconds occur.
    
    Returns:
    
    the leap seconds rules
  - getModifiedJulianDays
```
public long getModifiedJulianDays()
```
    Gets the Modified Julian Day (MJD).
    The Modified Julian Day count is a simple incrementing count of days where day 0 is 1858-11-17. The nanosecond part of the day is returned by getNanosOfDay.
    A Modified Julian Day varies in length, being one second longer on a leap day.
    
    Returns:
    
    the Modified Julian Day based on the epoch 1858-11-17
  - getNanoOfDay
```
public long getNanoOfDay()
```
    Gets the number of nanoseconds, later along the time-line, from the start of the Modified Julian Day.
    The nanosecond-of-day value measures the total number of nanoseconds from the Modified Julian Day returned by getModifiedJulianDay. This value will include any additional leap seconds.
    
    Returns:
    
    the nanoseconds within the day, including leap seconds
  - isLeapSecond
```
public boolean isLeapSecond()
```
    Checks if the instant is within a leap second.
    This method returns true when an accurate clock would return a seconds field of 60.
    
    Returns:
    
    true if this instant is within a leap second
  - plus
```
public UTCInstant 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 UTCInstant with the duration added, never null
    
    Throws:
    
    ArithmeticException - if the calculation exceeds the supported range
  - minus
```
public UTCInstant 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 UTCInstant with the duration subtracted, never null
    
    Throws:
    
    ArithmeticException - if the calculation exceeds the supported range
  - durationUntil
```
public Duration durationUntil(UTCInstant utcInstant)
```
    Returns the duration between this instant and the specified instant.
    This calculates the duration between this instant and another based on the UTC time-scale. Any leap seconds that occur will be included in the duration. Adding the duration to this instant using plus(javax.time.Duration) will always result in an instant equal to the specified instant.
    
    Parameters:
    
    utcInstant - 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
  - toTAIInstant
```
public TAIInstant toTAIInstant()
```
    Converts this instant to a TAIInstant using the stored leap second rules.
    This method converts from the UTC to the TAI time-scale using the stored leap-second rules. Conversion to a TAIInstant retains the same point on the time-line but loses the stored rules. If the TAI instant is converted back to a UTC instant with different or updated rules then the calculated UTC instant may be different.
    
    Returns:
    
    a TAIInstant representing the same instant, never null
    
    Throws:
    
    ArithmeticException - if the calculation exceeds the supported range
  - toInstant
```
public Instant toInstant()
```
    Converts this instant to an Instant using the system default leap second rules.
    This method converts this instant from the UTC to the UTC-SLS time-scale using the stored leap-second rules. This conversion will lose information around a leap second in accordance with UTC-SLS. Converting back to a UTCInstant may result in a slightly different instant.
    
    Returns:
    
    an Instant representing the best approximation of this instant, never null
    
    Throws:
    
    ArithmeticException - if the calculation exceeds the supported range
  - compareTo
```
public int compareTo(UTCInstant otherInstant)
```
    Compares this instant to another based on the time-line, then the name of the rules.
    The comparison is based on the positions on the time-line and the rules. This definition means that two instants representing the same instant on the time-line will differ if the rules differ. To compare the time-line instant, convert both instants to a TAIInstant.
    
    Specified by:
    
    compareTo in interface Comparable<UTCInstant>
    
    Parameters:
    
    otherInstant - the other instant to compare to, not null
    
    Returns:
    
    the comparator value, negative if less, positive if greater
  - equals
```
public boolean equals(Object otherInstant)
```
    Checks if this instant is equal to the specified UTCInstant.
    The comparison is based on the positions on the time-line and the rules. This definition means that two instants representing the same instant on the time-line will differ if the rules differ. To compare the time-line instant, convert both instants to a TAIInstant.
    
    Overrides:
    
    equals in class Object
    
    Parameters:
    
    otherInstant - the other instant, null returns false
    
    Returns:
    
    true if the other instant is equal to this one
  - hashCode
```
public int hashCode()
```
    Returns a hash code for this instant.
    
    Overrides:
    
    hashCode in class Object
    
    Returns:
    
    a suitable hash code
  - toString
```
public String toString()
```
    A string representation of this instant.
    The string is formatted using ISO-8601.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    a representation of this instant, never null

Class UTCInstant

Time-scale

Method Summary

Methods inherited from class java.lang.Object

Method Detail

ofModifiedJulianDays

ofModifiedJulianDays

of

of

of

of

getRules

getModifiedJulianDays

getNanoOfDay

isLeapSecond

plus

minus

durationUntil

toTAIInstant

toInstant

compareTo

equals

hashCode

toString