Class Instant
- java.lang.Object
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- org.threeten.bp.jdk8.DefaultInterfaceTemporalAccessor
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- org.threeten.bp.Instant
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- All Implemented Interfaces:
java.io.Serializable
,java.lang.Comparable<Instant>
,Temporal
,TemporalAccessor
,TemporalAdjuster
public final class Instant extends DefaultInterfaceTemporalAccessor implements Temporal, TemporalAdjuster, java.lang.Comparable<Instant>, java.io.Serializable
An instantaneous point on the time-line.This class models a single instantaneous point on the time-line. This might be used to record event time-stamps in the application.
For practicality, the instant is stored with some constraints. The measurable time-line is restricted to the number of seconds that can be held in a
long
. This is greater than the current estimated age of the universe. The instant is stored to nanosecond resolution.The range of an instant requires the storage of a number larger than a
long
. To achieve this, the class stores along
representing epoch-seconds and anint
representing nanosecond-of-second, which will always be between 0 and 999,999,999. The epoch-seconds are measured from the standard Java epoch of1970-01-01T00:00:00Z
where instants after the epoch have positive values, and earlier instants have negative values. For both the epoch-second and nanosecond parts, a larger value is always later on the time-line than a smaller value.Time-scale
The length of the solar day is the standard way that humans measure time. This has traditionally been subdivided into 24 hours of 60 minutes of 60 seconds, forming a 86400 second day.
Modern timekeeping is based on atomic clocks which precisely define an SI second relative to the transitions of a Caesium atom. The length of an SI second was defined to be very close to the 86400th fraction of a day.
Unfortunately, as the Earth rotates the length of the day varies. In addition, over time the average length of the day is getting longer as the Earth slows. As a result, the length of a solar day in 2012 is slightly longer than 86400 SI seconds. The actual length of any given day and the amount by which the Earth is slowing are not predictable and can only be determined by measurement. The UT1 time-scale captures the accurate length of day, but is only available some time after the day has completed.
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. As such, UTC permits a day to have 86399 SI seconds or 86401 SI seconds where necessary in order to keep the day aligned with the Sun.
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 the notional second. As of 2012, discussions are underway to change the definition of UTC again, with the potential to remove leap seconds or introduce other changes.
Given the complexity of accurate timekeeping described above, this Java API defines its own time-scale with a simplification. The Java time-scale is defined as follows:
- midday will always be exactly as defined by the agreed international civil time
- other times during the day will be broadly in line with the agreed international civil time
- the day will be divided into exactly 86400 subdivisions, referred to as "seconds"
- the Java "second" may differ from an SI second
Agreed international civil time is the base time-scale agreed by international convention, which in 2012 is UTC (with leap-seconds).
In 2012, the definition of the Java time-scale is the same as UTC for all days except those where a leap-second occurs. On days where a leap-second does occur, the time-scale effectively eliminates the leap-second, maintaining the fiction of 86400 seconds in the day.
The main benefit of always dividing the day into 86400 subdivisions is that it matches the expectations of most users of the API. The alternative is to force every user to understand what a leap second is and to force them to have special logic to handle them. Most applications do not have access to a clock that is accurate enough to record leap-seconds. Most applications also do not have a problem with a second being a very small amount longer or shorter than a real SI second during a leap-second.
If an application does have access to an accurate clock that reports leap-seconds, then the recommended technique to implement the Java time-scale is to use the UTC-SLS convention. UTC-SLS effectively smoothes the leap-second over the last 1000 seconds of the day, making each of the last 1000 "seconds" 1/1000th longer or shorter than a real SI second.
One final problem is the definition of the agreed international civil time before the introduction of modern UTC in 1972. This includes the Java epoch of
1970-01-01
. It is intended that instants before 1972 be interpreted based on the solar day divided into 86400 subdivisions.The Java time-scale is used by all date-time classes. This includes
Instant
,LocalDate
,LocalTime
,OffsetDateTime
,ZonedDateTime
andDuration
.Specification for implementors
This class is immutable and thread-safe.- See Also:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description static Instant
EPOCH
Constant for the 1970-01-01T00:00:00Z epoch instant.static TemporalQuery<Instant>
FROM
Simulate JDK 8 method reference Instant::from.static Instant
MAX
The maximum supportedInstant
, '1000000000-12-31T23:59:59.999999999Z'.static Instant
MIN
The minimum supportedInstant
, '-1000000000-01-01T00:00Z'.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description Temporal
adjustInto(Temporal temporal)
Adjusts the specified temporal object to have this instant.OffsetDateTime
atOffset(ZoneOffset offset)
Combines this instant with an offset to create anOffsetDateTime
.ZonedDateTime
atZone(ZoneId zone)
Combines this instant with a time-zone to create aZonedDateTime
.int
compareTo(Instant otherInstant)
Compares this instant to the specified instant.boolean
equals(java.lang.Object otherInstant)
Checks if this instant is equal to the specified instant.static Instant
from(TemporalAccessor temporal)
Obtains an instance ofInstant
from a temporal object.int
get(TemporalField field)
Gets the value of the specified field from this instant as anint
.long
getEpochSecond()
Gets the number of seconds from the Java epoch of 1970-01-01T00:00:00Z.long
getLong(TemporalField field)
Gets the value of the specified field from this instant as along
.int
getNano()
Gets the number of nanoseconds, later along the time-line, from the start of the second.int
hashCode()
Returns a hash code for this instant.boolean
isAfter(Instant otherInstant)
Checks if this instant is after the specified instant.boolean
isBefore(Instant otherInstant)
Checks if this instant is before the specified instant.boolean
isSupported(TemporalField field)
Checks if the specified field is supported.boolean
isSupported(TemporalUnit unit)
Checks if the specified unit is supported.Instant
minus(long amountToSubtract, TemporalUnit unit)
Returns an object of the same type as this object with the specified period subtracted.Instant
minus(TemporalAmount amount)
Returns an object of the same type as this object with an amount subtracted.Instant
minusMillis(long millisToSubtract)
Returns a copy of this instant with the specified duration in milliseconds subtracted.Instant
minusNanos(long nanosToSubtract)
Returns a copy of this instant with the specified duration in nanoseconds subtracted.Instant
minusSeconds(long secondsToSubtract)
Returns a copy of this instant with the specified duration in seconds subtracted.static Instant
now()
Obtains the current instant from the system clock.static Instant
now(Clock clock)
Obtains the current instant from the specified clock.static Instant
ofEpochMilli(long epochMilli)
Obtains an instance ofInstant
using milliseconds from the epoch of 1970-01-01T00:00:00Z.static Instant
ofEpochSecond(long epochSecond)
Obtains an instance ofInstant
using seconds from the epoch of 1970-01-01T00:00:00Z.static Instant
ofEpochSecond(long epochSecond, long nanoAdjustment)
Obtains an instance ofInstant
using seconds from the epoch of 1970-01-01T00:00:00Z and nanosecond fraction of second.static Instant
parse(java.lang.CharSequence text)
Obtains an instance ofInstant
from a text string such as2007-12-23T10:15:30.000Z
.Instant
plus(long amountToAdd, TemporalUnit unit)
Returns an object of the same type as this object with the specified period added.Instant
plus(TemporalAmount amount)
Returns an object of the same type as this object with an amount added.Instant
plusMillis(long millisToAdd)
Returns a copy of this instant with the specified duration in milliseconds added.Instant
plusNanos(long nanosToAdd)
Returns a copy of this instant with the specified duration in nanoseconds added.Instant
plusSeconds(long secondsToAdd)
Returns a copy of this instant with the specified duration in seconds added.<R> R
query(TemporalQuery<R> query)
Queries this instant using the specified query.ValueRange
range(TemporalField field)
Gets the range of valid values for the specified field.long
toEpochMilli()
Converts this instant to the number of milliseconds from the epoch of 1970-01-01T00:00:00Z.java.lang.String
toString()
A string representation of this instant using ISO-8601 representation.Instant
truncatedTo(TemporalUnit unit)
Returns a copy of thisInstant
truncated to the specified unit.long
until(Temporal endExclusive, TemporalUnit unit)
Calculates the period between this instant and another instant in terms of the specified unit.Instant
with(TemporalAdjuster adjuster)
Returns an adjusted copy of this instant.Instant
with(TemporalField field, long newValue)
Returns a copy of this instant with the specified field set to a new value.
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Field Detail
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EPOCH
public static final Instant EPOCH
Constant for the 1970-01-01T00:00:00Z epoch instant.
-
MIN
public static final Instant MIN
The minimum supportedInstant
, '-1000000000-01-01T00:00Z'. This could be used by an application as a "far past" instant.This is one year earlier than the minimum
LocalDateTime
. This provides sufficient values to handle the range ofZoneOffset
which affect the instant in addition to the local date-time. The value is also chosen such that the value of the year fits in anint
.
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MAX
public static final Instant MAX
The maximum supportedInstant
, '1000000000-12-31T23:59:59.999999999Z'. This could be used by an application as a "far future" instant.This is one year later than the maximum
LocalDateTime
. This provides sufficient values to handle the range ofZoneOffset
which affect the instant in addition to the local date-time. The value is also chosen such that the value of the year fits in anint
.
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FROM
public static final TemporalQuery<Instant> FROM
Simulate JDK 8 method reference Instant::from.
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-
Method Detail
-
now
public static Instant now()
Obtains the current instant from the system clock.This will query the
system UTC clock
to obtain the current instant.Using this method will prevent the ability to use an alternate time-source for testing because the clock is effectively hard-coded.
- Returns:
- the current instant using the system clock, not null
-
now
public static Instant now(Clock clock)
Obtains the current instant from the specified clock.This will query the specified clock to obtain the current time.
Using this method allows the use of an alternate clock for testing. The alternate clock may be introduced using
dependency injection
.- Parameters:
clock
- the clock to use, not null- Returns:
- the current instant, not null
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ofEpochSecond
public static Instant ofEpochSecond(long epochSecond)
Obtains an instance ofInstant
using seconds from the epoch of 1970-01-01T00:00:00Z.The nanosecond field is set to zero.
- Parameters:
epochSecond
- the number of seconds from 1970-01-01T00:00:00Z- Returns:
- an instant, not null
- Throws:
DateTimeException
- if the instant exceeds the maximum or minimum instant
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ofEpochSecond
public static Instant ofEpochSecond(long epochSecond, long nanoAdjustment)
Obtains an instance ofInstant
using seconds from the epoch of 1970-01-01T00:00:00Z and 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:
Instant.ofSeconds(3, 1); Instant.ofSeconds(4, -999_999_999); Instant.ofSeconds(2, 1000_000_001);
- Parameters:
epochSecond
- the number of seconds from 1970-01-01T00:00:00ZnanoAdjustment
- the nanosecond adjustment to the number of seconds, positive or negative- Returns:
- an instant, not null
- Throws:
DateTimeException
- if the instant exceeds the maximum or minimum instantjava.lang.ArithmeticException
- if numeric overflow occurs
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ofEpochMilli
public static Instant ofEpochMilli(long epochMilli)
Obtains an instance ofInstant
using milliseconds from the epoch of 1970-01-01T00:00:00Z.The seconds and nanoseconds are extracted from the specified milliseconds.
- Parameters:
epochMilli
- the number of milliseconds from 1970-01-01T00:00:00Z- Returns:
- an instant, not null
- Throws:
DateTimeException
- if the instant exceeds the maximum or minimum instant
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from
public static Instant from(TemporalAccessor temporal)
Obtains an instance ofInstant
from a temporal object.A
TemporalAccessor
represents some form of date and time information. This factory converts the arbitrary temporal object to an instance ofInstant
.The conversion extracts the
INSTANT_SECONDS
andNANO_OF_SECOND
fields.This method matches the signature of the functional interface
TemporalQuery
allowing it to be used as a query via method reference,Instant::from
.- Parameters:
temporal
- the temporal object to convert, not null- Returns:
- the instant, not null
- Throws:
DateTimeException
- if unable to convert to anInstant
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parse
public static Instant parse(java.lang.CharSequence text)
Obtains an instance ofInstant
from a text string such as2007-12-23T10:15:30.000Z
.The string must represent a valid instant in UTC and is parsed using
DateTimeFormatter.ISO_INSTANT
.- Parameters:
text
- the text to parse, not null- Returns:
- the parsed instant, not null
- Throws:
DateTimeParseException
- if the text cannot be parsed
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isSupported
public boolean isSupported(TemporalField field)
Checks if the specified field is supported.This checks if this instant can be queried for the specified field. If false, then calling the
range
andget
methods will throw an exception.If the field is a
ChronoField
then the query is implemented here. The supported fields are:NANO_OF_SECOND
MICRO_OF_SECOND
MILLI_OF_SECOND
INSTANT_SECONDS
ChronoField
instances will return false.If the field is not a
ChronoField
, then the result of this method is obtained by invokingTemporalField.isSupportedBy(TemporalAccessor)
passingthis
as the argument. Whether the field is supported is determined by the field.- Specified by:
isSupported
in interfaceTemporalAccessor
- Parameters:
field
- the field to check, null returns false- Returns:
- true if the field is supported on this instant, false if not
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isSupported
public boolean isSupported(TemporalUnit unit)
Description copied from interface:Temporal
Checks if the specified unit is supported.This checks if the date-time can be queried for the specified unit. If false, then calling the
plus
andminus
methods will throw an exception.Specification for implementors
Implementations must check and handle all fields defined inChronoUnit
. If the field is supported, then true is returned, otherwise falseIf the field is not a
ChronoUnit
, then the result of this method is obtained by invokingTemporalUnit.isSupportedBy(Temporal)
passingthis
as the argument.Implementations must not alter this object.
- Specified by:
isSupported
in interfaceTemporal
- Parameters:
unit
- the unit to check, null returns false- Returns:
- true if this date-time can be queried for the unit, false if not
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range
public ValueRange range(TemporalField field)
Gets the range of valid values for the specified field.The range object expresses the minimum and maximum valid values for a field. This instant is used to enhance the accuracy of the returned range. If it is not possible to return the range, because the field is not supported or for some other reason, an exception is thrown.
If the field is a
ChronoField
then the query is implemented here. Thesupported fields
will return appropriate range instances. All otherChronoField
instances will throw aDateTimeException
.If the field is not a
ChronoField
, then the result of this method is obtained by invokingTemporalField.rangeRefinedBy(TemporalAccessor)
passingthis
as the argument. Whether the range can be obtained is determined by the field.- Specified by:
range
in interfaceTemporalAccessor
- Overrides:
range
in classDefaultInterfaceTemporalAccessor
- Parameters:
field
- the field to query the range for, not null- Returns:
- the range of valid values for the field, not null
- Throws:
DateTimeException
- if the range for the field cannot be obtained
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get
public int get(TemporalField field)
Gets the value of the specified field from this instant as anint
.This queries this instant for the value for the specified field. The returned value will always be within the valid range of values for the field. If it is not possible to return the value, because the field is not supported or for some other reason, an exception is thrown.
If the field is a
ChronoField
then the query is implemented here. Thesupported fields
will return valid values based on this date-time, exceptINSTANT_SECONDS
which is too large to fit in anint
and throws aDateTimeException
. All otherChronoField
instances will throw aDateTimeException
.If the field is not a
ChronoField
, then the result of this method is obtained by invokingTemporalField.getFrom(TemporalAccessor)
passingthis
as the argument. Whether the value can be obtained, and what the value represents, is determined by the field.- Specified by:
get
in interfaceTemporalAccessor
- Overrides:
get
in classDefaultInterfaceTemporalAccessor
- Parameters:
field
- the field to get, not null- Returns:
- the value for the field
- Throws:
DateTimeException
- if a value for the field cannot be obtainedjava.lang.ArithmeticException
- if numeric overflow occurs
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getLong
public long getLong(TemporalField field)
Gets the value of the specified field from this instant as along
.This queries this instant for the value for the specified field. If it is not possible to return the value, because the field is not supported or for some other reason, an exception is thrown.
If the field is a
ChronoField
then the query is implemented here. Thesupported fields
will return valid values based on this date-time. All otherChronoField
instances will throw aDateTimeException
.If the field is not a
ChronoField
, then the result of this method is obtained by invokingTemporalField.getFrom(TemporalAccessor)
passingthis
as the argument. Whether the value can be obtained, and what the value represents, is determined by the field.- Specified by:
getLong
in interfaceTemporalAccessor
- Parameters:
field
- the field to get, not null- Returns:
- the value for the field
- Throws:
DateTimeException
- if a value for the field cannot be obtainedjava.lang.ArithmeticException
- if numeric overflow occurs
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getEpochSecond
public long getEpochSecond()
Gets the number of seconds from the Java epoch of 1970-01-01T00:00:00Z.The epoch second count is a simple incrementing count of seconds where second 0 is 1970-01-01T00:00:00Z. The nanosecond part of the day is returned by
getNanosOfSecond
.- Returns:
- the seconds from the epoch of 1970-01-01T00:00:00Z
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getNano
public int getNano()
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
getEpochSecond
.- Returns:
- the nanoseconds within the second, always positive, never exceeds 999,999,999
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with
public Instant with(TemporalAdjuster adjuster)
Returns an adjusted copy of this instant.This returns a new
Instant
, based on this one, with the date adjusted. The adjustment takes place using the specified adjuster strategy object. Read the documentation of the adjuster to understand what adjustment will be made.The result of this method is obtained by invoking the
TemporalAdjuster.adjustInto(Temporal)
method on the specified adjuster passingthis
as the argument.This instance is immutable and unaffected by this method call.
- Specified by:
with
in interfaceTemporal
- Parameters:
adjuster
- the adjuster to use, not null- Returns:
- an
Instant
based onthis
with the adjustment made, not null - Throws:
DateTimeException
- if the adjustment cannot be madejava.lang.ArithmeticException
- if numeric overflow occurs
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with
public Instant with(TemporalField field, long newValue)
Returns a copy of this instant with the specified field set to a new value.This returns a new
Instant
, based on this one, with the value for the specified field changed. If it is not possible to set the value, because the field is not supported or for some other reason, an exception is thrown.If the field is a
ChronoField
then the adjustment is implemented here. The supported fields behave as follows:NANO_OF_SECOND
- Returns anInstant
with the specified nano-of-second. The epoch-second will be unchanged.MICRO_OF_SECOND
- Returns anInstant
with the nano-of-second replaced by the specified micro-of-second multiplied by 1,000. The epoch-second will be unchanged.MILLI_OF_SECOND
- Returns anInstant
with the nano-of-second replaced by the specified milli-of-second multiplied by 1,000,000. The epoch-second will be unchanged.INSTANT_SECONDS
- Returns anInstant
with the specified epoch-second. The nano-of-second will be unchanged.
In all cases, if the new value is outside the valid range of values for the field then a
DateTimeException
will be thrown.All other
ChronoField
instances will throw aDateTimeException
.If the field is not a
ChronoField
, then the result of this method is obtained by invokingTemporalField.adjustInto(Temporal, long)
passingthis
as the argument. In this case, the field determines whether and how to adjust the instant.This instance is immutable and unaffected by this method call.
- Specified by:
with
in interfaceTemporal
- Parameters:
field
- the field to set in the result, not nullnewValue
- the new value of the field in the result- Returns:
- an
Instant
based onthis
with the specified field set, not null - Throws:
DateTimeException
- if the field cannot be setjava.lang.ArithmeticException
- if numeric overflow occurs
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truncatedTo
public Instant truncatedTo(TemporalUnit unit)
Returns a copy of thisInstant
truncated to the specified unit.Truncating the instant returns a copy of the original with fields smaller than the specified unit set to zero. The fields are calculated on the basis of using a UTC offset as seen in
toString
. For example, truncating with theMINUTES
unit will round down to the nearest minute, setting the seconds and nanoseconds to zero.The unit must have a duration that divides into the length of a standard day without remainder. This includes all supplied time units on
ChronoUnit
andDAYS
. Other units throw an exception.This instance is immutable and unaffected by this method call.
- Parameters:
unit
- the unit to truncate to, not null- Returns:
- an
Instant
based on this instant with the time truncated, not null - Throws:
DateTimeException
- if the unit is invalid for truncation
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plus
public Instant plus(TemporalAmount amount)
Returns an object of the same type as this object with an amount added.This adjusts this temporal, adding according to the rules of the specified amount. The amount is typically a
Period
but may be any other type implementing theTemporalAmount
interface, such asDuration
.Some example code indicating how and why this method is used:
date = date.plus(period); // add a Period instance date = date.plus(duration); // add a Duration instance date = date.plus(workingDays(6)); // example user-written workingDays method
Note that calling
plus
followed byminus
is not guaranteed to return the same date-time.Specification for implementors
Implementations must not alter either this object. Instead, an adjusted copy of the original must be returned. This provides equivalent, safe behavior for immutable and mutable implementations.- Specified by:
plus
in interfaceTemporal
- Parameters:
amount
- the amount to add, not null- Returns:
- an object of the same type with the specified adjustment made, not null
- Throws:
DateTimeException
- if the addition cannot be madejava.lang.ArithmeticException
- if numeric overflow occurs
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plus
public Instant plus(long amountToAdd, TemporalUnit unit)
Returns an object of the same type as this object with the specified period added.This method returns a new object based on this one with the specified period added. For example, on a
LocalDate
, this could be used to add a number of years, months or days. The returned object will have the same observable type as this object.In some cases, changing a field is not fully defined. For example, if the target object is a date representing the 31st January, then adding one month would be unclear. In cases like this, the field is responsible for resolving the result. Typically it will choose the previous valid date, which would be the last valid day of February in this example.
If the implementation represents a date-time that has boundaries, such as
LocalTime
, then the permitted units must include the boundary unit, but no multiples of the boundary unit. For example,LocalTime
must acceptDAYS
but notWEEKS
orMONTHS
.Specification for implementors
Implementations must check and handle all units defined inChronoUnit
. If the unit is supported, then the addition must be performed. If unsupported, then aDateTimeException
must be thrown.If the unit is not a
ChronoUnit
, then the result of this method is obtained by invokingTemporalUnit.addTo(Temporal, long)
passingthis
as the first argument.Implementations must not alter either this object or 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:
plus
in interfaceTemporal
- Parameters:
amountToAdd
- the amount of the specified unit to add, may be negativeunit
- the unit of the period to add, not null- Returns:
- an object of the same type with the specified period added, not null
- Throws:
DateTimeException
- if the unit cannot be addedjava.lang.ArithmeticException
- if numeric overflow occurs
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plusSeconds
public Instant plusSeconds(long secondsToAdd)
Returns a copy of this instant with the specified duration in seconds added.This instance is immutable and unaffected by this method call.
- Parameters:
secondsToAdd
- the seconds to add, positive or negative- Returns:
- an
Instant
based on this instant with the specified seconds added, not null - Throws:
DateTimeException
- if the result exceeds the maximum or minimum instantjava.lang.ArithmeticException
- if numeric overflow occurs
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plusMillis
public Instant plusMillis(long millisToAdd)
Returns a copy of this instant with the specified duration in milliseconds added.This instance is immutable and unaffected by this method call.
- Parameters:
millisToAdd
- the milliseconds to add, positive or negative- Returns:
- an
Instant
based on this instant with the specified milliseconds added, not null - Throws:
DateTimeException
- if the result exceeds the maximum or minimum instantjava.lang.ArithmeticException
- if numeric overflow occurs
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plusNanos
public Instant plusNanos(long nanosToAdd)
Returns a copy of this instant with the specified duration in nanoseconds added.This instance is immutable and unaffected by this method call.
- Parameters:
nanosToAdd
- the nanoseconds to add, positive or negative- Returns:
- an
Instant
based on this instant with the specified nanoseconds added, not null - Throws:
DateTimeException
- if the result exceeds the maximum or minimum instantjava.lang.ArithmeticException
- if numeric overflow occurs
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minus
public Instant minus(TemporalAmount amount)
Returns an object of the same type as this object with an amount subtracted.This adjusts this temporal, subtracting according to the rules of the specified amount. The amount is typically a
Period
but may be any other type implementing theTemporalAmount
interface, such asDuration
.Some example code indicating how and why this method is used:
date = date.minus(period); // subtract a Period instance date = date.minus(duration); // subtract a Duration instance date = date.minus(workingDays(6)); // example user-written workingDays method
Note that calling
plus
followed byminus
is not guaranteed to return the same date-time.Specification for implementors
Implementations must not alter either this object. Instead, an adjusted copy of the original must be returned. This provides equivalent, safe behavior for immutable and mutable implementations.- Specified by:
minus
in interfaceTemporal
- Parameters:
amount
- the amount to subtract, not null- Returns:
- an object of the same type with the specified adjustment made, not null
- Throws:
DateTimeException
- if the subtraction cannot be madejava.lang.ArithmeticException
- if numeric overflow occurs
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minus
public Instant minus(long amountToSubtract, TemporalUnit unit)
Returns an object of the same type as this object with the specified period subtracted.This method returns a new object based on this one with the specified period subtracted. For example, on a
LocalDate
, this could be used to subtract a number of years, months or days. The returned object will have the same observable type as this object.In some cases, changing a field is not fully defined. For example, if the target object is a date representing the 31st March, then subtracting one month would be unclear. In cases like this, the field is responsible for resolving the result. Typically it will choose the previous valid date, which would be the last valid day of February in this example.
If the implementation represents a date-time that has boundaries, such as
LocalTime
, then the permitted units must include the boundary unit, but no multiples of the boundary unit. For example,LocalTime
must acceptDAYS
but notWEEKS
orMONTHS
.Specification for implementors
Implementations must behave in a manor equivalent to the default method behavior.Implementations must not alter either this object or 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:
minus
in interfaceTemporal
- Parameters:
amountToSubtract
- the amount of the specified unit to subtract, may be negativeunit
- the unit of the period to subtract, not null- Returns:
- an object of the same type with the specified period subtracted, not null
- Throws:
DateTimeException
- if the unit cannot be subtractedjava.lang.ArithmeticException
- if numeric overflow occurs
-
minusSeconds
public Instant minusSeconds(long secondsToSubtract)
Returns a copy of this instant with the specified duration in seconds subtracted.This instance is immutable and unaffected by this method call.
- Parameters:
secondsToSubtract
- the seconds to subtract, positive or negative- Returns:
- an
Instant
based on this instant with the specified seconds subtracted, not null - Throws:
DateTimeException
- if the result exceeds the maximum or minimum instantjava.lang.ArithmeticException
- if numeric overflow occurs
-
minusMillis
public Instant minusMillis(long millisToSubtract)
Returns a copy of this instant with the specified duration in milliseconds subtracted.This instance is immutable and unaffected by this method call.
- Parameters:
millisToSubtract
- the milliseconds to subtract, positive or negative- Returns:
- an
Instant
based on this instant with the specified milliseconds subtracted, not null - Throws:
DateTimeException
- if the result exceeds the maximum or minimum instantjava.lang.ArithmeticException
- if numeric overflow occurs
-
minusNanos
public Instant minusNanos(long nanosToSubtract)
Returns a copy of this instant with the specified duration in nanoseconds subtracted.This instance is immutable and unaffected by this method call.
- Parameters:
nanosToSubtract
- the nanoseconds to subtract, positive or negative- Returns:
- an
Instant
based on this instant with the specified nanoseconds subtracted, not null - Throws:
DateTimeException
- if the result exceeds the maximum or minimum instantjava.lang.ArithmeticException
- if numeric overflow occurs
-
query
public <R> R query(TemporalQuery<R> query)
Queries this instant using the specified query.This queries this instant using the specified query strategy object. The
TemporalQuery
object defines the logic to be used to obtain the result. Read the documentation of the query to understand what the result of this method will be.The result of this method is obtained by invoking the
TemporalQuery.queryFrom(TemporalAccessor)
method on the specified query passingthis
as the argument.- Specified by:
query
in interfaceTemporalAccessor
- Overrides:
query
in classDefaultInterfaceTemporalAccessor
- Type Parameters:
R
- the type of the result- Parameters:
query
- the query to invoke, not null- Returns:
- the query result, null may be returned (defined by the query)
- Throws:
DateTimeException
- if unable to query (defined by the query)java.lang.ArithmeticException
- if numeric overflow occurs (defined by the query)
-
adjustInto
public Temporal adjustInto(Temporal temporal)
Adjusts the specified temporal object to have this instant.This returns a temporal object of the same observable type as the input with the instant changed to be the same as this.
The adjustment is equivalent to using
Temporal.with(TemporalField, long)
twice, passingChronoField.INSTANT_SECONDS
andChronoField.NANO_OF_SECOND
as the fields.In most cases, it is clearer to reverse the calling pattern by using
Temporal.with(TemporalAdjuster)
:// these two lines are equivalent, but the second approach is recommended temporal = thisInstant.adjustInto(temporal); temporal = temporal.with(thisInstant);
This instance is immutable and unaffected by this method call.
- Specified by:
adjustInto
in interfaceTemporalAdjuster
- Parameters:
temporal
- the target object to be adjusted, not null- Returns:
- the adjusted object, not null
- Throws:
DateTimeException
- if unable to make the adjustmentjava.lang.ArithmeticException
- if numeric overflow occurs
-
until
public long until(Temporal endExclusive, TemporalUnit unit)
Calculates the period between this instant and another instant in terms of the specified unit.This calculates the period between two instants in terms of a single unit. The start and end points are
this
and the specified instant. The result will be negative if the end is before the start. The calculation returns a whole number, representing the number of complete units between the two instants. TheTemporal
passed to this method is converted to aInstant
usingfrom(TemporalAccessor)
. For example, the period in days between two dates can be calculated usingstartInstant.until(endInstant, SECONDS)
.This method operates in association with
TemporalUnit.between(org.threeten.bp.temporal.Temporal, org.threeten.bp.temporal.Temporal)
. The result of this method is along
representing the amount of the specified unit. By contrast, the result ofbetween
is an object that can be used directly in addition/subtraction:long period = start.until(end, SECONDS); // this method dateTime.plus(SECONDS.between(start, end)); // use in plus/minus
The calculation is implemented in this method for
ChronoUnit
. The unitsNANOS
,MICROS
,MILLIS
,SECONDS
,MINUTES
,HOURS
,HALF_DAYS
andDAYS
are supported. OtherChronoUnit
values will throw an exception.If the unit is not a
ChronoUnit
, then the result of this method is obtained by invokingTemporalUnit.between(Temporal, Temporal)
passingthis
as the first argument and the input temporal as the second argument.This instance is immutable and unaffected by this method call.
- Specified by:
until
in interfaceTemporal
- Parameters:
endExclusive
- the end date, which is converted to anInstant
, not nullunit
- the unit to measure the period in, not null- Returns:
- the amount of the period between this date and the end date
- Throws:
DateTimeException
- if the period cannot be calculatedjava.lang.ArithmeticException
- if numeric overflow occurs
-
atOffset
public OffsetDateTime atOffset(ZoneOffset offset)
Combines this instant with an offset to create anOffsetDateTime
.This returns an
OffsetDateTime
formed from this instant at the specified offset from UTC/Greenwich. An exception will be thrown if the instant is too large to fit into an offset date-time.This method is equivalent to
OffsetDateTime.ofInstant(this, offset)
.- Parameters:
offset
- the offset to combine with, not null- Returns:
- the offset date-time formed from this instant and the specified offset, not null
- Throws:
DateTimeException
- if the result exceeds the supported range
-
atZone
public ZonedDateTime atZone(ZoneId zone)
Combines this instant with a time-zone to create aZonedDateTime
.This returns an
ZonedDateTime
formed from this instant at the specified time-zone. An exception will be thrown if the instant is too large to fit into a zoned date-time.This method is equivalent to
ZonedDateTime.ofInstant(this, zone)
.- Parameters:
zone
- the zone to combine with, not null- Returns:
- the zoned date-time formed from this instant and the specified zone, not null
- Throws:
DateTimeException
- if the result exceeds the supported range
-
toEpochMilli
public long toEpochMilli()
Converts this instant to the number of milliseconds from the epoch of 1970-01-01T00:00:00Z.If this instant represents a point on the time-line too far in the future or past to fit in a
long
milliseconds, then an exception is thrown.If this instant has greater than millisecond precision, then the conversion will drop any excess precision information as though the amount in nanoseconds was subject to integer division by one million.
- Returns:
- the number of milliseconds since the epoch of 1970-01-01T00:00:00Z
- Throws:
java.lang.ArithmeticException
- if numeric overflow occurs
-
compareTo
public int compareTo(Instant otherInstant)
Compares this instant to the specified instant.The comparison is based on the time-line position of the instants. It is "consistent with equals", as defined by
Comparable
.- Specified by:
compareTo
in interfacejava.lang.Comparable<Instant>
- Parameters:
otherInstant
- the other instant to compare to, not null- Returns:
- the comparator value, negative if less, positive if greater
- Throws:
java.lang.NullPointerException
- if otherInstant is null
-
isAfter
public boolean isAfter(Instant otherInstant)
Checks if this instant is after the specified instant.The comparison is based on the time-line position of the instants.
- Parameters:
otherInstant
- the other instant to compare to, not null- Returns:
- true if this instant is after the specified instant
- Throws:
java.lang.NullPointerException
- if otherInstant is null
-
isBefore
public boolean isBefore(Instant otherInstant)
Checks if this instant is before the specified instant.The comparison is based on the time-line position of the instants.
- Parameters:
otherInstant
- the other instant to compare to, not null- Returns:
- true if this instant is before the specified instant
- Throws:
java.lang.NullPointerException
- if otherInstant is null
-
equals
public boolean equals(java.lang.Object otherInstant)
Checks if this instant is equal to the specified instant.The comparison is based on the time-line position of the instants.
- Overrides:
equals
in classjava.lang.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 classjava.lang.Object
- Returns:
- a suitable hash code
-
toString
public java.lang.String toString()
A string representation of this instant using ISO-8601 representation.The format used is the same as
DateTimeFormatter.ISO_INSTANT
.- Overrides:
toString
in classjava.lang.Object
- Returns:
- an ISO-8601 representation of this instant, not null
-
-