public interface Temporal extends TemporalAccessor
This is the base interface type for date, time and offset objects that
are complete enough to be manipulated using plus and minus.
It is implemented by those classes that can provide and manipulate information
as fields or queries.
See TemporalAccessor
for the read-only version of this interface.
Most date and time information can be represented as a number.
These are modeled using TemporalField
with the number held using
a long
to handle large values. Year, month and day-of-month are
simple examples of fields, but they also include instant and offsets.
See ChronoField
for the standard set of fields.
Two pieces of date/time information cannot be represented by numbers,
the chronology and the time-zone.
These can be accessed via queries
using
the static methods defined on Queries
.
This interface is a framework-level interface that should not be widely
used in application code. Instead, applications should create and pass
around instances of concrete types, such as LocalDate
.
There are many reasons for this, part of which is that implementations
of this interface may be in calendar systems other than ISO.
See ChronoLocalDate
for a fuller discussion of the issues.
A class should implement this interface if it meets three criteria:
TemporalAccessor
Four examples make this clear:
LocalDate
implements this interface as it represents a set of fields
that are contiguous from days to forever and require no external information to determine
the validity of each date. It is therefore able to implement plus/minus correctly.
LocalTime
implements this interface as it represents a set of fields
that are contiguous from nanos to within days and require no external information to determine
validity. It is able to implement plus/minus correctly, by wrapping around the day.
MonthDay
, the combination of month-of-year and day-of-month, does not implement
this interface. While the combination is contiguous, from days to months within years,
the combination does not have sufficient information to define the valid range of values
for day-of-month. As such, it is unable to implement plus/minus correctly.
Comparable
.Modifier and Type | Method and Description |
---|---|
default Temporal |
minus(long amountToSubtract,
TemporalUnit unit)
Returns an object of the same type as this object with the specified period subtracted.
|
default Temporal |
minus(TemporalSubtractor subtractor)
Returns an object of the same type as this object with an amount subtracted.
|
long |
periodUntil(Temporal endTemporal,
TemporalUnit unit)
Calculates the period between this temporal and another temporal in
terms of the specified unit.
|
Temporal |
plus(long amountToAdd,
TemporalUnit unit)
Returns an object of the same type as this object with the specified period added.
|
default Temporal |
plus(TemporalAdder adder)
Returns an object of the same type as this object with an amount added.
|
default Temporal |
with(TemporalAdjuster adjuster)
Returns an adjusted object of the same type as this object with the adjustment made.
|
Temporal |
with(TemporalField field,
long newValue)
Returns an object of the same type as this object with the specified field altered.
|
get, getLong, isSupported, query, range
default Temporal with(TemporalAdjuster adjuster)
This adjusts this date-time according to the rules of the specified adjuster.
A simple adjuster might simply set the one of the fields, such as the year field.
A more complex adjuster might set the date to the last day of the month.
A selection of common adjustments is provided in Adjusters
.
These include finding the "last day of the month" and "next Wednesday".
The adjuster is responsible for handling special cases, such as the varying
lengths of month and leap years.
Some example code indicating how and why this method is used:
date = date.with(Month.JULY); // most key classes implement TemporalAdjuster date = date.with(lastDayOfMonth()); // static import from Adjusters date = date.with(next(WEDNESDAY)); // static import from Adjusters and DayOfWeek
The default implementation must behave equivalent to this code:
return adjuster.adjustInto(this);
adjuster
- the adjuster to use, not nullDateTimeException
- if unable to make the adjustmentjava.lang.ArithmeticException
- if numeric overflow occursTemporal with(TemporalField field, long newValue)
This returns a new object based on this one with the value for the specified field changed.
For example, on a LocalDate
, this could be used to set the year, month or day-of-month.
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 changing the month to February 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.
ChronoField
.
If the field is supported, then the adjustment must be performed.
If unsupported, then a DateTimeException
must be thrown.
If the field is not a ChronoField
, then the result of this method
is obtained by invoking TemporalField.doWith(Temporal, long)
passing this
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.
field
- the field to set in the result, not nullnewValue
- the new value of the field in the resultDateTimeException
- if the field cannot be setjava.lang.ArithmeticException
- if numeric overflow occursdefault Temporal plus(TemporalAdder adder)
This adjusts this temporal, adding according to the rules of the specified adder.
The adder is typically a Period
but may be any other type implementing
the TemporalAdder
interface, such as Duration
.
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(MONTHS.between(start, end)); // static import of MONTHS field date = date.plus(workingDays(6)); // example user-written workingDays method
Note that calling plus
followed by minus
is not guaranteed to
return the same date-time.
The default implementation must behave equivalent to this code:
return adder.addTo(this);
adder
- the adder to use, not nullDateTimeException
- if the addition cannot be madejava.lang.ArithmeticException
- if numeric overflow occursTemporal plus(long amountToAdd, TemporalUnit unit)
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 accept DAYS
but not WEEKS
or MONTHS
.
ChronoUnit
.
If the unit is supported, then the addition must be performed.
If unsupported, then a DateTimeException
must be thrown.
If the unit is not a ChronoUnit
, then the result of this method
is obtained by invoking TemporalUnit.doPlus(Temporal, long)
passing this
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.
amountToAdd
- the amount of the specified unit to add, may be negativeunit
- the unit of the period to add, not nullDateTimeException
- if the unit cannot be addedjava.lang.ArithmeticException
- if numeric overflow occursdefault Temporal minus(TemporalSubtractor subtractor)
This adjusts this temporal, subtracting according to the rules of the specified subtractor.
The subtractor is typically a Period
but may be any other type implementing
the TemporalSubtractor
interface, such as Duration
.
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(MONTHS.between(start, end)); // static import of MONTHS field date = date.minus(workingDays(6)); // example user-written workingDays method
Note that calling plus
followed by minus
is not guaranteed to
return the same date-time.
The default implementation must behave equivalent to this code:
return subtractor.subtractFrom(this);
subtractor
- the subtractor to use, not nullDateTimeException
- if the subtraction cannot be madejava.lang.ArithmeticException
- if numeric overflow occursdefault Temporal minus(long amountToSubtract, TemporalUnit unit)
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 accept DAYS
but not WEEKS
or MONTHS
.
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.
The default implementation must behave equivalent to this code:
return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit));
amountToSubtract
- the amount of the specified unit to subtract, may be negativeunit
- the unit of the period to subtract, not nullDateTimeException
- if the unit cannot be subtractedjava.lang.ArithmeticException
- if numeric overflow occurslong periodUntil(Temporal endTemporal, TemporalUnit unit)
This calculates the period between two temporals in terms of a single unit.
The start and end points are this
and the specified temporal.
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 startTime.periodUntil(endTime, HOURS)
.
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 be one hour as it is one minute short of two hours.
This method operates in association with TemporalUnit.between(R, R)
.
The result of this method is a long
representing the amount of
the specified unit. By contrast, the result of between
is an
object that can be used directly in addition/subtraction:
long period = start.periodUntil(end, HOURS); // this method dateTime.plus(HOURS.between(start, end)); // use in plus/minus
ChronoUnit
.
A DateTimeException
must be thrown for ChronoUnit
instances that are unsupported.
If the unit is not a ChronoUnit
, then the result of this method
is obtained by invoking TemporalUnit.between(Temporal, Temporal)
passing this
as the first argument and the input temporal as
the second argument.
In summary, implementations must behave in a manner equivalent to this code:
// check input temporal is the same type as this class if (unit instanceof ChronoUnit) { // if unit is supported, then calculate and return result // else throw DateTimeException for unsupported units } return unit.between(this, endTime).getAmount();
The target object must not be altered by this method.
endTemporal
- the end temporal, of the same type as this object, not nullunit
- the unit to measure the period in, not nullDateTimeException
- if the period cannot be calculatedjava.lang.ArithmeticException
- if numeric overflow occurs