A query for the Chronology
.
A query for the Chronology
.
This queries a TemporalAccessor
for the chronology.
If the target TemporalAccessor
represents a date, or part of a date,
then it should return the chronology that the date is expressed in.
As a result of this definition, objects only representing time, such as
LocalTime
, will return null.
The result from JDK classes implementing TemporalAccessor
is as follows:
LocalDate
returns IsoChronology.INSTANCE
LocalTime
returns null (does not represent a date)
LocalDateTime
returns IsoChronology.INSTANCE
ZonedDateTime
returns IsoChronology.INSTANCE
OffsetTime
returns null (does not represent a date)
OffsetDateTime
returns IsoChronology.INSTANCE
ChronoLocalDate
returns the associated chronology
ChronoLocalDateTime
returns the associated chronology
ChronoZonedDateTime
returns the associated chronology
Era
returns the associated chronology
DayOfWeek
returns null (shared across chronologies)
Month
returns IsoChronology.INSTANCE
Year
returns IsoChronology.INSTANCE
YearMonth
returns IsoChronology.INSTANCE
MonthDay
returns null IsoChronology.INSTANCE
ZoneOffset
returns null (does not represent a date)
Instant
returns null (does not represent a date)
The method Chronology#from(TemporalAccessor)
can be used as a
TemporalQuery
via a method reference, Chrono::from
.
That method is equivalent to this query, except that it throws an
exception if a chronology cannot be obtained.
a query that can obtain the chronology of a temporal, not null
A query for LocalDate
returning null if not found.
A query for LocalDate
returning null if not found.
This returns a TemporalQuery
that can be used to query a temporal
object for the local date. The query will return null if the temporal
object cannot supply a local date.
The query implementation examines the EPOCH_DAY
field and uses it to create a LocalDate
.
a query that can obtain the date of a temporal, not null
A query for LocalTime
returning null if not found.
A query for LocalTime
returning null if not found.
This returns a TemporalQuery
that can be used to query a temporal
object for the local time. The query will return null if the temporal
object cannot supply a local time.
The query implementation examines the NANO_OF_DAY
field and uses it to create a LocalTime
.
a query that can obtain the date of a temporal, not null
A query for ZoneOffset
returning null if not found.
A query for ZoneOffset
returning null if not found.
This returns a TemporalQuery
that can be used to query a temporal
object for the offset. The query will return null if the temporal
object cannot supply an offset.
The query implementation examines the OFFSET_SECONDS
field and uses it to create a ZoneOffset
.
a query that can obtain the offset of a temporal, not null
A query for the smallest supported unit.
A query for the smallest supported unit.
This queries a TemporalAccessor
for the time precision.
If the target TemporalAccessor
represents a consistent or complete date-time,
date or time then this must return the smallest precision actually supported.
Note that fields such as NANO_OF_DAY
and NANO_OF_SECOND
are defined to always return ignoring the precision, thus this is the only
way to find the actual smallest supported unit.
For example, were GregorianCalendar
to implement TemporalAccessor
it would return a precision of MILLIS
.
The result from JDK classes implementing TemporalAccessor
is as follows:
LocalDate
returns DAYS
LocalTime
returns NANOS
LocalDateTime
returns NANOS
ZonedDateTime
returns NANOS
OffsetTime
returns NANOS
OffsetDateTime
returns NANOS
ChronoLocalDate
returns DAYS
ChronoLocalDateTime
returns NANOS
ChronoZonedDateTime
returns NANOS
Era
returns ERAS
DayOfWeek
returns DAYS
Month
returns MONTHS
Year
returns YEARS
YearMonth
returns MONTHS
MonthDay
returns null (does not represent a complete date or time)
ZoneOffset
returns null (does not represent a date or time)
Instant
returns NANOS
a query that can obtain the precision of a temporal, not null
A lenient query for the ZoneId
, falling back to the ZoneOffset
.
A lenient query for the ZoneId
, falling back to the ZoneOffset
.
This queries a TemporalAccessor
for the zone.
It first tries to obtain the zone, using #zoneId()
.
If that is not found it tries to obtain the #offset()
.
In most cases, applications should use this query rather than #zoneId()
.
This query examines the offset-seconds
field and uses it to create a ZoneOffset
.
The method ZoneId#from(TemporalAccessor)
can be used as a
TemporalQuery
via a method reference, ZoneId::from
.
That method is equivalent to this query, except that it throws an
exception if a zone cannot be obtained.
a query that can obtain the zone ID or offset of a temporal, not null
A strict query for the ZoneId
.
A strict query for the ZoneId
.
This queries a TemporalAccessor
for the zone.
The zone is only returned if the date-time conceptually contains a ZoneId
.
It will not be returned if the date-time only conceptually has an ZoneOffset
.
Thus a ZonedDateTime
will return the result of
getZone()
, but an OffsetDateTime
will
return null.
In most cases, applications should use #ZONE
as this query is too strict.
The result from JDK classes implementing TemporalAccessor
is as follows:
LocalDate
returns null
LocalTime
returns null
LocalDateTime
returns null
ZonedDateTime
returns the associated zone
OffsetTime
returns null
OffsetDateTime
returns null
ChronoLocalDate
returns null
ChronoLocalDateTime
returns null
ChronoZonedDateTime
returns the associated zone
Era
returns null
DayOfWeek
returns null
Month
returns null
Year
returns null
YearMonth
returns null
MonthDay
returns null
ZoneOffset
returns null
Instant
returns null
a query that can obtain the zone ID of a temporal, not null
Common implementations of
TemporalQuery
.This class provides common implementations of
TemporalQuery
. These queries are primarily used as optimizations, allowing the internals of other objects to be extracted effectively. Note that application code can also use thefrom(TemporalAccessor)
method on most temporal objects as a method reference matching the query interface, such asLocalDate::from
andZoneId::from
.There are two equivalent ways of using a
It is recommended to use the second approach,TemporalQuery
. The first is to invoke the method on the interface directly. The second is to useTemporalAccessor#query(TemporalQuery)
:query(TemporalQuery)
, as it is a lot clearer to read in code.Specification for implementors
This is a thread-safe utility class. All returned adjusters are immutable and thread-safe.