TemporalQueries
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package temporal
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::fromandZoneId::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.
query.queryFrom(dateTime); dateTime = dateTime.query(query); second approach,
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.