public interface Query
Feature
instances.Predicate<Feature>
while the second domain is equivalent to using
UnaryOperator<Feature>
.
It is technically possible to use Query
for performing more generic feature transformations,
for example inserting new properties computed from other properties, but such Query
usages
should be rare since transformations (or more generic processing) are the topic of another package.
Queries are rather descriptive objects used by FeatureSet
to optimize search operations
as much as possible on the resource, using for example caches and indexes.
Compared to the SQL language, Query
contains the information in the SELECT
and
WHERE
clauses of a SQL statement. A Query
typically contains filtering capabilities
and (sometime) simple attribute transformations. Well known query languages include SQL and CQL.
Defined in the sis-storage
module
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