Package com.apple.foundationdb.record.query

Interface IndexQueryabilityFilter

All Superinterfaces:

QueryHashable

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@API(EXPERIMENTAL)
@FunctionalInterface
public interface IndexQueryabilityFilter
extends QueryHashable

A filter used to determine whether an index should be considered when planning queries.

Nested Class Summary

Nested classes/interfaces inherited from interface com.apple.foundationdb.record.QueryHashable

QueryHashable.QueryHashKind

Field Summary

Fields

Modifier and Type	Field	Description
static IndexQueryabilityFilter	DEFAULT	The default index queryability filter which uses all indexes except those with the IndexOptions.ALLOWED_FOR_QUERY_OPTION set to false.

Method Summary

Modifier and Type	Method	Description
boolean	isQueryable(Index index)	Return whether the given index should be considered by the query planner.
default int	queryHash(QueryHashable.QueryHashKind hashKind)	Default implementation of QueryHashable.queryHash(com.apple.foundationdb.record.QueryHashable.QueryHashKind).

Field Detail

DEFAULT

static final IndexQueryabilityFilter DEFAULT

The default index queryability filter which uses all indexes except those with the IndexOptions.ALLOWED_FOR_QUERY_OPTION set to false.

Method Detail

isQueryable

boolean isQueryable(@Nonnull
                    Index index)

Return whether the given index should be considered by the query planner. Note that the planner is not required to use an index for which isQueryable() is true.

Parameters:

index - an index

Returns:

whether the given index should be considered by the planner

queryHash

default int queryHash(@Nonnull
                      QueryHashable.QueryHashKind hashKind)

Default implementation of QueryHashable.queryHash(com.apple.foundationdb.record.QueryHashable.QueryHashKind). This implementation returns '0' so unless the specific concrete implementation of IndexQueryabilityFilter overrides it, there will be no impact on the total hashcode for the query.

Note: This should be overridden in specific implementations in order to be able to distinguish among various queries that differ only by their IndexQueryabilityFilter.

Specified by:

queryHash in interface QueryHashable

Parameters:

hashKind - the "kind" of hash to calculate. Ignored for this implementation.

Returns:

0 as the calculated hash in all cases, to have no impact on query hashes.