Package org.apache.druid.segment.join
Interface JoinableFactory
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- All Known Implementing Classes:
FrameBasedInlineJoinableFactory
,InlineJoinableFactory
,MapJoinableFactory
,NoopJoinableFactory
public interface JoinableFactory
Utility for creatingJoinable
objects.- See Also:
to register factories
,to register factory types with datasource types
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Method Summary
All Methods Instance Methods Abstract Methods Default Methods Modifier and Type Method Description Optional<Joinable>
build(DataSource dataSource, JoinConditionAnalysis condition)
Create a Joinable object.default Optional<byte[]>
computeJoinCacheKey(DataSource dataSource, JoinConditionAnalysis condition)
Compute the cache key for a data source participating in join operation.boolean
isDirectlyJoinable(DataSource dataSource)
Returns true if aJoinable
**may** be created for a givenDataSource
, but is not a guarantee thatbuild(org.apache.druid.query.DataSource, org.apache.druid.segment.join.JoinConditionAnalysis)
will return a non-empty result.
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Method Detail
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isDirectlyJoinable
boolean isDirectlyJoinable(DataSource dataSource)
Returns true if aJoinable
**may** be created for a givenDataSource
, but is not a guarantee thatbuild(org.apache.druid.query.DataSource, org.apache.druid.segment.join.JoinConditionAnalysis)
will return a non-empty result. Successfully building aJoinable
might require specific criteria of theJoinConditionAnalysis
.
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build
Optional<Joinable> build(DataSource dataSource, JoinConditionAnalysis condition)
Create a Joinable object. This may be an expensive operation involving loading data, creating a hash table, etc.- Parameters:
dataSource
- the datasource to join oncondition
- the condition to join on- Returns:
- a Joinable if this datasource + condition combo is joinable; empty if not
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computeJoinCacheKey
default Optional<byte[]> computeJoinCacheKey(DataSource dataSource, JoinConditionAnalysis condition)
Compute the cache key for a data source participating in join operation. This is done separately from {build(DataSource, JoinConditionAnalysis)
} which can be an expensive operation and can potentially be avoided if cached results can be used.- Parameters:
dataSource
- the datasource to join oncondition
- the condition to join on
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