io.druid.query.lookup

Interface LookupExtractorFactory

All Superinterfaces:

com.google.common.base.Supplier<LookupExtractor>

All Known Implementing Classes:

KafkaLookupExtractorFactory, LoadingLookupFactory, MapLookupExtractorFactory, NamespaceLookupExtractorFactory, PollingLookupFactory

public interface LookupExtractorFactory
extends com.google.common.base.Supplier<LookupExtractor>

Users of Lookup Extraction need to implement a LookupExtractorFactory supplier of type LookupExtractor. Such factory will manage the state and life cycle of an given lookup. If a LookupExtractorFactory wishes to support idempotent updates, it needs to implement the `replaces` method

Method Summary

Modifier and Type	Method and Description
boolean	close() This method will be called to stop the LookupExtractor upon deletion.
LookupIntrospectHandler	getIntrospectHandler()
boolean	replaces(LookupExtractorFactory other) Determine if this LookupExtractorFactory should replace some other LookupExtractorFactory.
boolean	start() This method will be called to start the LookupExtractor upon registered Calling start multiple times should return true if successfully started.

Methods inherited from interface com.google.common.base.Supplier

get

Method Detail

start

boolean start()

This method will be called to start the LookupExtractor upon registered Calling start multiple times should return true if successfully started.

Returns:

Returns false if is not successfully started the LookupExtractor otherwise returns true.

close

boolean close()

This method will be called to stop the LookupExtractor upon deletion. Calling this method multiple times should always return true if successfully closed.

Returns:

Returns false if not successfully closed the LookupExtractor otherwise returns true

replaces

boolean replaces(@Nullable
                 LookupExtractorFactory other)

Determine if this LookupExtractorFactory should replace some other LookupExtractorFactory. This is used to implement no-down-time

Parameters:

other - Some other LookupExtractorFactory which might need replaced

Returns:

`true` if the other should be replaced by this one. `false` if this one should not replace the other factory

getIntrospectHandler

@Nullable
LookupIntrospectHandler getIntrospectHandler()

Returns:

Returns the actual introspection request handler, can return null if it is not supported. This will be called once per HTTP request to introspect the actual lookup.