org.apache.druid.client.cache

Interface CachePopulator

All Known Implementing Classes:

BackgroundCachePopulator, ForegroundCachePopulator

public interface CachePopulator

Abstraction of mechanism for populating a Cache by wrapping a Sequence and providing a function to extract the values from it. At runtime, the CachePopulator implementation is used as a singleton and injected where needed to share between all cacheables, which requires the Cache itself to be thread-safe. Consumers of the Sequence will either be a processing thread (in the case of a historical or task), or an http thread in the case of a broker. See: historicals: ServerManager and CachingQueryRunner realtime tasks: SinkQuerySegmentWalker and CachingQueryRunner brokers: ClientQuerySegmentWalker and CachingClusteredClient for additional details

Method Summary

Modifier and Type	Method and Description
<T,CacheType> Sequence<T>	wrap(Sequence<T> sequence, Function<T,CacheType> cacheFn, Cache cache, Cache.NamedKey cacheKey)

Method Detail

wrap

<T,CacheType> Sequence<T> wrap(Sequence<T> sequence,
                               Function<T,CacheType> cacheFn,
                               Cache cache,
                               Cache.NamedKey cacheKey)