org.apache.lucene.search

Interface QueryCachingPolicy

All Known Implementing Classes:

QueryCachingPolicy.CacheOnLargeSegments, UsageTrackingQueryCachingPolicy

public interface QueryCachingPolicy

A policy defining which filters should be cached. Implementations of this class must be thread-safe.

See Also:

UsageTrackingQueryCachingPolicy, LRUQueryCache

WARNING: This API is experimental and might change in incompatible ways in the next release.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	QueryCachingPolicy.CacheOnLargeSegments A simple policy that only caches on the largest segments of an index.

Field Summary

Fields

Modifier and Type	Field and Description
static QueryCachingPolicy	ALWAYS_CACHE A simple policy that caches all the provided filters on all segments.

Method Summary

Methods

Modifier and Type	Method and Description
void	onUse(Query query) Callback that is called every time that a cached filter is used.
boolean	shouldCache(Query query, LeafReaderContext context) Whether the given DocIdSet should be cached on a given segment.

Field Detail

ALWAYS_CACHE

static final QueryCachingPolicy ALWAYS_CACHE

A simple policy that caches all the provided filters on all segments.

Method Detail

onUse

void onUse(Query query)

Callback that is called every time that a cached filter is used. This is typically useful if the policy wants to track usage statistics in order to make decisions.

shouldCache

boolean shouldCache(Query query,
                  LeafReaderContext context)
                    throws IOException

Whether the given DocIdSet should be cached on a given segment. This method will be called on each leaf context to know if the filter should be cached on this particular leaf. The filter cache will first attempt to load a DocIdSet from the cache. If it is not cached yet and this method returns true then a cache entry will be generated. Otherwise an uncached set will be returned.

Throws:

IOException