org.apache.lucene.facet.sampling

Class SamplingAccumulator

java.lang.Object

org.apache.lucene.facet.search.FacetsAccumulator

org.apache.lucene.facet.search.TaxonomyFacetsAccumulator

org.apache.lucene.facet.old.OldFacetsAccumulator

org.apache.lucene.facet.sampling.SamplingAccumulator

public class SamplingAccumulator
extends OldFacetsAccumulator

Facets accumulation with sampling.

Note two major differences between this class and SamplingWrapper:

1. Latter can wrap any other FacetsAccumulator while this class directly extends OldFacetsAccumulator.
2. This class can effectively apply sampling on the complement set of matching document, thereby working efficiently with the complement optimization - see OldFacetsAccumulator.getComplementThreshold() .

Note: Sampling accumulation (Accumulation over a sampled-set of the results), does not guarantee accurate values for FacetResult.getNumValidDescendants().

See Also:

Sampler

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

Field Summary

Fields inherited from class org.apache.lucene.facet.old.OldFacetsAccumulator

DEFAULT_COMPLEMENT_THRESHOLD, DISABLE_COMPLEMENT, FORCE_COMPLEMENT, isUsingComplements, maxPartitions, partitionSize

Fields inherited from class org.apache.lucene.facet.search.TaxonomyFacetsAccumulator

facetArrays, indexReader, taxonomyReader

Fields inherited from class org.apache.lucene.facet.search.FacetsAccumulator

searchParams

Constructor Summary

Constructors

Constructor and Description
SamplingAccumulator(Sampler sampler, FacetSearchParams searchParams, IndexReader indexReader, TaxonomyReader taxonomyReader) Constructor...
SamplingAccumulator(Sampler sampler, FacetSearchParams searchParams, IndexReader indexReader, TaxonomyReader taxonomyReader, FacetArrays facetArrays)

Method Summary

Methods

Modifier and Type	Method and Description
List<FacetResult>	accumulate(ScoredDocIDs docids)
protected ScoredDocIDs	actualDocsToAccumulate(ScoredDocIDs docids) Set the actual set of documents over which accumulation should take place.
protected double	getTotalCountsFactor() Expert: factor by which counts should be multiplied when initializing the count arrays from total counts.

Methods inherited from class org.apache.lucene.facet.old.OldFacetsAccumulator

accumulate, createAggregator, createFacetResultsHandler, createOrdinalValueResolver, getCategoryListMap, getComplementThreshold, isUsingComplements, mayComplement, setComplementThreshold, shouldComplement

Methods inherited from class org.apache.lucene.facet.search.TaxonomyFacetsAccumulator

getAggregator, groupRequests, requiresDocScores

Methods inherited from class org.apache.lucene.facet.search.FacetsAccumulator

create, create, emptyResult

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SamplingAccumulator

public SamplingAccumulator(Sampler sampler,
                   FacetSearchParams searchParams,
                   IndexReader indexReader,
                   TaxonomyReader taxonomyReader,
                   FacetArrays facetArrays)

SamplingAccumulator

public SamplingAccumulator(Sampler sampler,
                   FacetSearchParams searchParams,
                   IndexReader indexReader,
                   TaxonomyReader taxonomyReader)

Constructor...

Method Detail

accumulate

public List<FacetResult> accumulate(ScoredDocIDs docids)
                             throws IOException

Overrides:

accumulate in class OldFacetsAccumulator

Throws:

IOException

actualDocsToAccumulate

protected ScoredDocIDs actualDocsToAccumulate(ScoredDocIDs docids)
                                       throws IOException

Description copied from class: OldFacetsAccumulator

Set the actual set of documents over which accumulation should take place.

Allows to override the set of documents to accumulate for. Invoked just before actual accumulating starts. From this point that set of documents remains unmodified. Default implementation just returns the input unchanged.

Overrides:

actualDocsToAccumulate in class OldFacetsAccumulator

Parameters:

docids - candidate documents to accumulate for

Returns:

actual documents to accumulate for

Throws:

IOException

getTotalCountsFactor

protected double getTotalCountsFactor()

Description copied from class: OldFacetsAccumulator

Expert: factor by which counts should be multiplied when initializing the count arrays from total counts. Default implementation for this returns 1, which is a no op.

Overrides:

getTotalCountsFactor in class OldFacetsAccumulator

Returns:

a factor by which total counts should be multiplied