org.apache.lucene.facet.partitions

Class PartitionsFacetResultsHandler

java.lang.Object

org.apache.lucene.facet.search.FacetResultsHandler

org.apache.lucene.facet.partitions.PartitionsFacetResultsHandler

Direct Known Subclasses:

TopKFacetResultsHandler, TopKInEachNodeHandler

public abstract class PartitionsFacetResultsHandler
extends FacetResultsHandler

A FacetResultsHandler designed to work with facet partitions.

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.search.FacetResultsHandler

facetArrays, facetRequest, taxonomyReader

Constructor Summary

Constructors

Constructor and Description
PartitionsFacetResultsHandler(TaxonomyReader taxonomyReader, FacetRequest facetRequest, FacetArrays facetArrays)

Method Summary

Methods

Modifier and Type	Method and Description
FacetResult	compute() Computes the FacetResult for the given FacetArrays.
abstract IntermediateFacetResult	fetchPartitionResult(int offset) Fetch results of a single partition, given facet arrays for that partition, and based on the matching documents and faceted search parameters.
protected boolean	isSelfPartition(int ordinal, FacetArrays facetArrays, int offset) Check if an array contains the partition which contains ordinal
abstract void	labelResult(FacetResult facetResult) Label results according to settings in FacetRequest, such as FacetRequest.getNumLabel().
abstract IntermediateFacetResult	mergeResults(IntermediateFacetResult... tmpResults) Merge results of several facet partitions.
abstract FacetResult	rearrangeFacetResult(FacetResult facetResult) Perform any rearrangement as required on a facet result that has changed after it was rendered.
abstract FacetResult	renderFacetResult(IntermediateFacetResult tmpResult) Create a facet result from the temporary result.

Methods inherited from class java.lang.Object

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

Constructor Detail

PartitionsFacetResultsHandler

public PartitionsFacetResultsHandler(TaxonomyReader taxonomyReader,
                             FacetRequest facetRequest,
                             FacetArrays facetArrays)

Method Detail

fetchPartitionResult

public abstract IntermediateFacetResult fetchPartitionResult(int offset)
                                                      throws IOException

Fetch results of a single partition, given facet arrays for that partition, and based on the matching documents and faceted search parameters.

Parameters:

offset - offset in input arrays where partition starts

Returns:

temporary facet result, potentially, to be passed back to this result handler for merging, or null in case that constructor parameter, facetRequest, requests an illegal FacetResult, like, e.g., a root node category path that does not exist in constructor parameter taxonomyReader .

Throws:

IOException - on error

mergeResults

public abstract IntermediateFacetResult mergeResults(IntermediateFacetResult... tmpResults)
                                              throws IOException

Merge results of several facet partitions. Logic of the merge is undefined and open for interpretations. For example, a merge implementation could keep top K results. Passed IntermediateFacetResult must be ones that were created by this handler otherwise a ClassCastException is thrown. In addition, all passed IntermediateFacetResult must have the same FacetRequest otherwise an IllegalArgumentException is thrown.

Parameters:

tmpResults - one or more temporary results created by this handler.

Returns:

temporary facet result that represents to union, as specified by this handler, of the input temporary facet results.

Throws:

IOException - on error.

ClassCastException - if the temporary result passed was not created by this handler

IllegalArgumentException - if passed facetResults do not have the same FacetRequest

See Also:

IntermediateFacetResult.getFacetRequest()

renderFacetResult

public abstract FacetResult renderFacetResult(IntermediateFacetResult tmpResult)
                                       throws IOException

Create a facet result from the temporary result.

Parameters:

tmpResult - temporary result to be rendered as a FacetResult

Throws:

IOException - on error.

rearrangeFacetResult

public abstract FacetResult rearrangeFacetResult(FacetResult facetResult)

Perform any rearrangement as required on a facet result that has changed after it was rendered.

Possible use case: a sampling facets accumulator invoked another other facets accumulator on a sample set of documents, obtained rendered facet results, fixed their counts, and now it is needed to sort the results differently according to the fixed counts.

Parameters:

facetResult - result to be rearranged.

See Also:

FacetResultNode.value

labelResult

public abstract void labelResult(FacetResult facetResult)
                          throws IOException

Label results according to settings in FacetRequest, such as FacetRequest.getNumLabel(). Usually invoked by StandardFacetsAccumulator.accumulate(ScoredDocIDs)

Parameters:

facetResult - facet result to be labeled.

Throws:

IOException - on error

isSelfPartition

protected boolean isSelfPartition(int ordinal,
                      FacetArrays facetArrays,
                      int offset)

Check if an array contains the partition which contains ordinal

Parameters:

ordinal - checked facet

facetArrays - facet arrays for the certain partition

offset - offset in input arrays where partition starts

compute

public final FacetResult compute()
                          throws IOException

Description copied from class: FacetResultsHandler

Computes the FacetResult for the given FacetArrays.

Specified by:

compute in class FacetResultsHandler

Throws:

IOException