Package org.apache.lucene.facet

Class StringValueFacetCounts

java.lang.Object

org.apache.lucene.facet.Facets

org.apache.lucene.facet.StringValueFacetCounts

public class StringValueFacetCounts
extends Facets

Compute facet counts from a previously indexed SortedSetDocValues or SortedDocValues field. This approach will execute facet counting against the string values found in the specified field, with no assumptions on their format. Unlike SortedSetDocValuesFacetCounts, no assumption is made about a "dimension" path component being indexed. Because of this, the field itself is effectively treated as the "dimension", and counts for all unique string values are produced. This approach is meant to complement LongValueFacetCounts in that they both provide facet counting on a doc value field with no assumptions of content.

This implementation is useful if you want to dynamically count against any string doc value field without relying on FacetField and FacetsConfig. The disadvantage is that a separate field is required for each "dimension". If you want to pack multiple dimensions into the same doc values field, you probably want one of FastTaxonomyFacetCounts or SortedSetDocValuesFacetCounts.

Note that there is an added cost on every IndexReader open to create a new StringDocValuesReaderState. Also note that this class should be instantiated and used from a single thread, because it holds a thread-private instance of SortedSetDocValues.

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

Constructor Summary

Constructors

Constructor	Description
StringValueFacetCounts(StringDocValuesReaderState state)	Returns all facet counts for the field, same result as searching on MatchAllDocsQuery but faster.
StringValueFacetCounts(StringDocValuesReaderState state, FacetsCollector facetsCollector)	Counts facets across the provided hits.

Method Summary

Modifier and Type	Method	Description
List<FacetResult>	getAllDims(int topN)	Returns topN labels for any dimension that had hits, sorted by the number of hits that dimension matched; this is used for "sparse" faceting, where many different dimensions were indexed, for example depending on the type of document.
Number	getSpecificValue(String dim, String... path)	Return the count or value for a specific path.
FacetResult	getTopChildren(int topN, String dim, String... path)	Returns the topN child labels under the specified path.

Methods inherited from class java.lang.Object

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

Constructor Detail

StringValueFacetCounts

public StringValueFacetCounts(StringDocValuesReaderState state)
                       throws IOException

Returns all facet counts for the field, same result as searching on MatchAllDocsQuery but faster.

Throws:

IOException

StringValueFacetCounts

public StringValueFacetCounts(StringDocValuesReaderState state,
                              FacetsCollector facetsCollector)
                       throws IOException

Counts facets across the provided hits.

Throws:

IOException

Method Detail

getTopChildren

public FacetResult getTopChildren(int topN,
                                  String dim,
                                  String... path)
                           throws IOException

Description copied from class: Facets

Returns the topN child labels under the specified path. Returns null if the specified path doesn't exist or if this dimension was never seen.

Specified by:

getTopChildren in class Facets

Throws:

IOException

getSpecificValue

public Number getSpecificValue(String dim,
                               String... path)
                        throws IOException

Description copied from class: Facets

Return the count or value for a specific path. Returns -1 if this path doesn't exist, else the count.

Specified by:

getSpecificValue in class Facets

Throws:

IOException

getAllDims

public List<FacetResult> getAllDims(int topN)
                             throws IOException

Description copied from class: Facets

Returns topN labels for any dimension that had hits, sorted by the number of hits that dimension matched; this is used for "sparse" faceting, where many different dimensions were indexed, for example depending on the type of document.

Specified by:

getAllDims in class Facets

Throws:

IOException