Package org.apache.lucene.facet

Class Facets

java.lang.Object

org.apache.lucene.facet.Facets

Direct Known Subclasses:

ConcurrentSortedSetDocValuesFacetCounts, FacetCountsWithFilterQuery, LongValueFacetCounts, MultiFacets, SortedSetDocValuesFacetCounts, StringValueFacetCounts, TaxonomyFacets

public abstract class Facets
extends Object

Common base class for all facets implementations.

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

Constructor Summary

Constructors

Constructor	Description
Facets()	Default constructor.

Method Summary

Modifier and Type	Method	Description
abstract FacetResult	getAllChildren(String dim, String... path)	Returns all child labels with non-zero counts under the specified path.
abstract 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.
abstract Number	getSpecificValue(String dim, String... path)	Return the count or value for a specific path.
abstract FacetResult	getTopChildren(int topN, String dim, String... path)	Returns the topN child labels under the specified path.
List<FacetResult>	getTopDims(int topNDims, int topNChildren)	Returns labels for topN dimensions and their topNChildren sorted by the number of hits/aggregated values that dimension matched.
protected static void	validateTopN(int topN)	This helper method checks if topN is valid for getTopChildren and getAllDims.

Methods inherited from class java.lang.Object

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

Constructor Detail

Facets

public Facets()

Default constructor.

Method Detail

getAllChildren

public abstract FacetResult getAllChildren(String dim,
                                           String... path)
                                    throws IOException

Returns all child labels with non-zero counts under the specified path. Users should make no assumptions about ordering of the children. Returns null if the specified path doesn't exist or if this dimension was never seen.

Throws:

IOException

getTopChildren

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

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.

Throws:

IOException

getSpecificValue

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

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

Throws:

IOException

getAllDims

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

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.

Throws:

IOException

getTopDims

public List<FacetResult> getTopDims(int topNDims,
                                    int topNChildren)
                             throws IOException

Returns labels for topN dimensions and their topNChildren sorted by the number of hits/aggregated values that dimension matched. Results should be the same as calling getAllDims and then only using the first topNDims. Note that dims should be configured as requiring dim counts if using this functionality to ensure accurate counts are available (see: FacetsConfig.setRequireDimCount(String, boolean)).

Sub-classes may want to override this implementation with a more efficient one if they are able.

Throws:

IOException

validateTopN

protected static void validateTopN(int topN)

This helper method checks if topN is valid for getTopChildren and getAllDims. Throws IllegalArgumentException if topN is invalid.

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

it may not exist in future versions of Lucene