Package org.apache.lucene.facet.taxonomy

Class TaxonomyFacetLabels.FacetLabelReader

java.lang.Object

org.apache.lucene.facet.taxonomy.TaxonomyFacetLabels.FacetLabelReader

Enclosing class:

TaxonomyFacetLabels

public class TaxonomyFacetLabels.FacetLabelReader
extends Object

Utility class to retrieve facet labels for multiple documents.

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

Constructor Summary

Constructors

Constructor	Description
FacetLabelReader(OrdinalsReader ordsReader, LeafReaderContext readerContext)	Deprecated. Custom binary encodings for taxonomy ordinals are no longer supported starting with Lucene 9
FacetLabelReader(SortedNumericDocValues ordinalValues)	Construct from a specified SortedNumericDocValues field; useful for reading the default encoding.

Method Summary

Modifier and Type	Method	Description
FacetLabel	nextFacetLabel(int docId)	Retrieves the next FacetLabel for the specified docId, or null if there are no more.
FacetLabel	nextFacetLabel(int docId, String facetDimension)	Retrieves the next FacetLabel for the specified docId under the requested facetDimension, or null if there are no more.

Methods inherited from class java.lang.Object

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

Constructor Detail

FacetLabelReader

public FacetLabelReader(SortedNumericDocValues ordinalValues)

Construct from a specified SortedNumericDocValues field; useful for reading the default encoding.

FacetLabelReader

@Deprecated
public FacetLabelReader(OrdinalsReader ordsReader,
                        LeafReaderContext readerContext)
                 throws IOException

Deprecated.

Custom binary encodings for taxonomy ordinals are no longer supported starting with Lucene 9

Construct using a custom OrdinalsReader; useful if using a custom binary format.

Note: If using the default encoding, you can use FacetLabelReader(SortedNumericDocValues) directly

Throws:

IOException

Method Detail

nextFacetLabel

public FacetLabel nextFacetLabel(int docId)
                          throws IOException

Retrieves the next FacetLabel for the specified docId, or null if there are no more. This method has state: if the provided docId is the same as the previous invocation, it returns the next FacetLabel for that document. Otherwise, it advances to the new docId and provides the first FacetLabel for that document, or null if that document has no indexed facets. Each new docId must be in strictly monotonic (increasing) order.

NOTE: The returned FacetLabels may not be in the same order in which they were indexed

Parameters:

docId - input docId provided in monotonic (non-decreasing) order

Returns:

the first or next FacetLabel, or null if there are no more

Throws:

IOException - when a low-level IO issue occurs

IllegalArgumentException - if docId provided is less than docId supplied in an earlier invocation

nextFacetLabel

public FacetLabel nextFacetLabel(int docId,
                                 String facetDimension)
                          throws IOException

Retrieves the next FacetLabel for the specified docId under the requested facetDimension, or null if there are no more. This method has state: if the provided docId is the same as the previous invocation, it returns the next FacetLabel for that document. Otherwise, it advances to the new docId and provides the first FacetLabel for that document, or null if that document has no indexed facets. Each new docId must be in strictly monotonic (increasing) order.

NOTE: This method loads the int[] parents array from the taxonomy index. The returned FacetLabels may not be in the same order in which they were indexed.

Parameters:

docId - input docId provided in non-decreasing order

Returns:

the first or next FacetLabel, or null if there are no more

Throws:

IOException - if TaxonomyReader has problems getting path for an ordinal

IllegalArgumentException - if docId provided is less than docId supplied in an earlier invocation

IllegalArgumentException - if facetDimension is null