## org.apache.lucene.facet.search
Class FacetsCollector

    java.lang.Object
      org.apache.lucene.search.Collector
          org.apache.lucene.facet.search.FacetsCollector

    public class FacetsCollector

extends org.apache.lucene.search.Collector

Collector for facet accumulation. *

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

Field Summary
`protected FacetsAccumulator` `facetsAccumulator`

Constructor Summary
`FacetsCollector(FacetSearchParams facetSearchParams, org.apache.lucene.index.IndexReader indexReader, TaxonomyReader taxonomyReader)` Create a collector for accumulating facets while collecting documents during search.

Method Summary
`boolean` `acceptsDocsOutOfOrder()`
`void` `collect(int doc)`
`List<FacetResult>` `getFacetResults()` Return accumulated facets results (according to faceted search parameters) for collected documents.
`protected FacetsAccumulator` `initFacetsAccumulator(FacetSearchParams facetSearchParams, org.apache.lucene.index.IndexReader indexReader, TaxonomyReader taxonomyReader)` Create the `FacetsAccumulator` to be used.
`protected ScoredDocIdCollector` `initScoredDocCollector(FacetSearchParams facetSearchParams, org.apache.lucene.index.IndexReader indexReader, TaxonomyReader taxonomyReader)` Create a `ScoredDocIdCollector` to be used as the first phase of the facet collection.
`void` `setNextReader(org.apache.lucene.index.IndexReader reader, int docBase)`
`void` `setScorer(org.apache.lucene.search.Scorer scorer)`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

### facetsAccumulator

    protected final FacetsAccumulator facetsAccumulator

Constructor Detail

### FacetsCollector

    public FacetsCollector(FacetSearchParams facetSearchParams,
                           org.apache.lucene.index.IndexReader indexReader,
                           TaxonomyReader taxonomyReader)

  Create a collector for accumulating facets while collecting documents during search.

  Parameters:
    `facetSearchParams` - faceted search parameters defining which facets are required and how.
    `indexReader` - searched index.
    `taxonomyReader` - taxonomy containing the facets.

Method Detail

### initScoredDocCollector

    protected ScoredDocIdCollector initScoredDocCollector(FacetSearchParams facetSearchParams,
                                                          org.apache.lucene.index.IndexReader indexReader,
                                                          TaxonomyReader taxonomyReader)

  Create a `ScoredDocIdCollector` to be used as the first phase of the facet collection. If all facetRequests are do not require the document score, a ScoredDocIdCollector which does not store the document scores would be returned. Otherwise a SDIC which does store the documents will be returned, having an initial allocated space for 1000 such documents' scores.

### initFacetsAccumulator

    protected FacetsAccumulator initFacetsAccumulator(FacetSearchParams facetSearchParams,
                                                      org.apache.lucene.index.IndexReader indexReader,
                                                      TaxonomyReader taxonomyReader)

  Create the `FacetsAccumulator` to be used. Default is `StandardFacetsAccumulator`. Called once at the constructor of the collector.

  Parameters:
    `facetSearchParams` - The search params.
    `indexReader` - A reader to the index to search in.
    `taxonomyReader` - A reader to the active taxonomy.
  Returns:
    The `FacetsAccumulator` to use.

### getFacetResults

    public List<FacetResult> getFacetResults()
                                      throws IOException

  Return accumulated facets results (according to faceted search parameters) for collected documents.

  Throws:
    `IOException` - on error

### acceptsDocsOutOfOrder

    public boolean acceptsDocsOutOfOrder()

  Specified by:
    `acceptsDocsOutOfOrder` in class `org.apache.lucene.search.Collector`

### collect

    public void collect(int doc)
                 throws IOException

  Specified by:
    `collect` in class `org.apache.lucene.search.Collector`
  Throws:
    `IOException`

### setNextReader

    public void setNextReader(org.apache.lucene.index.IndexReader reader,
                              int docBase)
                       throws IOException

  Specified by:
    `setNextReader` in class `org.apache.lucene.search.Collector`
  Throws:
    `IOException`

### setScorer

    public void setScorer(org.apache.lucene.search.Scorer scorer)
                   throws IOException

  Specified by:
    `setScorer` in class `org.apache.lucene.search.Collector`
  Throws:
    `IOException`