Class FacetsCollector


  • public class FacetsCollector
    extends Collector
    Collector for facet accumulation. *
    WARNING: This API is experimental and might change in incompatible ways in the next release.
    • Constructor Detail

      • FacetsCollector

        public FacetsCollector​(FacetSearchParams facetSearchParams,
                               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,
                                                              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.
      • 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()
        Description copied from class: Collector
        Return true if this collector does not require the matching docIDs to be delivered in int sort order (smallest to largest) to Collector.collect(int).

        Most Lucene Query implementations will visit matching docIDs in order. However, some queries (currently limited to certain cases of BooleanQuery) can achieve faster searching if the Collector allows them to deliver the docIDs out of order.

        Many collectors don't mind getting docIDs out of order, so it's important to return true here.

        Specified by:
        acceptsDocsOutOfOrder in class Collector
      • collect

        public void collect​(int doc)
                     throws IOException
        Description copied from class: Collector
        Called once for every document matching a query, with the unbased document number.

        Note: This is called in an inner search loop. For good search performance, implementations of this method should not call Searcher.doc(int) or IndexReader.document(int) on every hit. Doing so can slow searches by an order of magnitude or more.

        Specified by:
        collect in class Collector
        Throws:
        IOException