org.apache.lucene.facet

## Class DrillSideways

- java.lang.Object
- - org.apache.lucene.facet.DrillSideways

-     public class DrillSideways
      extends Object

  Computes drill down and sideways counts for the provided `DrillDownQuery`. Drill sideways counts include alternative values/aggregates for the drill-down dimensions so that a dimension does not disappear after the user drills down into it.

  Use one of the static search methods to do the search, and then get the hits and facet results from the returned `DrillSideways.DrillSidewaysResult`.

  NOTE: this allocates one `FacetsCollector` for each drill-down, plus one. If your index has high number of facet labels then this will multiply your memory usage.

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

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `DrillSideways.ConcurrentDrillSidewaysResult<R>` Result of a concurrent drill sideways search, including the `Facets` and `TopDocs`.
    `static class` | `DrillSideways.DrillSidewaysResult` Result of a drill sideways search, including the `Facets` and `TopDocs`.

  - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `protected FacetsConfig` | `config` `FacetsConfig` passed to constructor.
    `protected IndexSearcher` | `searcher` `IndexSearcher` passed to constructor.
    `protected SortedSetDocValuesReaderState` | `state` `SortedSetDocValuesReaderState` passed to constructor; can be null.
    `protected TaxonomyReader` | `taxoReader` `TaxonomyReader` passed to constructor.

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `DrillSideways(IndexSearcher searcher, FacetsConfig config, SortedSetDocValuesReaderState state)` Create a new `DrillSideways` instance, assuming the categories were indexed with `SortedSetDocValuesFacetField`.
    `DrillSideways(IndexSearcher searcher, FacetsConfig config, TaxonomyReader taxoReader)` Create a new `DrillSideways` instance.
    `DrillSideways(IndexSearcher searcher, FacetsConfig config, TaxonomyReader taxoReader, SortedSetDocValuesReaderState state)` Create a new `DrillSideways` instance, where some dimensions were indexed with `SortedSetDocValuesFacetField` and others were indexed with `FacetField`.
    `DrillSideways(IndexSearcher searcher, FacetsConfig config, TaxonomyReader taxoReader, SortedSetDocValuesReaderState state, ExecutorService executor)` Create a new `DrillSideways` instance, where some dimensions were indexed with `SortedSetDocValuesFacetField` and others were indexed with `FacetField`.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `protected Facets` | `buildFacetsResult(FacetsCollector drillDowns, FacetsCollector[] drillSideways, String[] drillSidewaysDims)` Subclass can override to customize per-dim Facets impl.
    `protected boolean` | `scoreSubDocsAtOnce()` Override this and return true if your collector (e.g., `ToParentBlockJoinCollector`) expects all sub-scorers to be positioned on the document being collected.
    `DrillSideways.DrillSidewaysResult` | `search(DrillDownQuery query, Collector hitCollector)` Search, collecting hits with a `Collector`, and computing drill down and sideways counts.
    `<R> DrillSideways.ConcurrentDrillSidewaysResult<R>` | `search(DrillDownQuery query, CollectorManager<?,R> hitCollectorManager)` Runs a search, using a `CollectorManager` to gather and merge search results
    `DrillSideways.DrillSidewaysResult` | `search(DrillDownQuery query, int topN)` Search, sorting by score, and computing drill down and sideways counts.
    `DrillSideways.DrillSidewaysResult` | `search(DrillDownQuery query, Query filter, FieldDoc after, int topN, Sort sort, boolean doDocScores)` Search, sorting by `Sort`, and computing drill down and sideways counts.
    `DrillSideways.DrillSidewaysResult` | `search(ScoreDoc after, DrillDownQuery query, int topN)` Search, sorting by score, and computing drill down and sideways counts.

    - ### Methods inherited from class java.lang.Object

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

- - ### Field Detail

    - #### searcher

          protected final IndexSearcher searcher

      `IndexSearcher` passed to constructor.

    - #### taxoReader

          protected final TaxonomyReader taxoReader

      `TaxonomyReader` passed to constructor.

    - #### state

          protected final SortedSetDocValuesReaderState state

      `SortedSetDocValuesReaderState` passed to constructor; can be null.

    - #### config

          protected final FacetsConfig config

      `FacetsConfig` passed to constructor.

  - ### Constructor Detail

    - #### DrillSideways

          public DrillSideways(IndexSearcher searcher,
                               FacetsConfig config,
                               TaxonomyReader taxoReader)

      Create a new `DrillSideways` instance.

    - #### DrillSideways

          public DrillSideways(IndexSearcher searcher,
                               FacetsConfig config,
                               SortedSetDocValuesReaderState state)

      Create a new `DrillSideways` instance, assuming the categories were indexed with `SortedSetDocValuesFacetField`.

    - #### DrillSideways

          public DrillSideways(IndexSearcher searcher,
                               FacetsConfig config,
                               TaxonomyReader taxoReader,
                               SortedSetDocValuesReaderState state)

      Create a new `DrillSideways` instance, where some dimensions were indexed with `SortedSetDocValuesFacetField` and others were indexed with `FacetField`.

    - #### DrillSideways

          public DrillSideways(IndexSearcher searcher,
                               FacetsConfig config,
                               TaxonomyReader taxoReader,
                               SortedSetDocValuesReaderState state,
                               ExecutorService executor)

      Create a new `DrillSideways` instance, where some dimensions were indexed with `SortedSetDocValuesFacetField` and others were indexed with `FacetField`.

      Use this constructor to use the concurrent implementation and/or the CollectorManager

  - ### Method Detail

    - #### buildFacetsResult

          protected Facets buildFacetsResult(FacetsCollector drillDowns,
                                             FacetsCollector[] drillSideways,
                                             String[] drillSidewaysDims)
                                      throws IOException

      Subclass can override to customize per-dim Facets impl.
      Throws:
        `IOException`

    - #### search

          public DrillSideways.DrillSidewaysResult search(DrillDownQuery query,
                                                          Collector hitCollector)
                                                   throws IOException

      Search, collecting hits with a `Collector`, and computing drill down and sideways counts.
      Throws:
        `IOException`

    - #### search

          public DrillSideways.DrillSidewaysResult search(DrillDownQuery query,
                                                          Query filter,
                                                          FieldDoc after,
                                                          int topN,
                                                          Sort sort,
                                                          boolean doDocScores)
                                                   throws IOException

      Search, sorting by `Sort`, and computing drill down and sideways counts.
      Throws:
        `IOException`

    - #### search

          public DrillSideways.DrillSidewaysResult search(DrillDownQuery query,
                                                          int topN)
                                                   throws IOException

      Search, sorting by score, and computing drill down and sideways counts.
      Throws:
        `IOException`

    - #### search

          public DrillSideways.DrillSidewaysResult search(ScoreDoc after,
                                                          DrillDownQuery query,
                                                          int topN)
                                                   throws IOException

      Search, sorting by score, and computing drill down and sideways counts.
      Throws:
        `IOException`

    - #### scoreSubDocsAtOnce

          protected boolean scoreSubDocsAtOnce()

      Override this and return true if your collector (e.g., `ToParentBlockJoinCollector`) expects all sub-scorers to be positioned on the document being collected. This will cause some performance loss; default is false.

    - #### search

          public <R> DrillSideways.ConcurrentDrillSidewaysResult<R> search(DrillDownQuery query,
                                                                           CollectorManager<?,R> hitCollectorManager)
                                                                    throws IOException

      Runs a search, using a `CollectorManager` to gather and merge search results
      Throws:
        `IOException`

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