org.apache.lucene.facet.sortedset

## Class SortedSetDocValuesReaderState

- java.lang.Object
- - org.apache.lucene.facet.sortedset.SortedSetDocValuesReaderState

- All Implemented Interfaces:
    Accountable
  Direct Known Subclasses:
    DefaultSortedSetDocValuesReaderState

      public abstract class SortedSetDocValuesReaderState
      extends Object
      implements Accountable

  Wraps a `IndexReader` and resolves ords using existing `SortedSetDocValues` APIs without a separate taxonomy index. This only supports flat facets (dimension + label), and it makes faceting a bit slower, adds some cost at reopen time, but avoids managing the separate taxonomy index. It also requires less RAM than the taxonomy index, as it manages the flat (2-level) hierarchy more efficiently. In addition, the tie-break during faceting is now meaningful (in label sorted order).

  NOTE: creating an instance of this class is somewhat costly, as it computes per-segment ordinal maps, so you should create it once and re-use that one instance for a given `IndexReader`.

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `SortedSetDocValuesReaderState.OrdRange` Holds start/end range of ords, which maps to one dimension (someday we may generalize it to map to hierarchies within one dimension).

  - ### Constructor Summary

    Constructors
    Modifier | Constructor and Description
    --- | ---
    `protected` | `SortedSetDocValuesReaderState()` Sole constructor.

  - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method and Description
    --- | ---
    `abstract SortedSetDocValues` | `getDocValues()` Return top-level doc values.
    `abstract String` | `getField()` Indexed field we are reading.
    `abstract SortedSetDocValuesReaderState.OrdRange` | `getOrdRange(String dim)` Returns the `SortedSetDocValuesReaderState.OrdRange` for this dimension.
    `abstract Map<String,SortedSetDocValuesReaderState.OrdRange>` | `getPrefixToOrdRange()` Returns mapping from prefix to `SortedSetDocValuesReaderState.OrdRange`.
    `abstract IndexReader` | `getReader()` Returns top-level index reader.
    `abstract int` | `getSize()` Number of unique labels.

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

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

    - ### Methods inherited from interface org.apache.lucene.util.Accountable

      `getChildResources, ramBytesUsed`

- - ### Constructor Detail

    - #### SortedSetDocValuesReaderState

          protected SortedSetDocValuesReaderState()

      Sole constructor.

  - ### Method Detail

    - #### getDocValues

          public abstract SortedSetDocValues getDocValues()
                                                   throws IOException

      Return top-level doc values.
      Throws:
        `IOException`

    - #### getField

          public abstract String getField()

      Indexed field we are reading.

    - #### getOrdRange

          public abstract SortedSetDocValuesReaderState.OrdRange getOrdRange(String dim)

      Returns the `SortedSetDocValuesReaderState.OrdRange` for this dimension.

    - #### getPrefixToOrdRange

          public abstract Map<String,SortedSetDocValuesReaderState.OrdRange> getPrefixToOrdRange()

      Returns mapping from prefix to `SortedSetDocValuesReaderState.OrdRange`.

    - #### getReader

          public abstract IndexReader getReader()

      Returns top-level index reader.

    - #### getSize

          public abstract int getSize()

      Number of unique labels.

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