## org.apache.lucene.index
Class MultiDocValues

    java.lang.Object
      org.apache.lucene.index.MultiDocValues

    public class MultiDocValues

extends Object

A wrapper for CompositeIndexReader providing access to DocValues.

NOTE: for multi readers, you'll get better performance by gathering the sub readers using `IndexReader.getContext()` to get the atomic leaves and then operate per-AtomicReader, instead of using this class.

NOTE: This is very costly.

WARNING: This API is experimental and might change in incompatible ways in the next release.
NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

Nested Class Summary
`static class` `MultiDocValues.MultiSortedDocValues` Implements SortedDocValues over n subs, using an OrdinalMap
`static class` `MultiDocValues.MultiSortedSetDocValues` Implements MultiSortedSetDocValues over n subs, using an OrdinalMap
`static class` `MultiDocValues.OrdinalMap` maps per-segment ordinals to/from global ordinal space

Method Summary
`static BinaryDocValues` `getBinaryValues(IndexReader r, String field)` Returns a BinaryDocValues for a reader's docvalues (potentially merging on-the-fly)
`static NumericDocValues` `getNormValues(IndexReader r, String field)` Returns a NumericDocValues for a reader's norms (potentially merging on-the-fly).
`static NumericDocValues` `getNumericValues(IndexReader r, String field)` Returns a NumericDocValues for a reader's docvalues (potentially merging on-the-fly)
`static SortedSetDocValues` `getSortedSetValues(IndexReader r, String field)` Returns a SortedSetDocValues for a reader's docvalues (potentially doing extremely slow things).
`static SortedDocValues` `getSortedValues(IndexReader r, String field)` Returns a SortedDocValues for a reader's docvalues (potentially doing extremely slow things).

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

Method Detail

### getNormValues

    public static NumericDocValues getNormValues(IndexReader r,
                                                 String field)
                                          throws IOException

  Returns a NumericDocValues for a reader's norms (potentially merging on-the-fly).

  This is a slow way to access normalization values. Instead, access them per-segment with `AtomicReader.getNormValues(String)`

  Throws:
    `IOException`

### getNumericValues

    public static NumericDocValues getNumericValues(IndexReader r,
                                                    String field)
                                             throws IOException

  Returns a NumericDocValues for a reader's docvalues (potentially merging on-the-fly)

  This is a slow way to access numeric values. Instead, access them per-segment with `AtomicReader.getNumericDocValues(String)`

  Throws:
    `IOException`

### getBinaryValues

    public static BinaryDocValues getBinaryValues(IndexReader r,
                                                  String field)
                                           throws IOException

  Returns a BinaryDocValues for a reader's docvalues (potentially merging on-the-fly)

  This is a slow way to access binary values. Instead, access them per-segment with `AtomicReader.getBinaryDocValues(String)`

  Throws:
    `IOException`

### getSortedValues

    public static SortedDocValues getSortedValues(IndexReader r,
                                                  String field)
                                           throws IOException

  Returns a SortedDocValues for a reader's docvalues (potentially doing extremely slow things).

  This is an extremely slow way to access sorted values. Instead, access them per-segment with `AtomicReader.getSortedDocValues(String)`

  Throws:
    `IOException`

### getSortedSetValues

    public static SortedSetDocValues getSortedSetValues(IndexReader r,
                                                        String field)
                                                 throws IOException

  Returns a SortedSetDocValues for a reader's docvalues (potentially doing extremely slow things).

  This is an extremely slow way to access sorted values. Instead, access them per-segment with `AtomicReader.getSortedSetDocValues(String)`

  Throws:
    `IOException`

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