Package org.apache.lucene.search

# Class DocIdSet

java.lang.Object
org.apache.lucene.search.DocIdSet

All Implemented Interfaces:
  `Accountable`

Direct Known Subclasses:
  `BitDocIdSet`, `DocsWithFieldSet`, `NotDocIdSet`, `RoaringDocIdSet`

public abstract class DocIdSet extends Object implements Accountable
A DocIdSet contains a set of doc ids. Implementing classes must only implement `iterator()` to provide access to the set.

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `static final DocIdSet`
  `EMPTY`
  An empty `DocIdSet` instance

  ### Fields inherited from interface org.apache.lucene.util.Accountable

  `NULL_ACCOUNTABLE`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `DocIdSet()`

- ## Method Summary

  Modifier and Type
  Method
  Description
  `static DocIdSet`
  `all(int maxDoc)`
  Deprecated.
  no longer needed since Query and Filter were merged
  `Bits`
  `bits()`
  Deprecated.
  this method is redundant and will be removed.
  `abstract DocIdSetIterator`
  `iterator()`
  Provides a `DocIdSetIterator` to access the set.

  ### 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`

- ## Field Details

  - ### EMPTY

    public static final DocIdSet EMPTY
    An empty `DocIdSet` instance

- ## Constructor Details

  - ### DocIdSet

    public DocIdSet()

- ## Method Details

  - ### all

    @Deprecated public static DocIdSet all(int maxDoc)
    Deprecated.
    no longer needed since Query and Filter were merged
    A `DocIdSet` that matches all doc ids up to a specified doc (exclusive).

  - ### iterator

    public abstract DocIdSetIterator iterator() throws IOException
    Provides a `DocIdSetIterator` to access the set. This implementation can return `null` if there are no docs that match.
    Throws:
      `IOException`

  - ### bits

    @Deprecated public Bits bits() throws IOException
    Deprecated.
    this method is redundant and will be removed.
    Optionally provides a `Bits` interface for random access to matching documents.
    Returns:
      `null`, if this `DocIdSet` does not support random access. In contrast to `iterator()`, a return value of `null` does not imply that no documents match the filter! The default implementation does not provide random access, so you only need to implement this method if your DocIdSet can guarantee random access to every docid in O(1) time without external disk access (as `Bits` interface cannot throw `IOException`). This is generally true for bit sets like `FixedBitSet`, which return itself if they are used as `DocIdSet`.
    Throws:
      `IOException`