FilterDocIdSetIterator (Lucene 10.5.1 core API)
Description: declaration: package: org.apache.lucene.search, class: FilterDocIdSetIterator

Package org.apache.lucene.search

# Class FilterDocIdSetIterator

java.lang.Object
org.apache.lucene.search.DocIdSetIterator
org.apache.lucene.search.FilterDocIdSetIterator

Direct Known Subclasses:
  `ImpactsDISI`

public class FilterDocIdSetIterator extends DocIdSetIterator
Wrapper around a `DocIdSetIterator`.

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `protected final DocIdSetIterator`
  `in`
  Wrapped instance.

  ### Fields inherited from class org.apache.lucene.search.DocIdSetIterator

  `NO_MORE_DOCS`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `FilterDocIdSetIterator(DocIdSetIterator in)`
  Sole constructor.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `int`
  `advance(int target)`
  Advances to the first beyond the current whose document number is greater than or equal to target, and returns the document number itself.
  `long`
  `cost()`
  Returns the estimated cost of this `DocIdSetIterator`.
  `int`
  `docID()`
  Returns the following: `-1` if `DocIdSetIterator.nextDoc()` or `DocIdSetIterator.advance(int)` were not called yet.
  `int`
  `nextDoc()`
  Advances to the next document in the set and returns the doc it is currently on, or `DocIdSetIterator.NO_MORE_DOCS` if there are no more docs in the set.
  NOTE: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior.

  ### Methods inherited from class org.apache.lucene.search.DocIdSetIterator

  `all, docIDRunEnd, empty, intoBitSet, range, slowAdvance`

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

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

- ## Field Details

  - ### in

    protected final DocIdSetIterator in
    Wrapped instance.

- ## Constructor Details

  - ### FilterDocIdSetIterator

    public FilterDocIdSetIterator(DocIdSetIterator in)
    Sole constructor.

- ## Method Details

  - ### docID

    public int docID()
    Description copied from class: `DocIdSetIterator`
    Returns the following:
    - `-1` if `DocIdSetIterator.nextDoc()` or `DocIdSetIterator.advance(int)` were not called yet.
    - `DocIdSetIterator.NO_MORE_DOCS` if the iterator has exhausted.
    - Otherwise it should return the doc ID it is currently on.
    Specified by:
      `docID` in class `DocIdSetIterator`

  - ### nextDoc

    public int nextDoc() throws IOException
    Description copied from class: `DocIdSetIterator`
    Advances to the next document in the set and returns the doc it is currently on, or `DocIdSetIterator.NO_MORE_DOCS` if there are no more docs in the set.
    NOTE: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior.
    Specified by:
      `nextDoc` in class `DocIdSetIterator`
    Throws:
      `IOException`

  - ### advance

    public int advance(int target) throws IOException
    Description copied from class: `DocIdSetIterator`
    Advances to the first beyond the current whose document number is greater than or equal to target, and returns the document number itself. Exhausts the iterator and returns `DocIdSetIterator.NO_MORE_DOCS` if target is greater than the highest document number in the set.

    The behavior of this method is undefined when called with `target ≤ current` , or after the iterator has exhausted. Both cases may result in unpredicted behavior.

    When `target > current` it behaves as if written:

         int advance(int target) {
           int doc;
           while ((doc = nextDoc()) < target) {
           }
           return doc;
         }

    Some implementations are considerably more efficient than that.

    NOTE: this method may be called with `DocIdSetIterator.NO_MORE_DOCS` for efficiency by some Scorers. If your implementation cannot efficiently determine that it should exhaust, it is recommended that you check for that value in each call to this method.

    Specified by:
      `advance` in class `DocIdSetIterator`
    Throws:
      `IOException`

  - ### cost

    public long cost()
    Description copied from class: `DocIdSetIterator`
    Returns the estimated cost of this `DocIdSetIterator`.

    This is generally an upper bound of the number of documents this iterator might match, but may be a rough heuristic, hardcoded value, or otherwise completely inaccurate.

    Specified by:
      `cost` in class `DocIdSetIterator`