Class DocIdSetIterator

java.lang.Object
org.apache.lucene.search.DocIdSetIterator
Direct Known Subclasses:
BinaryDocValues, BitSetIterator, DisjunctionDISIApproximation, DocBaseBitSetIterator, FilterDocIdSetIterator, FilteredDocIdSetIterator, ImpactsDISI, IndexedDISI, KnnVectorValues.DocIndexIterator, MinDocIterator, NumericDocValues, PostingsEnum, SortedDocValues, SortedNumericDocValues, SortedSetDocValues

public abstract class DocIdSetIterator extends Object
This abstract class defines methods to iterate over a set of non-decreasing doc ids. Note that this class assumes it iterates on doc Ids, and therefore NO_MORE_DOCS is set to 2147483647 in order to be used as a sentinel object. Implementations of this class are expected to consider Integer.MAX_VALUE as an invalid value.
  • Field Details

  • Constructor Details

    • DocIdSetIterator

      public DocIdSetIterator()
  • Method Details

    • empty

      public static DocIdSetIterator empty()
      An empty DocIdSetIterator instance
    • all

      public static DocIdSetIterator all(int maxDoc)
      A DocIdSetIterator that matches all documents up to maxDoc - 1.
    • range

      public static DocIdSetIterator range(int minDoc, int maxDoc)
      A DocIdSetIterator that matches a range documents from minDocID (inclusive) to maxDocID (exclusive).
    • docID

      public abstract int docID()
      Returns the following:
      Since:
      2.9
    • nextDoc

      public abstract int nextDoc() throws IOException
      Advances to the next document in the set and returns the doc it is currently on, or 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.
      Throws:
      IOException
      Since:
      2.9
    • advance

      public abstract int advance(int target) throws IOException
      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 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 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.

      Throws:
      IOException
      Since:
      2.9
    • slowAdvance

      protected final int slowAdvance(int target) throws IOException
      Slow (linear) implementation of advance(int) relying on nextDoc() to advance beyond the target position.
      Throws:
      IOException
    • cost

      public abstract long cost()
      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.

    • intoBitSet

      public void intoBitSet(int upTo, FixedBitSet bitSet, int offset) throws IOException
      Load doc IDs into a FixedBitSet. This should behave exactly as if implemented as below, which is the default implementation:
       for (int doc = docID(); doc < upTo; doc = nextDoc()) {
         bitSet.set(doc - offset);
       }
       

      Note: offset must be less than or equal to the current doc ID. Behaviour is undefined if this iterator is unpositioned.

      Note: It is important not to clear bits from bitSet that may be already set.

      Note: offset may be negative.

      Throws:
      IOException
      NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.
    • docIDRunEnd

      public int docIDRunEnd() throws IOException
      Returns the end of the run of consecutive doc IDs that match this DocIdSetIterator and that contains the current docID(), that is: one plus the last doc ID of the run.
      1. The returned doc is greater than docID().
      2. All docs in range [docID(), docIDRunEnd()) match this iterator.
      3. The current position of this iterator is not affected by calling docIDRunEnd().

      Note: It is illegal to call this method when the iterator is exhausted or not positioned.

      The default implementation assumes runs of a single doc ID and returns docID()) + 1.

      Throws:
      IOException