Package org.apache.lucene.search.spans

Class NearSpansOrdered

  • public class NearSpansOrdered
extends Spans
    A Spans that is formed from the ordered subspans of a SpanNearQuery where the subspans do not overlap and have a maximum slop between them.

    The formed spans only contains minimum slop matches.
    The matching slop is computed from the distance(s) between the non overlapping matching Spans.
    Successive matches are always formed from the successive Spans of the SpanNearQuery.

    The formed spans may contain overlaps when the slop is at least 1. For example, when querying using 

    t1 t2 t3
    with slop at least 1, the fragment: 
    t1 t2 t1 t3 t2 t3
    matches twice: 
    t1 t2 .. t3      
          t1 .. t2 t3
    Expert: Only public for subclassing. Most implementations should not need this class

    • Field Detail

      • matchStart

        protected int matchStart

      • matchEnd

        protected int matchEnd

      • matchWidth

        protected int matchWidth

    • Method Detail

      • nextStartPosition

        public int nextStartPosition()
                      throws IOException
        Description copied from class: Spans
        Returns the next start position for the current doc. There is always at least one start/end position per doc. After the last start/end position at the current doc this returns Spans.NO_MORE_POSITIONS.
        Specified by:
        nextStartPosition in class Spans
        Throws:
        IOException

      • endPosition

        public int endPosition()
        Description copied from class: Spans
        Returns the end position for the current start position, or -1 when Spans.nextStartPosition() was not yet called on the current doc. After the last start/end position at the current doc this returns Spans.NO_MORE_POSITIONS.
        Specified by:
        endPosition in class Spans

      • width

        public int width()
        Description copied from class: Spans
        Return the width of the match, which is typically used to sloppy freq. It is only legal to call this method when the iterator is on a valid doc ID and positioned. The return value must be positive, and lower values means that the match is better.
        Specified by:
        width in class Spans

      • 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

      • 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

      • positionsCost

        public float positionsCost()
        Description copied from class: Spans
        Return an estimation of the cost of using the positions of this Spans for any single document, but only after Spans.asTwoPhaseIterator() returned null. Otherwise this method should not be called. The returned value is independent of the current document.
        Specified by:
        positionsCost in class Spans

      • getSubSpans

        public Spans[] getSubSpans()