Interface LeafCollector

    • Method Detail

      • setScorer

        void setScorer​(Scorable scorer)
                throws java.io.IOException
        Called before successive calls to collect(int). Implementations that need the score of the current document (passed-in to collect(int)), should save the passed-in Scorer and call scorer.score() when needed.
        Throws:
        java.io.IOException
      • collect

        void collect​(int doc)
              throws java.io.IOException
        Called once for every document matching a query, with the unbased document number.

        Note: The collection of the current segment can be terminated by throwing a CollectionTerminatedException. In this case, the last docs of the current LeafReaderContext will be skipped and IndexSearcher will swallow the exception and continue collection with the next leaf.

        Note: This is called in an inner search loop. For good search performance, implementations of this method should not call StoredFields.document(int) on every hit. Doing so can slow searches by an order of magnitude or more.

        Throws:
        java.io.IOException
      • collect

        default void collect​(DocIdStream stream)
                      throws java.io.IOException
        Bulk-collect doc IDs.

        Note: The provided DocIdStream may be reused across calls and should be consumed immediately.

        Note: The provided DocIdStream typically only holds a small subset of query matches. This method may be called multiple times per segment.

        Like collect(int), it is guaranteed that doc IDs get collected in order, ie. doc IDs are collected in order within a DocIdStream, and if called twice, all doc IDs from the second DocIdStream will be greater than all doc IDs from the first DocIdStream.

        It is legal for callers to mix calls to collect(DocIdStream) and collect(int).

        The default implementation calls stream.forEach(this::collect).

        Throws:
        java.io.IOException
      • competitiveIterator

        default DocIdSetIterator competitiveIterator()
                                              throws java.io.IOException
        Optionally returns an iterator over competitive documents.

        Collectors should delegate this method to their comparators if their comparators provide the skipping functionality over non-competitive docs.

        The default is to return null which is interpreted as the collector provide any competitive iterator.

        Throws:
        java.io.IOException
      • finish

        default void finish()
                     throws java.io.IOException
        Hook that gets called once the leaf that is associated with this collector has finished collecting successfully, including when a CollectionTerminatedException is thrown. This is typically useful to compile data that has been collected on this leaf, e.g. to convert facet counts on leaf ordinals to facet counts on global ordinals. The default implementation does nothing.

        Note: It can be assumed that this method will only be called once per LeafCollector instance.

        Throws:
        java.io.IOException