Class MultiCollector

    • Method Detail

      • wrap

        public static Collector wrap​(Collector... collectors)
        Wraps a list of Collectors with a MultiCollector. This method works as follows:
        • Filters out the null collectors, so they are not used during search time.
        • If the input contains 1 real collector (i.e. non-null ), it is returned.
        • Otherwise the method returns a MultiCollector which wraps the non-null ones.
        Throws:
        IllegalArgumentException - if either 0 collectors were input, or all collectors are null.
      • acceptsDocsOutOfOrder

        public boolean acceptsDocsOutOfOrder()
        Description copied from class: Collector
        Return true if this collector does not require the matching docIDs to be delivered in int sort order (smallest to largest) to Collector.collect(int).

        Most Lucene Query implementations will visit matching docIDs in order. However, some queries (currently limited to certain cases of BooleanQuery) can achieve faster searching if the Collector allows them to deliver the docIDs out of order.

        Many collectors don't mind getting docIDs out of order, so it's important to return true here.

        Specified by:
        acceptsDocsOutOfOrder in class Collector
      • collect

        public void collect​(int doc)
                     throws IOException
        Description copied from class: Collector
        Called once for every document matching a query, with the unbased document number.

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

        Specified by:
        collect in class Collector
        Throws:
        IOException