Class PForDeltaDocIdSet


  • public final class PForDeltaDocIdSet
    extends DocIdSet
    DocIdSet implementation based on pfor-delta encoding.

    This implementation is inspired from LinkedIn's Kamikaze (http://data.linkedin.com/opensource/kamikaze) and Daniel Lemire's JavaFastPFOR (https://github.com/lemire/JavaFastPFOR).

    On the contrary to the original PFOR paper, exceptions are encoded with FOR instead of Simple16.

    • Method Detail

      • isCacheable

        public boolean isCacheable()
        Description copied from class: DocIdSet
        This method is a hint for CachingWrapperFilter, if this DocIdSet should be cached without copying it. The default is to return false. If you have an own DocIdSet implementation that does its iteration very effective and fast without doing disk I/O, override this method and return true.
        Overrides:
        isCacheable in class DocIdSet
      • cardinality

        public int cardinality()
        Return the number of documents in this DocIdSet in constant time.
      • ramBytesUsed

        public long ramBytesUsed()
        Return the memory usage of this instance.