Package org.apache.lucene.search

Class FieldCacheDocIdSet

  • public abstract class FieldCacheDocIdSet
extends DocIdSet
    Base class for DocIdSet to be used with FieldCache. The implementation of its iterator is very stupid and slow if the implementation of the matchDoc(int) method is not optimized, as iterators simply increment the document id until matchDoc(int) returns true. Because of this matchDoc(int) must be as fast as possible and in no case do any I/O.

    • Field Detail

      • maxDoc

        protected final int maxDoc

      • acceptDocs

        protected final Bits acceptDocs

    • Constructor Detail

      • FieldCacheDocIdSet

        public FieldCacheDocIdSet​(int maxDoc,
                          Bits acceptDocs)

    • Method Detail

      • matchDoc

        protected abstract boolean matchDoc​(int doc)
        this method checks, if a doc is a hit

      • isCacheable

        public final boolean isCacheable()
        this DocIdSet is always cacheable (does not go back to the reader for iteration)
        Overrides:
        isCacheable in class DocIdSet

      • bits

        public final Bits bits()
        Description copied from class: DocIdSet
        Optionally provides a Bits interface for random access to matching documents.
        Overrides:
        bits in class DocIdSet
        Returns:
        null, if this DocIdSet does not support random access. In contrast to DocIdSet.iterator(), a return value of null does not imply that no documents match the filter! The default implementation does not provide random access, so you only need to implement this method if your DocIdSet can guarantee random access to every docid in O(1) time without external disk access (as Bits interface cannot throw IOException). This is generally true for bit sets like FixedBitSet, which return itself if they are used as DocIdSet.