Package org.apache.lucene.search

Class FieldCacheDocIdSet

java.lang.Object
org.apache.lucene.search.DocIdSet
org.apache.lucene.search.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 Details

    • maxDoc

      protected final int maxDoc

    • acceptDocs

      protected final Bits acceptDocs

  • Constructor Details

    • FieldCacheDocIdSet

      public FieldCacheDocIdSet(int maxDoc, Bits acceptDocs)

  • Method Details

    • 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.

    • iterator

      public final DocIdSetIterator iterator() throws IOException
      Description copied from class: DocIdSet
      Provides a DocIdSetIterator to access the set. This implementation can return null if there are no docs that match.
      Specified by:
      iterator in class DocIdSet
      Throws:
      IOException