Package org.apache.lucene.index

Class FilterLeafReader

  • All Implemented Interfaces:
    Closeable, AutoCloseable
    Direct Known Subclasses:
    ExitableDirectoryReader.ExitableFilterAtomicReader
    public abstract class FilterLeafReader
extends LeafReader
    A FilterLeafReader contains another LeafReader, which it uses as its basic source of data, possibly transforming the data along the way or providing additional functionality. The class FilterLeafReader itself simply implements all abstract methods of IndexReader with versions that pass all requests to the contained index reader. Subclasses of FilterLeafReader may further override some of these methods and may also provide additional methods and fields.

    NOTE: If you override getLiveDocs(), you will likely need to override numDocs() as well and vice-versa.

    NOTE: If this FilterLeafReader does not change the content the contained reader, you could consider delegating calls to LeafReader.getCoreCacheHelper() and IndexReader.getReaderCacheHelper().

    • Field Detail

      • in

        protected final LeafReader in
        The underlying LeafReader.

    • Constructor Detail

      • FilterLeafReader

        protected FilterLeafReader​(LeafReader in)
        Construct a FilterLeafReader based on the specified base reader.

        Note that base reader is closed if this FilterLeafReader is closed.

        Parameters:
        in - specified base reader.

    • Method Detail

      • getLiveDocs

        public Bits getLiveDocs()
        Description copied from class: LeafReader
        Returns the Bits representing live (not deleted) docs. A set bit indicates the doc ID has not been deleted. If this method returns null it means there are no deleted documents (all documents are live).

        The returned instance has been safely published for use by multiple threads without additional synchronization.

        Specified by:
        getLiveDocs in class LeafReader

      • getFieldInfos

        public FieldInfos getFieldInfos()
        Description copied from class: LeafReader
        Get the FieldInfos describing all fields in this reader.

        Note: Implementations should cache the FieldInfos instance returned by this method such that subsequent calls to this method return the same instance.

        Specified by:
        getFieldInfos in class LeafReader

      • searchNearestVectors

        public void searchNearestVectors​(String field,
                                 float[] target,
                                 KnnCollector knnCollector,
                                 Bits acceptDocs)
                          throws IOException
        Description copied from class: LeafReader
        Return the k nearest neighbor documents as determined by comparison of their vector values for this field, to the given vector, by the field's similarity function. The score of each document is derived from the vector similarity in a way that ensures scores are positive and that a larger score corresponds to a higher ranking.

        The search is allowed to be approximate, meaning the results are not guaranteed to be the true k closest neighbors. For large values of k (for example when k is close to the total number of documents), the search may also retrieve fewer than k documents.

        The returned TopDocs will contain a ScoreDoc for each nearest neighbor, in order of their similarity to the query vector (decreasing scores). The TotalHits contains the number of documents visited during the search. If the search stopped early because it hit visitedLimit, it is indicated through the relation TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO.

        The behavior is undefined if the given field doesn't have KNN vectors enabled on its FieldInfo. The return value is never null.

        Specified by:
        searchNearestVectors in class LeafReader
        Parameters:
        field - the vector field to search
        target - the vector-valued query
        knnCollector - collector with settings for gathering the vector results.
        acceptDocs - Bits that represents the allowed documents to match, or null if they are all allowed to match.
        Throws:
        IOException

      • searchNearestVectors

        public void searchNearestVectors​(String field,
                                 byte[] target,
                                 KnnCollector knnCollector,
                                 Bits acceptDocs)
                          throws IOException
        Description copied from class: LeafReader
        Return the k nearest neighbor documents as determined by comparison of their vector values for this field, to the given vector, by the field's similarity function. The score of each document is derived from the vector similarity in a way that ensures scores are positive and that a larger score corresponds to a higher ranking.

        The search is allowed to be approximate, meaning the results are not guaranteed to be the true k closest neighbors. For large values of k (for example when k is close to the total number of documents), the search may also retrieve fewer than k documents.

        The returned TopDocs will contain a ScoreDoc for each nearest neighbor, in order of their similarity to the query vector (decreasing scores). The TotalHits contains the number of documents visited during the search. If the search stopped early because it hit visitedLimit, it is indicated through the relation TotalHits.Relation.GREATER_THAN_OR_EQUAL_TO.

        The behavior is undefined if the given field doesn't have KNN vectors enabled on its FieldInfo. The return value is never null.

        Specified by:
        searchNearestVectors in class LeafReader
        Parameters:
        field - the vector field to search
        target - the vector-valued query
        knnCollector - collector with settings for gathering the vector results.
        acceptDocs - Bits that represents the allowed documents to match, or null if they are all allowed to match.
        Throws:
        IOException

      • getTermVectors

        public Fields getTermVectors​(int docID)
                      throws IOException
        Description copied from class: IndexReader
        Retrieve term vectors for this document, or null if term vectors were not indexed. The returned Fields instance acts like a single-document inverted index (the docID will be 0).
        Specified by:
        getTermVectors in class IndexReader
        Throws:
        IOException

      • termVectors

        public TermVectors termVectors()
                        throws IOException
        Description copied from class: IndexReader
        Returns a TermVectors reader for the term vectors of this index.

        This call never returns null, even if no term vectors were indexed. The returned instance should only be used by a single thread.

        Example: 

         TopDocs hits = searcher.search(query, 10);
 TermVectors termVectors = reader.termVectors();
 for (ScoreDoc hit : hits.scoreDocs) {
   Fields vector = termVectors.get(hit.doc);
 }
        Specified by:
        termVectors in class IndexReader
        Throws:
        IOException - If there is a low-level IO error

      • numDocs

        public int numDocs()
        Description copied from class: IndexReader
        Returns the number of documents in this index.

        NOTE: This operation may run in O(maxDoc). Implementations that can't return this number in constant-time should cache it.

        Specified by:
        numDocs in class IndexReader

      • maxDoc

        public int maxDoc()
        Description copied from class: IndexReader
        Returns one greater than the largest possible document number. This may be used to, e.g., determine how big to allocate an array which will have an element for every document number in an index.
        Specified by:
        maxDoc in class IndexReader

      • storedFields

        public StoredFields storedFields()
                          throws IOException
        Description copied from class: IndexReader
        Returns a StoredFields reader for the stored fields of this index.

        This call never returns null, even if no stored fields were indexed. The returned instance should only be used by a single thread.

        Example: 

         TopDocs hits = searcher.search(query, 10);
 StoredFields storedFields = reader.storedFields();
 for (ScoreDoc hit : hits.scoreDocs) {
   Document doc = storedFields.document(hit.doc);
 }
        Specified by:
        storedFields in class IndexReader
        Throws:
        IOException - If there is a low-level IO error

      • checkIntegrity

        public void checkIntegrity()
                    throws IOException
        Description copied from class: LeafReader
        Checks consistency of this reader.

        Note that this may be costly in terms of I/O, e.g. may involve computing a checksum value against large data files.

        Specified by:
        checkIntegrity in class LeafReader
        Throws:
        IOException