Class ToParentBlockJoinQuery


  • public class ToParentBlockJoinQuery
    extends Query
    This query requires that you index children and parent docs as a single block, using the IndexWriter.addDocuments() or IndexWriter.updateDocuments() API. In each block, the child documents must appear first, ending with the parent document. At search time you provide a Filter identifying the parents, however this Filter must provide an BitSet per sub-reader.

    Once the block index is built, use this query to wrap any sub-query matching only child docs and join matches in that child document space up to the parent document space. You can then use this Query as a clause with other queries in the parent document space.

    See ToChildBlockJoinQuery if you need to join in the reverse order.

    The child documents must be orthogonal to the parent documents: the wrapped child query must never return a parent document.

    See org.apache.lucene.search.join for an overview.

    • Field Detail

      • childQuery

        private final Query childQuery
      • scoreMode

        private final ScoreMode scoreMode
    • Constructor Detail

      • ToParentBlockJoinQuery

        public ToParentBlockJoinQuery​(Query childQuery,
                                      BitSetProducer parentsFilter,
                                      ScoreMode scoreMode)
        Create a ToParentBlockJoinQuery.
        Parameters:
        childQuery - Query matching child documents.
        parentsFilter - Filter identifying the parent documents.
        scoreMode - How to aggregate multiple child scores into a single parent score.
    • Method Detail

      • visit

        public void visit​(QueryVisitor visitor)
        Description copied from class: Query
        Recurse through the query tree, visiting any child queries
        Overrides:
        visit in class Query
        Parameters:
        visitor - a QueryVisitor to be called by each query in the tree
      • createWeight

        public Weight createWeight​(IndexSearcher searcher,
                                   ScoreMode weightScoreMode,
                                   float boost)
                            throws java.io.IOException
        Description copied from class: Query
        Expert: Constructs an appropriate Weight implementation for this query.

        Only implemented by primitive queries, which re-write to themselves.

        Overrides:
        createWeight in class Query
        weightScoreMode - How the produced scorers will be consumed.
        boost - The boost that is propagated by the parent queries.
        Throws:
        java.io.IOException
      • getChildQuery

        public Query getChildQuery()
        Return our child query.
      • rewrite

        public Query rewrite​(IndexReader reader)
                      throws java.io.IOException
        Description copied from class: Query
        Expert: called to re-write queries into primitive queries. For example, a PrefixQuery will be rewritten into a BooleanQuery that consists of TermQuerys.
        Overrides:
        rewrite in class Query
        Throws:
        java.io.IOException
      • toString

        public java.lang.String toString​(java.lang.String field)
        Description copied from class: Query
        Prints a query to a string, with field assumed to be the default field and omitted.
        Specified by:
        toString in class Query
      • equals

        public boolean equals​(java.lang.Object other)
        Description copied from class: Query
        Override and implement query instance equivalence properly in a subclass. This is required so that QueryCache works properly. Typically a query will be equal to another only if it's an instance of the same class and its document-filtering properties are identical that other instance. Utility methods are provided for certain repetitive code.
        Specified by:
        equals in class Query
        See Also:
        Query.sameClassAs(Object), Query.classHash()
      • hashCode

        public int hashCode()
        Description copied from class: Query
        Override and implement query hash code properly in a subclass. This is required so that QueryCache works properly.
        Specified by:
        hashCode in class Query
        See Also:
        Query.equals(Object)