org.apache.lucene.search.join

Class ToParentBlockJoinQuery

java.lang.Object

org.apache.lucene.search.Query

org.apache.lucene.search.join.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.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Constructor Summary

Constructors

Constructor and Description
ToParentBlockJoinQuery(Query childQuery, BitSetProducer parentsFilter, ScoreMode scoreMode) Create a ToParentBlockJoinQuery.

Method Summary

Modifier and Type	Method and Description
Weight	createWeight(IndexSearcher searcher, ScoreMode weightScoreMode, float boost)
boolean	equals(Object other)
Query	getChildQuery() Return our child query.
int	hashCode()
Query	rewrite(IndexReader reader)
String	toString(String field)

Methods inherited from class org.apache.lucene.search.Query

classHash, sameClassAs, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

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

createWeight

public Weight createWeight(IndexSearcher searcher,
                           ScoreMode weightScoreMode,
                           float boost)
                    throws IOException

Overrides:

createWeight in class Query

Throws:

IOException

getChildQuery

public Query getChildQuery()

Return our child query.

rewrite

public Query rewrite(IndexReader reader)
              throws IOException

Overrides:

rewrite in class Query

Throws:

IOException

toString

public String toString(String field)

Specified by:

toString in class Query

equals

public boolean equals(Object other)

Specified by:

equals in class Query

hashCode

public int hashCode()

Specified by:

hashCode in class Query