org.apache.lucene.search.join
Class BlockJoinQuery

java.lang.Object
  org.apache.lucene.search.Query
      org.apache.lucene.search.join.BlockJoinQuery

All Implemented Interfaces:

Serializable, Cloneable

public class BlockJoinQuery
extends org.apache.lucene.search.Query

This query requires that you index children and parent docs as a single block, using the IndexWriter.addDocuments(java.util.Collection) or IndexWriter.updateDocuments(org.apache.lucene.index.Term, java.util.Collection) 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 FixedBitSet 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.

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

If you'd like to retrieve TopGroups for the resulting query, use the BlockJoinCollector. Note that this is not necessary, ie, if you simply want to collect the parent documents and don't need to see which child documents matched under that parent, then you can use any collector.

NOTE: If the overall query contains parent-only matches, for example you OR a parent-only query with a joined child-only query, then the resulting collected documents will be correct, however the TopGroups you get from BlockJoinCollector will not contain every child for parents that had matched.

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

See Also:

Serialized Form

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

Nested Class Summary

static class

BlockJoinQuery.ScoreMode

Constructor Summary

BlockJoinQuery(org.apache.lucene.search.Query childQuery, org.apache.lucene.search.Filter parentsFilter, BlockJoinQuery.ScoreMode scoreMode)

Method Summary

Object	clone()
org.apache.lucene.search.Weight	createWeight(org.apache.lucene.search.Searcher searcher)
boolean	equals(Object _other)
void	extractTerms(Set<org.apache.lucene.index.Term> terms)
float	getBoost()
int	hashCode()
org.apache.lucene.search.Query	rewrite(org.apache.lucene.index.IndexReader reader)
void	setBoost(float boost)
String	toString(String field)

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

combine, getSimilarity, mergeBooleanQueries, toString, weight

Methods inherited from class java.lang.Object

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

Constructor Detail

BlockJoinQuery

public BlockJoinQuery(org.apache.lucene.search.Query childQuery,
                      org.apache.lucene.search.Filter parentsFilter,
                      BlockJoinQuery.ScoreMode scoreMode)

Method Detail

createWeight

public org.apache.lucene.search.Weight createWeight(org.apache.lucene.search.Searcher searcher)
                                             throws IOException

Overrides:

createWeight in class org.apache.lucene.search.Query

Throws:

IOException

extractTerms

public void extractTerms(Set<org.apache.lucene.index.Term> terms)

Overrides:

extractTerms in class org.apache.lucene.search.Query

rewrite

public org.apache.lucene.search.Query rewrite(org.apache.lucene.index.IndexReader reader)
                                       throws IOException

Overrides:

rewrite in class org.apache.lucene.search.Query

Throws:

IOException

toString

public String toString(String field)

Specified by:

toString in class org.apache.lucene.search.Query

setBoost

public void setBoost(float boost)

Overrides:

setBoost in class org.apache.lucene.search.Query

getBoost

public float getBoost()

Overrides:

getBoost in class org.apache.lucene.search.Query

equals

public boolean equals(Object _other)

Overrides:

equals in class org.apache.lucene.search.Query

hashCode

public int hashCode()

Overrides:

hashCode in class org.apache.lucene.search.Query

clone

public Object clone()

Overrides:

clone in class org.apache.lucene.search.Query