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.
Methods inherited from class org.apache.lucene.search.Query |
combine, getBoost, getSimilarity, mergeBooleanQueries, setBoost, toString, weight |
BlockJoinQuery
public BlockJoinQuery(org.apache.lucene.search.Query childQuery,
org.apache.lucene.search.Filter parentsFilter,
BlockJoinQuery.ScoreMode scoreMode)
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
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
Copyright © 2000-2011 Apache Software Foundation. All Rights Reserved.