public class ToParentBlockJoinQuery extends Query
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 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.
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.
If you'd like to retrieveTopGroups
for the
resulting query, use the ToParentBlockJoinCollector
.
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 ToParentBlockJoinCollector
will not contain every
child for parents that had matched.
See org.apache.lucene.search.join
for an
overview.
Constructor and Description |
---|
ToParentBlockJoinQuery(Query childQuery,
Filter parentsFilter,
ScoreMode scoreMode)
Create a ToParentBlockJoinQuery.
|
Modifier and Type | Method and Description |
---|---|
Weight |
createWeight(IndexSearcher searcher)
Expert: Constructs an appropriate Weight implementation for this query.
|
boolean |
equals(Object _other) |
void |
extractTerms(Set<Term> terms)
Expert: adds all terms occurring in this query to the terms set.
|
int |
hashCode() |
Query |
rewrite(IndexReader reader)
Expert: called to re-write queries into primitive queries.
|
String |
toString(String field)
Prints a query to a string, with
field assumed to be the
default field and omitted. |
public ToParentBlockJoinQuery(Query childQuery, Filter parentsFilter, ScoreMode scoreMode)
childQuery
- Query matching child documents.parentsFilter
- Filter (must produce FixedBitSet
per-segment, like FixedBitSetCachingWrapperFilter
)
identifying the parent documents.scoreMode
- How to aggregate multiple child scores
into a single parent score.public Weight createWeight(IndexSearcher searcher) throws IOException
Query
Only implemented by primitive queries, which re-write to themselves.
createWeight
in class Query
IOException
public void extractTerms(Set<Term> terms)
Query
rewritten
form.extractTerms
in class Query
public Query rewrite(IndexReader reader) throws IOException
Query
rewrite
in class Query
IOException
public String toString(String field)
Query
field
assumed to be the
default field and omitted.Copyright © 2000-2016 The Apache Software Foundation. All Rights Reserved.