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java.lang.Object org.apache.lucene.search.Query org.apache.lucene.search.join.ToParentBlockJoinQuery
public class ToParentBlockJoinQuery
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 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 Summary | |
---|---|
ToParentBlockJoinQuery(Query childQuery,
Filter parentsFilter,
ScoreMode scoreMode)
Create a ToParentBlockJoinQuery. |
Method Summary | |
---|---|
Weight |
createWeight(IndexSearcher searcher)
|
boolean |
equals(Object _other)
|
void |
extractTerms(Set<Term> terms)
|
int |
hashCode()
|
Query |
rewrite(IndexReader reader)
|
String |
toString(String field)
|
Methods inherited from class org.apache.lucene.search.Query |
---|
clone, getBoost, setBoost, toString |
Methods inherited from class java.lang.Object |
---|
finalize, getClass, notify, notifyAll, wait, wait, wait |
Constructor Detail |
---|
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.Method Detail |
---|
public Weight createWeight(IndexSearcher searcher) throws IOException
createWeight
in class Query
IOException
public void extractTerms(Set<Term> terms)
extractTerms
in class Query
public Query rewrite(IndexReader reader) throws IOException
rewrite
in class Query
IOException
public String toString(String field)
toString
in class Query
public boolean equals(Object _other)
equals
in class Query
public int hashCode()
hashCode
in class Query
|
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