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 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.
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.
| Modifier and Type | Class and Description |
|---|---|
static class |
ToParentBlockJoinQuery.ChildrenMatchesScorer
Ascendant for
ToParentBlockJoinQuery's scorer. |
| Constructor and Description |
|---|
ToParentBlockJoinQuery(Query childQuery,
BitSetProducer parentsFilter,
ScoreMode scoreMode)
Create a ToParentBlockJoinQuery.
|
| Modifier and Type | Method and Description |
|---|---|
Weight |
createWeight(IndexSearcher searcher,
boolean needsScores)
Expert: Constructs an appropriate Weight implementation for this query.
|
boolean |
equals(Object other)
Override and implement query instance equivalence properly in a subclass.
|
Query |
getChildQuery()
Return our child query.
|
int |
hashCode()
Override and implement query hash code properly in a subclass.
|
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. |
classHash, sameClassAs, toStringpublic ToParentBlockJoinQuery(Query childQuery, BitSetProducer parentsFilter, ScoreMode scoreMode)
childQuery - Query matching child documents.parentsFilter - Filter identifying the parent documents.scoreMode - How to aggregate multiple child scores
into a single parent score.public Weight createWeight(IndexSearcher searcher, boolean needsScores) throws IOException
QueryOnly implemented by primitive queries, which re-write to themselves.
createWeight in class QueryneedsScores - True if document scores (Scorer.score()) or match
frequencies (Scorer.freq()) are needed.IOExceptionpublic Query getChildQuery()
public Query rewrite(IndexReader reader) throws IOException
Queryrewrite in class QueryIOExceptionpublic String toString(String field)
Queryfield assumed to be the
default field and omitted.public boolean equals(Object other)
QueryQueryCache works properly.
Typically a query will be equal to another only if it's an instance of
the same class and its document-filtering properties are identical that other
instance. Utility methods are provided for certain repetitive code.equals in class QueryQuery.sameClassAs(Object),
Query.classHash()public int hashCode()
QueryQueryCache works properly.hashCode in class QueryQuery.equals(Object)