public class ToParentBlockJoinQuery
extends org.apache.lucene.search.Query
IndexWriter.addDocuments(java.util.Collection<org.apache.lucene.document.Document>) or IndexWriter.updateDocuments(org.apache.lucene.index.Term, java.util.Collection<org.apache.lucene.document.Document>) 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.
WARNING: to create the parents filter, always use
RawTermFilter (so that the filter
includes deleted docs), wrapped with CachingWrapperFilter (so that the returned bit set per
reader is a FixedBitSet), specifying
DeletesMode.IGNORE (so that on reopen, the filter still
includes deleted docs). Failure to do this can result in
completely wrong documents being returned! For example:
Filter parents = new CachingWrapperFilter(
new RawTermFilter(new Term("parent", "yes")),
CachingWrapperFilter.DeletesMode.IGNORE);
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.ScoreMode
How to aggregate multiple child hit scores into a
single parent score.
|
| Constructor and Description |
|---|
ToParentBlockJoinQuery(org.apache.lucene.search.Query childQuery,
org.apache.lucene.search.Filter parentsFilter,
ToParentBlockJoinQuery.ScoreMode scoreMode)
Create a ToParentBlockJoinQuery.
|
| Modifier and Type | Method and Description |
|---|---|
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) |
int |
hashCode() |
org.apache.lucene.search.Query |
rewrite(org.apache.lucene.index.IndexReader reader) |
String |
toString(String field) |
public ToParentBlockJoinQuery(org.apache.lucene.search.Query childQuery,
org.apache.lucene.search.Filter parentsFilter,
ToParentBlockJoinQuery.ScoreMode scoreMode)
childQuery - Query matching child documents.parentsFilter - Filter (must produce FixedBitSet
per-seegment) identifying the parent documents.scoreMode - How to aggregate multiple child scores
into a single parent score.public org.apache.lucene.search.Weight createWeight(org.apache.lucene.search.Searcher searcher)
throws IOException
createWeight in class org.apache.lucene.search.QueryIOExceptionpublic void extractTerms(Set<org.apache.lucene.index.Term> terms)
extractTerms in class org.apache.lucene.search.Querypublic org.apache.lucene.search.Query rewrite(org.apache.lucene.index.IndexReader reader)
throws IOException
rewrite in class org.apache.lucene.search.QueryIOExceptionpublic String toString(String field)
toString in class org.apache.lucene.search.Querypublic boolean equals(Object _other)
equals in class org.apache.lucene.search.Querypublic int hashCode()
hashCode in class org.apache.lucene.search.Querypublic Object clone()
clone in class org.apache.lucene.search.QueryCopyright © 2000-2012 Apache Software Foundation. All Rights Reserved.