Class ToParentBlockJoinQuery
- java.lang.Object
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- org.apache.lucene.search.Query
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- org.apache.lucene.search.join.ToParentBlockJoinQuery
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- All Implemented Interfaces:
Serializable
,Cloneable
public class ToParentBlockJoinQuery extends org.apache.lucene.search.Query
This query requires that you index children and parent docs as a single block, using theIndexWriter.addDocuments(java.util.Collection<org.apache.lucene.document.Document>)
orIndexWriter.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 anFixedBitSet
per sub-reader.WARNING: to create the parents filter, always use
RawTermFilter
(so that the filter includes deleted docs), wrapped withCachingWrapperFilter
(so that the returned bit set per reader is aFixedBitSet
), 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 theToParentBlockJoinCollector
. 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 fromToParentBlockJoinCollector
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.
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
ToParentBlockJoinQuery.ScoreMode
How to aggregate multiple child hit scores into a single parent score.
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Constructor Summary
Constructors Constructor Description ToParentBlockJoinQuery(org.apache.lucene.search.Query childQuery, org.apache.lucene.search.Filter parentsFilter, ToParentBlockJoinQuery.ScoreMode scoreMode)
Create a ToParentBlockJoinQuery.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method 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)
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Constructor Detail
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ToParentBlockJoinQuery
public ToParentBlockJoinQuery(org.apache.lucene.search.Query childQuery, org.apache.lucene.search.Filter parentsFilter, ToParentBlockJoinQuery.ScoreMode scoreMode)
Create a ToParentBlockJoinQuery.- Parameters:
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.
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Method Detail
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createWeight
public org.apache.lucene.search.Weight createWeight(org.apache.lucene.search.Searcher searcher) throws IOException
- Overrides:
createWeight
in classorg.apache.lucene.search.Query
- Throws:
IOException
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extractTerms
public void extractTerms(Set<org.apache.lucene.index.Term> terms)
- Overrides:
extractTerms
in classorg.apache.lucene.search.Query
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rewrite
public org.apache.lucene.search.Query rewrite(org.apache.lucene.index.IndexReader reader) throws IOException
- Overrides:
rewrite
in classorg.apache.lucene.search.Query
- Throws:
IOException
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toString
public String toString(String field)
- Specified by:
toString
in classorg.apache.lucene.search.Query
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equals
public boolean equals(Object _other)
- Overrides:
equals
in classorg.apache.lucene.search.Query
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hashCode
public int hashCode()
- Overrides:
hashCode
in classorg.apache.lucene.search.Query
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clone
public Object clone()
- Overrides:
clone
in classorg.apache.lucene.search.Query
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