Class ToParentBlockJoinQuery

This query requires that you index children and parent docs as a single block, using the AddDocuments(IEnumerable<IEnumerable<IIndexableField>>, Analyzer) or UpdateDocuments(Term, IEnumerable<IEnumerable<IIndexableField>>, Analyzer) API. In each block, the child documents must appear first, ending with the parent document. At search time you provide a Lucene.Net.Search.Filter identifying the parents, however this Lucene.Net.Search.Filter must provide an Lucene.Net.Util.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 Lucene.Net.Search.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 retrieve Lucene.Net.Search.Grouping.ITopGroups<TGroupValue> 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 Lucene.Net.Search.Grouping.ITopGroups<TGroupValue> you get from ToParentBlockJoinCollector will not contain every child for parents that had matched.

See http://lucene.apache.org/core/4_8_0/join/ for an overview.

Note

This API is experimental and might change in incompatible ways in the next release.

Inheritance

object

Query

ToParentBlockJoinQuery

Inherited Members

Query.Boost

Query.ToString()

Query.Clone()

object.Equals(object, object)

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

Namespace: Lucene.Net.Search.Join

Assembly: Lucene.Net.Join.dll

Syntax

public class ToParentBlockJoinQuery : Query

Constructors

ToParentBlockJoinQuery(Query, Filter, ScoreMode)

Create a ToParentBlockJoinQuery.

Declaration

public ToParentBlockJoinQuery(Query childQuery, Filter parentsFilter, ScoreMode scoreMode)

Parameters

Type	Name	Description
Query	childQuery	Lucene.Net.Search.Query matching child documents.
Filter	parentsFilter	Lucene.Net.Search.Filter (must produce Lucene.Net.Util.FixedBitSet per-segment, like FixedBitSetCachingWrapperFilter) identifying the parent documents.
ScoreMode	scoreMode	How to aggregate multiple child scores into a single parent score.

Methods

CreateWeight(IndexSearcher)

Expert: Constructs an appropriate Lucene.Net.Search.Weight implementation for this query.

Only implemented by primitive queries, which re-write to themselves.

Declaration

public override Weight CreateWeight(IndexSearcher searcher)

Parameters

Type	Name	Description
IndexSearcher	searcher

Returns

Type	Description
Weight

Overrides

Lucene.Net.Search.Query.CreateWeight(Lucene.Net.Search.IndexSearcher)

Equals(object)

Determines whether the specified object is equal to the current object.

Declaration

public override bool Equals(object obj)

Parameters

Type	Name	Description
object	obj	The object to compare with the current object.

Returns

Type	Description
bool	true if the specified object is equal to the current object; otherwise, false.

Overrides

Query.Equals(object)

ExtractTerms(ISet<Term>)

Expert: adds all terms occurring in this query to the terms set. Only works if this query is in its rewritten (Lucene.Net.Search.Query.Rewrite(Lucene.Net.Index.IndexReader)) form.

Declaration

public override void ExtractTerms(ISet<Term> terms)

Parameters

Type	Name	Description
ISet<Term>	terms

Overrides

Query.ExtractTerms(ISet<Term>)

Exceptions

Type	Condition
InvalidOperationException	If this query is not yet rewritten

GetHashCode()

Serves as the default hash function.

Declaration

public override int GetHashCode()

Returns

Type	Description
int	A hash code for the current object.

Overrides

Lucene.Net.Search.Query.GetHashCode()

Rewrite(IndexReader)

Expert: called to re-write queries into primitive queries. For example, a Lucene.Net.Search.PrefixQuery will be rewritten into a Lucene.Net.Search.BooleanQuery that consists of Lucene.Net.Search.TermQuerys.

Declaration

public override Query Rewrite(IndexReader reader)

Parameters

Type	Name	Description
IndexReader	reader

Returns

Type	Description
Query

Overrides

Lucene.Net.Search.Query.Rewrite(Lucene.Net.Index.IndexReader)

ToString(string)

Prints a query to a string, with field assumed to be the default field and omitted.

Declaration

public override string ToString(string field)

Parameters

Type	Name	Description
string	field

Returns

Type	Description
string

Overrides

Query.ToString(string)