org.apache.lucene.search.join

Class ToChildBlockJoinQuery

java.lang.Object

org.apache.lucene.search.Query

org.apache.lucene.search.join.ToChildBlockJoinQuery

All Implemented Interfaces:

Serializable, Cloneable

public class ToChildBlockJoinQuery
extends Query

Just like ToParentBlockJoinQuery, except this query joins in reverse: you provide a Query matching parent documents and it joins down to child documents.

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);
 

See Also:

Serialized Form

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

Constructor Summary

Constructors

Constructor and Description
ToChildBlockJoinQuery(Query parentQuery, Filter parentsFilter, boolean doScores)

Method Summary

Methods

Modifier and Type	Method and Description
Object	clone() Returns a clone of this query.
Weight	createWeight(Searcher searcher) Expert: Constructs an appropriate Weight implementation for this query.
boolean	equals(Object _other)
void	extractTerms(Set<Term> terms) Expert: adds all terms occurring in this query to the terms set.
int	hashCode()
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.

Methods inherited from class org.apache.lucene.search.Query

combine, getBoost, getSimilarity, mergeBooleanQueries, setBoost, toString, weight

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ToChildBlockJoinQuery

public ToChildBlockJoinQuery(Query parentQuery,
                     Filter parentsFilter,
                     boolean doScores)

Method Detail

createWeight

public Weight createWeight(Searcher searcher)
                    throws IOException

Description copied from class: Query

Expert: Constructs an appropriate Weight implementation for this query.

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

Overrides:

createWeight in class Query

Throws:

IOException

extractTerms

public void extractTerms(Set<Term> terms)

Description copied from class: Query

Expert: adds all terms occurring in this query to the terms set. Only works if this query is in its rewritten form.

Overrides:

extractTerms in class Query

rewrite

public Query rewrite(IndexReader reader)
              throws IOException

Description copied from class: Query

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

Overrides:

rewrite in class Query

Throws:

IOException

toString

public String toString(String field)

Description copied from class: Query

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

The representation used is one that is supposed to be readable by QueryParser. However, there are the following limitations:

• If the query was created by the parser, the printed representation may not be exactly what was parsed. For example, characters that need to be escaped will be represented without the required backslash.
• Some of the more complicated queries (e.g. span queries) don't have a representation that can be parsed by QueryParser.

Specified by:

toString in class Query

equals

public boolean equals(Object _other)

Overrides:

equals in class Query

hashCode

public int hashCode()

Overrides:

hashCode in class Query

clone

public Object clone()

Description copied from class: Query

Returns a clone of this query.

Overrides:

clone in class Query