org.apache.lucene.search.join
Class JoinUtil

java.lang.Object
  org.apache.lucene.search.join.JoinUtil

public final class JoinUtil
extends Object

Utility for query time joining using TermsQuery and TermsCollector.

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

Method Summary

static Query

createJoinQuery(String fromField, String toField, Query fromQuery, IndexSearcher fromSearcher) Method for query time joining.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

createJoinQuery

public static Query createJoinQuery(String fromField,
                                    String toField,
                                    Query fromQuery,
                                    IndexSearcher fromSearcher)
                             throws IOException

Method for query time joining.

Execute the returned query with a IndexSearcher to retrieve all documents that have the same terms in the to field that match with documents matching the specified fromQuery and have the same terms in the from field. Notice: Can't join documents with a fromField that holds more then one term.

Parameters:

fromField - The from field to join from

toField - The to field to join to

fromQuery - The query to match documents on the from side

fromSearcher - The searcher that executed the specified fromQuery

Returns:

a Query instance that can be used to join documents based on the terms in the from and to field

Throws:

IOException - If I/O related errors occur