org.apache.lucene.search

Class IndexOrDocValuesQuery

java.lang.Object

org.apache.lucene.search.Query

org.apache.lucene.search.IndexOrDocValuesQuery

public final class IndexOrDocValuesQuery
extends Query

A query that uses either an index structure (points or terms) or doc values in order to run a query, depending which one is more efficient. This is typically useful for range queries, whose Weight.scorer(org.apache.lucene.index.LeafReaderContext) is costly to create since it usually needs to sort large lists of doc ids. For instance, for a field that both indexed LongPoints and SortedNumericDocValuesFields with the same values, an efficient range query could be created by doing:

   String field;
   long minValue, maxValue;
   Query pointQuery = LongPoint.newRangeQuery(field, minValue, maxValue);
   Query dvQuery = SortedNumericDocValuesField.newSlowRangeQuery(field, minValue, maxValue);
   Query query = new IndexOrDocValuesQuery(pointQuery, dvQuery);
 

The above query will be efficient as it will use points in the case that they perform better, ie. when we need a good lead iterator that will be almost entirely consumed; and doc values otherwise, ie. in the case that another part of the query is already leading iteration but we still need the ability to verify that some documents match.

NOTEThis query currently only works well with point range/exact queries and their equivalent doc values queries.

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

Constructor Summary

Constructors

Constructor and Description
IndexOrDocValuesQuery(Query indexQuery, Query dvQuery) Create an IndexOrDocValuesQuery.

Method Summary

Modifier and Type	Method and Description
Weight	createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost) Expert: Constructs an appropriate Weight implementation for this query.
boolean	equals(Object obj) Override and implement query instance equivalence properly in a subclass.
Query	getIndexQuery() Return the wrapped query that may be costly to initialize but has a good iterator.
Query	getRandomAccessQuery() Return the wrapped query that may be slow at identifying all matching documents, but which is cheap to initialize and can efficiently verify that some documents match.
int	hashCode() Override and implement query hash code properly in a subclass.
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.
void	visit(QueryVisitor visitor) Recurse through the query tree, visiting any child queries

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

classHash, sameClassAs, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

IndexOrDocValuesQuery

public IndexOrDocValuesQuery(Query indexQuery,
                             Query dvQuery)

Create an IndexOrDocValuesQuery. Both provided queries must match the same documents and give the same scores.

Parameters:

indexQuery - a query that has a good iterator but whose scorer may be costly to create

dvQuery - a query whose scorer is cheap to create that can quickly check whether a given document matches

Method Detail

getIndexQuery

public Query getIndexQuery()

Return the wrapped query that may be costly to initialize but has a good iterator.

getRandomAccessQuery

public Query getRandomAccessQuery()

Return the wrapped query that may be slow at identifying all matching documents, but which is cheap to initialize and can efficiently verify that some documents match.

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.

Specified by:

toString in class Query

equals

public boolean equals(Object obj)

Description copied from class: Query

Override and implement query instance equivalence properly in a subclass. This is required so that QueryCache works properly. Typically a query will be equal to another only if it's an instance of the same class and its document-filtering properties are identical that other instance. Utility methods are provided for certain repetitive code.

Specified by:

equals in class Query

See Also:

Query.sameClassAs(Object), Query.classHash()

hashCode

public int hashCode()

Description copied from class: Query

Override and implement query hash code properly in a subclass. This is required so that QueryCache works properly.

Specified by:

hashCode in class Query

See Also:

Query.equals(Object)

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

visit

public void visit(QueryVisitor visitor)

Description copied from class: Query

Recurse through the query tree, visiting any child queries

Overrides:

visit in class Query

Parameters:

visitor - a QueryVisitor to be called by each query in the tree

createWeight

public Weight createWeight(IndexSearcher searcher,
                           ScoreMode scoreMode,
                           float boost)
                    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

scoreMode - How the produced scorers will be consumed.

boost - The boost that is propagated by the parent queries.

Throws:

IOException