org.apache.lucene.search

Class CoveringQuery

java.lang.Object

org.apache.lucene.search.Query

org.apache.lucene.search.CoveringQuery

All Implemented Interfaces:

Accountable

public final class CoveringQuery
extends Query
implements Accountable

A Query that allows to have a configurable number or required matches per document. This is typically useful in order to build queries whose query terms must all appear in documents.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	CoveringQuery.CoveringWeight

Field Summary

Fields

Modifier and Type	Field and Description
private static long	BASE_RAM_BYTES
private int	hashCode
private LongValuesSource	minimumNumberMatch
private java.util.Collection<Query>	queries
private long	ramBytesUsed

Constructor Summary

Constructors

Constructor and Description
CoveringQuery(java.util.Collection<Query> queries, LongValuesSource minimumNumberMatch) Sole constructor.

Method Summary

Modifier and Type	Method and Description
private int	computeHashCode()
Weight	createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost) Expert: Constructs an appropriate Weight implementation for this query.
boolean	equals(java.lang.Object obj) Override and implement query instance equivalence properly in a subclass.
int	hashCode() Override and implement query hash code properly in a subclass.
long	ramBytesUsed() Return the memory usage of this object in bytes.
Query	rewrite(IndexReader reader) Expert: called to re-write queries into primitive queries.
java.lang.String	toString(java.lang.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

Methods inherited from interface org.apache.lucene.util.Accountable

getChildResources

Field Detail

BASE_RAM_BYTES

private static final long BASE_RAM_BYTES

queries

private final java.util.Collection<Query> queries

minimumNumberMatch

private final LongValuesSource minimumNumberMatch

hashCode

private final int hashCode

ramBytesUsed

private final long ramBytesUsed

Constructor Detail

CoveringQuery

public CoveringQuery(java.util.Collection<Query> queries,
                     LongValuesSource minimumNumberMatch)

Sole constructor.

Parameters:

queries - Sub queries to match.

minimumNumberMatch - Per-document long value that records how many queries should match. Values that are less than 1 are treated like 1: only documents that have at least one matching clause will be considered matches. Documents that do not have a value for minimumNumberMatch do not match.

Method Detail

toString

public java.lang.String toString(java.lang.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(java.lang.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()

computeHashCode

private int computeHashCode()

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)

ramBytesUsed

public long ramBytesUsed()

Description copied from interface: Accountable

Return the memory usage of this object in bytes. Negative values are illegal.

Specified by:

ramBytesUsed in interface Accountable

rewrite

public Query rewrite(IndexReader reader)
              throws java.io.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:

java.io.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 java.io.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:

java.io.IOException