public class

CustomScoreQuery

extends Query
java.lang.Object
   ↳ org.apache.lucene.search.Query
     ↳ org.apache.lucene.search.function.CustomScoreQuery

Class Overview

Query that sets document score as a programmatic function of several (sub) scores:

  1. the score of its subQuery (any query)
  2. (optional) the score of its ValueSourceQuery (or queries). For most simple/convenient use cases this query is likely to be a FieldScoreQuery
Subclasses can modify the computation by overriding getCustomScoreProvider(IndexReader).

WARNING: The status of the search.function package is experimental. The APIs introduced here might change in the future and will not be supported anymore in such a case.

Summary

Public Constructors
CustomScoreQuery(Query subQuery)
Create a CustomScoreQuery over input subQuery.
CustomScoreQuery(Query subQuery, ValueSourceQuery valSrcQuery)
Create a CustomScoreQuery over input subQuery and a ValueSourceQuery.
CustomScoreQuery(Query subQuery, ValueSourceQuery... valSrcQueries)
Create a CustomScoreQuery over input subQuery and a ValueSourceQuery.
Public Methods
Object clone()
Returns a clone of this query.
Weight createWeight(Searcher searcher)
Expert: Constructs an appropriate Weight implementation for this query.
Explanation customExplain(int doc, Explanation subQueryExpl, Explanation valSrcExpl)
This method is deprecated. Will be removed in Lucene 3.1. The doc is relative to the current reader, which is unknown to CustomScoreQuery when using per-segment search (since Lucene 2.9). Please override getCustomScoreProvider(IndexReader) and return a subclass of CustomScoreProvider for the given IndexReader.
Explanation customExplain(int doc, Explanation subQueryExpl, Explanation[] valSrcExpls)
This method is deprecated. Will be removed in Lucene 3.1. The doc is relative to the current reader, which is unknown to CustomScoreQuery when using per-segment search (since Lucene 2.9). Please override getCustomScoreProvider(IndexReader) and return a subclass of CustomScoreProvider for the given IndexReader.
float customScore(int doc, float subQueryScore, float[] valSrcScores)
This method is deprecated. Will be removed in Lucene 3.1. The doc is relative to the current reader, which is unknown to CustomScoreQuery when using per-segment search (since Lucene 2.9). Please override getCustomScoreProvider(IndexReader) and return a subclass of CustomScoreProvider for the given IndexReader.
float customScore(int doc, float subQueryScore, float valSrcScore)
This method is deprecated. Will be removed in Lucene 3.1. The doc is relative to the current reader, which is unknown to CustomScoreQuery when using per-segment search (since Lucene 2.9). Please override getCustomScoreProvider(IndexReader) and return a subclass of CustomScoreProvider for the given IndexReader.
boolean equals(Object o)
Returns true if o is equal to this.
void extractTerms(Set<Term> terms)
Expert: adds all terms occurring in this query to the terms set.
int hashCode()
Returns a hash code value for this object.
boolean isStrict()
Checks if this is strict custom scoring.
String name()
A short name of this query, used in toString(String).
Query rewrite(IndexReader reader)
Expert: called to re-write queries into primitive queries.
void setStrict(boolean strict)
Set the strict mode of this query.
String toString(String field)
Prints a query to a string, with field assumed to be the default field and omitted.
Protected Methods
CustomScoreProvider getCustomScoreProvider(IndexReader reader)
Returns a CustomScoreProvider that calculates the custom scores for the given IndexReader.
[Expand]
Inherited Methods
From class org.apache.lucene.search.Query
From class java.lang.Object

Public Constructors

public CustomScoreQuery (Query subQuery)

Create a CustomScoreQuery over input subQuery.

Parameters
subQuery the sub query whose scored is being customed. Must not be null.

public CustomScoreQuery (Query subQuery, ValueSourceQuery valSrcQuery)

Create a CustomScoreQuery over input subQuery and a ValueSourceQuery.

Parameters
subQuery the sub query whose score is being customized. Must not be null.
valSrcQuery a value source query whose scores are used in the custom score computation. For most simple/convenient use case this would be a FieldScoreQuery. This parameter is optional - it can be null.

public CustomScoreQuery (Query subQuery, ValueSourceQuery... valSrcQueries)

Create a CustomScoreQuery over input subQuery and a ValueSourceQuery.

Parameters
subQuery the sub query whose score is being customized. Must not be null.
valSrcQueries value source queries whose scores are used in the custom score computation. For most simple/convenient use case these would be FieldScoreQueries. This parameter is optional - it can be null or even an empty array.

Public Methods

public Object clone ()

Returns a clone of this query.

public Weight createWeight (Searcher searcher)

Expert: Constructs an appropriate Weight implementation for this query.

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

Throws
IOException

public Explanation customExplain (int doc, Explanation subQueryExpl, Explanation valSrcExpl)

This method is deprecated.
Will be removed in Lucene 3.1. The doc is relative to the current reader, which is unknown to CustomScoreQuery when using per-segment search (since Lucene 2.9). Please override getCustomScoreProvider(IndexReader) and return a subclass of CustomScoreProvider for the given IndexReader.

Explain the custom score.

See Also

public Explanation customExplain (int doc, Explanation subQueryExpl, Explanation[] valSrcExpls)

This method is deprecated.
Will be removed in Lucene 3.1. The doc is relative to the current reader, which is unknown to CustomScoreQuery when using per-segment search (since Lucene 2.9). Please override getCustomScoreProvider(IndexReader) and return a subclass of CustomScoreProvider for the given IndexReader.

Explain the custom score.

See Also

public float customScore (int doc, float subQueryScore, float[] valSrcScores)

This method is deprecated.
Will be removed in Lucene 3.1. The doc is relative to the current reader, which is unknown to CustomScoreQuery when using per-segment search (since Lucene 2.9). Please override getCustomScoreProvider(IndexReader) and return a subclass of CustomScoreProvider for the given IndexReader.

Compute a custom score by the subQuery score and a number of ValueSourceQuery scores.

See Also

public float customScore (int doc, float subQueryScore, float valSrcScore)

This method is deprecated.
Will be removed in Lucene 3.1. The doc is relative to the current reader, which is unknown to CustomScoreQuery when using per-segment search (since Lucene 2.9). Please override getCustomScoreProvider(IndexReader) and return a subclass of CustomScoreProvider for the given IndexReader.

Compute a custom score by the subQuery score and the ValueSourceQuery score.

See Also

public boolean equals (Object o)

Returns true if o is equal to this.

public void extractTerms (Set<Term> terms)

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

public int hashCode ()

Returns a hash code value for this object.

public boolean isStrict ()

Checks if this is strict custom scoring. In strict custom scoring, the ValueSource part does not participate in weight normalization. This may be useful when one wants full control over how scores are modified, and does not care about normalizing by the ValueSource part. One particular case where this is useful if for testing this query.

Note: only has effect when the ValueSource part is not null.

public String name ()

A short name of this query, used in toString(String).

public Query rewrite (IndexReader reader)

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

Throws
IOException

public void setStrict (boolean strict)

Set the strict mode of this query.

Parameters
strict The strict mode to set.
See Also

public String toString (String field)

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.

Protected Methods

protected CustomScoreProvider getCustomScoreProvider (IndexReader reader)

Returns a CustomScoreProvider that calculates the custom scores for the given IndexReader. The default implementation returns a default implementation as specified in the docs of CustomScoreProvider.

Throws
IOException