# Package org.apache.lucene.queries.function

package org.apache.lucene.queries.function
Queries that compute score based upon a function.

Related Packages
Package
Description
org.apache.lucene.queries
Filters and Queries that add to core Lucene.
org.apache.lucene.queries.function.docvalues
FunctionValues for different data types.
org.apache.lucene.queries.function.valuesource
A variety of functions to use with FunctionQuery.
org.apache.lucene.queries.intervals
Intervals queries
org.apache.lucene.queries.mlt
Document similarity query generators.
org.apache.lucene.queries.payloads
The payloads package provides Query mechanisms for finding and using payloads.
org.apache.lucene.queries.spans
The calculus of spans.
Classes
Class
Description
FunctionMatchQuery
A query that retrieves all documents with a `DoubleValues` value matching a predicate
FunctionQuery
Returns a score for each document based on a ValueSource, often some function of the value of a field.
FunctionRangeQuery
A Query wrapping a `ValueSource` that matches docs in which the values in the value source match a configured range.
FunctionScoreQuery
A query that wraps another query, and uses a DoubleValuesSource to replace or modify the wrapped query's score
FunctionValues
Represents field values as different types.
FunctionValues.ValueFiller
Abstraction of the logic required to fill the value of a specified doc into a reusable `MutableValue`.
IndexReaderFunctions
Class exposing static helper methods for generating DoubleValuesSource instances over some IndexReader statistics
ValueSource
Instantiates `FunctionValues` for a particular reader.
ValueSourceScorer
`Scorer` which returns the result of `FunctionValues.floatVal(int)` as the score for a document, and which filters out documents that don't match `ValueSourceScorer.matches(int)`.