# All Classes

- All Classes Interface Summary Class Summary Enum Summary Exception Summary
  Class | Description
  --- | ---
  AveragePayloadFunction | Calculate the final score as the average score of all payloads seen.
  BoolDocValues | Abstract `FunctionValues` implementation which supports retrieving boolean values.
  BoolFunction | Abstract parent class for those `ValueSource` implementations which apply boolean logic to their values
  ByteKnnVectorFieldSource | An implementation for retrieving `FunctionValues` instances for byte knn vectors fields.
  BytesRefFieldSource | An implementation for retrieving `FunctionValues` instances for string based fields.
  ByteVectorSimilarityFunction | `ByteVectorSimilarityFunction` returns a similarity function between two knn vectors with byte elements.
  CommonTermsQuery | A query that executes high-frequency terms in a optional sub-query to prevent slow queries due to "common" terms like stopwords.
  ComparisonBoolFunction | Base class for comparison operators useful within an "if"/conditional.
  ConstKnnByteVectorValueSource | Function that returns a constant byte vector value for every document.
  ConstKnnFloatValueSource | Function that returns a constant float vector value for every document.
  ConstNumberSource | `ConstNumberSource` is the base class for all constant numbers
  ConstValueSource | `ConstValueSource` returns a constant for all documents
  DefFunction | `ValueSource` implementation which only returns the values from the provided ValueSources which are available for a particular docId.
  DivFloatFunction | Function to divide "a" by "b"
  DocFreqValueSource | `DocFreqValueSource` returns the number of documents containing the term.
  DocTermsIndexDocValues | Serves as base class for FunctionValues based on DocTermsIndex.
  DocTermsIndexDocValues.DocTermsIndexException | Custom Exception to be thrown when the DocTermsIndex for a field cannot be generated
  DoubleConstValueSource | Function that returns a constant double value for every document.
  DoubleDocValues | Abstract `FunctionValues` implementation which supports retrieving double values.
  DoubleFieldSource | Obtains double field values from `LeafReader.getNumericDocValues(java.lang.String)` and makes those values available as other numeric types, casting as needed.
  DualFloatFunction | Abstract `ValueSource` implementation which wraps two ValueSources and applies an extendible float function to their values.
  EnumFieldSource | Obtains int field values from `LeafReader.getNumericDocValues(java.lang.String)` and makes those values available as other numeric types, casting as needed.
  FieldCacheSource | A base class for ValueSource implementations that retrieve values for a single field from DocValues.
  FieldMaskingSpanQuery | Wrapper to allow `SpanQuery` objects participate in composite single-field SpanQueries by 'lying' about their search field.
  FilteredIntervalsSource | An IntervalsSource that filters the intervals from another IntervalsSource
  FilterSpans | A `Spans` implementation wrapping another spans instance, allowing to filter spans matches easily by implementing `FilterSpans.accept(org.apache.lucene.queries.spans.Spans)`
  FilterSpans.AcceptStatus | Status returned from `FilterSpans.accept(Spans)` that indicates whether a candidate match should be accepted, rejected, or rejected and move on to the next document.
  FloatDocValues | Abstract `FunctionValues` implementation which supports retrieving float values.
  FloatFieldSource | Obtains float field values from `LeafReader.getNumericDocValues(java.lang.String)` and makes those values available as other numeric types, casting as needed.
  FloatKnnVectorFieldSource | An implementation for retrieving `FunctionValues` instances for float knn vectors fields.
  FloatVectorSimilarityFunction | `FloatVectorSimilarityFunction` returns a similarity function between two knn vectors with float elements.
  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`.
  IDFValueSource | Function that returns `#idf(long, long)` for every document.
  IfFunction | Depending on the boolean value of the `ifSource` function, returns the value of the `trueSource` or `falseSource` function.
  IndexReaderFunctions | Class exposing static helper methods for generating DoubleValuesSource instances over some IndexReader statistics
  IntDocValues | Abstract `FunctionValues` implementation which supports retrieving int values.
  IntervalFilter | Wraps an `IntervalIterator` and passes through those intervals that match the `IntervalFilter.accept()` function
  IntervalIterator | A `DocIdSetIterator` that also allows iteration over matching intervals in a document.
  IntervalMatchesIterator | An extension of MatchesIterator that allows it to be treated as an IntervalIterator
  IntervalQuery | A query that retrieves documents containing intervals returned from an `IntervalsSource`
  Intervals | Factory functions for creating `interval sources`.
  IntervalsSource | A helper class for `IntervalQuery` that provides an `IntervalIterator` for a given field and segment
  IntFieldSource | Obtains int field values from `LeafReader.getNumericDocValues(java.lang.String)` and makes those values available as other numeric types, casting as needed.
  JoinDocFreqValueSource | Use a field value and find the Document Frequency within another field.
  LinearFloatFunction | `LinearFloatFunction` implements a linear function over another `ValueSource`.
  LiteralValueSource | Pass a the field value through as a String, no matter the type // Q: doesn't this mean it's a "string"?
  LongDocValues | Abstract `FunctionValues` implementation which supports retrieving long values.
  LongFieldSource | Obtains long field values from `LeafReader.getNumericDocValues(java.lang.String)` and makes those values available as other numeric types, casting as needed.
  MaxDocValueSource | Returns the value of `IndexReader.maxDoc()` for every document.
  MaxFloatFunction | `MaxFloatFunction` returns the max of its components.
  MaxPayloadFunction | Returns the maximum payload score seen, else 1 if there are no payloads on the doc.
  MinFloatFunction | `MinFloatFunction` returns the min of its components.
  MinPayloadFunction | Calculates the minimum payload seen
  MoreLikeThis | Generate "more like this" similarity queries.
  MoreLikeThisQuery | A simple wrapper for MoreLikeThis for use in scenarios where a Query object is required eg in custom QueryParser extensions.
  MultiBoolFunction | Abstract `ValueSource` implementation which wraps multiple ValueSources and applies an extendible boolean function to their values.
  MultiFloatFunction | Abstract `ValueSource` implementation which wraps multiple ValueSources and applies an extendible float function to their values.
  MultiFunction | Abstract parent class for `ValueSource` implementations that wrap multiple ValueSources and apply their own logic.
  MultiValuedDoubleFieldSource | Obtains double field values from `LeafReader.getSortedNumericDocValues(java.lang.String)` and using a `SortedNumericSelector` it gives a single-valued ValueSource view of a field.
  MultiValuedFloatFieldSource | Obtains float field values from `LeafReader.getSortedNumericDocValues(java.lang.String)` and using a `SortedNumericSelector` it gives a single-valued ValueSource view of a field.
  MultiValuedIntFieldSource | Obtains int field values from `LeafReader.getSortedNumericDocValues(java.lang.String)` and using a `SortedNumericSelector` it gives a single-valued ValueSource view of a field.
  MultiValuedLongFieldSource | Obtains long field values from `LeafReader.getSortedNumericDocValues(java.lang.String)` and using a `SortedNumericSelector` it gives a single-valued ValueSource view of a field.
  MultiValueSource | A `ValueSource` that abstractly represents `ValueSource`s for poly fields, and other things.
  NearSpansOrdered | A Spans that is formed from the ordered subspans of a SpanNearQuery where the subspans do not overlap and have a maximum slop between them.
  NearSpansUnordered | Similar to `NearSpansOrdered`, but for the unordered case.
  NormValueSource | Function that returns the decoded norm for every document.
  NumDocsValueSource | Returns the value of `IndexReader.numDocs()` for every document.
  PayloadDecoder | Defines a way of converting payloads to float values, for use by `PayloadScoreQuery`
  PayloadFunction | An abstract class that defines a way for PayloadScoreQuery instances to transform the cumulative effects of payload scores for a document.
  PayloadMatcher | Defines an interface for testing if two payloads should be consider to match
  PayloadMatcherFactory | Creates a payload matcher object based on a payload type and an operation.
  PayloadScoreQuery | A Query class that uses a `PayloadFunction` to modify the score of a wrapped SpanQuery
  PowFloatFunction | Function to raise the base "a" to the power "b"
  ProductFloatFunction | `ProductFloatFunction` returns the product of its components.
  QueryValueSource | `QueryValueSource` returns the relevance score of the query
  RangeMapFloatFunction | `RangeMapFloatFunction` implements a map function over another `ValueSource` whose values fall within min and max inclusive to target.
  ReciprocalFloatFunction | `ReciprocalFloatFunction` implements a reciprocal function f(x) = a/(mx+b), based on the float value of a field or function as exported by `ValueSource`.
  ScaleFloatFunction | Scales values to be between min and max.
  SimpleBoolFunction | `BoolFunction` implementation which applies an extendible boolean function to the values of a single wrapped `ValueSource`.
  SimpleFloatFunction | A simple float function with a single argument
  SingleFunction | A function with a single argument
  SortedSetFieldSource | Retrieves `FunctionValues` instances for multi-valued string based fields.
  SpanCollector | An interface defining the collection of postings information from the leaves of a `Spans`
  SpanContainingQuery | Keep matches that contain another SpanScorer.
  SpanDisiWrapper | Wrapper used in `SpanDisiPriorityQueue`.
  SpanFirstQuery | Matches spans near the beginning of a field.
  SpanMultiTermQueryWrapper<Q extends MultiTermQuery> | Wraps any `MultiTermQuery` as a `SpanQuery`, so it can be nested within other SpanQuery classes.
  SpanMultiTermQueryWrapper.SpanRewriteMethod | Abstract class that defines how the query is rewritten.
  SpanMultiTermQueryWrapper.TopTermsSpanBooleanQueryRewrite | A rewrite method that first translates each term into a SpanTermQuery in a `BooleanClause.Occur.SHOULD` clause in a BooleanQuery, and keeps the scores as computed by the query.
  SpanNearQuery | Matches spans which are near one another.
  SpanNearQuery.Builder | A builder for SpanNearQueries
  SpanNotQuery | Removes matches which overlap with another SpanQuery or which are within x tokens before or y tokens after another SpanQuery.
  SpanOrQuery | Matches the union of its clauses.
  SpanPayloadCheckQuery | Only return those matches that have a specific payload at the given position.
  SpanPayloadCheckQuery.MatchOperation | The payload type.
  SpanPayloadCheckQuery.PayloadType | The payload type.
  SpanPositionCheckQuery | Base class for filtering a SpanQuery based on the position of a match.
  SpanPositionRangeQuery | Checks to see if the `SpanPositionCheckQuery.getMatch()` lies between a start and end position
  SpanQuery | Base class for span-based queries.
  Spans | Iterates through combinations of start/end positions per-doc.
  SpanScorer | A basic `Scorer` over `Spans`.
  SpanTermQuery | Matches spans containing a term.
  SpanWeight | Expert-only.
  SpanWeight.Postings | Enumeration defining what postings information should be retrieved from the index for a given Spans
  SpanWithinQuery | Keep matches that are contained within another Spans.
  StrDocValues | Abstract `FunctionValues` implementation which supports retrieving String values.
  SumFloatFunction | `SumFloatFunction` returns the sum of its components.
  SumPayloadFunction | Calculate the final score as the sum of scores of all payloads seen.
  SumTotalTermFreqValueSource | `SumTotalTermFreqValueSource` returns the number of tokens.
  TermFreqValueSource | Function that returns `PostingsEnum.freq()` for the supplied term in every document.
  TermSpans | Expert: Public for extension only.
  TFValueSource | Function that returns `TFIDFSimilarity.tf(float)` for every document.
  TotalTermFreqValueSource | `TotalTermFreqValueSource` returns the total term freq (sum of term freqs across all documents).
  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)`.
  VectorFieldFunction | An implementation for retrieving `FunctionValues` instances for knn vectors fields.
  VectorSimilarityFunction | `VectorSimilarityFunction` returns a similarity function between two knn vectors.
  VectorValueSource | Converts individual ValueSource instances to leverage the FunctionValues *Val functions that work with multiple values, i.e.