All Classes

Class	Description
AfterEffect	This class acts as the base class for the implementations of the first normalization of the informative content in the DFR framework.
AfterEffect.NoAfterEffect	Implementation used when there is no aftereffect.
AfterEffectB	Model of the information gain based on the ratio of two Bernoulli processes.
AfterEffectL	Model of the information gain based on Laplace's law of succession.
AlreadyClosedException	This exception is thrown when there is an attempt to access something that has already been closed.
Analyzer	An Analyzer builds TokenStreams, which analyze text.
Analyzer.GlobalReuseStrategy	Deprecated. This implementation class will be hidden in Lucene 5.0.
Analyzer.PerFieldReuseStrategy	Deprecated. This implementation class will be hidden in Lucene 5.0.
Analyzer.ReuseStrategy	Strategy defining how TokenStreamComponents are reused per call to Analyzer.tokenStream(String, java.io.Reader).
Analyzer.TokenStreamComponents	This class encapsulates the outer components of a token stream.
AnalyzerWrapper	Extension to Analyzer suitable for Analyzers which wrap other Analyzers.
AppendingDeltaPackedLongBuffer	Utility class to buffer a list of signed longs in memory.
AppendingPackedLongBuffer	Utility class to buffer a list of signed longs in memory.
ArrayUtil	Methods for manipulating arrays.
AtomicReader	AtomicReader is an abstract class, providing an interface for accessing an index.
AtomicReaderContext	IndexReaderContext for AtomicReader instances.
Attribute	Base interface for attributes.
AttributeImpl	Base class for Attributes that can be added to a AttributeSource.
AttributeReflector	This interface is used to reflect contents of AttributeSource or AttributeImpl.
AttributeSource	An AttributeSource contains a list of different AttributeImpls, and methods to add and get them.
AttributeSource.AttributeFactory	An AttributeFactory creates instances of AttributeImpls.
AttributeSource.State	This class holds the state of an AttributeSource.
Automaton	Finite-state automaton with regular expression operations.
AutomatonProvider	Automaton provider for RegExp. RegExp.toAutomaton(AutomatonProvider)
AutomatonQuery	A Query that will match terms against a finite-state machine.
AveragePayloadFunction	Calculate the final score as the average score of all payloads seen.
BaseCompositeReader<R extends IndexReader>	Base class for implementing CompositeReaders based on an array of sub-readers.
BaseDirectory	Base implementation for a concrete Directory.
BasicAutomata	Construction of basic automata.
BasicModel	This class acts as the base class for the specific basic model implementations in the DFR framework.
BasicModelBE	Limiting form of the Bose-Einstein model.
BasicModelD	Implements the approximation of the binomial model with the divergence for DFR.
BasicModelG	Geometric as limiting form of the Bose-Einstein model.
BasicModelIF	An approximation of the I(ne) model.
BasicModelIn	The basic tf-idf model of randomness.
BasicModelIne	Tf-idf model of randomness, based on a mixture of Poisson and inverse document frequency.
BasicModelP	Implements the Poisson approximation for the binomial model for DFR.
BasicOperations	Basic automata operations.
BasicStats	Stores all statistics commonly used ranking methods.
BinaryDocValues	A per-document byte[]
BinaryDocValuesField	Field that stores a per-document BytesRef value.
Bits	Interface for Bitset-like structures.
Bits.MatchAllBits	Bits impl of the specified length with all bits set.
Bits.MatchNoBits	Bits impl of the specified length with no bits set.
BitsFilteredDocIdSet	This implementation supplies a filtered DocIdSet, that excludes all docids which are not in a Bits instance.
BitUtil	A variety of high efficiency bit twiddling routines.
BlockPackedReader	Provides random access to a stream written with BlockPackedWriter.
BlockPackedReaderIterator	Reader for sequences of longs written with BlockPackedWriter.
BlockPackedWriter	A writer for large sequences of longs.
BlockTermState	Holds all state required for PostingsReaderBase to produce a DocsEnum without re-seeking the terms dict.
BlockTreeTermsReader	A block-based terms index and dictionary that assigns terms to variable length blocks according to how they share prefixes.
BlockTreeTermsReader.Stats	BlockTree statistics for a single field returned by BlockTreeTermsReader.FieldReader.computeStats().
BlockTreeTermsWriter	Block-based terms index and dictionary writer.
BM25Similarity	BM25 Similarity.
BooleanClause	A clause in a BooleanQuery.
BooleanClause.Occur	Specifies how clauses are to occur in matching documents.
BooleanQuery	A Query that matches documents matching boolean combinations of other queries, e.g.
BooleanQuery.TooManyClauses	Thrown when an attempt is made to add more than BooleanQuery.getMaxClauseCount() clauses.
BoostAttribute	Add this Attribute to a TermsEnum returned by MultiTermQuery.getTermsEnum(Terms,AttributeSource) and update the boost on each returned term.
BoostAttributeImpl	Implementation class for BoostAttribute.
BroadWord	Methods and constants inspired by the article "Broadword Implementation of Rank/Select Queries" by Sebastiano Vigna, January 30, 2012: algorithm 1: BroadWord.bitCount(long), count of set bits in a long algorithm 2: BroadWord.select(long, int), selection of a set bit in a long, bytewise signed smaller <8 operator: BroadWord.smallerUpTo7_8(long,long).
BufferedIndexInput	Base implementation class for buffered IndexInput.
BufferedIndexOutput	Base implementation class for buffered IndexOutput.
Builder<T>	Builds a minimal FST (maps an IntsRef term to an arbitrary output) from pre-sorted terms with outputs.
Builder.Arc<T>	Expert: holds a pending (seen but not yet serialized) arc.
Builder.FreezeTail<T>	Expert: this is invoked by Builder whenever a suffix is serialized.
Builder.UnCompiledNode<T>	Expert: holds a pending (seen but not yet serialized) Node.
ByteArrayDataInput	DataInput backed by a byte array.
ByteArrayDataOutput	DataOutput backed by a byte array.
ByteBlockPool	Class that Posting and PostingVector use to write byte streams into shared fixed-size byte[] arrays.
ByteBlockPool.Allocator	Abstract class for allocating and freeing byte blocks.
ByteBlockPool.DirectAllocator	A simple ByteBlockPool.Allocator that never recycles.
ByteBlockPool.DirectTrackingAllocator	A simple ByteBlockPool.Allocator that never recycles, but tracks how much total RAM is in use.
ByteDocValuesField	Deprecated. use NumericDocValuesField instead.
ByteRunAutomaton	Automaton representation for matching UTF-8 byte[].
ByteSequenceOutputs	An FST Outputs implementation where each output is a sequence of bytes.
BytesRef	Represents byte[], as a slice (offset + length) into an existing byte[].
BytesRefFSTEnum<T>	Enumerates all input (BytesRef) + output pairs in an FST.
BytesRefFSTEnum.InputOutput<T>	Holds a single input (BytesRef) + output pair.
BytesRefHash	BytesRefHash is a special purpose hash-map like data-structure optimized for BytesRef instances.
BytesRefHash.BytesStartArray	Manages allocation of the per-term addresses.
BytesRefHash.DirectBytesStartArray	A simple BytesRefHash.BytesStartArray that tracks memory allocation using a private Counter instance.
BytesRefHash.MaxBytesLengthExceededException	Thrown if a BytesRef exceeds the BytesRefHash limit of ByteBlockPool.BYTE_BLOCK_SIZE-2.
BytesRefIterator	A simple iterator interface for BytesRef iteration.
CachingCollector	Caches all docs, and optionally also scores, coming from a search, and is then able to replay them to another collector.
CachingTokenFilter	This class can be used if the token attributes of a TokenStream are intended to be consumed more than once.
CachingWrapperFilter	Wraps another Filter's result and caches it.
CharacterRunAutomaton	Automaton representation for matching char[].
CharFilter	Subclasses of CharFilter can be chained to filter a Reader They can be used as Reader with additional offset correction.
CharSequenceOutputs	An FST Outputs implementation where each output is a sequence of characters.
CharsRef	Represents char[], as a slice (offset + length) into an existing char[].
CharTermAttribute	The term text of a Token.
CharTermAttributeImpl	Default implementation of CharTermAttribute.
CheckIndex	Basic tool and API to check the health of an index and write a new segments file that removes reference to problematic segments.
CheckIndex.Status	Returned from CheckIndex.checkIndex() detailing the health and status of the index.
CheckIndex.Status.DocValuesStatus	Status from testing DocValues
CheckIndex.Status.FieldNormStatus	Status from testing field norms.
CheckIndex.Status.SegmentInfoStatus	Holds the status of each segment in the index.
CheckIndex.Status.StoredFieldStatus	Status from testing stored fields.
CheckIndex.Status.TermIndexStatus	Status from testing term index.
CheckIndex.Status.TermVectorStatus	Status from testing stored fields.
ChecksumIndexInput	Reads bytes through to a primary IndexInput, computing checksum as it goes.
ChecksumIndexOutput	Writes bytes through to a primary IndexOutput, computing checksum.
CloseableThreadLocal<T>	Java's builtin ThreadLocal has a serious flaw: it can take an arbitrarily long amount of time to dereference the things you had stored in it, even once the ThreadLocal instance itself is no longer referenced.
Codec	Encodes/decodes an inverted index segment.
CodecUtil	Utility class for reading and writing versioned headers.
CollectionStatistics	Contains statistics for a collection (field)
CollectionTerminatedException	Throw this exception in Collector.collect(int) to prematurely terminate collection of the current leaf.
CollectionUtil	Methods for manipulating (sorting) collections.
Collector	Expert: Collectors are primarily meant to be used to gather raw results from a search, and implement sorting or custom result filtering, collation, etc.
CommandLineUtil	Class containing some useful methods used by command line tools
CompiledAutomaton	Immutable class holding compiled details for a given Automaton.
CompiledAutomaton.AUTOMATON_TYPE	Automata are compiled into different internal forms for the most efficient execution depending upon the language they accept.
ComplexExplanation	Expert: Describes the score computation for document and query, and can distinguish a match independent of a positive value.
CompositeReader	Instances of this reader type can only be used to get stored fields from the underlying AtomicReaders, but it is not possible to directly retrieve postings.
CompositeReaderContext	IndexReaderContext for CompositeReader instance.
CompoundFileDirectory	Class for accessing a compound stream.
CompoundFileDirectory.FileEntry	Offset/Length for a slice inside of a compound file
CompressingStoredFieldsFormat	A StoredFieldsFormat that is very similar to Lucene40StoredFieldsFormat but compresses documents in chunks in order to improve the compression ratio.
CompressingStoredFieldsIndexReader	Random-access reader for CompressingStoredFieldsIndexWriter.
CompressingStoredFieldsIndexWriter	Efficient index format for block-based Codecs.
CompressingStoredFieldsReader	StoredFieldsReader impl for CompressingStoredFieldsFormat.
CompressingStoredFieldsWriter	StoredFieldsWriter impl for CompressingStoredFieldsFormat.
CompressingTermVectorsFormat	A TermVectorsFormat that compresses chunks of documents together in order to improve the compression ratio.
CompressingTermVectorsReader	TermVectorsReader for CompressingTermVectorsFormat.
CompressingTermVectorsWriter	TermVectorsWriter for CompressingTermVectorsFormat.
CompressionMode	A compression mode.
CompressionTools	Simple utility class providing static methods to compress and decompress binary data for stored fields.
Compressor	A data compressor.
ConcurrentMergeScheduler	A MergeScheduler that runs each merge using a separate thread.
Constants	Some useful constants.
ConstantScoreQuery	A query that wraps another query or a filter and simply returns a constant score equal to the query boost for every document that matches the filter or query.
ControlledRealTimeReopenThread<T>	Utility class that runs a thread to manage periodicc reopens of a ReferenceManager, with methods to wait for a specific index changes to become visible.
CorruptIndexException	This exception is thrown when Lucene detects an inconsistency in the index.
Counter	Simple counter class
DataInput	Abstract base class for performing read operations of Lucene's low-level data types.
DataOutput	Abstract base class for performing write operations of Lucene's low-level data types.
DateTools	Provides support for converting dates to strings and vice-versa.
DateTools.Resolution	Specifies the time granularity.
Decompressor	A decompressor.
DefaultSimilarity	Expert: Default scoring implementation which encodes norm values as a single byte before being stored.
DerefBytesDocValuesField	Deprecated. Use BinaryDocValuesField instead.
DFRSimilarity	Implements the divergence from randomness (DFR) framework introduced in Gianni Amati and Cornelis Joost Van Rijsbergen.
Directory	A Directory is a flat list of files.
DirectoryReader	DirectoryReader is an implementation of CompositeReader that can read indexes in a Directory.
DisjunctionMaxQuery	A query that generates the union of documents produced by its subqueries, and that scores each document with the maximum score for that document as produced by any subquery, plus a tie breaking increment for any additional matching subqueries.
Distribution	The probabilistic distribution used to model term occurrence in information-based models.
DistributionLL	Log-logistic distribution.
DistributionSPL	The smoothed power-law (SPL) distribution for the information-based framework that is described in the original paper.
DocIdBitSet	Simple DocIdSet and DocIdSetIterator backed by a BitSet
DocIdSet	A DocIdSet contains a set of doc ids.
DocIdSetIterator	This abstract class defines methods to iterate over a set of non-decreasing doc ids.
DocsAndPositionsEnum	Also iterates through positions.
DocsEnum	Iterates through the documents and term freqs.
DocTermOrds	This class enables fast access to multiple term ords for a specified field across all docIDs.
DocTermOrdsRangeFilter	A range filter built on top of a cached multi-valued term field (in FieldCache).
DocTermOrdsRewriteMethod	Rewrites MultiTermQueries into a filter, using DocTermOrds for term enumeration.
Document	Documents are the unit of indexing and search.
DocumentStoredFieldVisitor	A StoredFieldVisitor that creates a Document containing all stored fields, or only specific requested fields provided to DocumentStoredFieldVisitor(Set).
DocValuesConsumer	Abstract API that consumes numeric, binary and sorted docvalues.
DocValuesFormat	Encodes/decodes per-document values.
DocValuesProducer	Abstract API that produces numeric, binary and sorted docvalues.
DocValuesProducer.SortedDocsWithField	A simple implementation of DocValuesProducer.getDocsWithField(org.apache.lucene.index.FieldInfo) that returns true if a document has an ordinal >= 0
DocValuesProducer.SortedSetDocsWithField	A simple implementation of DocValuesProducer.getDocsWithField(org.apache.lucene.index.FieldInfo) that returns true if a document has any ordinals.
DoubleBarrelLRUCache<K extends DoubleBarrelLRUCache.CloneableKey,V>	Simple concurrent LRU cache, using a "double barrel" approach where two ConcurrentHashMaps record entries.
DoubleBarrelLRUCache.CloneableKey	Object providing clone(); the key class must subclass this.
DoubleDocValuesField	Syntactic sugar for encoding doubles as NumericDocValues via Double.doubleToRawLongBits(double).
DoubleField	Field that indexes double values for efficient range filtering and sorting.
EliasFanoDecoder	A decoder for an EliasFanoEncoder.
EliasFanoDocIdSet	A DocIdSet in Elias-Fano encoding.
EliasFanoEncoder	Encode a non decreasing sequence of non negative whole numbers in the Elias-Fano encoding that was introduced in the 1970's by Peter Elias and Robert Fano.
Explanation	Expert: Describes the score computation for document and query.
Field	Expert: directly create a field for a document.
Field.Index	Deprecated. This is here only to ease transition from the pre-4.0 APIs.
Field.Store	Specifies whether and how a field should be stored.
Field.TermVector	Deprecated. This is here only to ease transition from the pre-4.0 APIs.
FieldCache	Expert: Maintains caches of term values.
FieldCache.ByteParser	Deprecated.
FieldCache.Bytes	Field values as 8-bit signed bytes
FieldCache.CacheEntry	EXPERT: A unique Identifier/Description for each item in the FieldCache.
FieldCache.CreationPlaceholder	Placeholder indicating creation of this cache is currently in-progress.
FieldCache.DoubleParser	Interface to parse doubles from document fields.
FieldCache.Doubles	Field values as 64-bit doubles
FieldCache.FloatParser	Interface to parse floats from document fields.
FieldCache.Floats	Field values as 32-bit floats
FieldCache.IntParser	Interface to parse ints from document fields.
FieldCache.Ints	Field values as 32-bit signed integers
FieldCache.LongParser	Interface to parse long from document fields.
FieldCache.Longs	Field values as 64-bit signed long integers
FieldCache.Parser	Marker interface as super-interface to all parsers.
FieldCache.ShortParser	Deprecated.
FieldCache.Shorts	Field values as 16-bit signed shorts
FieldCacheDocIdSet	Base class for DocIdSet to be used with FieldCache.
FieldCacheRangeFilter<T>	A range filter built on top of a cached single term field (in FieldCache).
FieldCacheRewriteMethod	Rewrites MultiTermQueries into a filter, using the FieldCache for term enumeration.
FieldCacheSanityChecker	Provides methods for sanity checking that entries in the FieldCache are not wasteful or inconsistent.
FieldCacheSanityChecker.Insanity	Simple container for a collection of related CacheEntry objects that in conjunction with each other represent some "insane" usage of the FieldCache.
FieldCacheSanityChecker.InsanityType	An Enumeration of the different types of "insane" behavior that may be detected in a FieldCache.
FieldCacheTermsFilter	A Filter that only accepts documents whose single term value in the specified field is contained in the provided set of allowed terms.
FieldComparator<T>	Expert: a FieldComparator compares hits so as to determine their sort order when collecting the top results with TopFieldCollector.
FieldComparator.ByteComparator	Deprecated.
FieldComparator.DocComparator	Sorts by ascending docID
FieldComparator.DoubleComparator	Parses field's values as double (using FieldCache.getDoubles(org.apache.lucene.index.AtomicReader, java.lang.String, boolean) and sorts by ascending value
FieldComparator.FloatComparator	Parses field's values as float (using FieldCache.getFloats(org.apache.lucene.index.AtomicReader, java.lang.String, boolean) and sorts by ascending value
FieldComparator.IntComparator	Parses field's values as int (using FieldCache.getInts(org.apache.lucene.index.AtomicReader, java.lang.String, boolean) and sorts by ascending value
FieldComparator.LongComparator	Parses field's values as long (using FieldCache.getLongs(org.apache.lucene.index.AtomicReader, java.lang.String, boolean) and sorts by ascending value
FieldComparator.NumericComparator<T extends Number>	Base FieldComparator class for numeric types
FieldComparator.RelevanceComparator	Sorts by descending relevance.
FieldComparator.ShortComparator	Deprecated.
FieldComparator.TermOrdValComparator	Sorts by field's natural Term sort order, using ordinals.
FieldComparator.TermValComparator	Sorts by field's natural Term sort order.
FieldComparatorSource	Provides a FieldComparator for custom field sorting.
FieldDoc	Expert: A ScoreDoc which also contains information about how to sort the referenced document.
FieldInfo	Access to the Field Info file that describes document fields and whether or not they are indexed.
FieldInfo.DocValuesType	DocValues types.
FieldInfo.IndexOptions	Controls how much information is stored in the postings lists.
FieldInfos	Collection of FieldInfos (accessible by number or by name).
FieldInfosFormat	Encodes/decodes FieldInfos
FieldInfosReader	Codec API for reading FieldInfos.
FieldInfosWriter	Codec API for writing FieldInfos.
FieldInvertState	This class tracks the number and position / offset parameters of terms being added to the index.
FieldMaskingSpanQuery	Wrapper to allow SpanQuery objects participate in composite single-field SpanQueries by 'lying' about their search field.
Fields	Flex API for access to fields and terms
FieldsConsumer	Abstract API that consumes terms, doc, freq, prox, offset and payloads postings.
FieldsProducer	Abstract API that produces terms, doc, freq, prox, offset and payloads postings.
FieldType	Describes the properties of a field.
FieldType.NumericType	Data type of the numeric value
FieldValueFilter	A Filter that accepts all documents that have one or more values in a given field.
FieldValueHitQueue<T extends FieldValueHitQueue.Entry>	Expert: A hit queue for sorting by hits by terms in more than one field.
FieldValueHitQueue.Entry	Extension of ScoreDoc to also store the FieldComparator slot.
FileSwitchDirectory	Expert: A Directory instance that switches files between two other Directory instances.
Filter	Abstract base class for restricting which documents may be returned during searching.
FilterAtomicReader	A FilterAtomicReader contains another AtomicReader, which it uses as its basic source of data, possibly transforming the data along the way or providing additional functionality.
FilterAtomicReader.FilterDocsAndPositionsEnum	Base class for filtering DocsAndPositionsEnum implementations.
FilterAtomicReader.FilterDocsEnum	Base class for filtering DocsEnum implementations.
FilterAtomicReader.FilterFields	Base class for filtering Fields implementations.
FilterAtomicReader.FilterTerms	Base class for filtering Terms implementations.
FilterAtomicReader.FilterTermsEnum	Base class for filtering TermsEnum implementations.
FilterCodec	A codec that forwards all its method calls to another codec.
FilterDirectory	Directory implementation that delegates calls to another directory.
FilterDirectoryReader	A FilterDirectoryReader wraps another DirectoryReader, allowing implementations to transform or extend it.
FilterDirectoryReader.StandardReaderWrapper	A no-op SubReaderWrapper that simply returns the parent DirectoryReader's original subreaders.
FilterDirectoryReader.SubReaderWrapper	Factory class passed to FilterDirectoryReader constructor that allows subclasses to wrap the filtered DirectoryReader's subreaders.
FilteredDocIdSet	Abstract decorator class for a DocIdSet implementation that provides on-demand filtering/validation mechanism on a given DocIdSet.
FilteredDocIdSetIterator	Abstract decorator class of a DocIdSetIterator implementation that provides on-demand filter/validation mechanism on an underlying DocIdSetIterator.
FilteredQuery	A query that applies a filter to the results of another query.
FilteredQuery.FilterStrategy	Abstract class that defines how the filter (DocIdSet) applied during document collection.
FilteredQuery.RandomAccessFilterStrategy	A FilteredQuery.FilterStrategy that conditionally uses a random access filter if the given DocIdSet supports random access (returns a non-null value from DocIdSet.bits()) and FilteredQuery.RandomAccessFilterStrategy.useRandomAccess(Bits, int) returns true.
FilteredTermsEnum	Abstract class for enumerating a subset of all terms.
FilteredTermsEnum.AcceptStatus	Return value, if term should be accepted or the iteration should END.
FilterIterator<T>	An Iterator implementation that filters elements with a boolean predicate.
FixedBitSet	BitSet of fixed length (numBits), backed by accessible (FixedBitSet.getBits()) long[], accessed with an int index, implementing Bits and DocIdSet.
FixedBitSet.FixedBitSetIterator	A DocIdSetIterator which iterates over set bits in a FixedBitSet.
FlagsAttribute	This attribute can be used to pass different flags down the Tokenizer chain, e.g.
FlagsAttributeImpl	Default implementation of FlagsAttribute.
FloatDocValuesField	Syntactic sugar for encoding floats as NumericDocValues via Float.floatToRawIntBits(float).
FloatField	Field that indexes float values for efficient range filtering and sorting.
FlushInfo	A FlushInfo provides information required for a FLUSH context.
FSDirectory	Base class for Directory implementations that store index files in the file system.
FSDirectory.FSIndexInput	Base class for reading input from a RandomAccessFile
FSDirectory.FSIndexOutput	Writes output with RandomAccessFile.write(byte[], int, int)
FSLockFactory	Base class for file system based locking implementation.
FST<T>	Represents an finite state machine (FST), using a compact byte[] format.
FST.Arc<T>	Represents a single arc.
FST.BytesReader	Reads bytes stored in an FST.
FST.INPUT_TYPE	Specifies allowed range of each int input label for this FST.
FuzzyQuery	Implements the fuzzy search query.
FuzzyTermsEnum	Subclass of TermsEnum for enumerating all terms that are similar to the specified filter term.
FuzzyTermsEnum.LevenshteinAutomataAttribute	reuses compiled automata across different segments, because they are independent of the index
FuzzyTermsEnum.LevenshteinAutomataAttributeImpl	Stores compiled automata as a list (indexed by edit distance)
GrowableByteArrayDataOutput	A DataOutput that can be used to build a byte[].
GrowableWriter	Implements PackedInts.Mutable, but grows the bit count of the underlying packed ints on-demand.
IBSimilarity	Provides a framework for the family of information-based models, as described in Stéphane Clinchant and Eric Gaussier.
IndexableBinaryStringTools	Deprecated. Implement TermToBytesRefAttribute and store bytes directly instead.
IndexableField	Represents a single field for indexing.
IndexableFieldType	Describes the properties of a field.
IndexCommit	Expert: represents a single commit into an index as seen by the IndexDeletionPolicy or IndexReader.
IndexDeletionPolicy	Expert: policy for deletion of stale index commits.
IndexFileNames	This class contains useful constants representing filenames and extensions used by lucene, as well as convenience methods for querying whether a file name matches an extension (matchesExtension), as well as generating file names from a segment name, generation and extension ( fileNameFromGeneration, segmentFileName).
IndexFormatTooNewException	This exception is thrown when Lucene detects an index that is newer than this Lucene version.
IndexFormatTooOldException	This exception is thrown when Lucene detects an index that is too old for this Lucene version
IndexInput	Abstract base class for input from a file in a Directory.
IndexNotFoundException	Signals that no index was found in the Directory.
IndexOutput	Abstract base class for output to a file in a Directory.
IndexReader	IndexReader is an abstract class, providing an interface for accessing an index.
IndexReader.ReaderClosedListener	A custom listener that's invoked when the IndexReader is closed.
IndexReaderContext	A struct like class that represents a hierarchical relationship between IndexReader instances.
IndexSearcher	Implements search over a single IndexReader.
IndexSearcher.LeafSlice	A class holding a subset of the IndexSearchers leaf contexts to be executed within a single thread.
IndexUpgrader	This is an easy-to-use tool that upgrades all segments of an index from previous Lucene versions to the current segment file format.
IndexWriter	An IndexWriter creates and maintains an index.
IndexWriter.IndexReaderWarmer	If DirectoryReader.open(IndexWriter,boolean) has been called (ie, this writer is in near real-time mode), then after a merge completes, this class can be invoked to warm the reader on the newly merged segment, before the merge commits.
IndexWriterConfig	Holds all the configuration that is used to create an IndexWriter.
IndexWriterConfig.OpenMode	Specifies the open mode for IndexWriter.
InfoStream	Debugging API for Lucene classes such as IndexWriter and SegmentInfos.
InPlaceMergeSorter	Sorter implementation based on the merge-sort algorithm that merges in place (no extra memory will be allocated).
InputStreamDataInput	A DataInput wrapping a plain InputStream.
IntBlockPool	A pool for int blocks similar to ByteBlockPool
IntBlockPool.Allocator	Abstract class for allocating and freeing int blocks.
IntBlockPool.DirectAllocator	A simple IntBlockPool.Allocator that never recycles.
IntBlockPool.SliceReader	A IntBlockPool.SliceReader that can read int slices written by a IntBlockPool.SliceWriter
IntBlockPool.SliceWriter	A IntBlockPool.SliceWriter that allows to write multiple integer slices into a given IntBlockPool.
IntDocValuesField	Deprecated. use NumericDocValuesField instead.
IntField	Field that indexes int values for efficient range filtering and sorting.
IntroSorter	Sorter implementation based on a variant of the quicksort algorithm called introsort: when the recursion level exceeds the log of the length of the array to sort, it falls back to heapsort.
IntSequenceOutputs	An FST Outputs implementation where each output is a sequence of ints.
IntsRef	Represents int[], as a slice (offset + length) into an existing int[].
IntsRefFSTEnum<T>	Enumerates all input (IntsRef) + output pairs in an FST.
IntsRefFSTEnum.InputOutput<T>	Holds a single input (IntsRef) + output pair.
IOContext	IOContext holds additional details on the merge/search context.
IOContext.Context	Context is a enumerator which specifies the context in which the Directory is being used for.
IOUtils	This class emulates the new Java 7 "Try-With-Resources" statement.
KeepOnlyLastCommitDeletionPolicy	This IndexDeletionPolicy implementation that keeps only the most recent commit and immediately removes all prior commits after a new commit is done.
KeywordAttribute	This attribute can be used to mark a token as a keyword.
KeywordAttributeImpl	Default implementation of KeywordAttribute.
Lambda	The lambda (λw) parameter in information-based models.
LambdaDF	Computes lambda as docFreq+1 / numberOfDocuments+1.
LambdaTTF	Computes lambda as totalTermFreq+1 / numberOfDocuments+1.
LevenshteinAutomata	Class to construct DFAs that match a word within some edit distance.
LiveDocsFormat	Format for live/deleted documents
LiveFieldValues<S,T>	Tracks live field values across NRT reader reopens.
LiveIndexWriterConfig	Holds all the configuration used by IndexWriter with few setters for settings that can be changed on an IndexWriter instance "live".
LMDirichletSimilarity	Bayesian smoothing using Dirichlet priors.
LMJelinekMercerSimilarity	Language model based on the Jelinek-Mercer smoothing method.
LMSimilarity	Abstract superclass for language modeling Similarities.
LMSimilarity.CollectionModel	A strategy for computing the collection language model.
LMSimilarity.DefaultCollectionModel	Models p(w|C) as the number of occurrences of the term in the collection, divided by the total number of tokens + 1.
LMSimilarity.LMStats	Stores the collection distribution of the current term.
Lock	An interprocess mutex lock.
Lock.With	Utility class for executing code with exclusive access.
LockFactory	Base class for Locking implementation.
LockObtainFailedException	This exception is thrown when the write.lock could not be acquired.
LockReleaseFailedException	This exception is thrown when the write.lock could not be released.
LockStressTest	Simple standalone tool that forever acquires & releases a lock using a specific LockFactory.
LockVerifyServer	Simple standalone server that must be running when you use VerifyingLockFactory.
LogByteSizeMergePolicy	This is a LogMergePolicy that measures size of a segment as the total byte size of the segment's files.
LogDocMergePolicy	This is a LogMergePolicy that measures size of a segment as the number of documents (not taking deletions into account).
LogMergePolicy	This class implements a MergePolicy that tries to merge segments into levels of exponentially increasing size, where each level has fewer segments than the value of the merge factor.
LongBitSet	BitSet of fixed length (numBits), backed by accessible (LongBitSet.getBits()) long[], accessed with a long index.
LongDocValuesField	Deprecated. use NumericDocValuesField instead.
LongField	Field that indexes long values for efficient range filtering and sorting.
LongsRef	Represents long[], as a slice (offset + length) into an existing long[].
LongValues	Abstraction over an array of longs.
Lucene3xCodec	Deprecated. Only for reading existing 3.x indexes
Lucene3xSegmentInfoFormat	Deprecated. (4.0) This is only used to read indexes created before 4.0.
Lucene3xSegmentInfoReader	Deprecated. Only for reading existing 3.x indexes
Lucene40Codec	Deprecated. Only for reading old 4.0 segments
Lucene40DocValuesFormat	Deprecated. Only for reading old 4.0 and 4.1 segments
Lucene40FieldInfosFormat	Deprecated. Only for reading old 4.0 and 4.1 segments
Lucene40LiveDocsFormat	Lucene 4.0 Live Documents Format.
Lucene40NormsFormat	Deprecated. Only for reading old 4.0 and 4.1 segments
Lucene40PostingsBaseFormat	Deprecated. Only for reading old 4.0 segments
Lucene40PostingsFormat	Deprecated. Only for reading old 4.0 segments
Lucene40PostingsReader	Deprecated. Only for reading old 4.0 segments
Lucene40SegmentInfoFormat	Deprecated. Only for reading old 4.0-4.5 segments, and supporting IndexWriter.addIndexes
Lucene40SegmentInfoReader	Deprecated. Only for reading old 4.0-4.5 segments
Lucene40SegmentInfoWriter	Deprecated.
Lucene40SkipListReader	Deprecated. Only for reading old 4.0 segments
Lucene40StoredFieldsFormat	Lucene 4.0 Stored Fields Format.
Lucene40StoredFieldsReader	Class responsible for access to stored document fields.
Lucene40StoredFieldsWriter	Class responsible for writing stored document fields.
Lucene40TermVectorsFormat	Lucene 4.0 Term Vectors format.
Lucene40TermVectorsReader	Lucene 4.0 Term Vectors reader.
Lucene40TermVectorsWriter	Lucene 4.0 Term Vectors writer.
Lucene41Codec	Deprecated. Only for reading old 4.0 segments
Lucene41PostingsBaseFormat	Provides a PostingsReaderBase and PostingsWriterBase.
Lucene41PostingsFormat	Lucene 4.1 postings format, which encodes postings in packed integer blocks for fast decode.
Lucene41PostingsReader	Concrete class that reads docId(maybe frq,pos,offset,payloads) list with postings format.
Lucene41PostingsWriter	Concrete class that writes docId(maybe frq,pos,offset,payloads) list with postings format.
Lucene41StoredFieldsFormat	Lucene 4.1 stored fields format.
Lucene42Codec	Deprecated. Only for reading old 4.2 segments
Lucene42DocValuesFormat	Deprecated. Only for reading old 4.2 segments
Lucene42FieldInfosFormat	Deprecated. Only for reading old 4.2-4.5 segments
Lucene42NormsFormat	Lucene 4.2 score normalization format.
Lucene42TermVectorsFormat	Lucene 4.2 term vectors format.
Lucene45Codec	Deprecated. Only for reading old 4.3-4.5 segments
Lucene45DocValuesConsumer	writer for Lucene45DocValuesFormat
Lucene45DocValuesFormat	Lucene 4.5 DocValues format.
Lucene45DocValuesProducer	reader for Lucene45DocValuesFormat
Lucene45DocValuesProducer.BinaryEntry	metadata entry for a binary docvalues field
Lucene45DocValuesProducer.NumericEntry	metadata entry for a numeric docvalues field
Lucene45DocValuesProducer.SortedSetEntry	metadata entry for a sorted-set docvalues field
Lucene46Codec	Implements the Lucene 4.6 index format, with configurable per-field postings and docvalues formats.
Lucene46FieldInfosFormat	Lucene 4.6 Field Infos format.
Lucene46SegmentInfoFormat	Lucene 4.6 Segment info format.
Lucene46SegmentInfoReader	Lucene 4.6 implementation of SegmentInfoReader.
Lucene46SegmentInfoWriter	Lucene 4.0 implementation of SegmentInfoWriter.
LucenePackage	Lucene's package information, including version.
MapOfSets<K,V>	Helper class for keeping Lists of Objects associated with keys.
MappingMultiDocsAndPositionsEnum	Exposes flex API, merged from flex API of sub-segments, remapping docIDs (this is used for segment merging).
MappingMultiDocsEnum	Exposes flex API, merged from flex API of sub-segments, remapping docIDs (this is used for segment merging).
MatchAllDocsQuery	A query that matches all documents.
MathUtil	Math static utility methods.
MaxNonCompetitiveBoostAttribute	Add this Attribute to a fresh AttributeSource before calling MultiTermQuery.getTermsEnum(Terms,AttributeSource).
MaxNonCompetitiveBoostAttributeImpl	Implementation class for MaxNonCompetitiveBoostAttribute.
MaxPayloadFunction	Returns the maximum payload score seen, else 1 if there are no payloads on the doc.
MergedIterator<T extends Comparable<T>>	Provides a merged sorted view from several sorted iterators.
MergeInfo	A MergeInfo provides information required for a MERGE context.
MergePolicy	Expert: a MergePolicy determines the sequence of primitive merge operations.
MergePolicy.DocMap	A map of doc IDs.
MergePolicy.MergeAbortedException	Thrown when a merge was explicity aborted because IndexWriter.close(boolean) was called with false.
MergePolicy.MergeException	Exception thrown if there are any problems while executing a merge.
MergePolicy.MergeSpecification	A MergeSpecification instance provides the information necessary to perform multiple merges.
MergePolicy.MergeTrigger	MergeTrigger is passed to MergePolicy.findMerges(MergeTrigger, SegmentInfos) to indicate the event that triggered the merge.
MergePolicy.OneMerge	OneMerge provides the information necessary to perform an individual primitive merge operation, resulting in a single new segment.
MergeScheduler	Expert: IndexWriter uses an instance implementing this interface to execute the merges selected by a MergePolicy.
MergeState	Holds common state used during segment merging.
MergeState.CheckAbort	Class for recording units of work when merging segments.
MergeState.DocMap	Remaps docids around deletes during merge
MinimizationOperations	Operations for minimizing automata.
MinPayloadFunction	Calculates the minimum payload seen
MMapDirectory	File-based Directory implementation that uses mmap for reading, and FSDirectory.FSIndexOutput for writing.
MonotonicAppendingLongBuffer	Utility class to buffer signed longs in memory, which is optimized for the case where the sequence is monotonic, although it can encode any sequence of arbitrary longs.
MonotonicBlockPackedReader	Provides random access to a stream written with MonotonicBlockPackedWriter.
MonotonicBlockPackedWriter	A writer for large monotonically increasing sequences of positive longs.
MultiCollector	A Collector which allows running a search with several Collectors.
MultiDocsAndPositionsEnum	Exposes flex API, merged from flex API of sub-segments.
MultiDocsAndPositionsEnum.EnumWithSlice	Holds a DocsAndPositionsEnum along with the corresponding ReaderSlice.
MultiDocsEnum	Exposes DocsEnum, merged from DocsEnum API of sub-segments.
MultiDocsEnum.EnumWithSlice	Holds a DocsEnum along with the corresponding ReaderSlice.
MultiDocValues	A wrapper for CompositeIndexReader providing access to DocValues.
MultiDocValues.MultiSortedDocValues	Implements SortedDocValues over n subs, using an OrdinalMap
MultiDocValues.MultiSortedSetDocValues	Implements MultiSortedSetDocValues over n subs, using an OrdinalMap
MultiDocValues.OrdinalMap	maps per-segment ordinals to/from global ordinal space
MultiFields	Exposes flex API, merged from flex API of sub-segments.
MultiLevelSkipListReader	This abstract class reads skip lists with multiple levels.
MultiLevelSkipListWriter	This abstract class writes skip lists with multiple levels.
MultiPhraseQuery	MultiPhraseQuery is a generalized version of PhraseQuery, with an added method MultiPhraseQuery.add(Term[]).
MultiReader	A CompositeReader which reads multiple indexes, appending their content.
MultiSimilarity	Implements the CombSUM method for combining evidence from multiple similarity values described in: Joseph A.
MultiTermQuery	An abstract Query that matches documents containing a subset of terms provided by a FilteredTermsEnum enumeration.
MultiTermQuery.ConstantScoreAutoRewrite	A rewrite method that tries to pick the best constant-score rewrite method based on term and document counts from the query.
MultiTermQuery.RewriteMethod	Abstract class that defines how the query is rewritten.
MultiTermQuery.TopTermsBoostOnlyBooleanQueryRewrite	A rewrite method that first translates each term into BooleanClause.Occur.SHOULD clause in a BooleanQuery, but the scores are only computed as the boost.
MultiTermQuery.TopTermsScoringBooleanQueryRewrite	A rewrite method that first translates each term into BooleanClause.Occur.SHOULD clause in a BooleanQuery, and keeps the scores as computed by the query.
MultiTermQueryWrapperFilter<Q extends MultiTermQuery>	A wrapper for MultiTermQuery, that exposes its functionality as a Filter.
MultiTerms	Exposes flex API, merged from flex API of sub-segments.
MultiTermsEnum	Exposes TermsEnum API, merged from TermsEnum API of sub-segments.
MutableBits	Extension of Bits for live documents.
MutableValue	Base class for all mutable values.
MutableValueBool	MutableValue implementation of type boolean.
MutableValueDate	MutableValue implementation of type Date.
MutableValueDouble	MutableValue implementation of type double.
MutableValueFloat	MutableValue implementation of type float.
MutableValueInt	MutableValue implementation of type int.
MutableValueLong	MutableValue implementation of type long.
MutableValueStr	MutableValue implementation of type String.
NamedSPILoader<S extends NamedSPILoader.NamedSPI>	Helper class for loading named SPIs from classpath (e.g.
NamedSPILoader.NamedSPI	Interface to support NamedSPILoader.lookup(String) by name.
NamedThreadFactory	A default ThreadFactory implementation that accepts the name prefix of the created threads as a constructor argument.
NativeFSLockFactory	Implements LockFactory using native OS file locks.
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.
NGramPhraseQuery	This is a PhraseQuery which is optimized for n-gram phrase query.
NIOFSDirectory	An FSDirectory implementation that uses java.nio's FileChannel's positional read, which allows multiple threads to read from the same file without synchronizing.
NIOFSDirectory.NIOFSIndexInput	Reads bytes with FileChannel.read(ByteBuffer, long)
NoDeletionPolicy	An IndexDeletionPolicy which keeps all index commits around, never deleting them.
NoLockFactory	Use this LockFactory to disable locking entirely.
NoMergePolicy	A MergePolicy which never returns merges to execute (hence it's name).
NoMergeScheduler	A MergeScheduler which never executes any merges.
NoOutputs	A null FST Outputs implementation; use this if you just want to build an FSA.
Normalization	This class acts as the base class for the implementations of the term frequency normalization methods in the DFR framework.
Normalization.NoNormalization	Implementation used when there is no normalization.
NormalizationH1	Normalization model that assumes a uniform distribution of the term frequency.
NormalizationH2	Normalization model in which the term frequency is inversely related to the length.
NormalizationH3	Dirichlet Priors normalization
NormalizationZ	Pareto-Zipf Normalization
NormsFormat	Encodes/decodes per-document score normalization values.
NoSuchDirectoryException	This exception is thrown when you try to list a non-existent directory.
NRTCachingDirectory	Wraps a RAMDirectory around any provided delegate directory, to be used during NRT search.
NumericDocValues	A per-document numeric value.
NumericDocValuesField	Field that stores a per-document long value for scoring, sorting or value retrieval.
NumericRangeFilter<T extends Number>	A Filter that only accepts numeric values within a specified range.
NumericRangeQuery<T extends Number>	A Query that matches numeric values within a specified range.
NumericTokenStream	Expert: This class provides a TokenStream for indexing numeric values that can be used by NumericRangeQuery or NumericRangeFilter.
NumericTokenStream.NumericTermAttribute	Expert: Use this attribute to get the details of the currently generated token.
NumericTokenStream.NumericTermAttributeImpl	Implementation of NumericTokenStream.NumericTermAttribute.
NumericUtils	This is a helper class to generate prefix-encoded representations for numerical values and supplies converters to represent float/double values as sortable integers/longs.
NumericUtils.IntRangeBuilder	Callback for NumericUtils.splitIntRange(org.apache.lucene.util.NumericUtils.IntRangeBuilder, int, int, int).
NumericUtils.LongRangeBuilder	Callback for NumericUtils.splitLongRange(org.apache.lucene.util.NumericUtils.LongRangeBuilder, int, long, long).
OffsetAttribute	The start and end character offset of a Token.
OffsetAttributeImpl	Default implementation of OffsetAttribute.
OpenBitSet	An "open" BitSet implementation that allows direct access to the array of words storing the bits.
OpenBitSetDISI	OpenBitSet with added methods to bulk-update the bits from a DocIdSetIterator.
OpenBitSetIterator	An iterator to iterate over set bits in an OpenBitSet.
OrdTermState	An ordinal based TermState
Outputs<T>	Represents the outputs for an FST, providing the basic algebra required for building and traversing the FST.
OutputStreamDataOutput	A DataOutput wrapping a plain OutputStream.
PackedDataInput	A DataInput wrapper to read unaligned, variable-length packed integers.
PackedDataOutput	A DataOutput wrapper to write unaligned, variable-length packed integers.
PackedInts	Simplistic compression for array of unsigned long values.
PackedInts.Decoder	A decoder for packed integers.
PackedInts.Encoder	An encoder for packed integers.
PackedInts.Format	A format to write packed ints.
PackedInts.FormatAndBits	Simple class that holds a format and a number of bits per value.
PackedInts.Header	Header identifying the structure of a packed integer array.
PackedInts.Mutable	A packed integer array that can be modified.
PackedInts.NullReader	A PackedInts.Reader which has all its values equal to 0 (bitsPerValue = 0).
PackedInts.Reader	A read-only random access array of positive integers.
PackedInts.ReaderIterator	Run-once iterator interface, to decode previously saved PackedInts.
PackedInts.Writer	A write-once Writer.
PackedLongDocValuesField	Deprecated. use NumericDocValuesField instead.
PagedBytes	Represents a logical byte[] as a series of pages.
PagedBytes.Reader	Provides methods to read BytesRefs from a frozen PagedBytes.
PagedGrowableWriter	A PagedGrowableWriter.
PagedMutable	A PagedMutable.
PairOutputs<A,B>	An FST Outputs implementation, holding two other outputs.
PairOutputs.Pair<A,B>	Holds a single pair of two outputs.
ParallelAtomicReader	An AtomicReader which reads multiple, parallel indexes.
ParallelCompositeReader	An CompositeReader which reads multiple, parallel indexes.
PayloadAttribute	The payload of a Token.
PayloadAttributeImpl	Default implementation of PayloadAttribute.
PayloadFunction	An abstract class that defines a way for Payload*Query instances to transform the cumulative effects of payload scores for a document.
PayloadNearQuery	This class is very similar to SpanNearQuery except that it factors in the value of the payloads located at each of the positions where the TermSpans occurs.
PayloadSpanUtil	Experimental class to get set of payloads for most standard Lucene queries.
PayloadTermQuery	This class is very similar to SpanTermQuery except that it factors in the value of the payload located at each of the positions where the Term occurs.
PerFieldDocValuesFormat	Enables per field docvalues support.
PerFieldPostingsFormat	Enables per field postings support.
PerFieldSimilarityWrapper	Provides the ability to use a different Similarity for different fields.
PersistentSnapshotDeletionPolicy	A SnapshotDeletionPolicy which adds a persistence layer so that snapshots can be maintained across the life of an application.
PForDeltaDocIdSet	DocIdSet implementation based on pfor-delta encoding.
PForDeltaDocIdSet.Builder	A builder for PForDeltaDocIdSet.
PhraseQuery	A Query that matches documents containing a particular sequence of terms.
PositionIncrementAttribute	Determines the position of this token relative to the previous Token in a TokenStream, used in phrase searching.
PositionIncrementAttributeImpl	Default implementation of PositionIncrementAttribute.
PositionLengthAttribute	Determines how many positions this token spans.
PositionLengthAttributeImpl	Default implementation of PositionLengthAttribute.
PositiveIntOutputs	An FST Outputs implementation where each output is a non-negative long value.
PositiveScoresOnlyCollector	A Collector implementation which wraps another Collector and makes sure only documents with scores > 0 are collected.
PostingsBaseFormat	Provides a PostingsReaderBase and PostingsWriterBase.
PostingsConsumer	Abstract API that consumes postings for an individual term.
PostingsFormat	Encodes/decodes terms, postings, and proximity data.
PostingsReaderBase	The core terms dictionaries (BlockTermsReader, BlockTreeTermsReader) interact with a single instance of this class to manage creation of DocsEnum and DocsAndPositionsEnum instances.
PostingsWriterBase	Extension of PostingsConsumer to support pluggable term dictionaries.
PrefixFilter	A Filter that restricts search results to values that have a matching prefix in a given field.
PrefixQuery	A Query that matches documents containing terms with a specified prefix.
PrefixTermsEnum	Subclass of FilteredTermEnum for enumerating all terms that match the specified prefix filter term.
PrintStreamInfoStream	InfoStream implementation over a PrintStream such as System.out.
PriorityQueue<T>	A PriorityQueue maintains a partial ordering of its elements such that the least element can always be found in constant time.
Query	The abstract base class for queries.
QueryBuilder	Creates queries from the Analyzer chain.
QueryWrapperFilter	Constrains search results to only match those which also match a provided query.
RAMDirectory	A memory-resident Directory implementation.
RAMFile	Represents a file in RAM as a list of byte[] buffers.
RAMInputStream	A memory-resident IndexInput implementation.
RAMOutputStream	A memory-resident IndexOutput implementation.
RamUsageEstimator	Estimates the size (memory representation) of Java objects.
RamUsageEstimator.JvmFeature	JVM diagnostic features.
RateLimitedDirectoryWrapper	A Directory wrapper that allows IndexOutput rate limiting using IO context specific rate limiters.
RateLimiter	Abstract base class to rate limit IO.
RateLimiter.SimpleRateLimiter	Simple class to rate limit IO.
ReaderManager	Utility class to safely share DirectoryReader instances across multiple threads, while periodically reopening.
ReaderSlice	Subreader slice from a parent composite reader.
ReaderUtil	Common util methods for dealing with IndexReaders and IndexReaderContexts.
RecyclingByteBlockAllocator	A ByteBlockPool.Allocator implementation that recycles unused byte blocks in a buffer and reuses them in subsequent calls to RecyclingByteBlockAllocator.getByteBlock().
RecyclingIntBlockAllocator	A IntBlockPool.Allocator implementation that recycles unused int blocks in a buffer and reuses them in subsequent calls to RecyclingIntBlockAllocator.getIntBlock().
RefCount<T>	Manages reference counting for a given object.
ReferenceManager<G>	Utility class to safely share instances of a certain type across multiple threads, while periodically refreshing them.
ReferenceManager.RefreshListener	Use to receive notification when a refresh has finished.
RegExp	Regular Expression extension to Automaton.
RegexpQuery	A fast regular expression query based on the org.apache.lucene.util.automaton package.
RollingBuffer<T extends RollingBuffer.Resettable>	Acts like forever growing T[], but internally uses a circular buffer to reuse instances of T.
RollingBuffer.Resettable	Implement to reset an instance
RunAutomaton	Finite-state automaton with fast run operation.
ScoreCachingWrappingScorer	A Scorer which wraps another scorer and caches the score of the current document.
ScoreDoc	Holds one hit in TopDocs.
Scorer	Expert: Common scoring functionality for different types of queries.
Scorer.ChildScorer	A child Scorer and its relationship to its parent.
ScoringRewrite<Q extends Query>	Base rewrite method that translates each term into a query, and keeps the scores as computed by the query.
SearcherFactory	Factory class used by SearcherManager to create new IndexSearchers.
SearcherLifetimeManager	Keeps track of current plus old IndexSearchers, closing the old ones once they have timed out.
SearcherLifetimeManager.PruneByAge	Simple pruner that drops any searcher older by more than the specified seconds, than the newest searcher.
SearcherLifetimeManager.Pruner	See SearcherLifetimeManager.prune(org.apache.lucene.search.SearcherLifetimeManager.Pruner).
SearcherManager	Utility class to safely share IndexSearcher instances across multiple threads, while periodically reopening.
SegmentCommitInfo	Embeds a [read-only] SegmentInfo and adds per-commit fields.
SegmentInfo	Information about a segment such as it's name, directory, and files related to the segment.
SegmentInfoFormat	Expert: Controls the format of the SegmentInfo (segment metadata file).
SegmentInfoReader	Specifies an API for classes that can read SegmentInfo information.
SegmentInfos	A collection of segmentInfo objects with methods for operating on those segments in relation to the file system.
SegmentInfos.FindSegmentsFile	Utility class for executing code that needs to do something with the current segments file.
SegmentInfoWriter	Specifies an API for classes that can write out SegmentInfo data.
SegmentReader	IndexReader implementation over a single segment.
SegmentReader.CoreClosedListener	Called when the shared core for this SegmentReader is closed.
SegmentReadState	Holder class for common parameters used during read.
SegmentWriteState	Holder class for common parameters used during write.
SentinelIntSet	A native int hash-based set where one value is reserved to mean "EMPTY" internally.
SerialMergeScheduler	A MergeScheduler that simply does each merge sequentially, using the current thread.
SetOnce<T>	A convenient class which offers a semi-immutable object wrapper implementation which allows one to set the value of an object exactly once, and retrieve it many times.
SetOnce.AlreadySetException	Thrown when SetOnce.set(Object) is called more than once.
ShortDocValuesField	Deprecated. use NumericDocValuesField instead.
Similarity	Similarity defines the components of Lucene scoring.
Similarity.SimScorer	API for scoring "sloppy" queries such as TermQuery, SpanQuery, and PhraseQuery.
Similarity.SimWeight	Stores the weight for a query across the indexed collection.
SimilarityBase	A subclass of Similarity that provides a simplified API for its descendants.
SimpleFSDirectory	A straightforward implementation of FSDirectory using java.io.RandomAccessFile.
SimpleFSDirectory.SimpleFSIndexInput	Reads bytes with RandomAccessFile.seek(long) followed by RandomAccessFile.read(byte[], int, int).
SimpleFSLockFactory	Implements LockFactory using File.createNewFile().
SimpleMergedSegmentWarmer	A very simple merged segment warmer that just ensures data structures are initialized.
SingleInstanceLockFactory	Implements LockFactory for a single in-process instance, meaning all locking will take place through this one instance.
SingleTermsEnum	Subclass of FilteredTermsEnum for enumerating a single term.
SingletonSortedSetDocValues	Exposes multi-valued view over a single-valued instance.
SloppyMath	Math functions that trade off accuracy for speed.
SlowCompositeReaderWrapper	This class forces a composite reader (eg a MultiReader or DirectoryReader) to emulate an atomic reader.
SmallFloat	Floating point numbers smaller than 32 bits.
SnapshotDeletionPolicy	An IndexDeletionPolicy that wraps any other IndexDeletionPolicy and adds the ability to hold and later release snapshots of an index.
Sort	Encapsulates sort criteria for returned hits.
SortedBytesDocValuesField	Deprecated. Use SortedDocValuesField instead.
SortedDocValues	A per-document byte[] with presorted values.
SortedDocValuesField	Field that stores a per-document BytesRef value, indexed for sorting.
SortedSetDocValues	A per-document set of presorted byte[] values.
SortedSetDocValuesField	Field that stores a set of per-document BytesRef values, indexed for faceting,grouping,joining.
Sorter	Base class for sorting algorithms implementations.
SortField	Stores information about how to sort documents by terms in an individual field.
SortField.Type	Specifies the type of the terms to be sorted, or special types such as CUSTOM
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.
SpanNearPayloadCheckQuery	Only return those matches that have a specific payload at the given position.
SpanNearQuery	Matches spans which are near one another.
SpanNotQuery	Removes matches which overlap with another SpanQuery or within a 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.
SpanPositionCheckQuery	Base class for filtering a SpanQuery based on the position of a match.
SpanPositionCheckQuery.AcceptStatus	Return value for SpanPositionCheckQuery.acceptPosition(Spans).
SpanPositionRangeQuery	Checks to see if the SpanPositionCheckQuery.getMatch() lies between a start and end position
SpanQuery	Base class for span-based queries.
Spans	Expert: an enumeration of span matches.
SpanScorer	Public for extension only.
SpanTermQuery	Matches spans containing a term.
SpanWeight	Expert-only.
SpecialOperations	Special automata operations.
SPIClassIterator<S>	Helper class for loading SPI classes from classpath (META-INF files).
State	Automaton state.
StatePair	Pair of states.
StoredField	A field whose value is stored so that IndexSearcher.doc(int) and IndexReader.document(int, org.apache.lucene.index.StoredFieldVisitor) will return the field and its value.
StoredFieldsFormat	Controls the format of stored fields
StoredFieldsReader	Codec API for reading stored fields.
StoredFieldsWriter	Codec API for writing stored fields:
StoredFieldVisitor	Expert: provides a low-level means of accessing the stored field values in an index.
StoredFieldVisitor.Status	Enumeration of possible return values for StoredFieldVisitor.needsField(org.apache.lucene.index.FieldInfo).
StraightBytesDocValuesField	Deprecated. Use BinaryDocValuesField instead.
StringField	A field that is indexed but not tokenized: the entire String value is indexed as a single token.
StringHelper	Methods for manipulating strings.
Term	A Term represents a word from text.
TermContext	Maintains a IndexReader TermState view over IndexReader instances containing a single term.
TermQuery	A Query that matches documents containing a term.
TermRangeFilter	A Filter that restricts search results to a range of term values in a given field.
TermRangeQuery	A Query that matches documents within an range of terms.
TermRangeTermsEnum	Subclass of FilteredTermEnum for enumerating all terms that match the specified range parameters.
Terms	Access to the terms in a specific field.
TermsConsumer	Abstract API that consumes terms for an individual field.
TermsEnum	Iterator to seek (TermsEnum.seekCeil(BytesRef), TermsEnum.seekExact(BytesRef)) or step through (BytesRefIterator.next() terms to obtain frequency information (TermsEnum.docFreq()), DocsEnum or DocsAndPositionsEnum for the current term (TermsEnum.docs(org.apache.lucene.util.Bits, org.apache.lucene.index.DocsEnum).
TermsEnum.SeekStatus	Represents returned result from TermsEnum.seekCeil(org.apache.lucene.util.BytesRef).
TermSpans	Expert: Public for extension only
TermState	Encapsulates all required internal state to position the associated TermsEnum without re-seeking.
TermStatistics	Contains statistics for a specific term
TermStats	Holder for per-term statistics.
TermToBytesRefAttribute	This attribute is requested by TermsHashPerField to index the contents.
TermVectorsFormat	Controls the format of term vectors
TermVectorsReader	Codec API for reading term vectors:
TermVectorsWriter	Codec API for writing term vectors:
TextField	A field that is indexed and tokenized, without term vectors.
TFIDFSimilarity	Implementation of Similarity with the Vector Space Model.
ThreadInterruptedException	Thrown by lucene on detecting that Thread.interrupt() had been called.
TieredMergePolicy	Merges segments of approximately equal size, subject to an allowed number of segments per tier.
TieredMergePolicy.MergeScore	Holds score and explanation for a single candidate merge.
TimeLimitingCollector	The TimeLimitingCollector is used to timeout search requests that take longer than the maximum allowed search time limit.
TimeLimitingCollector.TimeExceededException	Thrown when elapsed search time exceeds allowed search time.
TimeLimitingCollector.TimerThread	Thread used to timeout search requests.
TimSorter	Sorter implementation based on the TimSort algorithm.
Token	A Token is an occurrence of a term from the text of a field.
Token.TokenAttributeFactory	Expert: Creates a TokenAttributeFactory returning Token as instance for the basic attributes and for all other attributes calls the given delegate factory.
TokenFilter	A TokenFilter is a TokenStream whose input is another TokenStream.
Tokenizer	A Tokenizer is a TokenStream whose input is a Reader.
TokenStream	A TokenStream enumerates the sequence of tokens, either from Fields of a Document or from query text.
TokenStreamToAutomaton	Consumes a TokenStream and creates an Automaton where the transition labels are UTF8 bytes (or Unicode code points if unicodeArcs is true) from the TermToBytesRefAttribute.
TopDocs	Represents hits returned by IndexSearcher.search(Query,Filter,int) and IndexSearcher.search(Query,int).
TopDocsCollector<T extends ScoreDoc>	A base class for all collectors that return a TopDocs output.
TopFieldCollector	A Collector that sorts by SortField using FieldComparators.
TopFieldDocs	Represents hits returned by IndexSearcher.search(Query,Filter,int,Sort).
TopScoreDocCollector	A Collector implementation that collects the top-scoring hits, returning them as a TopDocs.
TopTermsRewrite<Q extends Query>	Base rewrite method for collecting only the top terms via a priority queue.
ToStringUtils	Helper methods to ease implementing Object.toString().
TotalHitCountCollector	Just counts the total number of hits.
TrackingDirectoryWrapper	A delegating Directory that records which files were written to and deleted.
TrackingIndexWriter	Class that tracks changes to a delegated IndexWriter, used by ControlledRealTimeReopenThread to ensure specific changes are visible.
Transition	Automaton transition.
TwoPhaseCommit	An interface for implementations that support 2-phase commit.
TwoPhaseCommitTool	A utility for executing 2-phase commit on several objects.
TwoPhaseCommitTool.CommitFailException	Thrown by TwoPhaseCommitTool.execute(TwoPhaseCommit...) when an object fails to commit().
TwoPhaseCommitTool.PrepareCommitFailException	Thrown by TwoPhaseCommitTool.execute(TwoPhaseCommit...) when an object fails to prepareCommit().
TypeAttribute	A Token's lexical type.
TypeAttributeImpl	Default implementation of TypeAttribute.
UnicodeUtil	Class to encode java's UTF16 char[] into UTF8 byte[] without always allocating a new byte[] as String.getBytes("UTF-8") does.
UpgradeIndexMergePolicy	This MergePolicy is used for upgrading all existing segments of an index when calling IndexWriter.forceMerge(int).
UTF32ToUTF8	Converts UTF-32 automata to the equivalent UTF-8 representation.
Util	Static helper methods.
Util.FSTPath<T>	Represents a path in TopNSearcher.
Util.MinResult<T>	Holds a single input (IntsRef) + output, returned by shortestPaths().
Util.TopNSearcher<T>	Utility class to find top N shortest paths from start point(s).
VerifyingLockFactory	A LockFactory that wraps another LockFactory and verifies that each lock obtain/release is "correct" (never results in two processes holding the lock at the same time).
Version	Use by certain classes to match version compatibility across releases of Lucene.
VirtualMethod<C>	A utility for keeping backwards compatibility on previously abstract methods (or similar replacements).
WAH8DocIdSet	DocIdSet implementation based on word-aligned hybrid encoding on words of 8 bits.
WAH8DocIdSet.Builder	A builder for WAH8DocIdSets.
WeakIdentityMap<K,V>	Implements a combination of WeakHashMap and IdentityHashMap.
Weight	Expert: Calculate query weights and build query scorers.
WildcardQuery	Implements the wildcard search query.