Package org.apache.lucene.util
Some utility classes.
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Interface Summary Interface Description Accountable An object whose RAM usage can be computed.ArrayUtil.ByteArrayComparator Comparator for a fixed number of bytes.Attribute Base interface for attributes.AttributeReflector This interface is used to reflect contents ofAttributeSourceorAttributeImpl.Bits Interface for Bitset-like structures.BytesRefArray.IndexedBytesRefIterator An extension ofBytesRefIteratorthat allows retrieving the index of the current elementBytesRefIterator A simple iterator interface forBytesRefiteration.ClassLoaderUtils Helper class used by ServiceLoader to investigate parent/child relationships ofClassLoaders.GroupVIntUtil.IntReader Provides an abstraction for read int values, so that decoding logic can be reused in different DataInput.IOConsumer<T> An IO operation with a single input that may throw an IOException.IOFunction<T,R> A Function that may throw an IOExceptionIORunnable A Runnable that may throw an IOExceptionIOSupplier<T> This is a result supplier that is allowed to throw an IOException.IOUtils.IOConsumer<T> Deprecated, for removal: This API element is subject to removal in a future version. was replaced byIOConsumer.IOUtils.IOFunction<T,R> Deprecated, for removal: This API element is subject to removal in a future version. was replaced byIOFunction.NamedSPILoader.NamedSPI Interface to supportNamedSPILoader.lookup(String)by name.ResourceLoader Abstraction for loading resources (streams, files, and classes).ResourceLoaderAware Interface for a component that needs to be initialized by an implementation ofResourceLoader.RollingBuffer.Resettable Implement to reset an instanceUnwrappable<T> An object with this interface is a wrapper around another object (e.g., a filter with a delegate). -
Class Summary Class Description Accountables Helper methods for constructing nested resource descriptions and debugging RAM usage.ArrayUtil Methods for manipulating arrays.AttributeFactory An AttributeFactory creates instances ofAttributeImpls.AttributeFactory.StaticImplementationAttributeFactory<A extends AttributeImpl> Expert: AttributeFactory returning an instance of the givenclazzfor the attributes it implements.AttributeImpl Base class for Attributes that can be added to aAttributeSource.AttributeSource An AttributeSource contains a list of differentAttributeImpls, and methods to add and get them.AttributeSource.State This class holds the state of an AttributeSource.BitDocIdSet Bits.MatchAllBits Bits impl of the specified length with all bits set.Bits.MatchNoBits Bits impl of the specified length with no bits set.BitSet Base implementation for a bit set.BitSetIterator ADocIdSetIteratorwhich iterates over set bits in a bit set.BitUtil A variety of high efficiency bit twiddling routines and encoders for primitives.ByteBlockPool This class enables the allocation of fixed-size buffers and their management as part of a buffer array.ByteBlockPool.Allocator Abstract class for allocating and freeing byte blocks.ByteBlockPool.DirectAllocator A simpleByteBlockPool.Allocatorthat never recycles.ByteBlockPool.DirectTrackingAllocator A simpleByteBlockPool.Allocatorthat never recycles, but tracks how much total RAM is in use.BytesRef Represents byte[], as a slice (offset + length) into an existing byte[].BytesRefArray A simple append only random-accessBytesRefarray that stores full copies of the appended bytes in aByteBlockPool.BytesRefArray.SortState Used to iterate the elements of an array in a given order.BytesRefBlockPool Represents a logical list of ByteRef backed by aByteBlockPool.BytesRefBuilder A builder forBytesRefinstances.BytesRefComparator SpecializedBytesRefcomparator thatStringSorterhas optimizations for.BytesRefHash BytesRefHashis a special purpose hash-map like data-structure optimized forBytesRefinstances.BytesRefHash.BytesStartArray Manages allocation of the per-term addresses.BytesRefHash.DirectBytesStartArray A simpleBytesRefHash.BytesStartArraythat tracks memory allocation using a privateCounterinstance.CharsRef Represents char[], as a slice (offset + length) into an existing char[].CharsRefBuilder A builder forCharsRefinstances.ClasspathResourceLoader SimpleResourceLoaderthat usesClassLoader.getResourceAsStream(String)andClass.forName(String,boolean,ClassLoader)to open resources and classes, respectively.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.CollectionUtil Methods for manipulating (sorting) and creating collections.CommandLineUtil Class containing some useful methods used by command line toolsConstants Some useful constants.Counter Simple counter classDocBaseBitSetIterator ADocIdSetIteratorlikeBitSetIteratorbut has a doc base in onder to avoid storing previous 0s.DocIdSetBuilder A builder ofDocIdSets.DocIdSetBuilder.BulkAdder Utility class to efficiently add many docs in one go.FileDeleter This class provides ability to track the reference counts of a set of index files and delete them when their counts decreased to 0.FileDeleter.RefCount Tracks the reference count for a single index file:FilterIterator<T,InnerT extends T> AnIteratorimplementation that filters elements with a boolean predicate.FixedBitSet BitSet of fixed length (numBits), backed by accessible (FixedBitSet.getBits()) long[], accessed with an int index, implementingBitsandDocIdSet.FrequencyTrackingRingBuffer A ring buffer that tracks the frequency of the integers that it contains.GroupVIntUtil This class contains utility methods and constants for group varintInfoStream Debugging API for Lucene classes such asIndexWriterandSegmentInfos.InPlaceMergeSorter Sorterimplementation based on the merge-sort algorithm that merges in place (no extra memory will be allocated).IntBlockPool A pool for int blocks similar toByteBlockPoolIntBlockPool.Allocator Abstract class for allocating and freeing int blocks.IntBlockPool.DirectAllocator A simpleIntBlockPool.Allocatorthat never recycles.IntroSelector Adaptive selection algorithm based on the introspective quick select algorithm.IntroSorter IntsRef Represents int[], as a slice (offset + length) into an existing int[].IntsRefBuilder A builder forIntsRefinstances.IOUtils Utilities for dealing withCloseables.JavaLoggingInfoStream InfoStream implementation that logs every message using Java Utils Logging (JUL) with the supplied log level.LongBitSet BitSet of fixed length (numBits), backed by accessible (LongBitSet.getBits()) long[], accessed with a long index.LongHeap A min heap that stores longs; a primitive priority queue that like all priority queues maintains a partial ordering of its elements such that the least element can always be found in constant time.LongsRef Represents long[], as a slice (offset + length) into an existing long[].LongValues Abstraction over an array of longs.LSBRadixSorter A LSB Radix sorter for unsigned int values.MapOfSets<K,V> Helper class for keeping Lists of Objects associated with keys.MathUtil Math static utility methods.MergedIterator<T extends Comparable<T>> Provides a merged sorted view from several sorted iterators.ModuleResourceLoader SimpleResourceLoaderthat usesModule.getResourceAsStream(String)andClass.forName(Module,String)to open resources and classes, respectively.MSBRadixSorter Radix sorter for variable-length strings.NamedSPILoader<S extends NamedSPILoader.NamedSPI> Helper class for loading named SPIs from classpath (e.g.NamedThreadFactory A defaultThreadFactoryimplementation that accepts the name prefix of the created threads as a constructor argument.NotDocIdSet NumericUtils Helper APIs to encode numeric values as sortable bytes and vice-versa.OfflineSorter On-disk sorting of byte arrays.OfflineSorter.BufferSize A bit more descriptive unit for constructors.OfflineSorter.ByteSequencesReader Utility class to read length-prefixed byte[] entries from an input.OfflineSorter.ByteSequencesWriter Utility class to emit length-prefixed byte[] entries to an output stream for sorting.PagedBytes Represents a logical byte[] as a series of pages.PagedBytes.Reader Provides methods to read BytesRefs from a frozen PagedBytes.PrintStreamInfoStream InfoStream implementation over aPrintStreamsuch asSystem.out.PriorityQueue<T> A priority queue maintains a partial ordering of its elements such that the least element can always be found in constant time.QueryBuilder Creates queries from theAnalyzerchain.QueryBuilder.TermAndBoost Wraps a term and boostRadixSelector Radix selector.RamUsageEstimator Estimates the size (memory representation) of Java objects.RecyclingByteBlockAllocator AByteBlockPool.Allocatorimplementation that recycles unused byte blocks in a buffer and reuses them in subsequent calls toRecyclingByteBlockAllocator.getByteBlock().RecyclingIntBlockAllocator AIntBlockPool.Allocatorimplementation that recycles unused int blocks in a buffer and reuses them in subsequent calls toRecyclingIntBlockAllocator.getIntBlock().RefCount<T> Manages reference counting for a given object.RoaringDocIdSet DocIdSetimplementation inspired from http://roaringbitmap.org/RoaringDocIdSet.Builder A builder ofRoaringDocIdSets.RollingBuffer<T extends RollingBuffer.Resettable> Acts like forever growing T[], but internally uses a circular buffer to reuse instances of T.SameThreadExecutorService AnExecutorServicethat executes tasks immediately in the calling thread during submit.Selector An implementation of a selection algorithm, ie.SentinelIntSet A native int hash-based set where one value is reserved to mean "EMPTY" internally.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.SloppyMath Math functions that trade off accuracy for speed.SmallFloat Floating point numbers smaller than 32 bits.Sorter Base class for sorting algorithms implementations.SparseFixedBitSet A bit set that only stores longs that have at least one bit which is set.StableMSBRadixSorter Stable radix sorter for variable-length strings.StableMSBRadixSorter.MergeSorter A MergeSorter taking advantage of temporary storage.StringHelper Methods for manipulating strings.StringSorter ABytesRefsorter tries to use a efficient radix sorter ifStringSorter.cmpis aBytesRefComparator, otherwise fallback toStringSorter.fallbackSorter(java.util.Comparator<org.apache.lucene.util.BytesRef>)TermAndVector Word2Vec unit composed by a term with the associated vectorTimSorter ToStringUtils Helper methods to ease implementingObject.toString().UnicodeUtil Class to encode java's UTF16 char[] into UTF8 byte[] without always allocating a new byte[] as String.getBytes(StandardCharsets.UTF_8) does.UnicodeUtil.UTF8CodePoint Holds a codepoint along with the number of bytes required to represent it in UTF8VectorUtil Utilities for computations with numeric arrays, especially algebraic operations like vector dot products.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).WeakIdentityMap<K,V> Implements a combination ofWeakHashMapandIdentityHashMap. -
Enum Summary Enum Description FileDeleter.MsgType Types of messages this file deleter will broadcast REF: messages about reference FILE: messages about file -
Exception Summary Exception Description BytesRefHash.MaxBytesLengthExceededException SetOnce.AlreadySetException Thrown whenSetOnce.set(Object)is called more than once.ThreadInterruptedException Thrown by lucene on detecting that Thread.interrupt() had been called. -
Annotation Types Summary Annotation Type Description IgnoreRandomChains Annotation to not test a class or constructor withTestRandomChainsintegration test.SuppressForbidden Annotation to suppress forbidden-apis errors inside a whole class, a method, or a field.