Some utility classes.


Attribute Base interface for attributes. 


ArrayUtil Methods for manipulating arrays. 
AttributeImpl Base class for Attributes that can be added to a AttributeSource
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. 
AverageGuessMemoryModel An average, best guess, MemoryModel that should work okay on most systems. 
BitUtil A variety of high efficiency bit twiddling routines. 
BitVector Optimized implementation of a vector of bits. 
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. 
Constants Some useful constants. 
DocIdBitSet Simple DocIdSet and DocIdSetIterator backed by a BitSet  
DummyConcurrentLock A dummy lock as a replacement for ReentrantLock to disable locking  
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. 
IndexableBinaryStringTools Provides support for converting byte sequences to Strings and back again. 
MapOfSets<K, V> Helper class for keeping Lists of Objects associated with keys. 
MemoryModel Returns primitive memory sizes for estimating RAM usage. 
NamedThreadFactory A default ThreadFactory implementation that accepts the name prefix of the created threads as a constructor argument. 
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 Expert: Callback for splitIntRange(NumericUtils.IntRangeBuilder, int, int, int)
NumericUtils.LongRangeBuilder Expert: Callback for splitLongRange(NumericUtils.LongRangeBuilder, int, long, long)
OpenBitSet An "open" BitSet implementation that allows direct access to the array of words storing the bits. 
OpenBitSetIterator An iterator to iterate over set bits in an OpenBitSet. 
Parameter This class is deprecated. Use Java 5 enum, will be removed in a later Lucene 3.x release.  
PriorityQueue<T> A PriorityQueue maintains a partial ordering of its elements such that the least element can always be found in constant time. 
RamUsageEstimator Estimates the size of a given Object using a given MemoryModel for primitive size information. 
ReaderUtil Common util methods for dealing with IndexReaders. 
ScorerDocQueue A ScorerDocQueue maintains a partial ordering of its Scorers such that the least Scorer can always be found in constant time. 
SimpleStringInterner Simple lockless and memory barrier free String intern cache that is guaranteed to return the same String instance as String.intern() does. 
SmallFloat Floating point numbers smaller than 32 bits. 
SortedVIntList Stores and iterate on sorted integers in compressed form in RAM. 
SorterTemplate Borrowed from Cglib. 
StringHelper Methods for manipulating strings. 
StringInterner Subclasses of StringInterner are required to return the same single String object for all equal strings. 
ToStringUtils Helper methods to ease implementing toString()
UnicodeUtil Class to encode java's UTF16 char[] into UTF8 byte[] without always allocating a new byte[] as String.getBytes("UTF-8") does. 


Version Use by certain classes to match version compatibility across releases of Lucene. 


ThreadInterruptedException Thrown by lucene on detecting that Thread.interrupt() had been called.