# Package org.apache.lucene.util.automaton

Finite-state automaton for regular expressions.

See: Description

- Interface Summary
  Interface | Description
  --- | ---
  AutomatonProvider | Automaton provider for `RegExp.` `RegExp.toAutomaton(AutomatonProvider)`

- Class Summary
  Class | Description
  --- | ---
  Automaton | Finite-state automaton with regular expression operations.
  BasicAutomata | Construction of basic automata.
  BasicOperations | Basic automata operations.
  ByteRunAutomaton | Automaton representation for matching UTF-8 byte[].
  CharacterRunAutomaton | Automaton representation for matching char[].
  CompiledAutomaton | Immutable class holding compiled details for a given Automaton.
  LevenshteinAutomata | Class to construct DFAs that match a word within some edit distance.
  MinimizationOperations | Operations for minimizing automata.
  RegExp | Regular Expression extension to `Automaton`.
  RunAutomaton | Finite-state automaton with fast run operation.
  SpecialOperations | Special automata operations.
  State | `Automaton` state.
  StatePair | Pair of states.
  Transition | `Automaton` transition.
  UTF32ToUTF8 | Converts UTF-32 automata to the equivalent UTF-8 representation.

- Enum Summary
  Enum | Description
  --- | ---
  CompiledAutomaton.AUTOMATON_TYPE | Automata are compiled into different internal forms for the most efficient execution depending upon the language they accept.

## Package org.apache.lucene.util.automaton Description

Finite-state automaton for regular expressions.

This package contains a full DFA/NFA implementation with Unicode alphabet and support for all standard (and a number of non-standard) regular expression operations.

The most commonly used functionality is located in the classes ``Automaton`` and ``RegExp``.

For more information, go to the package home page at `http://www.brics.dk/automaton/`.

WARNING: This API is experimental and might change in incompatible ways in the next release.

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