Namespace Lucene.Net.Util.Automaton

Finite-state automaton with regular expression operations.

Class invariants:

• An automaton is either represented explicitly (with State and Transition objects) or with a singleton string (see Singleton and ExpandSingleton()) in case the automaton is known to accept exactly one string. (Implicitly, all states and transitions of an automaton are reachable from its initial state.)
• Automata are always reduced (see Reduce()) and have no transitions to dead states (see RemoveDeadTransitions()).
• If an automaton is nondeterministic, then IsDeterministic returns false (but the converse is not required).
• Automata provided as input to operations are generally assumed to be disjoint.

If the states or transitions are manipulated manually, the RestoreInvariant() method and IsDeterministic setter should be used afterwards to restore representation invariants that are assumed by the built-in automata operations.

Note: this class has internal mutable state and is not thread safe. It is the caller's responsibility to ensure any necessary synchronization if you wish to use the same Automaton from multiple threads. In general it is instead recommended to use a RunAutomaton for multithreaded matching: it is immutable, thread safe, and much faster.

Construction of basic automata.

@lucene.experimental

Basic automata operations.

@lucene.experimental

Automaton representation for matching UTF-8 byte[].

Automaton representation for matching char[].

Immutable class holding compiled details for a given Automaton. The Automaton is deterministic, must not have dead states but is not necessarily minimal.

@lucene.experimental

Class to construct DFAs that match a word within some edit distance.

Implements the algorithm described in: Schulz and Mihov: Fast String Correction with Levenshtein Automata

@lucene.experimental

Operations for minimizing automata.

@lucene.experimental

Regular Expression extension to Automaton.

Regular expressions are built from the following abstract syntax:

The productions marked [OPTIONAL] are only allowed if specified by the syntax flags passed to the RegExp constructor. The reserved characters used in the (enabled) syntax must be escaped with backslash (</code>) or double-quotes ("..."). (In contrast to other regexp syntaxes, this is required also in character classes.) Be aware that dash (-) has a special meaning in charclass expressions. An identifier is a string not containing right angle bracket (>) or dash (-). Numerical intervals are specified by non-negative decimal integers and include both end points, and if n and m have the same number of digits, then the conforming strings must have that length (i.e. prefixed by 0's).

@lucene.experimental

Finite-state automaton with fast run operation.

@lucene.experimental

Special automata operations.

@lucene.experimental

Automaton state.

@lucene.experimental

Pair of states.

@lucene.experimental

Automaton transition.

A transition, which belongs to a source state, consists of a Unicode codepoint interval and a destination state.

@lucene.experimental

Converts UTF-32 automata to the equivalent UTF-8 representation.

@lucene.internal

Automaton provider for RegExp.

@lucene.experimental

Automata are compiled into different internal forms for the most efficient execution depending upon the language they accept.