dk.brics.automaton

Class RunAutomaton

public class RunAutomaton extends Object implements Serializable

Finite-state automaton with fast run operation.

Author: Anders Møller <amoeller@brics.dk>

Constructor Summary
	RunAutomaton(Automaton a) Constructs a new `RunAutomaton` from a deterministic `Automaton`.
	RunAutomaton(Automaton a, boolean tableize) Constructs a new `RunAutomaton` from a deterministic `Automaton`.

Method Summary
char[]	getCharIntervals() Returns array of character class interval start points.
int	getInitialState() Returns initial state.
int	getSize() Returns number of states in automaton.
boolean	isAccept(int state) Returns acceptance status for given state.
static RunAutomaton	load(URL url) Retrieves a serialized `RunAutomaton` located by a URL.
static RunAutomaton	load(InputStream stream) Retrieves a serialized `RunAutomaton` from a stream.
boolean	run(String s) Returns true if the given string is accepted by this automaton.
int	run(String s, int offset) Returns the length of the longest accepted run of the given string starting at the given offset.
int	step(int state, char c) Returns the state obtained by reading the given char from the given state.
void	store(OutputStream stream) Writes this `RunAutomaton` to the given stream.

Constructor Detail

RunAutomaton

public RunAutomaton(Automaton a)

Constructs a new RunAutomaton from a deterministic Automaton. Same as RunAutomaton(a, true).

Parameters: a an automaton

RunAutomaton

public RunAutomaton(Automaton a, boolean tableize)

Constructs a new RunAutomaton from a deterministic Automaton. If the given automaton is not deterministic, it is determinized first.

Parameters: a an automaton tableize if true, a transition table is created which makes the run method faster in return of a higher memory usage

Method Detail

getCharIntervals

public char[] getCharIntervals()

Returns array of character class interval start points. The array should not be modified by the caller.

getInitialState

public int getInitialState()

Returns initial state.

getSize

public int getSize()

Returns number of states in automaton.

isAccept

public boolean isAccept(int state)

Returns acceptance status for given state.

load

public static RunAutomaton load(URL url)

Retrieves a serialized RunAutomaton located by a URL.

Parameters: url URL of serialized automaton

Throws: IOException if input/output related exception occurs OptionalDataException if the data is not a serialized object InvalidClassException if the class serial number does not match ClassCastException if the data is not a serialized RunAutomaton ClassNotFoundException if the class of the serialized object cannot be found

load

public static RunAutomaton load(InputStream stream)

Retrieves a serialized RunAutomaton from a stream.

Parameters: stream input stream with serialized automaton

run

public boolean run(String s)

Returns true if the given string is accepted by this automaton.

run

public int run(String s, int offset)

Returns the length of the longest accepted run of the given string starting at the given offset.

Parameters: s the string offset offset into s where the run starts

Returns: length of the longest accepted run, -1 if no run is accepted

step

public int step(int state, char c)

Returns the state obtained by reading the given char from the given state. Returns -1 if not obtaining any such state. (If the original Automaton had no dead states, -1 is returned here if and only if a dead state is entered in an equivalent automaton with a total transition function.)

store

public void store(OutputStream stream)

Writes this RunAutomaton to the given stream.

Parameters: stream output stream for serialized automaton

Throws: IOException if input/output related exception occurs