Package dk.brics.automaton

Class RunAutomaton

java.lang.Object

dk.brics.automaton.RunAutomaton

All Implemented Interfaces:

Serializable

public class RunAutomaton
extends Object
implements Serializable

Finite-state automaton with fast run operation.

Author:

Anders Møller <amoeller@cs.au.dk>

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
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

Modifier and Type	Method	Description
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(InputStream stream)	Retrieves a serialized RunAutomaton from a stream.
static RunAutomaton	load(URL url)	Retrieves a serialized RunAutomaton located by a URL.
AutomatonMatcher	newMatcher(CharSequence s)	Creates a new automaton matcher for the given input.
AutomatonMatcher	newMatcher(CharSequence s, int startOffset, int endOffset)	Creates a new automaton matcher for the given input.
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.
String	toString()	Returns a string representation of this automaton.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

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

toString

public String toString()

Returns a string representation of this automaton.

Overrides:

toString in class Object

getSize

public int getSize()

Returns number of states in automaton.

isAccept

public boolean isAccept(int state)

Returns acceptance status for given state.

getInitialState

public int getInitialState()

Returns initial state.

getCharIntervals

public char[] getCharIntervals()

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

load

public static RunAutomaton load(URL url)
                         throws IOException,
                                ClassCastException,
                                ClassNotFoundException

Retrieves a serialized RunAutomaton located by a URL.

Parameters:

url - URL of serialized automaton

Throws:

IOException - if input/output related exception occurs

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)
                         throws IOException,
                                ClassCastException,
                                ClassNotFoundException

Retrieves a serialized RunAutomaton from a stream.

Parameters:

stream - input stream with serialized automaton

Throws:

IOException - if input/output related exception occurs

ClassCastException - if the data is not a serialized RunAutomaton

ClassNotFoundException - if the class of the serialized object cannot be found

store

public void store(OutputStream stream)
           throws IOException

Writes this RunAutomaton to the given stream.

Parameters:

stream - output stream for serialized automaton

Throws:

IOException - if input/output related exception occurs

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.)

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

newMatcher

public AutomatonMatcher newMatcher(CharSequence s)

Creates a new automaton matcher for the given input.

Parameters:

s - the CharSequence to search

Returns:

A new automaton matcher for the given input

newMatcher

public AutomatonMatcher newMatcher(CharSequence s,
                                   int startOffset,
                                   int endOffset)

Creates a new automaton matcher for the given input.

Parameters:

s - the CharSequence to search

startOffset - the starting offset of the given character sequence

endOffset - the ending offset of the given character sequence

Returns:

A new automaton matcher for the given input