org.stekikun.dolmen.automaton

Class DFA.State

java.lang.Object

org.stekikun.dolmen.automaton.DFA.State

Enclosing class:

DFA

public static final class DFA.State
extends Object

A state in the (tagged) deterministic finite automaton corresponds to a set of states in the non-deterministic automaton, each being associated with a memory map.

NFA States of the form NFA.Event.onChars(int) are accounted for in others, and are indexed by the corresponding character set index. Besides, there can be at most one state of the form NFA.Event.toAction(int), i.e. a final state, in which case the DFA state is final itself. If there were more than one final state, there would be ambiguity as to what action should be performed when accepting the input.

Author:

Stéphane Lescuyer

Field Summary

Fields

Modifier and Type	Field and Description
static DFA.State	EMPTY The empty state
int	finalAction Describes the semantic action associated to this state, if final, or DFA.NO_ACTION if the state is not final
@Nullable DFA.MemMap	finisher The memory map associated to the final action or null if the state isn't final
Map<Integer,DFA.MemMap>	others Maps character sets indices to memory maps.

Method Summary

Modifier and Type	Method and Description
Map<TRegular.TagInfo,Integer>	getFinalLocs()
Map<TRegular.TagInfo,Integer>	getLocsFor(NFA.Event event)
boolean	isEmpty() Whether the DFA state is empty
boolean	isFinal() Whether the DFA state is final
String	toString()
DFA.State	withLocs(int n, DFA.MemMap newMmap)

Methods inherited from class java.lang.Object

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

Field Detail

finalAction

public final int finalAction

Describes the semantic action associated to this state, if final, or DFA.NO_ACTION if the state is not final

finisher

public final @Nullable DFA.MemMap finisher

The memory map associated to the final action or null if the state isn't final

others

public final Map<Integer,DFA.MemMap> others

Maps character sets indices to memory maps. The NFA states corresponding to these character sets are the non-final states in this DFA state.

EMPTY

public static final DFA.State EMPTY

The empty state

Method Detail

toString

public String toString()

Overrides:

toString in class Object

isEmpty

public boolean isEmpty()

Whether the DFA state is empty

isFinal

public boolean isFinal()

Whether the DFA state is final

getFinalLocs

public Map<TRegular.TagInfo,Integer> getFinalLocs()

Returns:

the location map associated to the final action in this state, or an empty map if the state isn't final

getLocsFor

public Map<TRegular.TagInfo,Integer> getLocsFor(NFA.Event event)

Parameters:

event -

Returns:

the location map associated to the given NFA state

Throws:

IllegalArgumentException - if the given state is not part of this DFA state (in particular, if it is a different final action that the one specified in the DFA state)

withLocs

public DFA.State withLocs(int n,
                          DFA.MemMap newMmap)

Parameters:

n -

newMmap -

Returns:

a new DFA state exactly like the receiver except that the character set n is mapped to newMap