org.antlr.v4.runtime.dfa

Class DFA

java.lang.Object

org.antlr.v4.runtime.dfa.DFA

public class DFA
extends Object

Field Summary

Fields

Modifier and Type	Field and Description
DecisionState	atnStartState From which ATN state did we create this DFA?
int	decision
DFAState	s0
Map<DFAState,DFAState>	states A set of all DFA states.

Constructor Summary

Constructors

Constructor and Description
DFA(DecisionState atnStartState)
DFA(DecisionState atnStartState, int decision)

Method Summary

Methods

Modifier and Type	Method and Description
DFAState	getPrecedenceStartState(int precedence) Get the start state for a specific precedence value.
List<DFAState>	getStates() Return a list of all states in this DFA, ordered by state number.
boolean	isPrecedenceDfa() Gets whether this DFA is a precedence DFA.
void	setPrecedenceDfa(boolean precedenceDfa) Sets whether this is a precedence DFA.
void	setPrecedenceStartState(int precedence, DFAState startState) Set the start state for a specific precedence value.
String	toLexerString()
String	toString()
String	toString(String[] tokenNames)

Methods inherited from class java.lang.Object

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

Field Detail

states

@NotNull
public final Map<DFAState,DFAState> states

A set of all DFA states. Use Map so we can get old state back (Set only allows you to see if it's there).

s0

@Nullable
public volatile DFAState s0

decision

public final int decision

atnStartState

@NotNull
public final DecisionState atnStartState

From which ATN state did we create this DFA?

Constructor Detail

DFA

public DFA(@NotNull
   DecisionState atnStartState)

DFA

public DFA(@NotNull
   DecisionState atnStartState,
   int decision)

Method Detail

isPrecedenceDfa

public final boolean isPrecedenceDfa()

Gets whether this DFA is a precedence DFA. Precedence DFAs use a special start state s0 which is not stored in states. The DFAState.edges array for this start state contains outgoing edges supplying individual start states corresponding to specific precedence values.

Returns:

true if this is a precedence DFA; otherwise, false.

See Also:

Parser.getPrecedence()

getPrecedenceStartState

public final DFAState getPrecedenceStartState(int precedence)

Get the start state for a specific precedence value.

Parameters:

precedence - The current precedence.

Returns:

The start state corresponding to the specified precedence, or null if no start state exists for the specified precedence.

Throws:

IllegalStateException - if this is not a precedence DFA.

See Also:

isPrecedenceDfa()

setPrecedenceStartState

public final void setPrecedenceStartState(int precedence,
                           DFAState startState)

Set the start state for a specific precedence value.

Parameters:

precedence - The current precedence.

startState - The start state corresponding to the specified precedence.

Throws:

IllegalStateException - if this is not a precedence DFA.

See Also:

isPrecedenceDfa()

setPrecedenceDfa

public final void setPrecedenceDfa(boolean precedenceDfa)

Sets whether this is a precedence DFA. If the specified value differs from the current DFA configuration, the following actions are taken; otherwise no changes are made to the current DFA.

• The states map is cleared
• If precedenceDfa is false, the initial state s0 is set to null; otherwise, it is initialized to a new DFAState with an empty outgoing DFAState.edges array to store the start states for individual precedence values.
• The precedenceDfa field is updated

Parameters:

precedenceDfa - true if this is a precedence DFA; otherwise, false

getStates

@NotNull
public List<DFAState> getStates()

Return a list of all states in this DFA, ordered by state number.

toString

public String toString()

Overrides:

toString in class Object

toString

public String toString(@Nullable
              String[] tokenNames)

toLexerString

public String toLexerString()