ANTLR 4 Runtime (Optimized) 4.9.0 · org.antlr.v4.runtime.dfa.DFA

Field Summary

Modifier and Type	Field and Description
public final ATNState	atnStartState From which ATN state did we create this DFA?
public final int	decision
private static final EmptyEdgeMap<DFAState>	EMPTY_PRECEDENCE_EDGES This field initializes the outgoing edge map for the special starting DFA state created for precedence DFAs.
private final EmptyEdgeMap<DFAState>	emptyContextEdgeMap This is the backing field for `getEmptyContextEdgeMap()`.
private final EmptyEdgeMap<DFAState>	emptyEdgeMap This is the backing field for `getEmptyEdgeMap()`.
private final int	maxDfaEdge This is the backing field for `getMaxDfaEdge()`.
private final int	minDfaEdge This is the backing field for `getMinDfaEdge()`.
private final AtomicInteger	nextStateNumber
private final boolean	precedenceDfa `true` if this DFA is for a precedence decision; otherwise, `false`.
public final AtomicReference<DFAState>	s0 This is the start state for SLL prediction.
public final AtomicReference<DFAState>	s0full This is the start state for full context prediction.
public final ConcurrentMap<DFAState, DFAState>	states A set of all DFA states.

Constructor Summary

Access	Constructor and Description
public	DFA(ATNState The start state for the mode. atnStartState) Constructs a `DFA` instance associated with a lexer mode.
public	DFA(ATNState The decision associated with this DFA. atnStartState, int The decision number. decision) Constructs a `DFA` instance associated with a decision.

Method Summary

Modifier and Type	Method and Description
public DFAState	addState(DFAState state)
public EmptyEdgeMap<DFAState>	Returns: The empty context edge map used for initializing `DFAState` instances associated with this DFA. getEmptyContextEdgeMap() Gets an empty edge map initialized with the minimum and maximum context values allowed to be stored in this DFA.
public EmptyEdgeMap<DFAState>	Returns: The empty edge map used for initializing `DFAState` instances associated with this DFA. getEmptyEdgeMap() Gets an empty edge map initialized with the minimum and maximum symbol values allowed to be stored in this DFA.
public final int	Returns: The maximum input symbol which can be stored in this DFA. getMaxDfaEdge() Gets the maximum input symbol value which can be stored in this DFA.
public final int	Returns: The minimum input symbol which can be stored in this DFA. getMinDfaEdge() Gets the minimum input symbol value which can be stored in this DFA.
public final DFAState	Returns: The start state corresponding to the specified precedence, or `null` if no start state exists for the specified precedence. getPrecedenceStartState(int The current precedence. precedence, boolean fullContext) Get the start state for a specific precedence value.
public boolean	isContextSensitive()
public boolean	isEmpty()
public final boolean	Returns: `true` if this is a precedence DFA; otherwise, `false`. isPrecedenceDfa() Gets whether this DFA is a precedence DFA.
public final void	setPrecedenceDfa(boolean `true` if this is a precedence DFA; otherwise, `false` precedenceDfa) Deprecated This method no longer performs any action. Sets whether this is a precedence DFA.
public final void	setPrecedenceStartState(int The current precedence. precedence, boolean fullContext, DFAState The start state corresponding to the specified precedence. startState) Set the start state for a specific precedence value.
public String	toLexerString()
public String	toString() Overrides java.lang.Object.toString. Returns a string representation of the object.
public String	toString(String[] tokenNames) Deprecated Use `toString(Vocabulary)` instead.
public String	toString(Vocabulary vocabulary)
public String	toString(String[] tokenNames, String[] ruleNames) Deprecated Use `toString(Vocabulary, String[])` instead.
public String	toString(Vocabulary vocabulary, String[] ruleNames)

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll wait wait wait

Field Detail

atnStartState	back to summary
public final ATNState atnStartState From which ATN state did we create this DFA? Annotations @NotNull

decision	back to summary
public final int decision

EMPTY_PRECEDENCE_EDGES back to summary

EMPTY_PRECEDENCE_EDGES	back to summary
private static final EmptyEdgeMap<DFAState> EMPTY_PRECEDENCE_EDGES This field initializes the outgoing edge map for the special starting DFA state created for precedence DFAs. The range of allowed values assigned to this map represent the precedence levels for which an edge will be stored in the DFA. If a precedence level is encountered outside this range, the DFA will not be able to hold an edge pointing to the start state for the decision, so prediction for this precedence level will always result in recomputing the start state. Should this occur, the existing start state can still be located within `states` so outgoing edges starting from the start state will not be dropped. Annotations @NotNull

private static final EmptyEdgeMap<DFAState> EMPTY_PRECEDENCE_EDGES

This field initializes the outgoing edge map for the special starting DFA state created for precedence DFAs.

The range of allowed values assigned to this map represent the precedence levels for which an edge will be stored in the DFA. If a precedence level is encountered outside this range, the DFA will not be able to hold an edge pointing to the start state for the decision, so prediction for this precedence level will always result in recomputing the start state. Should this occur, the existing start state can still be located within states so outgoing edges starting from the start state will not be dropped.

Annotations

@NotNull

emptyContextEdgeMap	back to summary
private final EmptyEdgeMap<DFAState> emptyContextEdgeMap This is the backing field for `getEmptyContextEdgeMap()`. Annotations @NotNull

emptyEdgeMap	back to summary
private final EmptyEdgeMap<DFAState> emptyEdgeMap This is the backing field for `getEmptyEdgeMap()`. Annotations @NotNull

maxDfaEdge	back to summary
private final int maxDfaEdge This is the backing field for `getMaxDfaEdge()`.

minDfaEdge	back to summary
private final int minDfaEdge This is the backing field for `getMinDfaEdge()`.

nextStateNumber	back to summary
private final AtomicInteger nextStateNumber

precedenceDfa	back to summary
private final boolean precedenceDfa `true` if this DFA is for a precedence decision; otherwise, `false`. This is the backing field for `isPrecedenceDfa`.

s0 back to summary

s0	back to summary
public final AtomicReference<DFAState> s0 This is the start state for SLL prediction. When `isPrecedenceDfa` is `true`, this state is not used directly. Rather, `getPrecedenceStartState` is used to obtain the true SLL start state by traversing an outgoing edge corresponding to the current precedence level in the parser. Annotations @NotNull

public final AtomicReference<DFAState> s0

This is the start state for SLL prediction.

When isPrecedenceDfa is true, this state is not used directly. Rather, getPrecedenceStartState is used to obtain the true SLL start state by traversing an outgoing edge corresponding to the current precedence level in the parser.

Annotations

@NotNull

s0full	back to summary
public final AtomicReference<DFAState> s0full This is the start state for full context prediction. Annotations @NotNull See Also `s0`

states back to summary

states	back to summary
public final ConcurrentMap<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). Note that this collection of states holds the DFA states for both SLL and LL prediction. Only the start state needs to be differentiated for these cases, which is tracked by the `s0` and `s0full` fields. Annotations @NotNull

public final ConcurrentMap<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).

Note that this collection of states holds the DFA states for both SLL and LL prediction. Only the start state needs to be differentiated for these cases, which is tracked by the s0 and s0full fields.

Annotations

@NotNull

Constructor Detail

DFA back to summary

DFA	back to summary
public DFA(ATNState atnStartState) Constructs a `DFA` instance associated with a lexer mode. The start state for a `DFA` constructed with this method should be a `TokensStartState`, which is the start state for a lexer mode. The prediction made by this DFA determines the lexer rule which matches the current input. Parameters atnStartState:ATNState The start state for the mode.

public DFA(ATNState atnStartState)

Constructs a DFA instance associated with a lexer mode.

The start state for a DFA constructed with this method should be a TokensStartState, which is the start state for a lexer mode. The prediction made by this DFA determines the lexer rule which matches the current input.

Parameters

atnStartState:ATNState: The start state for the mode.

DFA back to summary

DFA	back to summary
public DFA(ATNState atnStartState, int decision) Constructs a `DFA` instance associated with a decision. Parameters atnStartState:ATNState The decision associated with this DFA. decision:int The decision number.

public DFA(ATNState atnStartState, int decision)

Constructs a DFA instance associated with a decision.

Parameters

atnStartState:ATNState: The decision associated with this DFA.
decision:int: The decision number.

Method Detail

addState	back to summary
public DFAState addState(DFAState state)

getEmptyContextEdgeMap back to summary

getEmptyContextEdgeMap	back to summary
public EmptyEdgeMap<DFAState> getEmptyContextEdgeMap() Gets an empty edge map initialized with the minimum and maximum context values allowed to be stored in this DFA. The value assigned to a context edge within the DFA is an ATN state number, so the range of allowed values for the context edge map is `ATNState#INVALID_STATE_NUMBER` through the number of states stored in `ATN#states` for the ATN. This empty edge map serves a purpose similar to `getEmptyEdgeMap`. It is used for initializing `DFAState` instances without incurring memory overhead for the (especially) common case where no outgoing context edges are added to the DFA state. Returns:EmptyEdgeMap<DFAState> The empty context edge map used for initializing `DFAState` instances associated with this DFA. Annotations @NotNull

public EmptyEdgeMap<DFAState> getEmptyContextEdgeMap()

Gets an empty edge map initialized with the minimum and maximum context values allowed to be stored in this DFA.

The value assigned to a context edge within the DFA is an ATN state number, so the range of allowed values for the context edge map is ATNState#INVALID_STATE_NUMBER through the number of states stored in ATN#states for the ATN.

This empty edge map serves a purpose similar to getEmptyEdgeMap. It is used for initializing DFAState instances without incurring memory overhead for the (especially) common case where no outgoing context edges are added to the DFA state.

Returns:EmptyEdgeMap<DFAState>

The empty context edge map used for initializing DFAState instances associated with this DFA.

Annotations

@NotNull

getEmptyEdgeMap back to summary

getEmptyEdgeMap	back to summary
public EmptyEdgeMap<DFAState> getEmptyEdgeMap() Gets an empty edge map initialized with the minimum and maximum symbol values allowed to be stored in this DFA. Setting a range of allowed symbol values for a DFA bounds the memory overhead for storing the map of outgoing edges. The various implementations of `EdgeMap` use this range to determine the best memory savings will be obtained from sparse storage (e.g. `SingletonEdgeMap` or `SparseEdgeMap`) or dense storage (`ArrayEdgeMap`). Symbols values outside the range are supported during prediction, but since DFA edges are never created for these symbols they will always recompute the target state through a match and closure operation. Empty edge maps are immutable objects which track the allowed range of input symbols that can be stored as edges in the DFA. By storing an empty edge map instance in the DFA, new instances of `DFAState` created for the DFA can be initialized with a non-null outgoing edge map with the proper symbol range without incurring extra allocations. Returns:EmptyEdgeMap<DFAState> The empty edge map used for initializing `DFAState` instances associated with this DFA. Annotations @NotNull

public EmptyEdgeMap<DFAState> getEmptyEdgeMap()

Gets an empty edge map initialized with the minimum and maximum symbol values allowed to be stored in this DFA.

Setting a range of allowed symbol values for a DFA bounds the memory overhead for storing the map of outgoing edges. The various implementations of EdgeMap use this range to determine the best memory savings will be obtained from sparse storage (e.g. SingletonEdgeMap or SparseEdgeMap) or dense storage (ArrayEdgeMap). Symbols values outside the range are supported during prediction, but since DFA edges are never created for these symbols they will always recompute the target state through a match and closure operation.

Empty edge maps are immutable objects which track the allowed range of input symbols that can be stored as edges in the DFA. By storing an empty edge map instance in the DFA, new instances of DFAState created for the DFA can be initialized with a non-null outgoing edge map with the proper symbol range without incurring extra allocations.

Returns:EmptyEdgeMap<DFAState>

The empty edge map used for initializing DFAState instances associated with this DFA.

Annotations

@NotNull

getMaxDfaEdge back to summary

getMaxDfaEdge	back to summary
public final int getMaxDfaEdge() Gets the maximum input symbol value which can be stored in this DFA. Returns:int The maximum input symbol which can be stored in this DFA. See Also `getEmptyEdgeMap`

public final int getMaxDfaEdge()

Gets the maximum input symbol value which can be stored in this DFA.

Returns:int: The maximum input symbol which can be stored in this DFA.
See Also: getEmptyEdgeMap

getMinDfaEdge back to summary

getMinDfaEdge	back to summary
public final int getMinDfaEdge() Gets the minimum input symbol value which can be stored in this DFA. Returns:int The minimum input symbol which can be stored in this DFA. See Also `getEmptyEdgeMap`

public final int getMinDfaEdge()

Gets the minimum input symbol value which can be stored in this DFA.

Returns:int: The minimum input symbol which can be stored in this DFA.
See Also: getEmptyEdgeMap

getPrecedenceStartState back to summary

getPrecedenceStartState	back to summary
public final DFAState getPrecedenceStartState(int precedence, boolean fullContext) Get the start state for a specific precedence value. Parameters precedence:int The current precedence. Returns:DFAState The start state corresponding to the specified precedence, or `null` if no start state exists for the specified precedence. Annotations @SuppressWarnings:null Exceptions IllegalStateException: if this is not a precedence DFA. See Also `isPrecedenceDfa()`

public final DFAState getPrecedenceStartState(int precedence, boolean fullContext)

Get the start state for a specific precedence value.

Parameters

precedence:int: The current precedence.

Returns:DFAState

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

Annotations

@SuppressWarnings:null

Exceptions

IllegalStateException:: if this is not a precedence DFA.

See Also

isPrecedenceDfa()

isContextSensitive	back to summary
public boolean isContextSensitive()

isEmpty	back to summary
public boolean isEmpty()

isPrecedenceDfa back to summary

isPrecedenceDfa	back to summary
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:boolean `true` if this is a precedence DFA; otherwise, `false`. See Also `Parser#getPrecedence()`

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:boolean: true if this is a precedence DFA; otherwise, false.
See Also: Parser#getPrecedence()

setPrecedenceDfa back to summary

setPrecedenceDfa	back to summary
public final void setPrecedenceDfa(boolean precedenceDfa) Deprecated This method no longer performs any action. Sets whether this is a precedence DFA. Parameters precedenceDfa:boolean `true` if this is a precedence DFA; otherwise, `false` Annotations @Deprecated Exceptions UnsupportedOperationException: if `precedenceDfa` does not match the value of `isPrecedenceDfa` for the current DFA.

public final void setPrecedenceDfa(boolean precedenceDfa)

Deprecated

This method no longer performs any action.

Sets whether this is a precedence DFA.

Parameters

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

Annotations

@Deprecated

Exceptions

UnsupportedOperationException:: if precedenceDfa does not match the value of isPrecedenceDfa for the current DFA.

setPrecedenceStartState back to summary

setPrecedenceStartState	back to summary
public final void setPrecedenceStartState(int precedence, boolean fullContext, DFAState startState) Set the start state for a specific precedence value. Parameters precedence:int The current precedence. startState:DFAState The start state corresponding to the specified precedence. Annotations @SuppressWarnings:SynchronizeOnNonFinalField, null Exceptions IllegalStateException: if this is not a precedence DFA. See Also `isPrecedenceDfa()`

public final void setPrecedenceStartState(int precedence, boolean fullContext, DFAState startState)

Set the start state for a specific precedence value.

Parameters

precedence:int: The current precedence.
startState:DFAState: The start state corresponding to the specified precedence.

Annotations

@SuppressWarnings:SynchronizeOnNonFinalField, null

Exceptions

IllegalStateException:: if this is not a precedence DFA.

See Also

isPrecedenceDfa()

toLexerString	back to summary
public String toLexerString()

toString	back to summary
public String toString() Overrides java.lang.Object.toString. Doc from java.lang.Object.toString. Returns a string representation of the object. Returns:String a string representation of the object. Annotations @Override

toString

back to summary

public String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object.

Returns:String

a string representation of the object.

Annotations

@Override

toString	back to summary
public String toString(String[] tokenNames) Deprecated Use `toString(Vocabulary)` instead. Annotations @Deprecated

toString	back to summary
public String toString(Vocabulary vocabulary)

toString	back to summary
public String toString(String[] tokenNames, String[] ruleNames) Deprecated Use `toString(Vocabulary, String[])` instead. Annotations @Deprecated

toString	back to summary
public String toString(Vocabulary vocabulary, String[] ruleNames)

public Class DFA

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