Package org.antlr.v4.runtime

Class RecognitionException

java.lang.Object

java.lang.Throwable

java.lang.Exception

java.lang.RuntimeException

org.antlr.v4.runtime.RecognitionException

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

FailedPredicateException, InputMismatchException, LexerNoViableAltException, NoViableAltException

public class RecognitionException
extends RuntimeException

The root of the ANTLR exception hierarchy. In general, ANTLR tracks just 3 kinds of errors: prediction errors, failed predicate errors, and mismatched input errors. In each case, the parser knows where it is in the input, where it is in the ATN, the rule invocation stack, and what kind of problem occurred.

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
private final RuleContext	ctx
private final IntStream	input
private int	offendingState
private Token	offendingToken	The current Token when an error occurred.
private final Recognizer<?,?>	recognizer	The Recognizer where this exception originated.
private static final long	serialVersionUID

Constructor Summary

Constructors

Constructor	Description
RecognitionException(String message, Recognizer<Token,?> recognizer, IntStream input, ParserRuleContext ctx)
RecognitionException(Lexer lexer, CharStream input)
RecognitionException(Recognizer<Token,?> recognizer, IntStream input, ParserRuleContext ctx)

Method Summary

Modifier and Type	Method	Description
RuleContext	getContext()	Gets the RuleContext at the time this exception was thrown.
IntervalSet	getExpectedTokens()	Gets the set of input symbols which could potentially follow the previously matched symbol at the time this exception was thrown.
IntStream	getInputStream()	Gets the input stream which is the symbol source for the recognizer where this exception was thrown.
int	getOffendingState()	Get the ATN state number the parser was in at the time the error occurred.
Token	getOffendingToken()
<T> T	getOffendingToken(Recognizer<T,?> recognizer)
Recognizer<?,?>	getRecognizer()	Gets the Recognizer where this exception occurred.
protected final void	setOffendingState(int offendingState)
protected final <Symbol extends Token> void	setOffendingToken(Recognizer<Symbol,?> recognizer, Symbol offendingToken)

Methods inherited from class java.lang.Throwable

addSuppressed, fillInStackTrace, getCause, getLocalizedMessage, getMessage, getStackTrace, getSuppressed, initCause, printStackTrace, printStackTrace, printStackTrace, setStackTrace, toString

Methods inherited from class java.lang.Object

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

Field Details

serialVersionUID

private static final long serialVersionUID

See Also:

• Constant Field Values

recognizer

@Nullable
private final Recognizer<?,?> recognizer

The Recognizer where this exception originated.

ctx

@Nullable
private final RuleContext ctx

input

@Nullable
private final IntStream input

offendingToken

private Token offendingToken

The current Token when an error occurred. Since not all streams support accessing symbols by index, we have to track the Token instance itself.

offendingState

private int offendingState

Constructor Details

RecognitionException

public RecognitionException(@Nullable
 Lexer lexer,
 CharStream input)

RecognitionException

public RecognitionException(@Nullable
 Recognizer<Token,?> recognizer,
 @Nullable
 IntStream input,
 @Nullable
 ParserRuleContext ctx)

RecognitionException

public RecognitionException(String message,
 @Nullable
 Recognizer<Token,?> recognizer,
 @Nullable
 IntStream input,
 @Nullable
 ParserRuleContext ctx)

Method Details

getOffendingState

public int getOffendingState()

Get the ATN state number the parser was in at the time the error occurred. For NoViableAltException and LexerNoViableAltException exceptions, this is the DecisionState number. For others, it is the state whose outgoing edge we couldn't match.

If the state number is not known, this method returns -1.

setOffendingState

protected final void setOffendingState(int offendingState)

getExpectedTokens

@Nullable
public IntervalSet getExpectedTokens()

Gets the set of input symbols which could potentially follow the previously matched symbol at the time this exception was thrown.

If the set of expected tokens is not known and could not be computed, this method returns null.

Returns:

The set of token types that could potentially follow the current state in the ATN, or null if the information is not available.

getContext

@Nullable
public RuleContext getContext()

Gets the RuleContext at the time this exception was thrown.

If the context is not available, this method returns null.

Returns:

The RuleContext at the time this exception was thrown. If the context is not available, this method returns null.

getInputStream

@Nullable
public IntStream getInputStream()

Gets the input stream which is the symbol source for the recognizer where this exception was thrown.

If the input stream is not available, this method returns null.

Returns:

The input stream which is the symbol source for the recognizer where this exception was thrown, or null if the stream is not available.

getOffendingToken

@Nullable
public Token getOffendingToken()

setOffendingToken

protected final <Symbol extends Token> void setOffendingToken(Recognizer<Symbol,?> recognizer,
 @Nullable
 Symbol offendingToken)

getRecognizer

@Nullable
public Recognizer<?,?> getRecognizer()

Gets the Recognizer where this exception occurred.

If the recognizer is not available, this method returns null.

Returns:

The recognizer where this exception occurred, or null if the recognizer is not available.

getOffendingToken

public <T> T getOffendingToken(Recognizer<T,?> recognizer)