org.antlr.v4.runtime

Class BailErrorStrategy

java.lang.Object

org.antlr.v4.runtime.DefaultErrorStrategy

org.antlr.v4.runtime.BailErrorStrategy

All Implemented Interfaces:

ANTLRErrorStrategy

public class BailErrorStrategy
extends DefaultErrorStrategy

This implementation of ANTLRErrorStrategy responds to syntax errors by immediately canceling the parse operation with a ParseCancellationException. The implementation ensures that the ParserRuleContext.exception field is set for all parse tree nodes that were not completed prior to encountering the error.

This error strategy is useful in the following scenarios.

• Two-stage parsing: This error strategy allows the first stage of two-stage parsing to immediately terminate if an error is encountered, and immediately fall back to the second stage. In addition to avoiding wasted work by attempting to recover from errors here, the empty implementation of sync(org.antlr.v4.runtime.Parser) improves the performance of the first stage.
• Silent validation: When syntax errors are not being reported or logged, and the parse result is simply ignored if errors occur, the BailErrorStrategy avoids wasting work on recovering from errors when the result will be ignored either way.

myparser.setErrorHandler(new BailErrorStrategy());

See Also:

Parser.setErrorHandler(ANTLRErrorStrategy)

Field Summary

Fields inherited from class org.antlr.v4.runtime.DefaultErrorStrategy

errorRecoveryMode, lastErrorIndex, lastErrorStates, nextTokensContext, nextTokensState

Constructor Summary

Constructors

Constructor and Description
BailErrorStrategy()

Method Summary

Modifier and Type	Method and Description
void	recover(Parser recognizer, RecognitionException e) Instead of recovering from exception e, re-throw it wrapped in a ParseCancellationException so it is not caught by the rule function catches.
Token	recoverInline(Parser recognizer) Make sure we don't attempt to recover inline; if the parser successfully recovers, it won't throw an exception.
void	sync(Parser recognizer) Make sure we don't attempt to recover from problems in subrules.

Methods inherited from class org.antlr.v4.runtime.DefaultErrorStrategy

beginErrorCondition, consumeUntil, endErrorCondition, escapeWSAndQuote, getErrorRecoverySet, getExpectedTokens, getMissingSymbol, getSymbolText, getSymbolType, getTokenErrorDisplay, inErrorRecoveryMode, reportError, reportFailedPredicate, reportInputMismatch, reportMatch, reportMissingToken, reportNoViableAlternative, reportUnwantedToken, reset, singleTokenDeletion, singleTokenInsertion

Methods inherited from class java.lang.Object

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

Constructor Detail

BailErrorStrategy

public BailErrorStrategy()

Method Detail

recover

public void recover(Parser recognizer,
                    RecognitionException e)

Instead of recovering from exception e, re-throw it wrapped in a ParseCancellationException so it is not caught by the rule function catches. Use Throwable.getCause() to get the original RecognitionException.

Specified by:

recover in interface ANTLRErrorStrategy

Overrides:

recover in class DefaultErrorStrategy

Parameters:

recognizer - the parser instance

e - the recognition exception to recover from

See Also:

ANTLRErrorStrategy.reportError(org.antlr.v4.runtime.Parser, org.antlr.v4.runtime.RecognitionException)

recoverInline

public Token recoverInline(Parser recognizer)
                    throws RecognitionException

Make sure we don't attempt to recover inline; if the parser successfully recovers, it won't throw an exception.

Specified by:

recoverInline in interface ANTLRErrorStrategy

Overrides:

recoverInline in class DefaultErrorStrategy

Parameters:

recognizer - the parser instance

Throws:

RecognitionException - if the error strategy was not able to recover from the unexpected input symbol

sync

public void sync(Parser recognizer)

Make sure we don't attempt to recover from problems in subrules.

Specified by:

sync in interface ANTLRErrorStrategy

Overrides:

sync in class DefaultErrorStrategy

Parameters:

recognizer - the parser instance

See Also:

DefaultErrorStrategy.sync(org.antlr.v4.runtime.Parser)