| java.lang.Object
 java.lang.Throwable
java.lang.Exception
org.antlr.runtime.RecognitionException
All known Subclasses: org.antlr.runtime.NoViableAltException, org.antlr.runtime.FailedPredicateException, org.antlr.runtime.MismatchedRangeException, org.antlr.runtime.MismatchedTreeNodeException, org.antlr.runtime.MismatchedTokenException, org.antlr.runtime.EarlyExitException, org.antlr.runtime.MismatchedSetException,
| RecognitionException | | public class RecognitionException extends Exception (Code) | | The root of the ANTLR exception hierarchy.
To avoid English-only error messages and to generally make things
as flexible as possible, these exceptions are not created with strings,
but rather the information necessary to generate an error. Then
the various reporting methods in Parser and Lexer can be overridden
to generate a localized error message. For example, MismatchedToken
exceptions are built with the expected token type.
So, don't expect getMessage() to return anything.
Note that as of Java 1.4, you can access the stack trace, which means
that you can compute the complete trace of rules from the start symbol.
This gives you considerable context information with which to generate
useful error messages.
ANTLR generates code that throws exceptions upon recognition error and
also generates code to catch these exceptions in each rule. If you
want to quit upon first error, you can turn off the automatic error
handling mechanism using rulecatch action, but you still need to
override methods mismatch and recoverFromMismatchSet.
In general, the recognition exceptions can track where in a grammar a
problem occurred and/or what was the expected input. While the parser
knows its state (such as current input symbol and line info) that
state can change before the exception is reported so current token index
is computed and stored at exception time. From this info, you can
perhaps print an entire line of input not just a single token, for example.
Better to just say the recognizer had a problem and then let the parser
figure out a fancy report.
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| Field Summary | |
| public boolean | approximateLineInfo
If you are parsing a tree node stream, you will encounter som
imaginary nodes w/o line/col info. | | public int | c
The current char when an error occurred. | | public int | charPositionInLine
| | public int | index
| | public transient IntStream | input
| | public int | line
Track the line at which the error occurred in case this is
generated from a lexer. | | public Object | node
If this is a tree parser exception, node is set to the node with
the problem. | | public Token | token
The current Token when an error occurred. |
| approximateLineInfo | | public boolean approximateLineInfo(Code) | | If you are parsing a tree node stream, you will encounter som
imaginary nodes w/o line/col info. We now search backwards looking
for most recent token with line/col info, but notify getErrorHeader()
that info is approximate.
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| c | | public int c(Code) | | The current char when an error occurred. For lexers.
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| charPositionInLine | | public int charPositionInLine(Code) | | |
| index | | public int index(Code) | | What is index of token/char were we looking at when the error occurred?
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| input | | public transient IntStream input(Code) | | What input stream did the error occur in?
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| line | | public int line(Code) | | Track the line at which the error occurred in case this is
generated from a lexer. We need to track this since the
unexpected char doesn't carry the line info.
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| node | | public Object node(Code) | | If this is a tree parser exception, node is set to the node with
the problem.
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| token | | public Token token(Code) | | The current Token when an error occurred. Since not all streams
can retrieve the ith Token, we have to track the Token object.
For parsers. Even when it's a tree parser, token might be set.
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| RecognitionException | | public RecognitionException()(Code) | | Used for remote debugger deserialization
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| extractInformationFromTreeNodeStream | | protected void extractInformationFromTreeNodeStream(IntStream input)(Code) | | |
| getUnexpectedType | | public int getUnexpectedType()(Code) | | Return the token type or char of the unexpected input element
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