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Updated documentation in RecognitionException

This commit is contained in:
Sam Harwell 2013-03-26 16:02:17 -05:00
parent df9685ecaf
commit c577f5abfe
1 changed files with 68 additions and 20 deletions
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88
runtime/Java/src/org/antlr/v4/runtime/RecognitionException.java
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@ -29,6 +29,7 @@
*/
package org.antlr.v4.runtime;
import org.antlr.v4.runtime.atn.DecisionState;
import org.antlr.v4.runtime.misc.IntervalSet;
import org.antlr.v4.runtime.misc.Nullable;
@ -39,26 +40,27 @@ import org.antlr.v4.runtime.misc.Nullable;
* and what kind of problem occurred.
*/
public class RecognitionException extends RuntimeException {
/** Who threw the exception? */
private Recognizer<?, ?> recognizer;
/** The {@link Recognizer} where this exception originated. */
@Nullable
private final Recognizer<?, ?> recognizer;
// TODO: make a dummy recognizer for the interpreter to use?
// Next two (ctx,input) should be what is in recognizer, but
// won't work when interpreting
@Nullable
private final RuleContext ctx;
private RuleContext ctx;
@Nullable
private final IntStream input;
private IntStream input;
/** 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.
/**
* The current {@link Token} when an error occurred. Since not all streams
* support accessing symbols by index, we have to track the {@link Token}
* instance itself.
*/
private Token offendingToken;
private int offendingState;
private int offendingState = -1;
public RecognitionException(@Nullable Recognizer<?, ?> recognizer, IntStream input,
public RecognitionException(@Nullable Recognizer<?, ?> recognizer,
@Nullable IntStream input,
@Nullable ParserRuleContext ctx)
{
this.recognizer = recognizer;
@ -67,7 +69,9 @@ public class RecognitionException extends RuntimeException {
if ( recognizer!=null ) this.offendingState = recognizer.getState();
}
public RecognitionException(String message, @Nullable Recognizer<?, ?> recognizer, IntStream input,
public RecognitionException(String message,
@Nullable Recognizer<?, ?> recognizer,
@Nullable IntStream input,
@Nullable ParserRuleContext ctx)
{
super(message);
@ -77,11 +81,14 @@ public class RecognitionException extends RuntimeException {
if ( recognizer!=null ) this.offendingState = recognizer.getState();
}
/** Where was the parser in the ATN when the error occurred?
* For No viable alternative exceptions, this is the decision state number.
* For others, it is the state whose emanating edge we couldn't match.
* This will help us tie into the grammar and syntax diagrams in
* ANTLRWorks v2.
/**
* Get the ATN state number the parser was in at the time the error
* occurred. For {@link NoViableAltException} and
* {@link LexerNoViableAltException} exceptions, this is the
* {@link DecisionState} number. For others, it is the state whose outgoing
* edge we couldn't match.
* <p/>
* If the state number is not known, this method returns -1.
*/
public int getOffendingState() {
return offendingState;
@ -91,6 +98,17 @@ public class RecognitionException extends RuntimeException {
this.offendingState = offendingState;
}
/**
* Gets the set of input symbols which could potentially follow the
* previously matched symbol at the time this exception was thrown.
* <p/>
* If the set of expected tokens is not known and could not be computed,
* this method returns {@code null}.
*
* @return The set of token types that could potentially follow the current
* state in the ATN, or {@code null} if the information is not available.
*/
@Nullable
public IntervalSet getExpectedTokens() {
if (recognizer != null) {
return recognizer.getATN().getExpectedTokens(offendingState, ctx);
@ -99,22 +117,52 @@ public class RecognitionException extends RuntimeException {
return null;
}
/**
* Gets the {@link RuleContext} at the time this exception was thrown.
* <p/>
* If the context is not available, this method returns {@code null}.
*
* @return The {@link RuleContext} at the time this exception was thrown.
* If the context is not available, this method returns {@code null}.
*/
@Nullable
public RuleContext getCtx() {
return ctx;
}
/**
* Gets the input stream which is the symbol source for the recognizer where
* this exception was thrown.
* <p/>
* If the input stream is not available, this method returns {@code null}.
*
* @return The input stream which is the symbol source for the recognizer
* where this exception was thrown, or {@code null} if the stream is not
* available.
*/
@Nullable
public IntStream getInputStream() {
return input;
}
@Nullable
public Token getOffendingToken() {
return offendingToken;
}
protected final void setOffendingToken(Token offendingToken) {
protected final void setOffendingToken(@Nullable Token offendingToken) {
this.offendingToken = offendingToken;
}
/**
* Gets the {@link Recognizer} where this exception occurred.
* <p/>
* If the recognizer is not available, this method returns {@code null}.
*
* @return The recognizer where this exception occurred, or {@code null} if
* the recognizer is not available.
*/
@Nullable
public Recognizer<?, ?> getRecognizer() {
return recognizer;
}