org.antlr.v4.runtime.RecognitionException.java Source code

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Here is the source code for org.antlr.v4.runtime.RecognitionException.java

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/*
 * Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
 * Use of this file is governed by the BSD 3-clause license that
 * can be found in the LICENSE.txt file in the project root.
 */
package org.antlr.v4.runtime;

import org.antlr.v4.runtime.atn.DecisionState;
import org.antlr.v4.runtime.misc.IntervalSet;

/** 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.
 */
public class RecognitionException extends RuntimeException {
    /** The {@link Recognizer} where this exception originated. */
    private final Recognizer<?, ?> recognizer;

    private final RuleContext ctx;

    private final IntStream input;

    /**
     * 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 = -1;

    public RecognitionException(Recognizer<?, ?> recognizer, IntStream input, ParserRuleContext ctx) {
        this.recognizer = recognizer;
        this.input = input;
        this.ctx = ctx;
        if (recognizer != null)
            this.offendingState = recognizer.getState();
    }

    public RecognitionException(String message, Recognizer<?, ?> recognizer, IntStream input,
            ParserRuleContext ctx) {
        super(message);
        this.recognizer = recognizer;
        this.input = input;
        this.ctx = ctx;
        if (recognizer != null)
            this.offendingState = recognizer.getState();
    }

    /**
     * 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.</p>
     */
    public int getOffendingState() {
        return offendingState;
    }

    protected final void setOffendingState(int offendingState) {
        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}.</p>
     *
     * @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.
     */
    public IntervalSet getExpectedTokens() {
        if (recognizer != null) {
            return recognizer.getATN().getExpectedTokens(offendingState, ctx);
        }

        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}.</p>
     *
     * @return The {@link RuleContext} at the time this exception was thrown.
     * If the context is not available, this method returns {@code null}.
     */
    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}.</p>
     *
     * @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.
     */
    public IntStream getInputStream() {
        return input;
    }

    public Token getOffendingToken() {
        return offendingToken;
    }

    protected final void setOffendingToken(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}.</p>
     *
     * @return The recognizer where this exception occurred, or {@code null} if
     * the recognizer is not available.
     */
    public Recognizer<?, ?> getRecognizer() {
        return recognizer;
    }
}