org.apache.lucene.expressions.js.JavascriptParserErrorStrategy.java Source code

Introduction

Here is the source code for org.apache.lucene.expressions.js.JavascriptParserErrorStrategy.java

Source

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.lucene.expressions.js;

import java.text.ParseException;

import org.antlr.v4.runtime.DefaultErrorStrategy;
import org.antlr.v4.runtime.InputMismatchException;
import org.antlr.v4.runtime.NoViableAltException;
import org.antlr.v4.runtime.Parser;
import org.antlr.v4.runtime.RecognitionException;
import org.antlr.v4.runtime.Token;

/**
 * Allows for proper error handling in the ANTLR 4 parser
 */
class JavascriptParserErrorStrategy extends DefaultErrorStrategy {
    /**
     * Ensures the ANTLR parser will throw an exception after the first error
     *
     * @param recognizer the parser being used
     * @param re the original exception from the parser
     */
    @Override
    public void recover(Parser recognizer, RecognitionException re) {
        Token token = re.getOffendingToken();
        String message;

        if (token == null) {
            message = "error " + getTokenErrorDisplay(token);
        } else if (re instanceof InputMismatchException) {
            message = "unexpected token " + getTokenErrorDisplay(token) + " on line (" + token.getLine()
                    + ") position (" + token.getCharPositionInLine() + ")" + " was expecting one of "
                    + re.getExpectedTokens().toString(recognizer.getVocabulary());
        } else if (re instanceof NoViableAltException) {
            if (token.getType() == JavascriptParser.EOF) {
                message = "unexpected end of expression";
            } else {
                message = "invalid sequence of tokens near " + getTokenErrorDisplay(token) + " on line ("
                        + token.getLine() + ") position (" + token.getCharPositionInLine() + ")";
            }
        } else {
            message = " unexpected token near " + getTokenErrorDisplay(token) + " on line (" + token.getLine()
                    + ") position (" + token.getCharPositionInLine() + ")";
        }

        ParseException parseException = new ParseException(message, token.getStartIndex());
        parseException.initCause(re);
        throw new RuntimeException(parseException);
    }

    /**
     * Ensures the ANTLR parser will throw an exception after the first error
     *
     * @param recognizer the parser being used
     * @return no actual return value
     * @throws RecognitionException not used as a ParseException wrapped in a RuntimeException is thrown instead
     */
    @Override
    public Token recoverInline(Parser recognizer) throws RecognitionException {
        Token token = recognizer.getCurrentToken();
        String message = "unexpected token " + getTokenErrorDisplay(token) + " on line (" + token.getLine()
                + ") position (" + token.getCharPositionInLine() + ")" + " was expecting one of "
                + recognizer.getExpectedTokens().toString(recognizer.getVocabulary());
        ParseException parseException = new ParseException(message, token.getStartIndex());
        throw new RuntimeException(parseException);
    }

    /**
     * Do not allow syncing after errors to ensure the ANTLR parser will throw an exception
     *
     * @param recognizer the parser being used
     */
    @Override
    public void sync(Parser recognizer) {
    }
}