ParseException.java

/*
* Copyright 2016 Nabarun Mondal
* Licensed 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 com.noga.njexl.lang.parser;

/**
 * This exception is thrown when parse errors are encountered.
 */
public class ParseException extends Exception {
    /**
     * The version identifier.
     */
    private static final long serialVersionUID = 1L;
    /**
     * Last correct input before error occurs.
     */
    private String after = "";
    /**
     * Error line.
     */
    private int line = -1;
    /**
     * Error column.
     */
    private int column = -1;
    
    /**
     * Gets the line number.
     * @return line number.
     */
    public int getLine() {
        return line;
    }

    /**
     * Gets the column number.
     * @return the column.
     */
    public int getColumn() {
        return column;
    }
    
    /**
     * Gets the last correct input.
     * @return the string after which the error occured
     */
    public String getAfter() {
        return after;
    }
    
    /**
     * This constructor is used by the method "generateParseException"
     * in the generated parser.  Calling this constructor generates
     * a new object of this type with the fields "currentToken",
     * "expectedTokenSequences", and "tokenImage" set.
     * @param currentToken This is the last token that has been consumed successfully.  If
     * this object has been created due to a parse error, the token
     * followng this token will (therefore) be the first error token.
     * @param expectedTokenSequences Each entry in this array is an array of integers.  Each array
     * of integers represents a sequence of tokens (by their ordinal
     * values) that is expected at this point of the parse.
     * @param tokenImage This is a reference to the "tokenImage" array of the generated
     * parser within which the parse error occurred.  This array is
     * defined in the generated ...Constants interface.
     */
    public ParseException(Token currentToken, int[][] expectedTokenSequences, String[] tokenImage) {
        super("parse error");
        Token tok = currentToken.next;
        after = tok.image;
        line = tok.beginLine;
        column = tok.beginColumn;
    }

    /**
     * Default ctor.
     */
    public ParseException() {
        super();
    }

    /** Constructor with message. */
    public ParseException(String message) {
        super(message);
    }

    /**
     * Creates a localized description of this throwable.
     * Subclasses may override this method in order to produce a
     * locale-specific message.  For subclasses that do not override this
     * method, the default implementation returns the same result as
     * {@code getMessage()}.
     *
     * @return The localized description of this throwable.
     * @since JDK1.1
     */
    @Override
    public String getMessage() {
        return String.format("parse error starting at line %d, column %d near '%s'", line, column,after);
    }
}