/*
 * 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.ATNConfigSet;

Indicates that the parser could not decide which of two or more paths
 to take based upon the remaining input. It tracks the starting token
 of the offending input and also knows where the parser was
 in the various paths when the error. Reported by reportNoViableAlternative()
/** Indicates that the parser could not decide which of two or more paths
 *  to take based upon the remaining input. It tracks the starting token
 *  of the offending input and also knows where the parser was
 *  in the various paths when the error. Reported by reportNoViableAlternative()
 */
public class NoViableAltException extends RecognitionException {
	
Which configurations did we try at input.index() that couldn't match input.LT(1)? /** Which configurations did we try at input.index() that couldn't match input.LT(1)? */

	private final ATNConfigSet deadEndConfigs;

	
The token object at the start index; the input stream might
	not be buffering tokens so get a reference to it. (At the
 time the error occurred, of course the stream needs to keep a
 buffer all of the tokens but later we might not have access to those.)
/** The token object at the start index; the input stream might
	 * 	not be buffering tokens so get a reference to it. (At the
	 *  time the error occurred, of course the stream needs to keep a
	 *  buffer all of the tokens but later we might not have access to those.)
	 */

	private final Token startToken;

	public NoViableAltException(Parser recognizer) { // LL(1) error
		this(recognizer,
			 recognizer.getInputStream(),
			 recognizer.getCurrentToken(),
			 recognizer.getCurrentToken(),
			 null,
			 recognizer._ctx);
	}

	public NoViableAltException(Parser recognizer,
								TokenStream input,
								Token startToken,
								Token offendingToken,
								ATNConfigSet deadEndConfigs,
								ParserRuleContext ctx)
	{
		super(recognizer, input, ctx);
		this.deadEndConfigs = deadEndConfigs;
		this.startToken = startToken;
		this.setOffendingToken(offendingToken);
	}


	public Token getStartToken() {
		return startToken;
	}


	public ATNConfigSet getDeadEndConfigs() {
		return deadEndConfigs;
	}

}