package org.apache.groovy.parser.antlr4;

import org.antlr.v4.runtime.CharStream;
import org.antlr.v4.runtime.Lexer;
import org.antlr.v4.runtime.LexerNoViableAltException;
import org.antlr.v4.runtime.atn.ATN;
import org.antlr.v4.runtime.atn.LexerATNSimulator;
import org.apache.groovy.parser.antlr4.internal.atnmanager.AtnManager;
import org.apache.groovy.parser.antlr4.internal.atnmanager.LexerAtnManager;

/**
 * The lexer for Groovy programming language, which is based on the lexer generated by Antlr4
 *
 * @author <a href="mailto:realbluesun@hotmail.com">Daniel.Sun</a>
 * Created on 2016/08/14
 */
public class GroovyLangLexer extends GroovyLexer {
    public GroovyLangLexer(CharStream input) {
        super(input);

        this.setInterpreter(new PositionAdjustingLexerATNSimulator(this, LexerAtnManager.INSTANCE.getATN()));
    }

    @Override
    public void recover(LexerNoViableAltException e) {
        throw e; // if some lexical error occurred, stop parsing!
    }

    @Override
    protected void rollbackOneChar() {
        ((PositionAdjustingLexerATNSimulator) getInterpreter()).resetAcceptPosition(getInputStream(), _tokenStartCharIndex - 1, _tokenStartLine, _tokenStartCharPositionInLine - 1);
    }

    private static class PositionAdjustingLexerATNSimulator extends LexerATNSimulator {
        public PositionAdjustingLexerATNSimulator(Lexer recog, ATN atn) {
            super(recog, atn);
        }

        protected void resetAcceptPosition(CharStream input, int index, int line, int charPositionInLine) {
            input.seek(index);
            this.line = line;
            this.charPositionInLine = charPositionInLine;
            this.consume(input);
        }
    }
}

@@ -1,8 +1,830 @@
+/*%0A *  Licensed to the Apache Software Foundation (ASF) under one%0A *  or more contributor license agreements.  See the NOTICE file%0A *  distributed with this work for additional information%0A *  regarding copyright ownership.  The ASF licenses this file%0A *  to you under the Apache License, Version 2.0 (the%0A *  %22License%22); you may not use this file except in compliance%0A *  with the License.  You may obtain a copy of the License at%0A *%0A *    http://www.apache.org/licenses/LICENSE-2.0%0A *%0A *  Unless required by applicable law or agreed to in writing,%0A *  software distributed under the License is distributed on an%0A *  %22AS IS%22 BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY%0A *  KIND, either express or implied.  See the License for the%0A *  specific language governing permissions and limitations%0A *  under the License.%0A */%0A
 package 
@@ -897,16 +897,57 @@
 Stream;%0A
+import org.antlr.v4.runtime.CharStreams;%0A
 import o
@@ -1120,79 +1120,8 @@
 or;%0A
-import org.apache.groovy.parser.antlr4.internal.atnmanager.AtnManager;%0A
 impo
@@ -1193,16 +1193,68 @@
 nager;%0A%0A
+import java.io.IOException;%0Aimport java.io.Reader;%0A%0A
 /**%0A * T
@@ -1442,16 +1442,16 @@
 /14%0A */%0A
-
 public c
@@ -1489,24 +1489,140 @@
 oovyLexer %7B%0A
+    public GroovyLangLexer(Reader reader) throws IOException %7B%0A        this(CharStreams.fromReader(reader));%0A    %7D%0A%0A
     public G

Add a constructor to `GroovyLangLexer`