/*

 * Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.jvmstat.perfdata.monitor;

import java.net.*;

import java.io.*;

import java.util.*;

import java.util.regex.*;

/**

 * Class for parsing alias files. File format is expected to follow

 * the following syntax:

 *

 *     alias name [alias]*

 *

 * Java style comments can occur anywhere within the file.

 * @author Brian Doherty

 * @since 1.5

 */

public class AliasFileParser {

    private static final String ALIAS = "alias";

    private static final boolean DEBUG = false;

    // other variables

    private URL inputfile;

    private StreamTokenizer st;

    private Token currentToken;

    AliasFileParser(URL inputfile) {

        this.inputfile = inputfile;

    }

    // value class to hold StreamTokenizer token values

    private class Token {

        public String sval;

        public int ttype;

        public Token(int ttype, String sval) {

            this.ttype = ttype;

            this.sval = sval;

        }

    }

    private void logln(String s) {

        if (DEBUG) {

            System.err.println(s);

        }

    }

    /**

     * method to get the next token as a Token type

     */

    private void nextToken() throws IOException {

        st.nextToken();

        currentToken = new Token(st.ttype, st.sval);

        logln("Read token: type = " + currentToken.ttype

              + " string = " + currentToken.sval);

    }

    /**

     * method to match the current Token to a specified token type and

     * value Throws a SyntaxException if token doesn't match.

     */

    private void match(int ttype, String token)

                 throws IOException, SyntaxException {

        if ((currentToken.ttype == ttype)

                && (currentToken.sval.compareTo(token) == 0)) {

            logln("matched type: " + ttype + " and token = "

                  + currentToken.sval);

            nextToken();

        } else {

            throw new SyntaxException(st.lineno());

        }

    }

    /*

     * method to match the current Token to a specified token type.

     * Throws a SyntaxException if token doesn't match.

     */

    private void match(int ttype) throws IOException, SyntaxException {

        if (currentToken.ttype == ttype) {

            logln("matched type: " + ttype + ", token = " + currentToken.sval);

            nextToken();

        } else {

            throw new SyntaxException(st.lineno());

        }

    }

    private void match(String token) throws IOException, SyntaxException {

        match(StreamTokenizer.TT_WORD, token);

    }

    /**

     * method to parse the given input file.

     */

    public void parse(Map<String, ArrayList<String>> map) throws SyntaxException, IOException {

        if (inputfile == null) {

            return;

        }

        BufferedReader r = new BufferedReader(

                new InputStreamReader(inputfile.openStream()));

        st = new StreamTokenizer(r);

        // allow both forms of commenting styles

        st.slashSlashComments(true);

        st.slashStarComments(true);

        st.wordChars('_','_');

        nextToken();

        while (currentToken.ttype != StreamTokenizer.TT_EOF) {

            // look for the start symbol

            if ((currentToken.ttype != StreamTokenizer.TT_WORD)

                    || (currentToken.sval.compareTo(ALIAS) != 0)) {

                nextToken();

                continue;

            }

            match(ALIAS);

            String name = currentToken.sval;

            match(StreamTokenizer.TT_WORD);

            ArrayList<String> aliases = new ArrayList<String>();

            do {

                aliases.add(currentToken.sval);

                match(StreamTokenizer.TT_WORD);

            } while ((currentToken.ttype != StreamTokenizer.TT_EOF)

                     && (currentToken.sval.compareTo(ALIAS) != 0));

            logln("adding map entry for " + name + " values = " + aliases);

            map.put(name, aliases);

        }

    }

}