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Java example source code file (CommandLineParser.java)

This example Java source code file (CommandLineParser.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

commandlineparser, illegalargumentexception, listiterator, runtimeexception, sortedmap, space, string, stringbuffer, treemap, util

The CommandLineParser.java Java example source code

/*
 * Copyright (c) 2010, 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 xmlkit; // -*- mode: java; indent-tabs-mode: nil -*-

import java.util.*;
/*
 * @author jrose
 */
public class CommandLineParser {

    public CommandLineParser(String optionString) {
        setOptionMap(optionString);
    }
    TreeMap<String, String[]> optionMap;

    public void setOptionMap(String options) {
        // Convert options string into optLines dictionary.
        TreeMap<String, String[]> optmap = new TreeMap();
        loadOptmap:
        for (String optline : options.split("\n")) {
            String[] words = optline.split("\\p{Space}+");
            if (words.length == 0) {
                continue loadOptmap;
            }
            String opt = words[0];
            words[0] = "";  // initial word is not a spec
            if (opt.length() == 0 && words.length >= 1) {
                opt = words[1];  // initial "word" is empty due to leading ' '
                words[1] = "";
            }
            if (opt.length() == 0) {
                continue loadOptmap;
            }
            String[] prevWords = optmap.put(opt, words);
            if (prevWords != null) {
                throw new RuntimeException("duplicate option: "
                        + optline.trim());
            }
        }
        optionMap = optmap;
    }

    public String getOptionMap() {
        TreeMap<String, String[]> optmap = optionMap;
        StringBuffer sb = new StringBuffer();
        for (String opt : optmap.keySet()) {
            sb.append(opt);
            for (String spec : optmap.get(opt)) {
                sb.append(' ').append(spec);
            }
            sb.append('\n');
        }
        return sb.toString();
    }

    /**
     * Remove a set of command-line options from args,
     * storing them in the properties map in a canonicalized form.
     */
    public String parse(List<String> args, Map properties) {
        //System.out.println(args+" // "+properties);

        String resultString = null;
        TreeMap<String, String[]> optmap = optionMap;

        // State machine for parsing a command line.
        ListIterator<String> argp = args.listIterator();
        ListIterator<String> pbp = new ArrayList().listIterator();
        doArgs:
        for (;;) {
            // One trip through this loop per argument.
            // Multiple trips per option only if several options per argument.
            String arg;
            if (pbp.hasPrevious()) {
                arg = pbp.previous();
                pbp.remove();
            } else if (argp.hasNext()) {
                arg = argp.next();
            } else {
                // No more arguments at all.
                break doArgs;
            }
            tryOpt:
            for (int optlen = arg.length();; optlen--) {
                // One time through this loop for each matching arg prefix.
                String opt;
                // Match some prefix of the argument to a key in optmap.
                findOpt:
                for (;;) {
                    opt = arg.substring(0, optlen);
                    if (optmap.containsKey(opt)) {
                        break findOpt;
                    }
                    if (optlen == 0) {
                        break tryOpt;
                    }
                    // Decide on a smaller prefix to search for.
                    SortedMap<String, String[]> pfxmap = optmap.headMap(opt);
                    // pfxmap.lastKey is no shorter than any prefix in optmap.
                    int len = pfxmap.isEmpty() ? 0 : pfxmap.lastKey().length();
                    optlen = Math.min(len, optlen - 1);
                    opt = arg.substring(0, optlen);
                    // (Note:  We could cut opt down to its common prefix with
                    // pfxmap.lastKey, but that wouldn't save many cycles.)
                }
                opt = opt.intern();
                assert (arg.startsWith(opt));
                assert (opt.length() == optlen);
                String val = arg.substring(optlen);  // arg == opt+val

                // Execute the option processing specs for this opt.
                // If no actions are taken, then look for a shorter prefix.
                boolean didAction = false;
                boolean isError = false;

                int pbpMark = pbp.nextIndex();  // in case of backtracking
                String[] specs = optmap.get(opt);
                eachSpec:
                for (String spec : specs) {
                    if (spec.length() == 0) {
                        continue eachSpec;
                    }
                    if (spec.startsWith("#")) {
                        break eachSpec;
                    }
                    int sidx = 0;
                    char specop = spec.charAt(sidx++);

                    // Deal with '+'/'*' prefixes (spec conditions).
                    boolean ok;
                    switch (specop) {
                        case '+':
                            // + means we want an non-empty val suffix.
                            ok = (val.length() != 0);
                            specop = spec.charAt(sidx++);
                            break;
                        case '*':
                            // * means we accept empty or non-empty
                            ok = true;
                            specop = spec.charAt(sidx++);
                            break;
                        default:
                            // No condition prefix means we require an exact
                            // match, as indicated by an empty val suffix.
                            ok = (val.length() == 0);
                            break;
                    }
                    if (!ok) {
                        continue eachSpec;
                    }

                    String specarg = spec.substring(sidx);
                    switch (specop) {
                        case '.':  // terminate the option sequence
                            resultString = (specarg.length() != 0) ? specarg.intern() : opt;
                            break doArgs;
                        case '?':  // abort the option sequence
                            resultString = (specarg.length() != 0) ? specarg.intern() : arg;
                            isError = true;
                            break eachSpec;
                        case '@':  // change the effective opt name
                            opt = specarg.intern();
                            break;
                        case '>':  // shift remaining arg val to next arg
                            pbp.add(specarg + val);  // push a new argument
                            val = "";
                            break;
                        case '!':  // negation option
                            String negopt = (specarg.length() != 0) ? specarg.intern() : opt;
                            properties.remove(negopt);
                            properties.put(negopt, null);  // leave placeholder
                            didAction = true;
                            break;
                        case '$':  // normal "boolean" option
                            String boolval;
                            if (specarg.length() != 0) {
                                // If there is a given spec token, store it.
                                boolval = specarg;
                            } else {
                                String old = properties.get(opt);
                                if (old == null || old.length() == 0) {
                                    boolval = "1";
                                } else {
                                    // Increment any previous value as a numeral.
                                    boolval = "" + (1 + Integer.parseInt(old));
                                }
                            }
                            properties.put(opt, boolval);
                            didAction = true;
                            break;
                        case '=':  // "string" option
                        case '&':  // "collection" option
                            // Read an option.
                            boolean append = (specop == '&');
                            String strval;
                            if (pbp.hasPrevious()) {
                                strval = pbp.previous();
                                pbp.remove();
                            } else if (argp.hasNext()) {
                                strval = argp.next();
                            } else {
                                resultString = arg + " ?";
                                isError = true;
                                break eachSpec;
                            }
                            if (append) {
                                String old = properties.get(opt);
                                if (old != null) {
                                    // Append new val to old with embedded delim.
                                    String delim = specarg;
                                    if (delim.length() == 0) {
                                        delim = " ";
                                    }
                                    strval = old + specarg + strval;
                                }
                            }
                            properties.put(opt, strval);
                            didAction = true;
                            break;
                        default:
                            throw new RuntimeException("bad spec for "
                                    + opt + ": " + spec);
                    }
                }

                // Done processing specs.
                if (didAction && !isError) {
                    continue doArgs;
                }

                // The specs should have done something, but did not.
                while (pbp.nextIndex() > pbpMark) {
                    // Remove anything pushed during these specs.
                    pbp.previous();
                    pbp.remove();
                }

                if (isError) {
                    throw new IllegalArgumentException(resultString);
                }

                if (optlen == 0) {
                    // We cannot try a shorter matching option.
                    break tryOpt;
                }
            }

            // If we come here, there was no matching option.
            // So, push back the argument, and return to caller.
            pbp.add(arg);
            break doArgs;
        }
        // Report number of arguments consumed.
        args.subList(0, argp.nextIndex()).clear();
        // Report any unconsumed partial argument.
        while (pbp.hasPrevious()) {
            args.add(0, pbp.previous());
        }
        //System.out.println(args+" // "+properties+" -> "+resultString);
        return resultString;
    }
}

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