commandgroupadapter.java

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        } catch (Exception e) {
            out.println(e.getMessage());
            return -1;
        }
    }

    /**
     * Method to do argument parsing. See parsed syntax in class
     * <tt>CommandGroupAdapter</tt> description.
     * 
     * @param args
     *            argument list passed to the command
     * @param usage
     *            usage string
     * @return Dictionary with parsed arguments
     * @exception Exception
     *                Thrown if it fails to parse args or usage
     */
    public Dictionary getOpt(String[] args, String usage) throws Exception {
        Hashtable res = new Hashtable();
        res.put("command", args[0]);
        args[0] = null;
        parseUsage(usage.trim(), 0, args, res, 0);
        for (int i = 0; i < args.length; i++) {
            if (args[i] != null) {
                throw new Exception("Unknown argument: " + args[i]);
            }
        }
        return res;
    }

    //
    // Internal methods
    //

    private final static String DOING_ARGS = "_D_";

    private final static String LAST = "_L_";

    private int parseUsage(String usage, int pos, String[] args, Hashtable res,
            int level) throws Exception {
        int ulen = usage.length();
        while (pos < ulen) {
            switch (usage.charAt(pos)) {
            case '-':
                if (res.containsKey(DOING_ARGS)) {
                    throw new Exception("Can not mix flags and args: "
                            + usage.substring(pos));
                }
                boolean found = false;
                String flag = "";
                boolean alt;
                do {
                    alt = false;
                    int start = pos++;
                    while (pos < ulen && usage.charAt(pos) != ' '
                            && usage.charAt(pos) != ']')
                        pos++;
                    flag = usage.substring(start, pos);
                    Object val = new Integer(1);
                    int fpos = -1;
                    for (int i = 0; i < args.length; i++) {
                        if (flag.equals(args[i])) {
                            fpos = i;
                            break;
                        }
                    }
                    while (pos < ulen && usage.charAt(pos) == ' ')
                        pos++;
                    if (pos < ulen) {
                        if (usage.charAt(pos) == '#') {
                            while (pos < ulen && usage.charAt(pos) != ' '
                                    && usage.charAt(pos) != ']')
                                pos++;
                            if (fpos >= 0) {
                                if (fpos + 1 < args.length) {
                                    val = args[fpos + 1];
                                    args[fpos + 1] = null;
                                } else {
                                    throw new Exception("No value for: " + flag);
                                }
                            }
                            while (pos < ulen && usage.charAt(pos) == ' ')
                                pos++;
                        }
                        if (pos < ulen) {
                            if (usage.charAt(pos) == '|') {
                                pos++;
                                while (pos < ulen && usage.charAt(pos) == ' ')
                                    pos++;
                                if (usage.charAt(pos) == '-') {
                                    alt = true;
                                } else {
                                    throw new Exception(
                                            "Missing flag in OR-expression: "
                                                    + usage.substring(pos));
                                }
                            }
                        }
                    }
                    if (fpos >= 0) {
                        Object old = res.put(args[fpos], val);
                        if (old != null) {
                            if (old instanceof Integer) {
                                res.put(args[fpos], new Integer(((Integer) old)
                                        .intValue() + 1));
                            } else {
                                throw new Exception(
                                        "Duplicate flagname with value in usage: "
                                                + args[fpos]);
                            }
                        }
                        args[fpos] = null;
                        found = true;
                    }
                } while (alt);
                if (!found && level == 0) {
                    throw new Exception("Mandatory flag not set, flags: "
                            + usage);
                }
                break;
            case '<':
                res.put(DOING_ARGS, "");
                int wstart = ++pos;
                pos = usage.indexOf('>', ++pos);
                if (pos == -1) {
                    throw new Exception("Unmatched: "
                            + usage.substring(wstart - 1));
                }
                String key = usage.substring(wstart, pos++);
                int i;
                for (i = 0; i < args.length; i++) {
                    if (args[i] != null) {
                        if (args[i].startsWith("-")) {
                            // '--' means '-' at begining of args
                            if (args[i].startsWith("--")) {
                                args[i] = args[i].substring(1);
                            } else {
                                throw new Exception("Unknown flag: " + args[i]);
                            }
                        }
                        if (res.put(key, args[i]) != null) {
                            throw new Exception("Duplicate argname in usage: "
                                    + key);
                        }
                        args[i] = null;
                        break;
                    }
                }
                if (i == args.length && level == 0) {
                    throw new Exception("Mandatory argument not set: " + key);
                }
                res.put(LAST, key);
                break;
            case '[':
                pos = parseUsage(usage, pos + 1, args, res, level + 1);
                break;
            case ']':
                if (level == 0) {
                    throw new Exception("Unmatched: " + usage.substring(pos));
                }
                return pos + 1;
            case '.':
                if (usage.substring(pos).equals("...")) {
                    String repeat = (String) res.get(LAST);
                    if (repeat != null && res.containsKey(repeat)) {
                        ArrayList v = new ArrayList();
                        do {
                            v.add(res.remove(repeat));
                            parseUsage("<" + repeat + ">]", 0, args, res, 1);
                        } while (res.containsKey(repeat));
                        String[] vres = new String[v.size()];
                        res.put(repeat, v.toArray(vres));
                    }
                    pos = ulen;
                } else {
                    throw new Exception("Unexpected usage end: "
                            + usage.substring(pos));
                }
                break;
            case ' ':
                pos++;
                break;
            default:
                throw new Exception("Unexpected character: "
                        + usage.charAt(pos));
            }
        }
        if (level > 0) {
            throw new Exception("Missing " + level + " closing ']'");
        }
        res.remove(DOING_ARGS);
        res.remove(LAST);
        return pos;
    }

}

class DynamicCmd {

    Method cmd;

    String usage;

    String[] help;

    DynamicCmd(CommandGroup cg, String name) throws Exception {
        try {
            Class cls = cg.getClass();
            String hname = "HELP_" + name.toUpperCase();
            Field[] f = cls.getFields();
            int match = -1;
            for (int i = 0; i < f.length; i++) {
                String fname = f[i].getName();
                if (fname.startsWith(hname)) {
                    if (match != -1) {
                        throw new Exception("Multiple matching commands for: "
                                + hname.substring(5));
                    }
                    match = i;
                    if (fname.equals(hname)) {
                        break;
                    }
                    name = fname.substring(5);
                }
            }
            if (match == -1) {
                throw new Exception("No such command: " + name);
            }
            help = (String[]) f[match].get(cg);
            usage = (String) cls.getField("USAGE_" + name.toUpperCase())
                    .get(cg);
            cmd = cls.getMethod("cmd" + name.substring(0, 1).toUpperCase()
                    + name.substring(1).toLowerCase(), new Class[] {
                    java.util.Dictionary.class, java.io.Reader.class,
                    java.io.PrintWriter.class, Session.class });
            if (!cmd.getReturnType().getName().equals("int")) {
                throw new Exception("No such command: " + name);
            }
        } catch (ClassNotFoundException e) {
            throw new Exception("Internal error");
        } catch (NoSuchFieldException e) {
            throw new Exception(
                    "Command implementation incomplete (USAGE string missing): "
                            + name);
        } catch (NoSuchMethodException e) {
            throw new Exception(
                    "Command implementation incomplete (cmd method missing): "
                            + name);
        }
    }

}