Java Argument Parser V4

import java.util.Map;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.ArrayList;
import java.util.InputMismatchException;

public class ArgParser{

    public static void main(String[] args) {
        Map<String, List<String>> parsedArgs = parseArgs(args);
        Map<String, String[]> rules = new HashMap<String, String[]>();

        rules.put("-filmes", new String[]{"nome_ator1", "nome_ator2", "decada"});
        rules.put("-episodios", new String[]{"nome_ator", "titulo_serie"});
        rules.put("-generos", new String[]{"nome_ator"});

        if(!validateArgs(parsedArgs, rules, true, true))
            return;

        for(Map.Entry<String, List<String>> arg: parsedArgs.entrySet()) {
            System.out.println(arg.getKey());

            if(arg.getValue() != null)
                for(String subArg: arg.getValue())
                    System.out.println("\t" + subArg);
        }
    }

    public static Map<String, List<String>> parseArgs(String[] args) {
        Map<String, List<String>> result = new LinkedHashMap<String, List<String>>();
        List<String> params = null;

        for(String arg: args)
            if(arg.startsWith("-"))
                result.put(arg, params = new ArrayList<String>());
            else if(params != null)
                params.add(arg);
            else
                result.put(arg, null);

        return result;
    }

    public static Boolean validateArgs(Map<String, List<String>> args, Map<String, String[]> rules, Boolean anonArgs, Boolean aLeastOne) {
        Boolean result = true;

        if(aLeastOne && args.isEmpty())
            System.err.println("E necessario ao menos um argumento!");

        for(Map.Entry<String, List<String>> arg: args.entrySet()) {
            String[] params = rules.get(arg.getKey());

            if(rules.containsKey(arg.getKey())) {
                if(params != null && (arg.getValue() == null || arg.getValue().size() != params.length)) {
                    String Msg = String.format("O argumento <%s> espera %d parametro(s).\nModo de uso: <%s>"
                                              , arg.getKey(), params.length, arg.getKey());

                    for(String str: params)
                        Msg += " <" + str + ">";

                    System.err.println(Msg);
                    result = false;
                }
            } else if(arg.getValue() != null || !anonArgs) {
                System.err.println(String.format("Argumento desconhecido <%s>", arg.getKey()));
                result = false;
            }
        }

        return result;
    }
}