CryChat/crychat/server/util/ServerBuilder.java

package server.util;

import server.Main;
import server.net.ChatServer;

public class ServerBuilder {

    private static final int DEFAULT_PORT = 5000;
    private static final int MAX_USERS = 5;
    private static final String HELP_MSG = """
            -h, -help:              prints this help message.
            -p, -port:              sets the port for the ChatServer
            """;

    public static ChatServer buildServerFromConsoleArgs(String[] args) {
        int port = DEFAULT_PORT;
        int max_users = MAX_USERS;
        int ptr = 0;
        while (ptr < args.length) {
            switch (args[ptr]) {
                case "-h":
                case "-help":
                    if (ptr != 0 || args.length > 1) {
                        Main.console.error("You cannot use -h or -help in combination with other commands!");
                        return null;
                    }
                    Main.console.println(HELP_MSG);
                    return null;
                case "-p":
                case "-port":
                    try {
                        if (++ptr == args.length) {
                            Main.console.error("Please enter a port-number (0 to 65536)!");
                            return null;
                        }
                        port = Integer.parseInt(args[ptr], 10);
                        if (port < 0 || port >= 65536) {
                            Main.console.error("Please enter a valid port-number (0 to 65536)!");
                            return null;
                        }
                    } catch (NumberFormatException e) {
                        Main.console.error("Please enter a valid port-number (0 to 65536)!");
                        return null;
                    }
                    break;
                case "-m":
                case "-max_users":
                    try {
                        if (++ptr == args.length) {
                            Main.console.error("Please enter a user count!");
                            return null;
                        }
                        max_users = Integer.parseInt(args[ptr], 10);
                    } catch (NumberFormatException e) {
                        Main.console.error("Please enter a valid user count!");
                        return null;
                    }
                    break;
                default:
                    Main.console.error("Couldn't parse argument: '" + args[ptr] + "', please try '-h' or '-help' for help.");
                    return null;
            }
            ++ptr;
        }
        return new ChatServer(port, max_users);
    }
}