private void processCommand(Command command) {
        if (command.commandIsUnknown()) {
            System.out.println("I don't know what you mean...");
        } else {
            String commandWord = command.getCommandWord();
            // process all possible commands
            if (commandWord.equals("help")) {
                printHelp();
            } else if (commandWord.equals("go")) {
                if (!command.hasSecondWord()) {
                    System.out.println("Go where?");
                } else {
                    goDirection(command);
                }
            } else if (commandWord.equals("quit")) {
                if (command.hasSecondWord()) {
                    System.out.println("Quit what?");
                } else {
                    finished = true;
                }
            }
        }
    }