code: @Override
    protected Object getOptionValue(Queue<String> argq) {
      String name = argq.remove();
      File file = new File(name);
      if (mustExist && !file.isFile()) {
        System.err.println("File does not exist: '" + name + "'");
        System.exit(1);
      }
      return file;
    }
docs: /* (non-Javadoc)
  @see ca.eandb.util.args.AbstractFieldOption#getOptionValue(java.util.Queue)