public void setOption(String option, Collection values) {
		if (option.startsWith("keywords")) {
			keywords = (String[]) values.toArray(new String[values.size()]);
		} else if (option.startsWith("backup")) {
			if (values.size() != 1)
				throw new IllegalArgumentException("Only one backup is allowed");
			backup = (Renamer) values.iterator().next();
		} else
			throw new IllegalArgumentException("Invalid option `" + option
					+ "'");
	}