public static UrlShortener createUrlShortener(String serviceName, 
			final Map<String, String> accountCredentials) {
		if (serviceName == null) {
			throw new IllegalArgumentException("service name cannot be null");
		}
		
		String serviceNameClean = serviceName.toLowerCase().replace(".", "");
		
		if (serviceNameClean.equals("isgd")) {
			return new SimpleUrlShortener(isgdApiUrl, accountCredentials);
		}
		
		else if (serviceNameClean.equals("bitly")) {
			return new SimpleUrlShortener(bitlyApiUrl, accountCredentials);
		}
		
		else {
			throw new IllegalArgumentException("no service called " + serviceNameClean);
		}
	}