code: private static String getUrl(final Map<String, String> properties) {
  		String url = properties.get("url");
  		if (url == null) {
  			throw new IllegalArgumentException("URL is missing for JDBC writer");
  		} else {
  			return url;
  		}
  	}
docs: Extracts the URL to database or data source from configuration.
  
  @param properties
  Configuration for writer
  @return Connection URL
  
  @throws IllegalArgumentException
  URL is not defined in configuration