code: private static Map<String, String> normalizeContext(TableFactory factory) {
  		Map<String, String> requiredContext = factory.requiredContext();
  		if (requiredContext == null) {
  			throw new TableException(
  				String.format("Required context of factory '%s' must not be null.", factory.getClass().getName()));
  		}
  		return requiredContext.keySet().stream()
  			.collect(Collectors.toMap(key -> key.toLowerCase(), key -> requiredContext.get(key)));
  	}
docs: Prepares the properties of a context to be used for match operations.