code: public static LogFile get(PropertyResolver propertyResolver) {
  		String file = getLogFileProperty(propertyResolver, FILE_NAME_PROPERTY,
  				FILE_PROPERTY);
  		String path = getLogFileProperty(propertyResolver, FILE_PATH_PROPERTY,
  				PATH_PROPERTY);
  		if (StringUtils.hasLength(file) || StringUtils.hasLength(path)) {
  			return new LogFile(file, path);
  		}
  		return null;
  	}
docs: Get a {@link LogFile} from the given Spring {@link Environment}.
  @param propertyResolver the {@link PropertyResolver} used to obtain the logging
  properties
  @return a {@link LogFile} or {@code null} if the environment didn't contain any
  suitable properties