code: public T setLogDirectory(final String path) {
          if (path == null) {
              logDir = null;
              return getThis();
          }
          return setLogDirectory(Paths.get(path));
      }
docs: Sets the log directory to be used for log files.
  <p/>
  If set to {@code null}, the default, the log directory will be resolved.
  
  @param path the path to the log directory or {@code null} to have the log directory resolved
  
  @return the builder
  
  @throws java.lang.IllegalArgumentException if the directory is not a valid directory