code: public List<E> getEntriesForActivities(Set<String> activities) {
          Validate.noNullElements(activities);
          List<E> result = new ArrayList<>();
          for (E entry : logEntries) {
              if (activities.contains(entry.getActivity())) {
                  result.add(entry);
              }
          }
          return result;
      }
docs: Returns all log entries of this trace whose activities are in the given
  activity set.
  
  @param activities
  @return