code: private String getDatastreamId(DigitalObject obj, Entry entry) {
          String entryId = entry.getId().toString();
          // matches info:fedora/pid/dsid/timestamp
          Pattern pattern =
                  Pattern.compile("^" + Constants.FEDORA.uri + ".+?/([^/]+)/?.*");
          Matcher matcher = pattern.matcher(entryId);
  
          if (matcher.find()) {
              return matcher.group(1);
          } else {
              return obj.newDatastreamID();
          }
      }
docs: Parses the id to determine a datastreamId.
  
  @param id
  @return