code: @Override
      public Datastream[] GetDatastreams(Date versDateTime, String state) {
          String[] ids = ListDatastreamIDs(null);
          ArrayList<Datastream> al = new ArrayList<Datastream>(ids.length);
          for (String element : ids) {
              Datastream ds = GetDatastream(element, versDateTime);
              if (ds != null && (state == null || ds.DSState.equals(state))) {
                  al.add(ds);
              }
          }
          return al.toArray(DATASTREAM_TYPE);
      }
docs: {@inheritDoc}