code: public TileSet getTileSet (int tileSetId)
          throws NoSuchTileSetException, PersistenceException
      {
          waitForBundles();
          TileSet tset = _idmap.get(tileSetId);
          if (tset == null) {
              throw new NoSuchTileSetException(tileSetId);
          }
          return tset;
      }
docs: documentation inherited from interface