code: private TileMatrixSetDao getTileMatrixSetDao() throws SQLException {
  		if (tileMatrixSetDao == null) {
  			tileMatrixSetDao = DaoManager.createDao(connectionSource,
  					TileMatrixSet.class);
  		}
  		return tileMatrixSetDao;
  	}
docs: Get or create a Tile Matrix Set DAO
  
  @return tile matrix set dao
  @throws SQLException
  upon dao creation failure