@Override
  public Map<String, String> loadNamespaceMetadata(String[] namespace)
      throws NoSuchNamespaceException {
    String database = namespace[0];
    return catalog.listDatabases().stream()
        .filter(d -> StringUtils.equals(d, database))
        .map(d -> new HashMap<String, String>())
        .findFirst()
        .orElseThrow(() -> new NoSuchNamespaceException(namespace));
  }
Base class of mixed-format spark catalog.
amoro-format-mixed/amoro-mixed-spark/amoro-mixed-spark-3-common/src/main/java/org/apache/amoro/spark/mixed/MixedSparkCatalogBase.java