@Override
  public List<String> getLabels(User user, Authorizations authorizations) {
    if (authorizations != null) {
      return authorizations.getLabels();
    }
    return null;
  }
This is a simple implementation for ScanLabelGenerator. It will just extract labels passed via
Scan#Authorizations.
hbase-server/src/main/java/org/apache/hadoop/hbase/security/visibility/SimpleScanLabelGenerator.java