@Override
  public final void onEvent(PreEventContext preEventContext)
      throws MetaException, NoSuchObjectException, InvalidOperationException {
    LOG.debug("==> HiveMetaStoreAuthorizer.onEvent(): EventType=" + preEventContext.getEventType());

    try {
      HiveMetaStoreAuthzInfo authzContext = buildAuthzContext(preEventContext);

      if (!skipAuthorization(authzContext)) {
        HiveAuthorizer hiveAuthorizer = createHiveMetaStoreAuthorizer();
        checkPrivileges(authzContext, hiveAuthorizer);
      }
    } catch (Exception e) {
      LOG.error("HiveMetaStoreAuthorizer.onEvent(): failed", e);
      throw MetaStoreUtils.newMetaException(e);
    }

    LOG.debug("<== HiveMetaStoreAuthorizer.onEvent(): EventType=" + preEventContext.getEventType());
  }
HiveMetaStoreAuthorizer :  Do authorization checks on MetaStore Events in MetaStorePreEventListener
ql/src/java/org/apache/hadoop/hive/ql/security/authorization/plugin/metastore/HiveMetaStoreAuthorizer.java