@Override
            public void notify(MetaStoreEventListener listener, ListenerEvent event) throws MetaException {
              listener.onAlterISchema((AlterISchemaEvent)event);
            }
This class is used to notify a list of listeners about specific MetaStore events.
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/MetaStoreListenerNotifier.java