}
// Create view factories and parent view based on a filter specification
// Since only for non-joins we get the existing stream's lock and try to reuse it's views
final FilterStreamSpecCompiled filterStreamSpec = (FilterStreamSpecCompiled) statementSpec.getStreamSpecs().get(0);
ViewableActivatorFilterProxy activator = new ViewableActivatorFilterProxy(services, filterStreamSpec.getFilterSpec(), statementContext.getAnnotations(), false);
// create data window view factories
ViewFactoryChain unmaterializedViewChain = services.getViewService().createFactories(0, filterStreamSpec.getFilterSpec().getResultEventType(), filterStreamSpec.getViewSpecs(), filterStreamSpec.getOptions(), statementContext);
// verify data window