public IndexOperationMessage handleDeIndexOldVersionEvent( final DeIndexOldVersionsEvent deIndexOldVersionsEvent) { final ApplicationScope applicationScope = deIndexOldVersionsEvent.getEntityIdScope().getApplicationScope(); final Id entityId = deIndexOldVersionsEvent.getEntityIdScope().getId(); final UUID markedVersion = deIndexOldVersionsEvent.getMarkedVersion(); // default this observable's return to empty index operation message if nothing is emitted return eventBuilder .deIndexOldVersions(applicationScope, entityId, markedVersion) .toBlocking() .lastOrDefault(new IndexOperationMessage()); }