@Override
    public Collection<? extends Ticket> getTickets() {
        return ticketCatalog.findAll().stream()
            .map(this::getTicketCollectionInstanceByMetadata)
            .flatMap(collectionName -> {
                val references = firestore.collection(collectionName).listDocuments();
                return StreamSupport.stream(references.spliterator(), false)
                    .map(doc -> FunctionUtils.doUnchecked(() -> doc.get().get()))
                    .map(doc -> doc.toObject(GoogleCloudFirestoreTicketDocument.class));
            })
            .map(doc -> {
                val ticket = deserializeTicket(doc.getJson(), doc.getType());
                return decodeTicket(ticket);
            })
            .filter(ticket -> !ticket.isExpired())
            .collect(Collectors.toSet());
    }
This is {@link GoogleCloudFirestoreTicketRegistry}.

@author Misagh Moayyed
@since 7.0.0
support/cas-server-support-gcp-firestore-ticket-registry/src/main/java/org/apereo/cas/ticket/registry/GoogleCloudFirestoreTicketRegistry.java