@Override public List<SubscriptionPath> listSubscriptions(ProjectPath project, TopicPath topic) throws IOException { ListSubscriptionsRequest.Builder request = ListSubscriptionsRequest.newBuilder() .setProject(project.getPath()) .setPageSize(LIST_BATCH_SIZE); ListSubscriptionsResponse response = subscriberStub().listSubscriptions(request.build()); if (response.getSubscriptionsCount() == 0) { return ImmutableList.of(); } List<SubscriptionPath> subscriptions = new ArrayList<>(response.getSubscriptionsCount()); while (true) { for (Subscription subscription : response.getSubscriptionsList()) { if (subscription.getTopic().equals(topic.getPath())) { subscriptions.add(subscriptionPathFromPath(subscription.getName())); } } if (response.getNextPageToken().isEmpty()) { break; } request.setPageToken(response.getNextPageToken()); response = subscriberStub().listSubscriptions(request.build()); } return subscriptions; }