class TenantApplications implements RequestHandler, HostValidator<ApplicationId> {

    public long requireActiveSessionOf(ApplicationId applicationId) {
        return activeSessionOf(applicationId)
                .orElseThrow(() -> new IllegalArgumentException("Application '" + applicationId + "' has no active session."));
    }

    public  TenantApplications(TenantName tenant, Curator curator, StripedExecutor<TenantName> zkWatcherExecutor,
                              ExecutorService zkCacheExecutor, Metrics metrics, ReloadListener reloadListener,
                              ConfigserverConfig configserverConfig, HostRegistry<ApplicationId> hostRegistry,
                              TenantFileSystemDirs tenantFileSystemDirs);

}