Retry.java

private static <T> FlowFuture<T> _exponentialWithJitter(Flows.SerCallable<FlowFuture<T>> op, RetrySettings settings, int attempt) {
    Flow f = Flows.currentFlow();
    try {
        FlowFuture<T> future = op.call();
        return future.exceptionallyCompose((e) -> {
            if (attempt < settings.maxAttempts) {

                long delay_max = (long) Math.min(
                    settings.timeUnit.toMillis(settings.delayMaxDuration),
                    settings.timeUnit.toMillis(settings.delayBaseDuration) * Math.pow(2, attempt));
                long delay = new Random().longs(1, 0, delay_max).findFirst().getAsLong();

                return f.delay(delay, TimeUnit.MILLISECONDS)
                        .thenCompose((a) -> _exponentialWithJitter(op, settings, attempt + 1));
            } else {
                return f.failedFuture(new RuntimeException());
            }
        });
    } catch (Exception ex) {
        return f.failedFuture(new RuntimeException());
    }
}