resilience-4-getAndCache.java

private T getAndCache(String key, Supplier<R> valueSupplier) {
  /*
    This has the disadvantage that the [get result, cache it] is not atomic. So if two requests try to update the same key at the same time, it might create an undetermined result.

    However, two calls to the same service should return the same value, so we should be able to live with that.

    This is not happening inside the compute method anymore due to problems acquiring the lock that led to significant timeouts.
   */
  var result = valueSupplier.get();
  if (result == null) {
    return null;
  }

  return Try.of(() -> {
    cache.save(result);
    return result;
  })
      .recover(Exception.class, e -> {
        log.error("Could not save result to cache", e);
        return result;
      })
      .map(Cacheable::data)
      .get();
}