[mono-with-retry] Repeat a GET if the Mono is empty #java

poll-webclient-repeat.java

  // https://stackoverflow.com/questions/55923326/conditional-repeat-or-retry-on-mono-with-webclient-from-spring-webflux
  private Either<Fault, String> poll(final String id) {
    JobResponse jr = webClient
                       .get()
                       .uri(baseUrl + "/jobs/" + id + "?f=json")
                       .retrieve()
                       .bodyToMono(JobResponse.class)
                       .filter(JobResponse::done)
                       .repeatWhenEmpty(
                         Repeat.onlyIf(ctx -> true).timeout(Duration.ofSeconds(10L))
                       ).block();
    return jr == null ? Either.left(Fault.serverSide("???")) : Either.right(jr.getJobId());
  }