229. Assembling StructuredTaskScope instances with timeout

Let’s continue our journey from Problem 228 by assuming that the ridesharing service should be implemented with a timeout/deadline. In other words, if any of the ridesharing servers don’t answer in 10 milliseconds, then we abort the request and report the thrown TimeoutException via a meaningful message to the user.

This means that instead of scope.join(), which waits indefinitely, we should use joinUntil(Instant deadline), which waits only for the given deadline before throwing a TimeoutException. So, the fetchRidesharingOffers() method should be modified as follows:

public static RidesharingOffer fetchRidesharingOffers(
    String loc, String dest) 
      throws InterruptedException, TimeoutException {
  try (StructuredTaskScope scope 
    = new StructuredTaskScope<RidesharingOffer>()) {
    ...
    scope.joinUntil(Instant.now().plusMillis(10));
    ...
  }
}

By simply simulating a delay...