What you observe is expected behaviour – yet of course it’s very bad. Good that known solutions and best practices exist to guard against it. In this answer I’d like to spend some time to explain the issue short, long, and then in depth – enjoy the read! Short answer: “don’t block the routing infrastructure!“, …
In both Python and ES6, await/async are based on generators. Is it a correct to think Futures are the same as Promises? Not Future, but Python’s Task is roughly equivalent to Javascript’s Promise. See more details below. I have seen the terms Task, Future and Coroutine used in the asyncio documentation. What are the differences …
I cannot answer it all, but i try on some parts: Is there some reason that the “most asynchronous” behavior—i.e., don’t consume the collection before returning, and don’t wait for each future to complete before moving on to the next—isn’t represented here? If you have dependent calculations and a limited number of threads, you can …
ExecutionException and InterruptedException are two very different things. ExecutionException wraps whatever exception the thread being executed threw, so if your thread was, for instance, doing some kind of IO that caused an IOException to get thrown, that would get wrapped in an ExecutionException and rethrown. An InterruptedException is not a sign of anything having gone …
Since it’s similar to async & await in C#, maybe I can provide some insight. In C#, it’s a general rule that Task that can be awaited should be returned ‘hot’, i.e. already running. I assume it’s the same in Scala, where the Future returned from the function does not have to be explicitly started, …
Well, when you have multiple generators in a single for comprehension, you are flattening the resulting type. That is, instead of getting a List[List[T]], you get a List[T]: scala> val list = List(1, 2, 3) list: List[Int] = List(1, 2, 3) scala> for (a <- list) yield for (b <- list) yield (a, b) res0: …
The C++11 standard does not provide a direct way to cancel a task started with std::async. You will have to implement your own cancellation mechanism, such as passing in an atomic flag variable to the async task which is periodically checked. Your code should not crash though. On reaching the end of main, the std::future<int> …
You can use Future.wait to wait for several Future to be completed. body: FutureBuilder<List<FlashCardList>>( future: Future.wait([ fetchFlashCardList(), fetchFlashCardListFromDB(), ]),
The std::async (part of the <future> header) function template is used to start a (possibly) asynchronous task. It returns a std::future object, which will eventually hold the return value of std::async‘s parameter function. When the value is needed, we call get() on the std::future instance; this blocks the thread until the future is ready and …
The futures are running concurrently because they have been started concurrently :). To run them sequentially you need to use flatMap: Future { println(“startFirst”); Thread.sleep(3000); println(“stopFirst”) }.flatMap{ _ => Future { println(“startSecond”); Thread.sleep(1000); println(“stopSecond”) } } Future.sequence just turns Seq[Future[T]] => Future[Seq[T]] which means gather results of all already started futures and put it in …