Databases
StackOverflow2013
Postsdbo
PORun multiple futures in parallel, return default value on timeout
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PORun multiple futures in parallel, return default value on timeout
    primarykey
    data
    text
    <p>I have to run multiple futures in parallel and the program shouldn't crash or hang.</p> <p>For now I wait on futures one by one, and use fallback value if there is TimeoutException.</p> <pre><code>val future1 = // start future1 val future2 = // start future2 val future3 = // start future3 // &lt;- at this point all 3 futures are running // waits for maximum of timeout1 seconds val res1 = toFallback(future1, timeout1, Map[String, Int]()) // .. timeout2 seconds val res2 = toFallback(future2, timeout2, List[Int]()) // ... timeout3 seconds val res3 = toFallback(future3, timeout3, Map[String, BigInt]()) def toFallback[T](f: Future[T], to: Int, default: T) = { Try(Await.result(f, to seconds)) .recover { case to: TimeoutException =&gt; default } } </code></pre> <p>As I can see, maximum wait time of this snippet is <code>timeout1 + timeout2 + timeout3</code></p> <p>My question is: how can I wait on all of those futures at once, so I can reduce wait time to <code>max(timeout1, timeout2, timeout3)</code>?</p> <p>EDIT: In the end I used modification of @Jatin and @senia answers:</p> <pre><code>private def composeWaitingFuture[T](fut: Future[T], timeout: Int, default: T) = future { Await.result(fut, timeout seconds) } recover { case e: Exception =&gt; default } </code></pre> <p>and later it's used as follows:</p> <pre><code>// starts futures immediately and waits for maximum of timeoutX seconds val res1 = composeWaitingFuture(future1, timeout1, Map[String, Int]()) val res2 = composeWaitingFuture(future2, timeout2, List[Int]()) val res3 = composeWaitingFuture(future3, timeout3, Map[String, BigInt]()) // takes the maximum of max(timeout1, timeout2, timeout3) to complete val combinedFuture = for { r1 &lt;- res1 r2 &lt;- res2 r3 &lt;- res3 } yield (r1, r2, r3) </code></pre> <p>and later I use <code>combinedFuture</code> as I see fit.</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USZotov
    1. USZotov
    plurals
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. PORun multiple futures in parallel, return default value on timeout
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PORun multiple futures in parallel, return default value on timeout
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PORun multiple futures in parallel, return default value on timeout
      1. USbguiz
      1. VTFavorite
    1. COWhat I do not understand is, how is it `timeout1 + timeout2 + timeout3`? It is rather `timeout1` for future1` , timeout2 for future2 and so on. The questions is still unclear to me
      singulars
      1. PORun multiple futures in parallel, return default value on timeout
      1. USJatin
    2. COHe wants to run the 3 tasks in parallel, such that the timeout is the maximum of the three tasks' timeout
      singulars
      1. PORun multiple futures in parallel, return default value on timeout
      1. USBrian Agnew
    3. COI think this answer I gave a while back is similar to what you want and it also leverages the non-blocking callbacks. http://stackoverflow.com/questions/16304471/scala-futures-built-in-timeout/16305056#16305056
      singulars
      1. PORun multiple futures in parallel, return default value on timeout
      1. UScmbaxter
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload