Loom on Scala

[Alex Otenko]

Most likely Scala's try-with-resource catches and handles the exception
during close()

Same with map(_.get) vs map(Future::resultNow) - the difference is only in
who's waiting and what kind of exception is thrown, so if Scala handles
checked exceptions for you, you aren't inconvenienced.

Alex

On Sat, 27 Nov 2021, 07:19 Eric Kolotyluk, <eric at kolotyluk.net> wrote:

> package net.kolotyluk.loom
>
> import java.util.concurrent.StructuredExecutor
> import scala.util.Using
>
> object HelloScala {
>   def main(args: Array[String]) {
>     Context.printHeader(HelloScala.getClass)
>
>     Using.Manager { use => // Scala's version of try-with-resources
>       val structuredExecutor = use(StructuredExecutor.open("HelloScala"))
>
>       val futureResults = (0 to 15).map{ item =>
>         println(s"item = $item, Thread ID = ${Thread.currentThread}")
>         structuredExecutor.fork{ () =>
>           println(s"\ttask = $item, Thread ID = ${Thread.currentThread}")
>           item
>         }
>       }
>       println(futureResults.map(_.get))
>       structuredExecutor.join
>     }
>   }
> }
>
> Yes, Loom does run on Scala 2.13... I cannot get Scala 3 to work with Maven
> yet... might have to resort to SBT... ��
>
> I wonder if ScopeLocal works correctly in Scala? �� I guess it should...
>
> Don't have to worry about lazy Stream termination here ��
>
> Don't need Future::resultNow either
>
> For some reason, if you don't call join(), close() does not throw an
> exception �� -- that's not right?
>
> The Kotlin version was much harder to write and I will post later...
>
> A fun way to end the week... ��
>
> Cheers, Eric
>
>
> "C:\Program Files (Open)\jdk-18\bin\java.exe" --enable-preview
> -Dfile.encoding=windows-1252 -jar
> C:\Users\ERIC\Documents\git\loom-lab\laboratory\target\laboratory.jar
> Hello net.kolotyluk.loom.HelloScala$
> PID       = 23312
> CPU Cores = 12
> Heap Size = 6442450944 bytes
>
> ______________________________________________________________________________
>
> item = 0, Thread ID = Thread[#1,main,5,main]
> item = 1, Thread ID = Thread[#1,main,5,main]
> item = 2, Thread ID = Thread[#1,main,5,main]
> item = 3, Thread ID = Thread[#1,main,5,main]
> item = 4, Thread ID = Thread[#1,main,5,main]
> item = 5, Thread ID = Thread[#1,main,5,main]
> item = 6, Thread ID = Thread[#1,main,5,main]
> item = 7, Thread ID = Thread[#1,main,5,main]
> item = 8, Thread ID = Thread[#1,main,5,main]
> item = 9, Thread ID = Thread[#1,main,5,main]
> item = 10, Thread ID = Thread[#1,main,5,main]
> item = 11, Thread ID = Thread[#1,main,5,main]
> item = 12, Thread ID = Thread[#1,main,5,main]
>      task = 0, Thread ID =
> VirtualThread[#15]/runnable at ForkJoinPool-1-worker-1
> item = 13, Thread ID = Thread[#1,main,5,main]
> item = 14, Thread ID = Thread[#1,main,5,main]
>      task = 1, Thread ID =
> VirtualThread[#17]/runnable at ForkJoinPool-1-worker-2
>      task = 2, Thread ID =
> VirtualThread[#18]/runnable at ForkJoinPool-1-worker-3
>      task = 4, Thread ID =
> VirtualThread[#20]/runnable at ForkJoinPool-1-worker-3
>      task = 5, Thread ID =
> VirtualThread[#22]/runnable at ForkJoinPool-1-worker-2
>      task = 7, Thread ID =
> VirtualThread[#24]/runnable at ForkJoinPool-1-worker-2
>      task = 6, Thread ID =
> VirtualThread[#23]/runnable at ForkJoinPool-1-worker-3
>      task = 8, Thread ID =
> VirtualThread[#25]/runnable at ForkJoinPool-1-worker-3
>      task = 9, Thread ID =
> VirtualThread[#27]/runnable at ForkJoinPool-1-worker-2
>      task = 3, Thread ID =
> VirtualThread[#19]/runnable at ForkJoinPool-1-worker-4
>      task = 10, Thread ID =
> VirtualThread[#28]/runnable at ForkJoinPool-1-worker-3
>      task = 11, Thread ID =
> VirtualThread[#29]/runnable at ForkJoinPool-1-worker-2
>      task = 12, Thread ID =
> VirtualThread[#31]/runnable at ForkJoinPool-1-worker-4
>      task = 13, Thread ID =
> VirtualThread[#34]/runnable at ForkJoinPool-1-worker-5
> item = 15, Thread ID = Thread[#1,main,5,main]
>      task = 14, Thread ID =
> VirtualThread[#35]/runnable at ForkJoinPool-1-worker-5
>      task = 15, Thread ID =
> VirtualThread[#42]/runnable at ForkJoinPool-1-worker-11
> Vector(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
>
> Process finished with exit code 0
>