type mismatch between java.util.concurrent.ExecutorService and java.util.concurrent.ScheduledExecutorService

[stone]

I tried translate the java version at
http://docs.oracle.com/javase/6/docs/api/java/util/concurrent/ScheduledExecutorService.html

import static java.util.concurrent.TimeUnit.*;
class BeeperControl {
private final ScheduledExecutorService scheduler =
Executors.newScheduledThreadPool(1);

public void beepForAnHour() {
final Runnable beeper = new Runnable() {
public void run() { System.out.println("beep"); }
};
final ScheduledFuture<?> beeperHandle =
scheduler.scheduleAtFixedRate(beeper, 10, 10, SECONDS);
scheduler.schedule(new Runnable() {
public void run() { beeperHandle.cancel(true); }
}, 60 * 60, SECONDS);
}
}

to the following scala code

ScheduledExecutorServiceDemo.scala
// run with `scala ScheduledExecutorServiceDemo.scala`
// ref : http://docs.oracle.com/javase/6/docs/api/java/util/concurrent/ScheduledExecutorService.html

import java.util.concurrent.{Executor, Executors, ExecutorService,
ScheduledExecutorService, TimeUnit}

val thread = new Runnable {
def run() {
println("scheduled in thread...")
}
}

val scheduler:ScheduledExecutorService =
Executors.newFixedThreadPool(1)

scheduler.scheduleWithFixedDelay(thread, 5, 5, TimeUnit.SECONDS)


But the scala compiler complains about type mismatch:

scala ScheduledExecutorServiceDemo.scala

~/debug/ScheduledExecutorServiceDemo.scala:9: error: type mismatch;
found : java.util.concurrent.ExecutorService
required: java.util.concurrent.ScheduledExecutorService
val scheduler:ScheduledExecutorService =
Executors.newFixedThreadPool(1)
^
one error found

Any suggestions why the scala version don't work ?

Thanks,
Stone

[Alan Mimms]

Don't you want to call Executors.newScheduledThreadPool(1) instead? Executors.newFixedThreadPool() returns ExecutorService which is what the compiler is complaining about. Executors.newScheduleThreadPool() returns ScheduledExecutorService which is what you want, no?

Cheers.

[Dave]

You translate

private final ScheduledExecutorService scheduler =
Executors.newScheduledThreadPool(1);

to

val scheduler:ScheduledExecutorService =
Executors.newFixedThreadPool(1)

which is different

It should be:
val scheduler:ScheduledExecutorService =
Executors.newScheduledThreadPool(1)


On 5 mrt, 18:21, stone <stones....@gmail.com> wrote:
> I tried translate the java version athttp://docs.oracle.com/javase/6/docs/api/java/util/concurrent/Schedul...

>
>  import static java.util.concurrent.TimeUnit.*;
>  class BeeperControl {
>     private final ScheduledExecutorService scheduler =
>        Executors.newScheduledThreadPool(1);
>
>     public void beepForAnHour() {
>         final Runnable beeper = new Runnable() {
>                 public void run() { System.out.println("beep"); }
>             };
>         final ScheduledFuture<?> beeperHandle =
>             scheduler.scheduleAtFixedRate(beeper, 10, 10, SECONDS);
>         scheduler.schedule(new Runnable() {
>                 public void run() { beeperHandle.cancel(true); }
>             }, 60 * 60, SECONDS);
>     }
>  }
>
> to the following scala code
>
> ScheduledExecutorServiceDemo.scala
> // run with `scala ScheduledExecutorServiceDemo.scala`

> // ref :http://docs.oracle.com/javase/6/docs/api/java/util/concurrent/Schedul...

[Dave]

Actually:
private final val scheduler:ScheduledExecutorService =
Executors.newScheduledThreadPool(1)

or if you want object privacy:

private[this] final val scheduler:ScheduledExecutorService =

[stone]

Thank you all for the suggestions. I stay up late last night, seems that my brain was not in debug mode :-)