Accessing value returned by scala futures

Question

I am a newbie to scala futures and I have a doubt regarding the return value of scala futures.

So, generally syntax for a scala future is

 def downloadPage(url: URL) = Future[List[Int]] {   } 

I want to know how to access the List[Int] from some other method which calls this method.

In other words,

val result = downloadPage("localhost")  

then what should be the approach to get List[Int] out of the future ?

I have tried using map method but not able to do this successfully.`

Answer 1

The case of Success(listInt) => I want to return the listInt and I am not able to figure out how to do that.

The best practice is that you don't return the value. Instead you just pass the future (or a version transformed with map, flatMap, etc.) to everyone who needs this value and they can add their own onComplete.

If you really need to return it (e.g. when implementing a legacy method), then the only thing you can do is to block (e.g. with Await.result) and you need to decide how long to await.