Scala: How to wait for a Future -

Scala: How to wait for a Future -

in next code snippet, method bookexists invokes method find determine whether book identified specified id exists:

class bookstore { def find(id: string): future[option[book]] = { // read db ... } def bookexists(id: string): boolean = { find(id).map { case some(_) => true case _ => false }.recover { case e => false } } }

the problem class above doesn't compile because need wait until future completes. next error message:

[error] /home/j3d/test/bookstore.scala:118: type mismatch; [error] found : scala.concurrent.future[boolean] [error] required: boolean [error] ).map { [error] ^

what's right way handle case?

unless awaiting result mapping future[option[book]] future of type future[boolean]. without await computation take place after find future completes (if @ all). alter homecoming type:

def bookexists(id: string): future[boolean] = { find(id).map { _ match { // '_' in map option[book] extracted future[option[book]] find returns case some(_) => true // '_' in match book extracted option[book] in match statement case _ => false }.recover { case e => false } } }

scala future