What's likely happening is that SignalData
is indirectly changing the subscribers dictionary under the hood during the loop and leading to that message. You can verify this by changing
foreach(Subscriber s in subscribers.Values)
To
foreach(Subscriber s in subscribers.Values.ToList())
If I'm right, the problem will disappear.
Calling subscribers.Values.ToList()
copies the values of subscribers.Values
to a separate list at the start of the foreach
. Nothing else has access to this list (it doesn't even have a variable name!), so nothing can modify it inside the loop.
If you are expecting to be able to "flatten" List(1, 2, List(3,4), 5)
into List(1, 2, 3, 4, 5)
, then you need something like:
implicit def any2iterable[A](a: A) : Iterable[A] = Some(a)
Along with:
val list: List[Iterable[Int]] = List(1, 2, List(3,4), 5) // providing type of list
// causes implicit
// conversion to be invoked
println(list.flatten( itr => itr )) // List(1, 2, 3, 4, 5)
EDIT: the following was in my original answer until the OP clarified his question in a comment on Mitch's answer
What are you expecting to happen when you flatten
a List[Int]
? Are you expecting the function to sum the Int
s in the List
? If so, you should be looking at the new aggegation functions in 2.8.x:
val list = List(1, 2, 3)
println( list.sum ) //6
Best Answer
Here is a quick mock-up of how I have done similar in the past.
codebehind: