通用Try [T]函数

Question

I want to refactor some common error handling logic in a generic Try[T] handler, similar to this:

def handler[T](t: Try[T], successFunc: T => Unit) = {

  t.map {
    case Success(res) => { // type mismatch required T, found Any (in successFunc line)
    //case Success(res: T) => { // Type abstract type pattern T is unchecked since it is eliminated by erasure
      successFunc(res)
    }
    case Failure(e: CustomException) => {
      // custom actions
    }
    case Failure(e) => {
      // custom actions
    } 
  }
}

Seems I can't match against the type T because of type erasure. But I can't pass an Any to successFunc .

How can I implement this function?

Answer 1

Mapping on a try applies a function to the value held by a success of that try, what you have there is not a Success or a Failure , it's a T , what you want is a match :

def handler[T](t: Try[T], successFunc: T => Unit) = {
  t match {
    case Success(res) =>
      successFunc(res)
    case Failure(e: FileNotFoundException) =>
    case Failure(e) =>
  }
}

The usage in your case of map would be:

t.map(someT => successFunc(someT))