A WeakReference-ish class that allows for restoring its argument with a function.

gistfile1.scala

  class RestoringWeakReference[T <: AnyRef](private var reference:WeakReference[T], restorer:()=>T) {
    def value : T = {
      val existing = reference.get
      if (! existing.isDefined) {
        restoreReference
        value
      } else {
        existing.get
      }
    }

    private def restoreReference = {
      reference = new WeakReference(restorer())
    }
  }
  object RestoringWeakReference {
    def apply[T <: AnyRef](restorer:()=>T) = {
      new RestoringWeakReference(new WeakReference(restorer()), restorer)
    }
    def apply[T <: AnyRef](starter:T, restorer:()=>T) = {
      new RestoringWeakReference(new WeakReference(starter), restorer)
    }
  }