title: Is it possible to monkey patch a scala final class with an annotation?
body: <p>I'm using Scala as my language.  I'm using Google Objectify as my persistence API to store objects into Google App Engine's Datastore.  Any class that is to be stored in the Google App Engine Datastore via Objectify has to have a @Entity annotation prefixing the class. You typically apply this annotation to your own classes for use in your own app or domain.  In one my classes, I'd like to be able to define a class attribute of type Option[String].  In order to do that, I would need to be able to apply the @Entity or @Subclass annotation (Objectify annotations) to the Option class.  But that is a built-in Scala language type.  Is there a way to use implicit classes or types or Scala macros to do "monkey patching" to the language to allow me add that annotation, after-the-fact, to a built-in Scala language type?</p>