Interface LexicalThreadLocal<T>

Helper trait for defining thread locals with lexical scoping. With this helper, the thread local is private and can only be set by the LexicalThreadLocal.Handle. The LexicalThreadLocal.Handle only exposes the thread local value to functions passed into its runWith method. This pattern allows for the lifetime of the thread local value to be strictly controlled.

Rather than calling tl.set(...) and tl.remove() you would get a handle and execute your code in handle.runWith { ... }.

Example:

   object Credentials extends LexicalThreadLocal[Int] {
     def create(creds: Map[String, String]) = new Handle(Some(creds))
   }
   ...
   val handle = Credentials.create(Map("key" -> "value"))
   assert(Credentials.get() == None)
   handle.runWith {
     assert(Credentials.get() == Some(Map("key" -> "value")))
   }