Generic in Scala

Generic classes are classes which take a type as a parameter. They are particularly useful for collection classes. Generic classes can be used in everyday data structure implementation, such as stack, queue, linked list, and so on. We will see some examples.

Defining a generic class

Generic classes take a type as a parameter within square brackets []. One convention is to use the letter A as a type parameter identifier, though any parameter name may be used. Let's see a minimal example on Scala REPL, as follows:

scala> class Stack[A] {
     |       private var elements: List[A] = Nil
     |       def push(x: A) { elements = x :: elements }
     |       def peek: A = elements.head
     |       def pop(...