Design Patterns em Scala: State

Segue mais dois padrões de projeto em Scala: State: State.scala package scala.behavioral // Mudar o comportamento mude de acordo com seu estado // Abstract Implementation class Context { var state:State = _ state = new NullState() def handle() { state.handle() } } trait State { def handle() } // Concrete Implementation class NullState extends State { override def handle() { println("blank algorithm, maybe throw an exception of unitilized context") } } class StateA extends State { override def handle() { println("algorithm for state A") } } class StateB extends State { override def handle() { println("algorithm for state B") } } // Client object StateClient extends Application { var context = new Context() context.state = new StateA() context.handle() context.state = new StateB() context.handle() }