@startuml
Context *-> State 
State <|-- ConcreteState1
State <|-- ConcreteState2

class Context {
  -state : State*
  +Request()
  +ChangeState()
}
interface State {
  {abstract} +Handle()
}
class ConcreteState1 {
  +Handle()
}
class ConcreteState2 {
  +Handle()
}

note bottom of Context
  Context::Request() {
    state->Handle();
  }
end note

hide empty attributes
hide empty methods
@enduml