@startuml
package com.iluwatar.observer {
  class Orcs {
    + Orcs()
    + update(currentWeather : WeatherType)
  }
  interface WeatherObserver {
    + update(WeatherType) {abstract}
  }
  class App {
    + App()
    + main(args : String[]) {static}
  }
  class Weather {
    - currentWeather : WeatherType
    - observers : List<WeatherObserver>
    + Weather()
    + addObserver(obs : WeatherObserver)
    - notifyObservers()
    + removeObserver(obs : WeatherObserver)
    + timePasses()
  }
  class Hobbits {
    + Hobbits()
    + update(currentWeather : WeatherType)
  }
  enum WeatherType {
    + COLD {static}
    + RAINY {static}
    + SUNNY {static}
    + WINDY {static}
    + toString() : String
    + valueOf(name : String) : WeatherType {static}
    + values() : WeatherType[] {static}
  }
}
package com.iluwatar.observer.generic {
  class GOrcs {
    + GOrcs()
    + update(weather : GWeather, weatherType : WeatherType)
  }
  interface Race {
  }
  class GWeather {
    - currentWeather : WeatherType
    + GWeather()
    + timePasses()
  }
  abstract class Observable<S extends Observable, O extends Observer<S, O, A>, A> {
    # observers : List<O extends Observer<S, O, A>>
    + Observable<S extends Observable, O extends Observer<S, O, A>, A>()
    + addObserver(observer : O extends Observer<S, O, A>)
    + notifyObservers(argument : A)
    + removeObserver(observer : O extends Observer<S, O, A>)
  }
  class GHobbits {
    + GHobbits()
    + update(weather : GWeather, weatherType : WeatherType)
  }
  interface Observer<S extends Observable<S, O, A>, O extends Observer, A> {
    + update(S extends Observable<S, O, A>, A) {abstract}
  }
}
Weather -->  "-currentWeather" WeatherType
GWeather -->  "-currentWeather" WeatherType
Weather -->  "-observers" WeatherObserver
GOrcs ..|> Race 
Orcs ..|> WeatherObserver 
Race --|> Observer 
GWeather --|> Observable 
GHobbits ..|> Race 
Hobbits ..|> WeatherObserver 
@enduml