Simple example of the Option type in Scala

NPE.scala

object CityDictionary{
  def getMeACity(cityCode:String) :Option[City]={
    if(cityCode=="75") Some(City("Paris","75"))
    else None
  }
  case class City(name: String,code:String)  
}


object NPEApplication {
  def getGreeting(cityName:String):Option[String] ={
    if(cityName=="Paris") Some("Welcome in Paris!") else None
  } 
  
 def getCityName(cityCode:String):String ={
  (for( c <- CityDictionary.getMeACity(cityCode);
        g <- getGreeting(c.name)) yield g).getOrElse("NotFound!")
     
 }
}