exemplo of dynamics no scala

agendaDynamic

//para compilar o exemplo faça =>  scalac arquivo.scala -Xexperimental

package br.com.caelum.dynamic

import java.util.{GregorianCalendar, Calendar}
import java.text.SimpleDateFormat

case class Contato(val nome: String, val email: String, val nascimento: Calendar) {
  override def toString = nome + ";" + email + ";" + new SimpleDateFormat("dd/MM/yyyy").format(nascimento.getTime)
}

class Agenda extends Dynamic {
  val contatos = List(Contato("alberto", "alberto@email.com.br", new GregorianCalendar(1983, 6, 9)),
    Contato("adriano", "adriano@email.com.br", new GregorianCalendar(1986, 10, 10)),
    Contato("diego", "diego@email.com.br", new GregorianCalendar(1987, 8, 23)),
    Contato("cecilia", "cecilia@email.com.br", new GregorianCalendar(1987, 2, 10)))

  def applyDynamic(fakeMethodName: String)(args: Any*) = {
    val FindBy = """(findBy)(\w+)""".r
    val Like = """(findByLike)(\w+)""".r
    val Contains = """(findBy)(\w+)(ThatContains)""".r
    
    val found = fakeMethodName match {
      case Like(_, property) => {
        val realMethodName = lowerFirstLetter(property)
        contatos.filter(c => invokeMethod[String](c,realMethodName).startsWith(args(0).toString))
      }
      case Contains(_, property, _) => {
        val realMethodName = lowerFirstLetter(property)
        contatos.filter(c => invokeMethod[String](c,realMethodName).contains(args(0).toString))
      }
      case FindBy(_, property) => {
        val realMethodName = lowerFirstLetter(property)
        contatos.filter(c => invokeMethod[Any](c,realMethodName).equals(args(0)))
      }
      case _ => throw new NoSuchMethodException(fakeMethodName)
    }
    found
  }

  private def invokeMethod[ReturnType](obj:AnyRef,name:String,args: Any*):ReturnType = {
    obj.getClass.getMethod(name).invoke(obj).asInstanceOf[ReturnType]
  }

  private def lowerFirstLetter(propertyWithFirstLetterUpperCase: String) = {
    propertyWithFirstLetterUpperCase.substring(0, 1).toLowerCase +
      propertyWithFirstLetterUpperCase.substring(1, propertyWithFirstLetterUpperCase.length)
  }
}

object Teste {
  def main(args: Array[String]) {
    val agenda = new Agenda
    println(agenda.findByNome("alberto"))
    println(agenda.findByEmailThatContains("email.com.br"))
  }
}