PropertyLoader.scala

import java.util.Properties

import cats.data.EitherNel
import cats.syntax.parallel._
import cats.syntax.either._
import cats.syntax.option._
import cats.instances.parallel._

import scala.util.Try

object PropertyLoader extends App {
  case class GroupActor(groupId: Int, accessToken: Long)

  def loadProperties(fileName: String): Either[Throwable, Properties] = {
    val properties = new Properties()
    Try(properties.load(Foo.getClass.getClassLoader.getResourceAsStream(fileName)))
      .toEither
      .map(_ => properties)
  }

  def typedProperty[A](properties: Properties, propertyName: String, parse: String => Try[A]) =
    Try(properties.getProperty(propertyName))
      .flatMap(parse)
      .toEither

  val properties = loadProperties("properties")

  val groupActor: EitherNel[Throwable, GroupActor] =
    (properties
       .flatMap(props => typedProperty(props, "group_id", s => Try(s.toInt)))
       .toEitherNel,
     properties
       .flatMap(props => typedProperty(props, "access_token", s => Try(s.toLong)))
       .toEitherNel)
      .parMapN(GroupActor)

  println(groupActor)
}