KafkaGreyhound_1.scala

// Job description
case class CronJob(id: UUID, cronString: CronExpr)
// App state
case class CronulaSate(jobs: Map[UUID, CronJob] = Map.empty[UUID, CronJob])
// Events
sealed trait CronulaEvent

case class RecordJob(id: UUID, cronString: CronExpr) extends CronulaEvent
case class DeleteJob(id: UUID) extends CronulaEvent
case class Updatejob(id: UUID, cronString: CronExpr) extends CronulaEvent
// Processing/interpreting the events to state changes
def process(event: CronulaSateEvents.CronulaEvent, state: CronulaSate = CronulaSate()): CronulaSate = event match {
  case CronulaSateEvents.RecordJob(id, cronString) => state.copy(jobs = state.jobs + (id -> CronJob(id, cronString)))
  case CronulaSateEvents.DeleteJob(id) => state.copy(jobs = state.jobs - id)
  case CronulaSateEvents.Updatejob(id, cronString) => state.copy(
    jobs = state.jobs.get(id).map(_ => state.jobs + (id -> CronJob(id, cronString))).getOrElse(state.jobs))
}