example.scala

// psuedo-code; will not actually compile

import com.spingo.op_rabbit.Json4sSupport._ // allows you to use Json4s directly to serialize / deserialize published messages
trait MarketOrEv

case class Market(mkt_id: Int, ev_id: Int, model_type:”Market”) extends MarketOrEv

case class Ev(ev_id: Int, model_type:”Ev”) extends MarketOrEv


implicit val formats = new Formats(
  override val typeHints = ShortTypeHints(classOf[Market] :: classOf[Ev] :: Nil)
  override val typeHintFieldName = "model_type"
)

val subscription = new Subscription {
  def config = channel(qos = 3) {
    consume(queue(name)) {
      body(as[MarketOrEv]) {
        case m: Market =>
          // do your thing...
          ack
        case e: Ev =>
          // do your thing...
          ack
      }
    }
  }
}