Scala sealed abstract class with enum object matching against string - scala

Question

I am a beginner in scala, I have a case class for the response I am getting as json payload
case class CallbackPayload(
automation_id: String,
business_key: String,
state: String #received , validating
)
I have a sealed abstract class
object ExecutionStatus {
sealed abstract class ExecutionState(status: String) {
override def toString: String = status
}
case object RECEIVED extends ExecutionState("received")
case object VALIDATING extends ExecutionState("validating")
}
Now based on the response payload state I want to do a match against the ExecutionStatus objects
Something like below
def callback(payload: CallbackPayload): Either[Throwable, Json] = {
payload.state match {
case VALIDATING => Right(Json.obj("status" -> Json.fromString("validating")))
.....
}
}
Now because of payload.state type string I am unable to . How to do that in scala.

Answer 1

It looks like you may want to match on the status string, like so (using a simplified model of your code):
object ExecutionStatus {
sealed abstract class ExecutionState(val status: String) {
override def toString: String = status
}
case object RECEIVED extends ExecutionState("received")
case object VALIDATING extends ExecutionState("validating")
}
def parse(state: String): Either[Throwable, Map[String, String]] = {
state match {
case ExecutionStatus.RECEIVED.status =>
Right(Map("status" -> "received"))
case ExecutionStatus.VALIDATING.status =>
Right(Map("status" -> "validating"))
case _ =>
Left(new IllegalArgumentException(s"unrecognized state $state"))
}
}
assert(parse("received") == Right(Map("status" -> "received")))
assert(parse("validating") == Right(Map("status" -> "validating")))
assert(parse("foo").isLeft)
You can play around with this code here on Scastie.
Notice that in order to do so I had to make status a val so that it's public (without it, status is only a constructor parameter).