Scala Implementation - scala

Question

I have a case class:
case class EvaluateAddress(addressFormat: String,
screeningAddressType: String,
value: Option[String])
This was working fine until I have a new use case where "value" parameter can be a class Object instead of String.
My initial implementation to handle this use case:
case class EvaluateAddress(addressFormat: String,
screeningAddressType: String,
addressId: Option[String],
addressValue: Option[MailingAddress]) {
def this(addressFormat: String, screeningAddressType: String, addressId: String) = {
this(addressFormat, screeningAddressType, Option(addressId), None)
}
def this(addressFormat: String, screeningAddressType: String, address: MailingAddress) = {
this(addressFormat, screeningAddressType, None, Option(address))
}
}
But because of some problem, I can not have four parameters in any constructor.
Is there a way I can create a class containing three parameters: ** addressFormat, screeningAddressType, value** and handle both the use cases?

Answer 1

Your code works fine, to use the other constructor's you just need to use the new keyword:
case class MailingAddress(i: Int)
case class EvaluateAddress(addressFormat: String, screeningAddressType: String, addressId: Option[String], addressValue: Option[MailingAddress]) {
def this(addressFormat: String, screeningAddressType: String, addressId: String) = {
this(addressFormat, screeningAddressType, Option(addressId), None)
}
def this(addressFormat: String, screeningAddressType: String, address: MailingAddress) = {
this(addressFormat, screeningAddressType, None, Option(address))
}
}
val e1 = EvaluateAddress("a", "b", None, None)
val e2 = new EvaluateAddress("a", "b", "c")
val e3 = new EvaluateAddress("a", "b", MailingAddress(0))

Answer 2

You can create an auxilliary ADT to wrap different types of values. Inside EvaluateAddress you can check the alternative that was provided with a match:
case class EvaluateAddress(addressFormat: String,
screeningAddressType: String,
value: Option[EvaluateAddress.Value]
) {
import EvaluateAddress._
def doEvaluation() = value match {
case Some(Value.AsId(id)) =>
case Some(Value.AsAddress(mailingAddress)) =>
case None =>
}
}
object EvaluateAddress {
sealed trait Value
object Value {
case class AsId(id: String) extends Value
case class AsAddress(address: MailingAddress) extends Value
}
}
It's then possible to also define some implicit conversions to automatically convert Strings and MailingAddresses into Values:
object EvaluateAddress {
sealed trait Value
object Value {
case class AsId(id: String) extends Value
case class AsAddress(address: MailingAddress) extends Value
implicit def idAsValue(id: String): Value = AsId(id)
implicit def addressAsValue(address: MailingAddress): Value = AsAddress(address)
}
def withRawValue[T](addressFormat: String,
screeningAddressType: String,
rawValue: Option[T])(implicit asValue: T => Value): EvaluateAddress =
{
EvaluateAddress(addressFormat, screeningAddressType, rawValue.map(asValue))
}
}
Some examples of using those implicit conversions:
scala> EvaluateAddress("a", "b", Some("c"))
res1: EvaluateAddress = EvaluateAddress(a,b,Some(AsId(c)))
scala> EvaluateAddress("a", "b", Some(MailingAddress("d")))
res2: EvaluateAddress = EvaluateAddress(a,b,Some(AsAddress(MailingAddress(d))))
scala> val id: Option[String] = Some("id")
id: Option[String] = Some(id)
scala> EvaluateAddress.withRawValue("a", "b", id)
res3: EvaluateAddress = EvaluateAddress(a,b,Some(AsId(id)))