Determine non-empty additional fields in a subclass - scala

Question

Assume I have a trait which looks something like this
trait MyTrait {
val x: Option[String] = None
val y: Option[String] = None
}
Post defining the trait I extend this trait to a class MyClass which looks something like this
case class MyClass(
override val x: Option[String] = None,
override val y: Option[String] = None,
z: Option[String] = None
) extends MyTrait
Now I need to find if any other property other than the properties extended by MyTrait is not None. In the sense if I need to write a method which is called getClassInfo which returns true/false based upon the values present in the case class. In this case it should return true if z is Non optional. My getClassInfo goes something like this
def getClassInfo(myClass: MyClass): Boolean = {
myClass
.productIterator
.filterNot(x => x.isInstanceOf[MyTrait])
.exists(_.isInstanceOf[Some[_]])
}
Ideally this should filter out all the fields which are not a part of Mytrait and return me z in this case.
I tried using variance, However It seems like isInstanceOf doesn't take the same
filterNot(x => x.isInstanceOf[+MyTrait])
However this cannot be possible
val a = getClassInfo(MyClass()) //Needs to return false
val b = getClassInfo(MyClass(Some("a"), Some("B"), Some("c"))) //returns true
val c = getClassInfo(MyClass(z = Some("z"))) //needs to return true
val d = getClassInfo(MyClass(x = Some("x"), y = Some("y"))) // needs to return false

Answer 1

The simple answer is to declare an abstract method that gives the result you want and override it in the subclass:
trait MyTrait {
def x: Option[String]
def y: Option[String]
def anyNonEmpty: Boolean = false
}
case class MyClass(x: Option[String] = None, y: Option[String] = None, z: Option[String] = None) extends MyTrait {
override def anyNonEmpty = z.nonEmpty
}
You can then call anyNonEmpty on your object to get the getClassInfo result.
Also note that I've used def here in the trait because val in a trait is generally a bad idea because of initialisation issues.

Answer 2

If you really need reflection you can try
import scala.reflect.runtime.currentMirror
import scala.reflect.runtime.universe._
def getClassInfo(myClass: MyClass): Boolean = {
def fields[A: TypeTag] = typeOf[A].members.collect {
case m: MethodSymbol if m.isGetter && m.isPublic => m
}
val mtFields = fields[MyTrait]
val mcFields = fields[MyClass]
val mtFieldNames = mtFields.map(_.name).toSet
val mcNotMtFields = mcFields.filterNot(f => mtFieldNames.contains(f.name))
val instanceMirror = currentMirror.reflect(myClass)
val mcNotMtFieldValues = mcNotMtFields.map(f => instanceMirror.reflectField(f).get)
mcNotMtFieldValues.exists(_.isInstanceOf[Some[_]])
}
val a = getClassInfo(MyClass()) //false
val b = getClassInfo(MyClass(Some("a"), Some("B"), Some("c"))) //true
val c = getClassInfo(MyClass(z = Some("z"))) //true
val d = getClassInfo(MyClass(x = Some("x"), y = Some("y")))//false