Question

I try to override my parametrized method in scala,

I have an abstract class like this :

abstract class Ranking[G <: AbstractGenome, MG <: MultiGoalLike] {
  def operate(individuals :IndexedSeq [IndividualMG[G,MG]]):IndexedSeq [IndividualMG[G,MG]
}

I want two type of ranking which need decorated version of IndividualMG : IndividualMG[G,MG] with IDistance, and IndividualMG[G,MG] with IRank.

My IndividualMG class signature :

class IndividualMG[G <: AbstractGenome,MG <: MultiGoalLike] (val genome: G,val multiGoal:MG) 

My two class for ranking :

class Ranking1 [G <: AbstractGenome, MG <: MultiGoalLike] extends Ranking[G,MG] {
override def operate(individuals :IndexedSeq [IndividualMG [G,MG] with IRanking])
:IndexedSeq [IndividualMG [G,MG] with IRanking]= {
return ...
}

class Ranking2 [G <: AbstractGenome, MG <: MultiGoalLike] extends Ranking[G,MG] {
override def operate(individuals :IndexedSeq [IndividualMG [G,MG] with IDistance])
:IndexedSeq [IndividualMG [G,MG] with IDistance] = {
return ...
}

I have an error, it’s logic because type differs when i try to override, but how can i make to verify inheritance type [I <: IndividualMG [G,MG]] for my two ranking operator in class Ranking1 and Ranking2 ?

Thanks stack,
SR.

Answer 1

What about

abstract class Ranking[
    -I <: IndividualMG[G, MG], 
    G <: AbstractGenome, 
    MG <: MultiGoalLike] {
  def operate(individuals :IndexedSeq[I])
}

class Ranking1[
   G <: AbstractGenome, 
   MG <: MultiGoalLike] 
  extends Ranking[IndividualMG[G,MG] with IDistance, G, MG] ...