CODEWITHSUNDEEP
scalaoverloadingtype-erasure
Kamal Banga
Kamal Banga

Reputation: 181

Can one not overload methods that just take a function (of different types) as parameter?

I have a method: 

def udf(func: RDD[Row] => RDD[Row]) = ...

and another method: 

def udf(func: List[String] => List[String]) = ...

in Scala. And it gives me this: 

Error:(...) double definition:
method udf:(func: List[String] => List[String])UDFOperator and
method udf:(func: org.apache.spark.rdd.RDD[Row] => org.apache.spark.rdd.RDD[Row])UDFOperator at ...
have same type after erasure: (func: Function1)UDFOperator
  def udf(func: List[String] => List[String]) = {
      ^

Upvotes: 0

Views: 259

Answers (1)

dhg
dhg

Reputation: 52701

The JVM doesn't support generics, so anything that Scala might need in order to resolve a runtime generic type check can't be done.

In your case, both methods are expecting Function1[_,_] parameters, and the JVM can't tell the difference between them. You'll have to rename one of them.

Upvotes: 4

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