DataSource_V1.scala

import org.apache.spark.sql.SparkSession

trait DataSource[D, P] {
  def read(parameters: P)(implicit spark: SparkSession): AnnotatedDataFrame[D]
}

object DataSource {
  def apply[D]: Helper[D] = new Helper[D]

  // Helper used to improve the type inference and make the reading API cleaner.
  final class Helper[D] {
    def read[P](parameters: P)(implicit S: DataSource[D, P], spark: SparkSession) =
      S.read(parameters)

    def read(implicit S: DataSource[D, Unit], spark: SparkSession) =
      S.read(())
  }
}