Scala case class private constructor but public apply method

Question

If I have the following case class with a private constructor and I can not access the apply-method in the companion object.

case class Meter private (m: Int)

val m = Meter(10) // constructor Meter in class Meter cannot be accessed...

Is there a way to use a case class with a private constructor but keep the generated apply-method in the companion public?

I am aware that there is no difference (in my example) between the two options:

val m1 = new Meter(10)
val m2 = Meter(10)

but I want to forbid the first option.

-- edit --

Surprisingly the following works (but is not really what i want):

val x = Meter
val m3 = x(10) // m3  : Meter = Meter(10)

Answer 1

Here's the technique to have a private constructor and a public apply method.

trait Meter {
  def m: Int
}

object Meter {   
  def apply(m: Int): Meter = { MeterImpl(m) }
  private case class MeterImpl(m: Int) extends Meter { println(m) }
}

object Application extends App {
  val m1 = new Meter(10) // Forbidden
  val m2 = Meter(10)
}

Background information private-and-protected-constructor-in-scala