I have a case class
case class SiteID(channel: String, locale: String)
Locale can be "en-GB" or "en_GB" . So I want to replace the hyphen by underscore.
The idea is to transform , so there is this equality
SiteID("blabla","en-GB") == SiteID("blabla","en_GB")
I tried with the following code
case class SiteID(channel: String, locale: String)
object SiteID{
def apply(channel: String, locale: String):SiteID = SiteID(channel,locale.replace("-","_") )
}
You are probably calling recursively the apply method of the companion object. Try using the new operator.
object SiteID {
def apply(channel: String, locale: String):SiteID =
new SiteID(channel,locale.replace("-","_") )
}
With the Scala case class construct, the compiler automatically generates an apply method for you with the declared parameters. If you declare another one with the same parameter types as your case class, it takes precedence over the compiler's generated one.
So as stated in another answer your apply method is calling itself recursively; a solution was provided. If you additionally need to ensure that no SiteID("bla","en-GB") value will get instantiated, you should declare the constructor of your case class as private:
case class SiteID private(channel: String, locale: String)
object SiteID {
def apply(channel: String, locale: String):SiteID =
new SiteID(channel,locale.replace("-","_") )
}
SiteID("bla","en-GB") //SiteID(a,en_GB)
new SiteID("bla","en-GB") //error
Here is something that's rather close to what you want (you can make the Point's constructor protected):
case class Point(x: Double, y: Double)
class PolarPoint(r: Double, alpha: Double) extends Point(r*Math.cos(alpha), r*Math.sin(alpha))
and
@main def main(): Unit = {
println(Point(10,10))
println(PolarPoint(10, Math.PI/4))
}
prints:
Point(10.0,10.0)
Point(7.0710678118654755,7.071067811865475)
and r and alpha do not become members of PolarPoint:
public class PolarPoint extends Point {
public PolarPoint(final double r, final double alpha) {
super(r * Math.cos(alpha), r * Math.sin(alpha));
}
}
If it's ok to reference objects as Foos but create FooImpls. you can do something like:
case class Foo protected(x:Int)
class FooImpl(x0:Int) extends Foo(myFunc(x0))
