Suppose I have:
trait A{
println("A")
}
Now I want to inherit this trait in my Java code:
class B implements A {}
It looks like constructor of trait A is not going to be executed.
Is it possible to force constructor of trait A to be executed in scope of class B?
That would become something like:
public interface A {
}
public abstract class A$class {
public static void $init$(A $this) {
Predef..MODULE$.println((Object)"A");
}
}
using a decompiler. Java speaking, that is:
public class AImpl implements A {}
public class User {
public User() {
A a = new AImpl();
A$class.$init$(a);
}
}
init method, then call it directly from trait's constructor, and in java's successor as well, right? Because I haven't seen an init method in that trait when was implementing it in java's class.
init method for trait's constuctor? I'm asking because I didn't found that when was trying to write such code...The most reasonable way to get a Java class implementing a trait which has a constructor and/or non-abstract members is to extend the trait with a class in Scala, then extend this class in Java:
// AbstractA.scala
abstract class AbstractA extends A
// B.java
class B extends AbstractA
This way the Scala compiler takes care of all the stuff you have to do manually in Java otherwise, as you can see in bjfletcher's answer.
A$class... stuff in successor.
A$class.something. I suppose, if there is abilities to call trait's regular methods in java's successor, then there should be some way to call a constructor as method as well...