In Scala, how can I subclass a Java class with multiple constructors?

Suppose I have a Java class with multiple constructors:

class Base {
    Base(int arg1) {...};
    Base(String arg2) {...};
    Base(double arg3) {...};
}

How can I extend it in Scala and still provide access to all three of Base's constructors? In Scala, a subclass can only call one of it's superclass's constructors. How can I work around this rule?

Assume the Java class is legacy code that I can't change.