scala - How to "extend" factory methods when extending class with companion object with factory methods -

say have class foo, abstraction on kind of text file, , companion object factory methods simplifies creation of foo:

class foo(val lines : seq[string], filepath : string) { ... }  object foo {   def apply(file : file) : foo = { new foo(scala.io.source.fromfile(file, "iso-8859-1").mkstring.split("\n").tolist, file.getpath }   def apply(file : string) : foo = { apply(new file(file) } } 

what happens when want extend foo bar , baz, if both subclasses need have same factory methods? don't want copy companion object foo companion object bar , companion object baz, right way of making factory methods "generic"?

you following:

trait foofactory[t <: foo] {    def apply(file : file) : t = //to implement in baz , bar class    def apply(file : string) : t = { apply(new file(file) }   //shared method, no need implement in subclassing classes  }   //example bar implementation------------------------------  class bar extends foo {      // specific bar code here }  object bar extends foofactory[bar] {   def apply(file : file) : bar = { new bar(scala.io.source.fromfile(file, "iso-8859-1").mkstring.split("\n").tolist, file.getpath } }