Scala alternative constructor vs. companion object for polymorphic constructors -

what considered correct way create polymorphic constructors in scala? on 1 hand, can use companion object:

class userrecord (override val userid: string,                        override val rep: int) extends record  object userrecord extends record {   def apply(line: string) = {     val elem = xml.loadstring(line)      val userid = elem \ "@id" text     val rep = (elem \ "@reputation" text).toint     val out = new userrecord(userid, rep)     out   } } 

but loses encapsulation, , call object without new obscures fact non-singleton object being created. on other hand, can use sequence of alternate constructors, bit clunky:

class userrecord (override val userid: string,                        override val rep: int) extends record {   def this(t: tuple2[string, int]) = this(t._1, t._2)    def this(line: string) = this({     val elem = xml.loadstring(line)      val userid = elem \ "@id" text     val rep = (elem \ "@reputation" text).toint     val out = (userid, rep)     out   }) } 

i've looked ways avoid using first alternate constructor using .tupled haven't cracked nut.