This is a standard practice used for chaining, to support a.setStepSize(..) .set setRegParam(...)
On Sun, Jul 23, 2017 at 8:47 PM, tao zhan <zhanta...@gmail.com> wrote: > Thank you for replying. > But I do not get it completely, why does the "this.type“” necessary? > why could not it be like: > > def setStepSize(step: Double): Unit = { > require(step > 0, > s"Initial step size must be positive but got ${step}") > this.stepSize = step > } > > On Mon, Jul 24, 2017 at 11:29 AM, M. Muvaffak ONUŞ < > onus.muvaf...@gmail.com> wrote: > >> Doesn't it mean the return type will be type of "this" class. So, it >> doesn't have to be this instance of the class but it has to be type of this >> instance of the class. When you have a stack of inheritance and call that >> function, it will return the same type with the level that you called it. >> >> On Sun, Jul 23, 2017 at 8:20 PM Reynold Xin <r...@databricks.com> wrote: >> >>> It means the same object ("this") is returned. >>> >>> On Sun, Jul 23, 2017 at 8:16 PM, tao zhan <zhanta...@gmail.com> wrote: >>> >>>> Hello, >>>> >>>> I am new to scala and spark. >>>> What does the "this.type" in set function for? >>>> >>>> >>>> >>>> https://github.com/apache/spark/blob/481f0792944d9a77f0fe8b5 >>>> e2596da1d600b9d0a/mllib/src/main/scala/org/apache/spark/ >>>> mllib/optimization/GradientDescent.scala#L48 >>>> >>>> Thanks! >>>> >>>> Zhan >>>> >>> >>> >