scala – 什么是Coneel中的克隆

1)

class Valid[+T <: Data](gen: T) extends Bundle
    {
    val valid = Output(Bool())
    val bits = Output(gen.chiselCloneType)//?????
    def fire(): Bool = valid
    override def cloneType: this.type = Valid(gen).asInstanceOf[this.type]
    }
    /** Adds a valid protocol to any interface */
    object Valid {
    def apply[T <: Data](gen: T): Valid[T] = new Valid(gen)
    }

2)

class Packet(n: Int,w: Int) extends Bundle {
val address = UInt(Log2Up(n).W)
val payload = UInt(w.W)
override def cloneType: this.type =
new Packet(n,w).asInstanceOf[this.type]
}

为什么cloneType是Override.它是否像Scala中的apply方法,或者只是更新Bundle中的cloneType方法.

谢谢