Scala伴生对象

package big.data.analyse.scala.classes

/**
  * Created by zhen on 2018/9/11.
  * 伴生对象
  */
//定义私有的构造方法
class Marker private(val color : String){
  override def toString() : String = "marker color " + color
}
object Marker{
  private val markers = Map(
    "red" -> new Marker("red"),
    "blue" -> new Marker("blue"),
    "green" -> new Marker("green")
  )
  def apply(color : String) = if(markers.contains(color)) markers(color) else null
}
object Main{
  def main (args: Array[String]) {
    //Error:(33, 18) constructor Marker in class Marker cannot be accessed in object Main
    //val marker = new Marker("haha")
    println(Marker("blue"))
    println(Marker("green"))
    println(Marker("red"))
    println(Marker("white"))
  }
}