Scala: Queue

object QueuePerformance {
  println("Test performance of Queue")            //> Test performance of Queue

  import scala.collection.immutable.Queue

  util.Properties.versionString                   //> res0: String = version 2.10.3

  System.getProperty("java.version")              //> res1: String = 1.7.0_25

  def time[A](f: => A) = {
    f
    for (_ <- 1 to 3) {
      val s = System.nanoTime
      f
      println("time: " + (System.nanoTime - s) / 1e6 + "ms")
    }
  }                                               //> time: [A](f: => A)Unit

  val count = 10000                               //> count  : Int = 10000

  time {
    var q = Queue.empty[Int]
    for (i <- 1 to count) {
      q = q enqueue i
    }
    println(q.dequeue._1)
  }                                               //> 1
                                                  //| 1
                                                  //| time: 19.326757ms
                                                  //| 1
                                                  //| time: 3.575115ms
                                                  //| 1
                                                  //| time: 1.428872ms
  time {
    var q = Queue.empty[Int]
    for (i <- 1 to count) {
      q = q :+ i
    }
    println(q.dequeue._1)
  }                                               //> 1
                                                  //| 1
                                                  //| time: 576.121048ms
                                                  //| 1
                                                  //| time: 511.96562ms
                                                  //| 1
                                                  //| time: 582.245494ms
}