Scala example source code file (MutableListTest.scala)

This example Scala source code file (MutableListTest.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

after, after, array, extlist, first, last, last, length, list, mutablelist, mutablelist, none, none, test

The Scala MutableListTest.scala source code

import scala.collection.mutable.MutableList



class ExtList[T] extends MutableList[T] {
  def printState {
    println("Length: " + len)
    println("Last elem: " + last0.elem)
    println("First elem: " + first0.elem)
    println("After first elem: " + first0.next.elem)
    println("After first: " + first0.next)
    println("Last: " + last0)
  }
}

object Test {

  def main(args: Array[String]) {
    testEmpty
    testAddElement
    testAddFewElements
    testAddMoreElements
    testTraversables
  }

  def testEmpty {
    val mlist = new MutableList[Int]
    assert(mlist.isEmpty)
    assert(mlist.get(0) == None)
  }

  def testAddElement {
    val mlist = new MutableList[Int]
    mlist += 17
    assert(mlist.nonEmpty)
    assert(mlist.length == 1)
    assert(mlist.head == 17)
    assert(mlist.last == 17)
    assert(mlist(0) == 17)
    assert(mlist.tail.isEmpty)
    assert(mlist.tail.length == 0)
    mlist(0) = 101
    assert(mlist(0) == 101)
    assert(mlist.toList == List(101))
    assert(mlist.tail.get(0) == None)
    assert((mlist.tail += 19).head == 19)
    assert(mlist.tail.length == 0)
  }

  def testAddFewElements {
    val mlist = new MutableList[Int]
    for (i <- 0 until 2) mlist += i
//    mlist.printState
    for (i <- 0 until 2) assert(mlist(i) == i)
    assert(mlist.length == 2)
    assert(mlist.nonEmpty)
    assert(mlist.tail.length == 1)
    assert(mlist.tail.tail.length == 0)
    assert(mlist.tail.tail.isEmpty)
  }

  def testAddMoreElements {
    val mlist = new MutableList[Int]
    for (i <- 0 until 10) mlist += i * i
    assert(mlist.nonEmpty)
    assert(mlist.length == 10)
    for (i <- 0 until 10) assert(mlist(i) == i * i)
    assert(mlist(5) == 5 * 5)
    assert(mlist(9) == 9 * 9)
    var sometail = mlist
    for (i <- 0 until 10) {
      assert(sometail.head == i * i)
      sometail = sometail.tail
    }
    mlist(5) = -25
    assert(mlist(5) == -25)
    mlist(0) = -1
    assert(mlist(0) == -1)
    mlist(9) = -81
    assert(mlist(9) == -81)
    assert(mlist(5) == -25)
    assert(mlist(0) == -1)
    assert(mlist.last == -81)
    mlist.clear
    assert(mlist.isEmpty)
    mlist += 1001
    assert(mlist.head == 1001)
    mlist += 9999
    assert(mlist.tail.head == 9999)
    assert(mlist.last == 9999)
  }

  def testTraversables {
    val mlist = new MutableList[Int]
    for (i <- 0 until 10) mlist += i * i
    var lst = mlist.drop(5)
    for (i <- 0 until 5) assert(lst(i) == (i + 5) * (i + 5))
    lst = lst.take(3)
    for (i <- 0 until 3) assert(lst(i) == (i + 5) * (i + 5))
    lst += 129
    assert(lst(3) == 129)
    assert(lst.last == 129)
    assert(lst.length == 4)
    lst += 7
    assert(lst.init.last == 129)
    assert(lst.length == 5)
    lst.clear
    assert(lst.length == 0)
    for (i <- 0 until 5) lst += i
    assert(lst.reduceLeft(_ + _) == 10)
  }

}