FusionBench.scala

package benchmarks

import java.util.concurrent.TimeUnit

import org.openjdk.jmh.annotations._

@BenchmarkMode(Array(Mode.AverageTime))
@OutputTimeUnit(TimeUnit.MICROSECONDS)
@State(Scope.Thread)
class FusionBench {
  var list1: List[Int] = _
  var list2: List[Int] = _
  var str1: Stream[Int] = _
  var seq1: Seq[Int] = _
  var arr1: Array[Int] = _
  var iterable1: Iterable[Int] = _
  var iterator1: Iterator[Int] = _

  @Setup
  def setup: Unit = {
    list1 = List.range(10000, 1, -1)
    list2 = List.range(10000, 1, -1)
    str1 = Stream.range(10000, 1, -1)
    seq1 = Seq.range(10000, 1, -1)
    arr1 = Array.range(10000, 1, -1)
    iterable1 = Iterable.range(10000, 1, -1)
    iterator1 = Iterator.range(10000, 1, -1)
  }

  @Benchmark
  def listFusion: List[Int] = list1.map(_ + 1).filter(_ % 2 == 0).map(_ * 2)
  @Benchmark
  def listViaIteratorFusion: List[Int] = list2.toIterator.map(_ + 1).filter(_ % 2 == 0).map(_ * 2).toList
  @Benchmark
  def streamFusion: Stream[Int] = str1.map(_ + 1).filter(_ % 2 == 0).map(_ * 2).force
  @Benchmark
  def seqFusion: Seq[Int] = seq1.map(_ + 1).filter(_ % 2 == 0).map(_ * 2)
  @Benchmark
  def arrFusion: Seq[Int] = arr1.map(_ + 1).filter(_ % 2 == 0).map(_ * 2)
  @Benchmark
  def iterableFusion: Iterable[Int] = iterable1.map(_ + 1).filter(_ % 2 == 0).map(_ * 2)
  @Benchmark
  def iteratorFusion: Iterator[Int] = iterator1.map(_ + 1).filter(_ % 2 == 0).map(_ * 2)
}