OptionBench.scala

/**
 * This is a benchmark to gauge if there is any performance hit into using Option.apply() in Scala.
 * Use JMH to build it: http://blog.vorona.ca/measuring-scala-performance-with-jmh.html
 */

package org.sample

import org.openjdk.jmh.annotations._
import java.util.concurrent.TimeUnit

@Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
@Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
@Fork(3)
@State(Scope.Benchmark)
class MyBenchmark {

  @Param(Array("4", "null"))
  var strValue: String = _

  @Benchmark
  def testOption(): Any = {
    val value = if(strValue.equals("null")) null else java.lang.Long.valueOf(strValue)
    Option(value).map(_ * 2).getOrElse(1L)
  }

  @Benchmark
  def testNull(): Any = {
    val value = if(strValue.equals("null")) null else java.lang.Long.valueOf(strValue)
    if(value != null) value * 2 else 1L
  }

}

/* Result:
Benchmark                     (strValue)   Mode  Samples          Score         Error  Units
o.s.MyBenchmark.testNull               4  thrpt       15   84314649.298 ± 1203713.827  ops/s
o.s.MyBenchmark.testNull            null  thrpt       15  158563487.854 ± 2074024.325  ops/s
o.s.MyBenchmark.testOption             4  thrpt       15   83276054.167 ±  574030.725  ops/s
o.s.MyBenchmark.testOption          null  thrpt       15  165543753.295 ± 2113093.244  ops/s

 * Conclusion: there is no performance impact
*/

/* Another version to make sure we'd see the difference if there was one.

class MyBenchmark {

  @Benchmark
  def testOption(): Any = {
    val value: java.lang.Long = 4L
    Option(value).map(_ * 2).getOrElse(1L)
  }

  @Benchmark
  def testNull(): Any = {
    val value: java.lang.Long = 4L
    if(value != null) value * 2 else 1L
  }

  @Benchmark
  def testPlus(): Any = {
    val value: java.lang.Long = 4L
    if(value != null) (value + 1) * 2 else 1L
  }
}

 * It's results:
Benchmark                      Mode  Samples          Score          Error  Units
o.s.MyBenchmark.testNull      thrpt      100  284044726.734 ± 11713071.741  ops/s
o.s.MyBenchmark.testOption    thrpt      100  293796734.747 ±  9904997.303  ops/s
o.s.MyBenchmark.testPlus      thrpt      100  261674420.570 ± 14340772.701  ops/s

 * As you can see, one extra "plus" operation causes a noticeable drop in throughput.
*/