package org.openjdk.jmh.samples

import org.openjdk.jmh.annotations._

import scala.collection.{mutable, immutable}
/*
  Scala immutable map is ~9x slower than java Hashmap for lookups.
  Scala mutable map is ~2x slower than java Hashmap for lookups.
  Benchmark results:
  Scala immutable map
  [info] ToBenchmark.imapBench  thrpt    3   45984712.982 ±  70602214.006  ops/s
  Java Hashmap
  [info] ToBenchmark.jmapBench  thrpt    3  420077614.268 ± 137667083.271  ops/s
  Scala mutable map
  [info] ToBenchmark.mmapBench  thrpt    3  232789150.801 ±  93773395.056  ops/s
*/
@Fork(1)
@Warmup(iterations = 3)
@Measurement(iterations = 3)
@State(Scope.Benchmark)
class ToBenchmark {
  val imap = (1 to 100000).map{ x => x -> x }.toMap
  val mmap = {
    val m = mutable.Map[Int, Int]()
    for (i <- 1 to 10000) m += i -> i
    m
  }

  val jmap = {
    val hm = new java.util.HashMap[Int, Int]()
    for (i <- 1 to 10000) hm.put(i, i)
    hm
  }

  @Benchmark
  def imapBench(): Unit = {
    imap(1)
  }

  @Benchmark
  def mmapBench(): Unit = {
    mmap(1)
  }

  @Benchmark
  def jmapBench(): Unit = {
    jmap.get(1)
  }

}