Akka/Scala example source code file (PrettyDuration.scala)

This example Akka source code file (PrettyDuration.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Akka and Scala source code examples by using tags.

All credit for the original source code belongs to akka.io; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Akka tags/keywords

concurrent, days, duration, hours, metrics, microseconds, milliseconds, minutes, nanoseconds, seconds, string, test, testing, time, timeunit

The PrettyDuration.scala Akka example source code

/**
 * Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
 */
package akka.testkit.metrics.reporter

import scala.concurrent.duration._

object PrettyDuration {

  implicit class PrettyPrintableDuration(val duration: Duration) extends AnyVal {

    def pretty: String = pretty(includeNanos = false)

    /** Selects most apropriate TimeUnit for given duration and formats it accordingly */
    def pretty(includeNanos: Boolean, precision: Int = 4): String = {
      require(precision > 0, "precision must be > 0")

      duration match {
        case d: FiniteDuration ⇒
          val nanos = d.toNanos
          val unit = chooseUnit(nanos)
          val value = nanos.toDouble / NANOSECONDS.convert(1, unit)

          s"%.${precision}g %s%s".format(value, abbreviate(unit), if (includeNanos) s" ($nanos ns)" else "")

        case d: Duration.Infinite if d == Duration.MinusInf ⇒ s" -∞ (minus infinity)"
        case d ⇒ s"∞ (infinity)"
      }
    }

    def chooseUnit(nanos: Long): TimeUnit = {
      val d = nanos.nanos

      if (d.toDays > 0) DAYS
      else if (d.toHours > 0) HOURS
      else if (d.toMinutes > 0) MINUTES
      else if (d.toSeconds > 0) SECONDS
      else if (d.toMillis > 0) MILLISECONDS
      else if (d.toMicros > 0) MICROSECONDS
      else NANOSECONDS
    }

    def abbreviate(unit: TimeUnit): String = unit match {
      case NANOSECONDS  ⇒ "ns"
      case MICROSECONDS ⇒ "μs"
      case MILLISECONDS ⇒ "ms"
      case SECONDS      ⇒ "s"
      case MINUTES      ⇒ "min"
      case HOURS        ⇒ "h"
      case DAYS         ⇒ "d"
    }
  }

}