From 0fe9e267c7cec7a176fc8b0a43e73e12b6606b9f Mon Sep 17 00:00:00 2001
From: Ivan Topolnjak <ivantopo@gmail.com>
Date: Tue, 25 Apr 2017 01:46:06 +0200
Subject: simple implementation of measurement units

---
 .../main/scala/kamon/util/MeasurementUnit.scala    | 71 +++++++++++++++++++---
 1 file changed, 61 insertions(+), 10 deletions(-)

(limited to 'kamon-core/src/main/scala/kamon')

diff --git a/kamon-core/src/main/scala/kamon/util/MeasurementUnit.scala b/kamon-core/src/main/scala/kamon/util/MeasurementUnit.scala
index 4130fa50..170c2913 100644
--- a/kamon-core/src/main/scala/kamon/util/MeasurementUnit.scala
+++ b/kamon-core/src/main/scala/kamon/util/MeasurementUnit.scala
@@ -1,15 +1,66 @@
 package kamon.util
 
-trait MeasurementUnit {
-  def dimension: Dimension
-  def magnitude: Magnitude
-}
+import kamon.util.MeasurementUnit.{Dimension, Magnitude}
 
-trait Magnitude {
-  def name: String
-}
+/**
+  * A MeasurementUnit is a simple representation of the dimension and magnitude of a quantity being measured, such as
+  * "Time in Seconds" or "Data in Kilobytes".
+  */
+case class MeasurementUnit(dimension: Dimension, magnitude: Magnitude)
+
+object MeasurementUnit {
+  val none = MeasurementUnit(Dimension.None, Magnitude("none", 1D))
+
+  val time: TimeUnits = new TimeUnits {
+    val seconds = MeasurementUnit(Dimension.Time, Magnitude("seconds", 1D))
+    val milliseconds = MeasurementUnit(Dimension.Time, Magnitude("milliseconds", 1e-3))
+    val microseconds = MeasurementUnit(Dimension.Time, Magnitude("microseconds", 1e-6))
+    val nanoseconds = MeasurementUnit(Dimension.Time, Magnitude("nanoseconds", 1e-9))
+  }
+
+  val information: DataUnits = new DataUnits {
+    val bytes = MeasurementUnit(Dimension.Information, Magnitude("byte", 1))
+    val kilobytes = MeasurementUnit(Dimension.Information, Magnitude("kilobytes", 1024))
+    val megabytes = MeasurementUnit(Dimension.Information, Magnitude("megabytes", 1024 * 1024))
+    val gigabytes = MeasurementUnit(Dimension.Information, Magnitude("gigabytes", 1024 * 1024 * 1024))
+  }
+
+  /**
+    * Scales the provided value between two MeasurementUnits of the same dimension.
+    *
+    * @param value value to be scaled.
+    * @param from value's [[MeasurementUnit]].
+    * @param to target [[MeasurementUnit]].
+    * @return equivalent of the provided value on the target [[MeasurementUnit]]
+    */
+  def scale(value: Long, from: MeasurementUnit, to: MeasurementUnit): Double = {
+    if(from.dimension != to.dimension)
+      sys.error(s"Can't scale values from the [${from.dimension.name}] dimension into the [${to.dimension.name}] dimension.")
+    else if(from == to)
+      value.toDouble
+    else (from.magnitude.scaleFactor / to.magnitude.scaleFactor) * value.toDouble
+  }
+
+  case class Dimension(name: String)
+  case class Magnitude(name: String, scaleFactor: Double)
+
+  object Dimension {
+    val None = Dimension("none")
+    val Time = Dimension("time")
+    val Information = Dimension("information")
+  }
+
+  trait TimeUnits {
+    def seconds: MeasurementUnit
+    def milliseconds: MeasurementUnit
+    def microseconds: MeasurementUnit
+    def nanoseconds: MeasurementUnit
+  }
 
-trait Dimension {
-  def name: String
-  def scale(value: Long, from: Magnitude, to: Magnitude): Double
+  trait DataUnits {
+    def bytes: MeasurementUnit
+    def kilobytes: MeasurementUnit
+    def megabytes: MeasurementUnit
+    def gigabytes: MeasurementUnit
+  }
 }
-- 
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