Rewrote cached gauge (#52) to use FiniteDuration instead of Java's Ti…

…meUnit, improved test.

Akka 2.3.4 -> 2.3.5.
Prepared for release of 3.2.1.

CHANGELOG.md

@@ -1,8 +1,9 @@
-TBD
-===
+v3.2.1: Aug 2014
+================
 
 * For future timing, invoke argument only once, closes #50. Bug report and solution from @JeffBellegarde.
-* Added MetricBuilder.cachedGauge method (from @pasieronen).
+* Added support for cached gauge, a nice pull request by @pasieronen (#52).
+* For Akka 2.3 build: build against Akka 2.3.5.
 
 v3.2.0: May 2014
 ================

build.sbt

@@ -1,13 +1,14 @@
 // See crossrelease.sh for valid combinations of akkaVersion and crossScalaVersion.
 
-// Akka versions: 2.1.4, 2.2.3, 2.3.2
-akkaVersion := "2.3.2"
+// Build against Akka versions: 2.1.4, 2.2.3, 2.3.5,
+// but developed against oldest supported version.
+akkaVersion := "2.1.4"
 
 organization := "nl.grons"
 
 name := "metrics-scala"
 
-lazy val baseVersion = "3.2.0"
+lazy val baseVersion = "3.2.1"
 
 version <<= (akkaVersion) { av =>
   val akkaVersion = if (av.nonEmpty) "_a" + av.split('.').take(2).mkString(".") else ""
@@ -19,6 +20,7 @@ description <<= (scalaVersion, akkaVersion) { (sv, av) =>
   "metrics-scala for " + akkaDescription + "Scala " + sbt.cross.CrossVersionUtil.binaryScalaVersion(sv)
 }
 
+// Developed with 2.10.0, build with 2.10.0 and 2.11.0.
 scalaVersion := "2.10.0"
 
 crossScalaVersions := Seq("2.10.0", "2.11.0")

crossrelease.sh

@@ -8,4 +8,4 @@ CMD=${1:-$DEFAULT_COMMAND}
 sbt '; set akkaVersion := "";      set crossScalaVersions := Seq("2.10.0", "2.11.0")' +$CMD \
     '; set akkaVersion := "2.1.4"; set crossScalaVersions := Seq("2.10.0")'           +$CMD \
     '; set akkaVersion := "2.2.4"; set crossScalaVersions := Seq("2.10.0")'           +$CMD \
-    '; set akkaVersion := "2.3.4"; set crossScalaVersions := Seq("2.10.0", "2.11.0")' +$CMD
+    '; set akkaVersion := "2.3.5"; set crossScalaVersions := Seq("2.10.0", "2.11.0")' +$CMD

src/main/scala/nl/grons/metrics/scala/MetricBuilder.scala

@@ -16,9 +16,10 @@
 
 package nl.grons.metrics.scala
 
-import java.util.concurrent.TimeUnit
+import java.util.concurrent.TimeUnit.MILLISECONDS
 import com.codahale.metrics.MetricRegistry
 import com.codahale.metrics.{Gauge => CHGauge, CachedGauge => CHCachedGauge}
+import scala.concurrent.duration.FiniteDuration
 
 /**
  * Builds and registering metrics.
@@ -35,15 +36,14 @@ class MetricBuilder(val baseName: MetricName, val registry: MetricRegistry) {
     new Gauge[A](registry.register(metricName(name, scope), new CHGauge[A] { def getValue: A = f }))
 
   /**
-   * Registers a new cached gauge metric.
+   * Registers a new gauge metric that caches its value for a given duration.
    *
-   * @param name  the name of the gauge
-   * @param timeout  the timeout
-   * @param timeoutUnit  the unit of <code>timeout</code>
-   * @param scope the scope of the gauge or null for no scope
+   * @param name    the name of the gauge
+   * @param timeout the timeout
+   * @param scope   the scope of the gauge or null for no scope
    */
-  def cachedGauge[A](name: String, timeout: Long, timeoutUnit: TimeUnit, scope: String = null)(f: => A): Gauge[A] =
-    new Gauge[A](registry.register(metricName(name, scope), new CHCachedGauge[A](timeout, timeoutUnit) { def loadValue: A = f }))
+  def cachedGauge[A](name: String, timeout: FiniteDuration, scope: String = null)(f: => A): Gauge[A] =
+    new Gauge[A](registry.register(metricName(name, scope), new CHCachedGauge[A](timeout.toMillis, MILLISECONDS) { def loadValue: A = f }))
 
   /**
    * Creates a new counter metric.

src/test/scala/nl/grons/metrics/scala/MetricBuilderSpec.scala

@@ -22,7 +22,7 @@ import org.scalatest.OneInstancePerTest
 import org.scalatest.FunSpec
 import org.scalatest.junit.JUnitRunner
 import com.codahale.metrics.MetricRegistry
-import java.util.concurrent.TimeUnit
+import scala.concurrent.duration._
 
 @RunWith(classOf[JUnitRunner])
 class MetricBuilderSpec extends FunSpec with OneInstancePerTest {
@@ -36,7 +36,7 @@ class MetricBuilderSpec extends FunSpec with OneInstancePerTest {
   class UnderTest extends Instrumented {
     val timer: Timer = metrics.timer("10ms")
     val gauge: Gauge[Int] = metrics.gauge("the answer")(value)
-    val cachedGauge: Gauge[Int] = metrics.cachedGauge("cached", 1, TimeUnit.HOURS)(cachedValue)
+    val cachedGauge: Gauge[Int] = metrics.cachedGauge("cached", 300 milliseconds)(cachedValue)
     val counter: Counter = metrics.counter("1..2..3..4")
     val histogram: Histogram = metrics.histogram("histo")
     val meter: Meter = metrics.meter("meter", "testscope")
@@ -81,6 +81,9 @@ class MetricBuilderSpec extends FunSpec with OneInstancePerTest {
       underTest.cachedCalls should equal (1)
       underTest.cachedGauge.value should equal (42)
       underTest.cachedCalls should equal (1)
+      Thread.sleep(400L)
+      underTest.cachedGauge.value should equal (42)
+      underTest.cachedCalls should equal (2)
     }
 
     it("defines a counter") {