1 files changed, 85 insertions, 0 deletions
diff --git a/kamon-system-metrics/src/main/scala/kamon/metrics/ClassLoadingMetrics.scala b/kamon-system-metrics/src/main/scala/kamon/metrics/ClassLoadingMetrics.scala
new file mode 100644
index 00000000..1e3bee27
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+++ b/kamon-system-metrics/src/main/scala/kamon/metrics/ClassLoadingMetrics.scala
@@ -0,0 +1,85 @@
+/*
+ * =========================================================================================
+ * Copyright © 2013-2014 the kamon project <http://kamon.io/>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the
+ * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+ * either express or implied. See the License for the specific language governing permissions
+ * and limitations under the License.
+ * =========================================================================================
+ */
+package kamon.metrics
+
+import java.lang.management.ManagementFactory
+
+import akka.actor.ActorSystem
+import com.typesafe.config.Config
+import kamon.metric._
+import kamon.metric.instrument.{ Gauge, Histogram }
+
+case class ClassLoadingMetrics(name: String) extends MetricGroupIdentity {
+  val category = ClassLoadingMetrics
+}
+
+object ClassLoadingMetrics extends MetricGroupCategory {
+  val name = "classes"
+
+  case object Loaded extends MetricIdentity { val name = "total-loaded" }
+  case object Unloaded extends MetricIdentity { val name = "total-unloaded" }
+  case object Current extends MetricIdentity { val name = "current-loaded" }
+
+  case class ClassLoadingMetricRecorder(loaded: Gauge, unloaded: Gauge, current: Gauge)
+      extends MetricGroupRecorder {
+
+    def collect(context: CollectionContext): MetricGroupSnapshot = {
+      ClassLoadingMetricSnapshot(loaded.collect(context), unloaded.collect(context), current.collect(context))
+    }
+
+    def cleanup: Unit = {}
+  }
+
+  case class ClassLoadingMetricSnapshot(loaded: Histogram.Snapshot, unloaded: Histogram.Snapshot, current: Histogram.Snapshot)
+      extends MetricGroupSnapshot {
+
+    type GroupSnapshotType = ClassLoadingMetricSnapshot
+
+    def merge(that: GroupSnapshotType, context: CollectionContext): GroupSnapshotType = {
+      ClassLoadingMetricSnapshot(loaded.merge(that.loaded, context), unloaded.merge(that.unloaded, context), current.merge(that.current, context))
+    }
+
+    lazy val metrics: Map[MetricIdentity, MetricSnapshot] = Map(
+      Loaded -> loaded,
+      Unloaded -> unloaded,
+      Current -> current)
+  }
+
+  val Factory = ClassLoadingMetricGroupFactory
+}
+
+case object ClassLoadingMetricGroupFactory extends MetricGroupFactory {
+
+  import ClassLoadingMetrics._
+
+  val classes = ManagementFactory.getClassLoadingMXBean
+
+  type GroupRecorder = ClassLoadingMetricRecorder
+
+  def create(config: Config, system: ActorSystem): GroupRecorder = {
+    val settings = config.getConfig("precision.jvm.classes")
+
+    val totalLoadedConfig = settings.getConfig("total-loaded")
+    val totalUnloadedConfig = settings.getConfig("total-unloaded")
+    val currentLoadedConfig = settings.getConfig("current-loaded")
+
+    new ClassLoadingMetricRecorder(
+      Gauge.fromConfig(totalLoadedConfig, system)(() ⇒ classes.getTotalLoadedClassCount),
+      Gauge.fromConfig(totalUnloadedConfig, system)(() ⇒ classes.getUnloadedClassCount),
+      Gauge.fromConfig(currentLoadedConfig, system)(() ⇒ classes.getLoadedClassCount.toLong))
+  }
+}
+