! core: revised semantics of .register on Metrics module to match our docs.

1 files changed, 13 insertions, 1 deletions

diff --git a/kamon-core/src/main/scala/kamon/util/TriemapAtomicGetOrElseUpdate.scala b/kamon-core/src/main/scala/kamon/util/TriemapAtomicGetOrElseUpdate.scala
index 5ad43c34..d1197a5a 100644
--- a/kamon-core/src/main/scala/kamon/util/TriemapAtomicGetOrElseUpdate.scala
+++ b/kamon-core/src/main/scala/kamon/util/TriemapAtomicGetOrElseUpdate.scala
@@ -24,10 +24,22 @@ object TriemapAtomicGetOrElseUpdate {
    *  why this is necessary can be found at [[https://issues.scala-lang.org/browse/SI-7943]].
    */
   implicit class Syntax[K, V](val trieMap: TrieMap[K, V]) extends AnyVal {
+
     def atomicGetOrElseUpdate(key: K, op: ⇒ V): V =
+      atomicGetOrElseUpdate(key, op, { v: V ⇒ Unit })
+
+    def atomicGetOrElseUpdate(key: K, op: ⇒ V, cleanup: V ⇒ Unit): V =
       trieMap.get(key) match {
         case Some(v) ⇒ v
-        case None    ⇒ val d = op; trieMap.putIfAbsent(key, d).getOrElse(d)
+        case None ⇒
+          val d = op
+          trieMap.putIfAbsent(key, d).map { oldValue ⇒
+            // If there was an old value then `d` was never added
+            // and thus need to be cleanup.
+            cleanup(d)
+            oldValue
+
+          } getOrElse (d)
       }
   }
 }