1 files changed, 34 insertions, 0 deletions
diff --git a/kamon-core/src/main/scala/kamon/metric/package.scala b/kamon-core/src/main/scala/kamon/metric/package.scala
new file mode 100644
index 00000000..43166058
--- /dev/null
+++ b/kamon-core/src/main/scala/kamon/metric/package.scala
@@ -0,0 +1,34 @@
+/*
+ * =========================================================================================
+ * Copyright © 2013 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
+
+import scala.annotation.tailrec
+import com.typesafe.config.Config
+
+package object metric {
+
+  @tailrec def combineMaps[K, V](left: Map[K, V], right: Map[K, V])(valueMerger: (V, V) ⇒ V): Map[K, V] = {
+    if (right.isEmpty)
+      left
+    else {
+      val (key, rightValue) = right.head
+      val value = left.get(key).map(valueMerger(_, rightValue)).getOrElse(rightValue)
+
+      combineMaps(left.updated(key, value), right.tail)(valueMerger)
+    }
+  }
+}