1 files changed, 40 insertions, 0 deletions
diff --git a/kamon-core/src/legacy-main/scala/kamon/util/Sequencer.scala b/kamon-core/src/legacy-main/scala/kamon/util/Sequencer.scala
new file mode 100644
index 00000000..f368e54f
--- /dev/null
+++ b/kamon-core/src/legacy-main/scala/kamon/util/Sequencer.scala
@@ -0,0 +1,40 @@
+/*
+ * =========================================================================================
+ * 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.util
+
+/**
+ * This class implements an extremely efficient, thread-safe way to generate a
+ * incrementing sequence of Longs with a simple Long overflow protection.
+ */
+class Sequencer {
+  private val CloseToOverflow = Long.MaxValue - 1000000000
+  private val sequenceNumber = new PaddedAtomicLong(1L)
+
+  def next(): Long = {
+    val current = sequenceNumber.getAndIncrement
+
+    // check if this value is getting close to overflow?
+    if (current > CloseToOverflow) {
+      sequenceNumber.set(current - CloseToOverflow) // we need maintain the order
+    }
+    current
+  }
+}
+
+object Sequencer {
+  def apply(): Sequencer = new Sequencer()
+}
+\ No newline at end of file