1 files changed, 23 insertions, 0 deletions
diff --git a/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/database/CasWriteFailed.java b/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/database/CasWriteFailed.java
new file mode 100644
index 00000000000..c62d8d4bcd5
--- /dev/null
+++ b/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/database/CasWriteFailed.java
@@ -0,0 +1,23 @@
+// Copyright 2019 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.clustercontroller.core.database;
+
+/**
+ * Exception used to signal that a write intended to overwrite a value previously
+ * read encountered an underlying version conflict during an atomic compare-and-swap
+ * operation. This generally means that another node has written to the value since
+ * we last read it, and that the information we hold may be stale.
+ *
+ * Upon receiving such an exception, the caller should no longer assume it holds
+ * up-to-date information and should drop and roles that build on top of such an
+ * assumption (such as leadership sessions).
+ */
+public class CasWriteFailed extends RuntimeException {
+
+    public CasWriteFailed(String message) {
+        super(message);
+    }
+
+    public CasWriteFailed(String message, Throwable cause) {
+        super(message, cause);
+    }
+}