diff --git a/core/api/src/main/java/org/onosproject/store/service/DocumentException.java b/core/api/src/main/java/org/onosproject/store/service/DocumentException.java
index d49b318..b2fd624 100644
--- a/core/api/src/main/java/org/onosproject/store/service/DocumentException.java
+++ b/core/api/src/main/java/org/onosproject/store/service/DocumentException.java
@@ -35,4 +35,30 @@
     public DocumentException(Throwable cause) {
         super(cause);
     }
+
+    /**
+     * DocumentTree operation timeout.
+     */
+    public static class Timeout extends DocumentException {
+        public Timeout() {
+        }
+
+        public Timeout(String message) {
+            super(message);
+        }
+
+        public Timeout(String message, Throwable cause) {
+            super(message, cause);
+        }
+
+        public Timeout(Throwable cause) {
+            super(cause);
+        }
+    }
+
+    /**
+     * DocumentTree operation interrupted.
+     */
+    public static class Interrupted extends DocumentException {
+    }
 }