--- /dev/null
+/*
+ * Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.controller.md.sal.dom.store.impl.tree.spi;
+
+/**
+ * The concept of a version, either node version, or a subtree version. The
+ * only interface contract this class has is that no two versions are the
+ * same.
+ */
+public final class Version {
+ private Version() {
+
+ }
+
+ /**
+ * Create a new version, distinct from any other version.
+ *
+ * @return a new version.
+ */
+ public Version next() {
+ return new Version();
+ }
+
+ /**
+ * Create an initial version.
+ *
+ * @return a new version.
+ */
+ public static final Version initial() {
+ return new Version();
+ }
+}