Initial implementation of kubevirt node along with test cases

Change-Id: I02f6abf2ae58dd79367a8b0b7e4a36fa966bf573
diff --git a/apps/kubevirt-node/api/src/main/java/org/onosproject/kubevirtnode/api/KubevirtNodeState.java b/apps/kubevirt-node/api/src/main/java/org/onosproject/kubevirtnode/api/KubevirtNodeState.java
new file mode 100644
index 0000000..87d921e
--- /dev/null
+++ b/apps/kubevirt-node/api/src/main/java/org/onosproject/kubevirtnode/api/KubevirtNodeState.java
@@ -0,0 +1,122 @@
+/*
+ * Copyright 2020-present Open Networking Foundation
+ *
+ * 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 org.onosproject.kubevirtnode.api;
+
+/**
+ * Defines the initialization stats of KubeVirt node.
+ */
+public enum KubevirtNodeState {
+
+    /**
+     * Indicates the node is in pre-on-board.
+     */
+    PRE_ON_BOARD {
+        @Override
+        public void process(KubevirtNodeHandler handler, KubevirtNode node) {
+
+        }
+
+        @Override
+        public KubevirtNodeState nodeState() {
+            return null;
+        }
+    },
+    /**
+     * Indicates the node is on-boarded.
+     */
+    ON_BOARDED {
+        @Override
+        public void process(KubevirtNodeHandler handler, KubevirtNode node) {
+
+        }
+
+        @Override
+        public KubevirtNodeState nodeState() {
+            return null;
+        }
+    },
+    /**
+     * Indicates the node is newly added.
+     */
+    INIT {
+        @Override
+        public void process(KubevirtNodeHandler handler, KubevirtNode node) {
+
+        }
+
+        @Override
+        public KubevirtNodeState nodeState() {
+            return null;
+        }
+    },
+    /**
+     * Indicates bridge devices are added according to the node state.
+     */
+    DEVICE_CREATED {
+        @Override
+        public void process(KubevirtNodeHandler handler, KubevirtNode node) {
+
+        }
+
+        @Override
+        public KubevirtNodeState nodeState() {
+            return null;
+        }
+    },
+    /**
+     * Indicates node initialization is done.
+     */
+    COMPLETE {
+        @Override
+        public void process(KubevirtNodeHandler handler, KubevirtNode node) {
+
+        }
+
+        @Override
+        public KubevirtNodeState nodeState() {
+            return null;
+        }
+    },
+    /**
+     * Indicates node is broken.
+     */
+    INCOMPLETE {
+        @Override
+        public void process(KubevirtNodeHandler handler, KubevirtNode node) {
+
+        }
+
+        @Override
+        public KubevirtNodeState nodeState() {
+            return null;
+        }
+    };
+
+    /**
+     * Processes the given kubevirt node which is under a certain state.
+     *
+     * @param handler kubevirt node handler
+     * @param node kubevirt node
+     */
+    public abstract void process(KubevirtNodeHandler handler, KubevirtNode node);
+
+    /**
+     * Transits to the next state.
+     *
+     * @return the next kubevirt node state
+     */
+    public abstract KubevirtNodeState nodeState();
+}