[ONOS-2607] Interface to implement BGP LS topology provider and listen on Node c…

…hanges of BGP Controller.

Change-Id: Ied67b5ebe9603aaa7bbfb7eb36a4145a6353b9af

+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * 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.bgp.controller;
+
+import org.onosproject.bgpio.protocol.linkstate.BGPNodeLSNlriVer4;
+
+/**
+ * Allows for providers interested in node events to be notified.
+ */
+public interface BgpNodeListener {
+
+    /**
+     * Notifies that the node was added.
+     *
+     * @param nodeNlri node rechability info
+     */
+    void addNode(BGPNodeLSNlriVer4 nodeNlri);
+
+    /**
+     * Notifies that the node was removed.
+     *
+     * @param nodeNlri node rechability info
+     */
+    void deleteNode(BGPNodeLSNlriVer4 nodeNlri);
+}