Add skeleton code for TAPI manager and topology generation feature

Change-Id: If7eaa3ceb7fe64122b1e640ac864d06d578530cb
diff --git a/apps/odtn/service/src/main/java/org/onosproject/odtn/internal/TapiTopologyManager.java b/apps/odtn/service/src/main/java/org/onosproject/odtn/internal/TapiTopologyManager.java
new file mode 100644
index 0000000..d997b45
--- /dev/null
+++ b/apps/odtn/service/src/main/java/org/onosproject/odtn/internal/TapiTopologyManager.java
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2018-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.odtn.internal;
+
+import org.onosproject.net.Device;
+import org.onosproject.net.Link;
+
+public interface TapiTopologyManager {
+
+    void addDevice(Device device);
+
+    void removeDevice(Device device);
+
+    void addLink(Link link);
+
+    void removeLink(Link link);
+
+    void addPort(Device device);
+
+    void removePort(Device device);
+}