Distributed topic primitive

Change-Id: Ia3ccd84c33075f297d7e6b9bc205efe92aec9bea
diff --git a/apps/vtn/vtnrsc/src/test/java/org/onosproject/vtnrsc/util/VtnStorageServiceAdapter.java b/apps/vtn/vtnrsc/src/test/java/org/onosproject/vtnrsc/util/VtnStorageServiceAdapter.java
index fa64b5d..8421bb2 100644
--- a/apps/vtn/vtnrsc/src/test/java/org/onosproject/vtnrsc/util/VtnStorageServiceAdapter.java
+++ b/apps/vtn/vtnrsc/src/test/java/org/onosproject/vtnrsc/util/VtnStorageServiceAdapter.java
@@ -15,6 +15,7 @@
  */
 package org.onosproject.vtnrsc.util;
 
+import org.onosproject.store.service.Topic;
 import org.onosproject.store.service.WorkQueue;
 import org.onosproject.store.service.EventuallyConsistentMapBuilder;
 import org.onosproject.store.service.ConsistentMapBuilder;
@@ -69,4 +70,9 @@
     public <E> WorkQueue<E> getWorkQueue(String name, Serializer serializer) {
         return null;
     }
+
+    @Override
+    public <T> Topic<T> getTopic(String name, Serializer serializer) {
+        return null;
+    }
 }