Add atomic mastership/term/backups method to MastershipService

Change-Id: I18c3aeaa5101c9ce08ff38fffd70eaec903a0f3e
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/VirtualNetworkMastershipStore.java b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/VirtualNetworkMastershipStore.java
index b34b085..31fdfcd 100644
--- a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/VirtualNetworkMastershipStore.java
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/VirtualNetworkMastershipStore.java
@@ -19,6 +19,7 @@
 import org.onosproject.cluster.NodeId;
 import org.onosproject.cluster.RoleInfo;
 import org.onosproject.mastership.MastershipEvent;
+import org.onosproject.mastership.MastershipInfo;
 import org.onosproject.mastership.MastershipStoreDelegate;
 import org.onosproject.mastership.MastershipTerm;
 import org.onosproject.net.DeviceId;
@@ -74,6 +75,15 @@
     RoleInfo getNodes(NetworkId networkId, DeviceId deviceId);
 
     /**
+     * Returns the mastership info for a device.
+     *
+     * @param networkId virtual network identifier
+     * @param deviceId  the device identifier
+     * @return the mastership info
+     */
+    MastershipInfo getMastership(NetworkId networkId, DeviceId deviceId);
+
+    /**
      * Returns the devices that a controller instance is master of.
      *
      * @param networkId virtual network identifier