CORD-349 Support VLAN cross-connect traffic

Change related to this topic:
- Support VLAN cross-connect traffic
    Utilize ports subjectClass to achieve. For non-xConnect port, set interface VLAN to -1
- Remove VLAN checking since we have multiple VLANs per port
- Hash the L2 interface group key generation to include VLAN as well
- Update the network-cfg.json sample

Other refactoring changes:
- Read next objective stores from srManager directly
- Use constant for flow priority
- CORD-267 Javadoc fix

Change-Id: I4ca8c2d9c8b3633a4a0101c5070d19343f7e5b90
diff --git a/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/grouphandler/PortNextObjectiveStoreKey.java b/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/grouphandler/PortNextObjectiveStoreKey.java
index 5555565..ec25ec3 100644
--- a/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/grouphandler/PortNextObjectiveStoreKey.java
+++ b/apps/segmentrouting/src/main/java/org/onosproject/segmentrouting/grouphandler/PortNextObjectiveStoreKey.java
@@ -7,15 +7,23 @@
 import java.util.Objects;
 
 /**
- * Class definition of Key for Device/Port to NextObjective store. Since there
- * can be multiple next objectives to the same physical port, we differentiate
- * between them by including the treatment in the key.
+ * Key of Device/Port to NextObjective store.
+ *
+ * Since there can be multiple next objectives to the same physical port,
+ * we differentiate between them by including the treatment in the key.
  */
 public class PortNextObjectiveStoreKey {
     private final DeviceId deviceId;
     private final PortNumber portNum;
     private final TrafficTreatment treatment;
 
+    /**
+     * Constructs the key of port next objective store.
+     *
+     * @param deviceId device ID
+     * @param portNum port number
+     * @param treatment treatment that will be applied to the interface
+     */
     public PortNextObjectiveStoreKey(DeviceId deviceId, PortNumber portNum,
                                      TrafficTreatment treatment) {
         this.deviceId = deviceId;