CORD-413 Implement MPLS Termination in OFDPA3 pipeliner

Additionally, this patch includes
- Minor refactoring
- Skip method length checkstyle for FlowEntryBuilder::hasSetField

Change-Id: I7887f454f552a9e346c323524f359929deadf427
diff --git a/drivers/default/src/main/java/org/onosproject/driver/extensions/codec/OfdpaMatchVlanVidCodec.java b/drivers/default/src/main/java/org/onosproject/driver/extensions/codec/OfdpaMatchVlanVidCodec.java
index bc0e876..65ed92b 100644
--- a/drivers/default/src/main/java/org/onosproject/driver/extensions/codec/OfdpaMatchVlanVidCodec.java
+++ b/drivers/default/src/main/java/org/onosproject/driver/extensions/codec/OfdpaMatchVlanVidCodec.java
@@ -30,15 +30,14 @@
 public class OfdpaMatchVlanVidCodec extends JsonCodec<OfdpaMatchVlanVid> {
 
     private static final String VLAN_ID = "vlanId";
-
     private static final String MISSING_MEMBER_MESSAGE = " member is required in OfdpaMatchVlanVid";
+    private static final String MISSING_VLAN_ID_MESSAGE = "Vlan ID cannot be null";
 
     @Override
     public ObjectNode encode(OfdpaMatchVlanVid vlanId, CodecContext context) {
-        checkNotNull(vlanId, "Vlan ID cannot be null");
-        ObjectNode root = context.mapper().createObjectNode()
+        checkNotNull(vlanId, MISSING_VLAN_ID_MESSAGE);
+        return context.mapper().createObjectNode()
                 .put(VLAN_ID, vlanId.vlanId().id());
-        return root;
     }
 
     @Override