Add NotNull and Argument check during object build for LISP object

Also correct IP enumeration type into IP4.

Change-Id: Id970ee608c885826cfd2de7b5448b2bc451e079f
diff --git a/protocols/lisp/msg/src/main/java/org/onosproject/lisp/msg/protocols/LispEidRecord.java b/protocols/lisp/msg/src/main/java/org/onosproject/lisp/msg/protocols/LispEidRecord.java
index 35fe975..9ceef6c 100644
--- a/protocols/lisp/msg/src/main/java/org/onosproject/lisp/msg/protocols/LispEidRecord.java
+++ b/protocols/lisp/msg/src/main/java/org/onosproject/lisp/msg/protocols/LispEidRecord.java
@@ -21,6 +21,7 @@
 import org.onosproject.lisp.msg.exceptions.LispWriterException;
 import org.onosproject.lisp.msg.types.LispAfiAddress;
 
+import static com.google.common.base.Preconditions.checkNotNull;
 import static org.onosproject.lisp.msg.types.LispAfiAddress.AfiAddressWriter;
 
 /**
@@ -39,6 +40,9 @@
      */
     public LispEidRecord(byte maskLength, LispAfiAddress prefix) {
         this.maskLength = maskLength;
+
+        checkNotNull(prefix, "Must specify an address prefix");
+
         this.prefix = prefix;
     }