YANG: Restriction resolution implementation

Change-Id: I69503e8229def07b289a0c8c762bfe0ae5530232
diff --git a/src/main/java/org/onosproject/yangutils/utils/builtindatatype/YangUint64.java b/src/main/java/org/onosproject/yangutils/utils/builtindatatype/YangUint64.java
index 70001ae..cc16a7a 100644
--- a/src/main/java/org/onosproject/yangutils/utils/builtindatatype/YangUint64.java
+++ b/src/main/java/org/onosproject/yangutils/utils/builtindatatype/YangUint64.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 Open Networking Laboratory
+ * Copyright 2016-present Open Networking Laboratory
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.onosproject.yangutils.utils.builtindatatype;
 
 import java.math.BigInteger;
@@ -71,7 +72,8 @@
         } else if (NON_NEGATIVE_INTEGER_PATTERN.matcher(valueInString).matches()) {
             value = new BigInteger(valueInString);
         } else {
-            throw new DataTypeException("YANG file error : " + valueInString + " is not valid.");
+            throw new DataTypeException("YANG file error : Input value \"" + valueInString + "\" is not a valid " +
+                    "uint64.");
         }
 
         if (value.compareTo(MIN_VALUE) < 0) {