[ONOS-3902, ONOS-3903, ONOS-3904] string type, integer type derrived type

Change-Id: I8279e93fcb7dfb82491cc09057c9d75165add68d
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangEnum.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangEnum.java
index be3f845..59da354 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangEnum.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangEnum.java
@@ -105,6 +105,7 @@
      *
      * @return the description.
      */
+    @Override
     public String getDescription() {
         return description;
     }
@@ -114,6 +115,7 @@
      *
      * @param description set the description.
      */
+    @Override
     public void setDescription(String description) {
         this.description = description;
     }
@@ -123,6 +125,7 @@
      *
      * @return the reference.
      */
+    @Override
     public String getReference() {
         return reference;
     }
@@ -132,6 +135,7 @@
      *
      * @param reference the reference to set.
      */
+    @Override
     public void setReference(String reference) {
         this.reference = reference;
     }
@@ -141,6 +145,7 @@
      *
      * @return the status.
      */
+    @Override
     public YangStatusType getStatus() {
         return status;
     }
@@ -150,6 +155,7 @@
      *
      * @param status the status to set.
      */
+    @Override
     public void setStatus(YangStatusType status) {
         this.status = status;
     }
@@ -177,6 +183,7 @@
      *
      * @return ParsedDataType returns ENUM_DATA
      */
+    @Override
     public ParsableDataType getParsableDataType() {
         return ParsableDataType.ENUM_DATA;
     }
@@ -186,6 +193,7 @@
      *
      * @throws DataModelException a violation of data model rules.
      */
+    @Override
     public void validateDataOnEntry() throws DataModelException {
         // TODO auto-generated method stub, to be implemented by parser
     }
@@ -195,6 +203,7 @@
      *
      * @throws DataModelException a violation of data model rules.
      */
+    @Override
     public void validateDataOnExit() throws DataModelException {
         // TODO auto-generated method stub, to be implemented by parser
     }