[ONOS-3897] Yang Listener for Enumeration Data Type

Change-Id: If257c73da8fe2dcc2f4111f103967cfcdd7fa273
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 59da354..76ab0f3 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
@@ -20,6 +20,8 @@
 import org.onosproject.yangutils.parser.Parsable;
 import org.onosproject.yangutils.parser.ParsableDataType;
 
+import java.util.Objects;
+
 /*-
  * The "ENUM" statement, which is a sub-statement to the "type"
  *  statement, MUST be present if the type is "enumeration".  It is
@@ -188,6 +190,23 @@
         return ParsableDataType.ENUM_DATA;
     }
 
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj instanceof YangEnum) {
+            final YangEnum other = (YangEnum) obj;
+            return Objects.equals(this.namedValue, other.namedValue);
+        }
+        return false;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(this.namedValue);
+    }
+
     /**
      * Validate the data on entering the corresponding parse tree node.
      *