added function to check emptiness of file handle

HIRS_Utils/src/main/java/hirs/utils/tpm/eventlog/uefi/UefiGuid.java

@@ -101,6 +101,17 @@ public class UefiGuid {
         return UefiConstants.SIZE_16;
     }
 
+    /**
+     *
+     * Checks whether the handle to the file needed to look up the UUID is valid. If empty,
+     * this likely means the file was not accessible to due to existence or permissions.
+     *
+     * @return true if the reference to the file handle needed to look up the UUID is empty
+     */
+    public boolean isUefiVendorRefEmpty() {
+        return uefiVendorRef.isEmpty();
+    }
+
     /**
      * Returns a String that represents a specification name referenced by the
      * EFI_CONFIGURATION_TABLE VendorGUID field.  For structure of