public static boolean valueChanged(Enum<?> before, Enum<?> after) {
        if (before == null && after == null) {
            return false;
        }
        if (after == null) {
            return false;
        }
        if (before == null && after != null) {
            return true;
        }
        return !(before == after);
    }
Returns true only if the value changed.
@param before the value before change
@param after the value after change
@return true if value changed, else false
manager/api/rest-impl/src/main/java/io/apiman/manager/api/rest/impl/audit/AuditUtils.java