+/**
+ *
+ * Map node which preserves user-supplied ordering.
+ *
+ * <p>
+ * This node represents a data instance of <code>list</code> with
+ * <code>ordered-by user;</code> substatement and <code>key</code> definition.
+ *
+ * <p>
+ * Except preserving user-ordering all other semantics and behaviour is same as
+ * in {@link MapNode}.
+ *
+ */