+protected:
+ DECLARE_LISTENER (finish);
+ DECLARE_LISTENER (prepare);
+ DECLARE_LISTENER (one_time_step);
+
+ /* Engraver_group_engraver interface */
+ virtual void connect_to_context (Context *);
+ virtual void disconnect_from_context ();
+ virtual void initialize ();
+ virtual void announce_element (Audio_element_info);
+ virtual void derived_mark () const;
+ virtual void acknowledge_audio_elements ();