Ball checks to see if it has stopped. The ball has stopped, so the player must swing the club again. Object diagrams have the advantage of being similar in appearance to class diagrams, since the representation of an object is very similar to the representation for a class. This is generally an advantage, but under certain circumstances it may confuse the reader as to whether it is actually an object or a class. Object diagrams become messy if one or more objects receive multiple events, since the object may have multiple arrows entering and leaving it.
Interaction diagrams are generally easier to read and less cluttered.
Because time is represented by vertical position in the diagram, it is not necessary to number the events. If one or more objects receive multiple events, the interaction diagram stays uncluttered, since the vertical position in the diagram differs for each event. I prefer interaction diagrams for their simplicity and readability. The Operator chooses to maintain seasons, teams, contestants, judges, scorekeepers, or dives by choosing the appropriate item from pulldown menus. The operator enters the Dive Team Scoring System, Maintain Seasons is selected.