The ?¬?nal piece of ?¬‚ow was in the time operations, where the value of the
calculation is assigned to a time Variable: this was shown with a hollow black
arrowhead.
As always, these decisions were a balancing act, trying to make the meaning of the
various parts of the model clear without straying into a graphical melee where every
part tries to scream its own importance. If the direction of information ?¬‚ow along a
role line was obvious from other context, no arrowhead was used. This was the case for
Actions turning Icons on or off, the Get, Plus, and Minus roles in time calculations,
and the role connecting a Display Function to its calculation. The direction for the
Button and Action roles of the Transition relationship could also be implied, but small
open arrows were added to make clear the part played by each of the roles in this n-ary
relationship.
9.4 MODELS
The three models we have looked at earlier in the chapter re?¬‚ect the three levels found
in most of the watch applications. The top level is a single diagram in the Watch
Family language (e.g., 2006 Models shown in Fig. 9.5). Each LogicalWatch there is
decomposed into a simple Watch Application diagram (e.g., TASTW shown in
Fig. 9.4) at the middle level showing how it is composed from various applications,
represented as a cycle of states.
Pages:
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384