??? EachWatch Model had a LogicalWatch, which pointed to the graph showing
202 DIGITAL WRISTWATCH
the cycle through the watch??™s applications, and a Display, corresponding to the
relevant parts of the physical watch body: icons, digit pair zones, and buttons. The
LogicalWatches and Displays would thus form components, and each might be used
in more than one full Watch Model.
As these concepts were different from those used in the Watch Application
modeling language, it was clear that we actually had a new modeling language
here. We decided to make it graphically rather verbose, for pedagogical rather
than practical reasons. Each Watch Model (rounded rectangles with a light
green ?¬?ll) showed the Display and Logical Watch it used, and the sets of
possible Logical Watches and Displays were also shown in the same diagram
(Fig. 9.5).
Another possibility here would have been to use a matrix representation rather
than a graphical diagram. In models shown as matrices, the axes contain objects
and each cell contains the relationship (if any) between the corresponding objects.
The Logical Watches could thus be listed down the left side of the matrix and the
Displays across the top. The cell at the intersection between a given LogicalWatch
and Display would then represent a possible Watch Model composed of those
parts.
Pages:
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377