CHAPTER 6 ■ OBJECTS AND DESIGN
Figure 6–16. A dependency relationship
Using Notes
Class diagrams can capture the structure of a system, but they provide no sense of process. Figure 6–16
tells us about the classes in our system. From Figure 6–16 you know that a Report object uses a
ShopProductWriter, but you don’t know the mechanics of this. In Figure 6–17, I use a note to clarify
things somewhat.
Figure 6–17. Using a note to clarify a dependency
As you can see, a note consists of a box with a folded corner. It will often contain scraps of pseudo-
code.
This clarifies Figure 6–16; you can now see that the Report object uses a ShopProductWriter to
output product data. This is hardly a revelation, but use relationships are not always so obvious. In some
cases, even a note might not provide enough information. Luckily, you can model the interactions of
objects in your system as well as the structure of your classes.