For our system, we can assume that a library has only one catalog, so the default association name catalog is fine. However, we need to explicitly show the multiplicity of the association:
The association between Library and Catalog should
now look something like this:
We also need to show multiplicity on the association between Catalog and CatalogEntry. In this case, each catalog must work with multiple entries, though each entry will be associated with only one catalog. To label this association, follow these steps:
The association between Catalog and CatalogEntry
should now look something like this:
The complete diagram, with labels, should now look something like this
(again, your diagram might be arranged differently):
This diagram shows the relationships between the objects we have defined in initial iteration: Library, Catalog, and CatalogEntry. It also shows protocol conformance and the dependency relationship between Catalog and the <CatalogEntry> protocol. This tells us that any class that conforms to the <CatalogEntry> protocol could be substituted for Catalog in this system.