UML Weekend Crash Course™ - To Parent Directory

Session 13—Modeling the Static View: The Object Diagram 143
0..*
VendorProduct
0..1
Shipment
0..1
CustomProduct
Figure 13-4 Initial Class diagram modeling products
Figure 13-4 tells you that each Shipment may have zero or more VendorProducts and zero
or more CustomProducts. Each type of Product may or may not have been shipped.
The rest of this session steps through the construction of an Object diagram that models
the set of test cases for the Product Class diagram in Figure 13-4. The construction process
demonstrates the model elements of the Object diagram and how the Object diagram illustrates
test cases.
I’m going to go through this one step at a time. You may spot more problems with the
original Class diagram than the current test case reveals. By the time I cover all the test
cases, we should have found all the problems. If we don’t, just send me a nice letter with
the corrections.
Test case 1
A CustomProduct is created by assembling VendorProducts. VendorProducts 28, 38, and 72
create CustomProduct 425.
Figure 13-5 shows how the Class diagram is changed to include the aggregation relationship
between CustomProduct and VendorProduct.
The change shows that a CustomProduct is created from one or more VendorProducts. But
a VendorProduct doesn’t have to be used in a CustomProduct.
Test case 2
0..*
What is the minimum number of objects that make up a CustomProduct configuration After
reviewing all the test data, we find that a CustomProduct must consist of at least
two VendorProducts. Otherwise, there is no way to distinguish a CustomProduct from a
VendorProduct.