UML Weekend Crash Course™ - To Parent Directory

102
Saturday Morning
Operation compartment
In Figure 9-2, the operations compartment occupies the bottom section of the class box.
Operations are simply listed in the operation compartment using the notation presented in
“Modeling an Operation.” The order does not matter. The operation compartment is placed
below the name compartment, and below the attribute compartment when all compartments
are visible.
Creating Different Views of a Class
The completed class definition can be shown with all three compartments visible or as just
the name compartment. This form is often used in the early stages of analysis when the
focus is on object definitions and relationships. As more information is discovered about the
attributes and operations, the other two compartments can be revealed as well.
Some tools also give the option to show some or all of the operation specifications. For
example, one view may show only the operation names. Another view may reveal the names
and the arguments, while yet another may show the entire signature with argument data
types and return data types. Figure 9-3 illustrates two ways of drawing the class symbol.
This facility helps focus evaluation of the diagram to the interests of the audience.
Customer
{last updated 12-15-01}
Customer
{last updated 12-15-01}
- name: String = blank
- mailingaddress: Address = null
- /accountbalance: Dollar = 0
- customerid: integer = none {assigned by system}
Customer
{last updated 12-15-01}
+ getName (): String
+ setName (name: String)
+ setAccountBalance (amount: Dollar)
+ getAccountBalance (): Dollar
+ setMailingAddress(street1: String, street2: String,
city: String, state: State, zipcode: integer)
Figure 9-3
Alternative views of a class symbol for different audiences and purposes
REVIEW
The Class diagram is the primary diagram for code generation and for reverse engineering.
Consequently, it tends to be the focus of most modeling efforts, with all the other diagrams
playing a supporting role. The term object model is actually a reference to two diagrams, the
Class diagram and the Object diagram, although when the term is used it most often refers
to a Class diagram.
The Class diagram represents all the rules regarding the construction and use of
objects. The Object diagram describes the facts about objects that actually exist.
Consequently, the Object diagram provides a valuable testing tool to verify the Class
diagram.