Explain the use of association role for an association on a class diagram. Give an example of generalization. Your example should include at least one superclass and three subclasses, and a minimum of...

Explain the use of association role for an association on a class diagram.

Give an example of generalization. Your example

should include at least one superclass and three

subclasses, and a minimum of one attribute and

one operation for each of the classes. Indicate the

discriminator and specify the semantic constraints among the subclasses.