Lesson Four

Dr. James E. Tomayko

Lesson Four Objectives

1. The student shall be able to differentiate among three methods of classification.
2. The student shall be able to apply at least two methods of analysis.
3. The student shall understand how abstractions can be defined at different levels.

Read Chapter Four of Booch1994 and be prepared to discuss the following in class. Turn in your answers to #1 and #2.

1. There are three approaches to classification: classical categorization, conceptual clustering, and prototype theory (association). Think of a domain in which you have done some software work. Give an example of a category, a concept, and an association that are usable for classification. This means you will have to think about the domain from three different points of view.
2. Think of an automatic teller machine. Describe one use case (withdrawal, deposit, or inquiry). What are the objects the user interacts with?
3. What are the advantages and disadvantages of Abbott's informal English description method of finding classes and objects?
4. Defining abstractions is highly iterative, since it is unusual to hit the "right" level of abstraction at the first shot. Returning to question #2, identify key abstractions used by the ATM and its customer.

   GENERAL CLASS ASSIGNMENT: It would be best if we use a "real" problem or problems to try out the method to be described in the next three chapters. Can you think about one or more Daxus projects currently underway that could use a "second opinion" as to analysis and design? Can we form teams that can exercise the method? We'll discuss this in class.