95-706 Spring 2000

Instructions

1. Answer all four questions.

2. Your exam paper is to be turned in electronically by 11:00 AM on Monday, March 13, 2000 using instructions provided in the course BBoard.

3. All four questions are weighted equally.

4. Note that UML provides a notation for actors extending other actors and the notation is just like a class extending another class.

1. Class Diagrams

Examine the class diagram shown in the figure below and then answer the following questions:

(a) What are the methods and attributes of class Square?

(b) Based on the class diagram, are there any properties of members of class Square that are different from members of class Rectangle?

(c) What are the methods and attributes of class Circle?

(d) What do the methods and attributes of class Polygon suggest about the way the polygon is to be represented?

(e) Class polygon has an operation display which is not directly present in classes Rectangle, Circle and Square. What does this imply about the display operation of class Polygon?

2. Associations, Aggregations, etc.

The figure below is intended to be a model of a school showing the major players in the system. Based on this diagram, describe how the school is organized in terms of relationships between the entities shown in the diagram. This is strictly a question about reading the diagram; don't invent extra things or leave any out.

3. Use Case Diagrams

The figure below shows the interaction between a number of actors and a credit card validation system. Study the diagram and then answer the following questions.

(a) Identify the actors in the diagram.

(b) What are the four major use cases in the system? Which actors interact with each use case?

(c) Are the use cases in this diagram likely to be high level abstract use cases or low level detailed use cases? How would you tell? (Be careful as you answer.)

4. Sequence and Collaboration Diagrams

(This question has a longer answer than any of the other questions. It's not more difficult -- it just requires a longer written response.)

The sequence diagram below describes the sequence of events from the time a customer picks up a telephone receiver (not cell phone) until the call is completed and both parties are connected.

(a) Describe the sequence of events as recorded in the sequence diagram.

(b) Are there any constraints in the sequence diagram? If so, what are they?

(c) Draw the collaboration diagram that corresponds to this sequence diagram.