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Spring 2014 Midterm Exam Sample Solutions
CS 319 Object-Oriented Software Engineering
Instructor: Uğur Doğrusöz
Reminders
Time: 120 minutes (2 Hours) Q1 08
Write your name and sign only in the last page as indicated. Q2 10
Show your work and reasoning clearly and write legibly, only within Q3 17
the space provided for each question. Do not detach any page(s). Q4 65
From the time you receive your exam script, you will have 60 minutes Total 100 pts
to read all questions and make sure you understand what is expected from you. During this time you
may ask your instructor any questions should you require any clarification.
Q1 [8 pts]
Describe iterative development approach and contrast it to sequential or “waterfall” lifecycle approach.
The iterative approach involves early programming and testing of a partial system (not all
requirements addressed), in repeating cycles. It also assumes development starts before all the
requirements are defined in detail; feedback is used to clarify and improve the evolving
specifications.
We rely on short quick development steps, feedback, and adaptation to clarify the requirements and
design. To contrast, waterfall values promoted big upfront speculative requirements and design steps
before programming. Research supports that the iterative methods are associated with higher success
and productivity rates, and lower defect levels.
Q2 [10 pts]
Consider the following sequence diagram. Write skeletal code (i.e., code that can be derived from this
diagram) for any non-boundary objects/classes involved in the below diagram. Specify only what is
conveyed in the diagram.
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public class Y {
…
boolean doB(X x) {
Y y2 = new Y();
x.doD(y2);
…
return flag;
}
void doE() {…}
}
Q3 [17 pts]
A mail-order company wants to automate its order processing. The order processing system should be
accessible to customers via the web. Customers can also call the company by phone and interact with the
system via a customer representative. The use-case analysis reveals use-cases such as “Place Order”,
“Check Status”, and “Cancel Order” for a customer and use-cases such as “Return Product” and “Cancel
Order” for a customer representative. Below is an activity diagram for detailing out part of the use
(business logic) of this mail-order company.
(a) Identify any problems with the diagram, and fix them on the diagram.
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“Enter” -> “Get” (activities of the system, not user)
“ID Check” -> “Check ID”
“Checkout selected” is not an activity, should be removed
Synchronization bars are not used when there is no concurrent activities
No start point is specified
(b) Describe in “plain English”, without using any technical/UML terminology (i.e., using language
understandable by the customer), the information the diagram conveys about the real life system
being modeled.
This activity diagram details out the processes and workflow for the use case “Place Order”. First the
customer is identified either by ID or by name & address. Then as many products as desired with
specified quantity are selected either by product ID or by browsing the catalogue if available, and
added to the shopping cart. When selection is finished, shipping info is taken, and upon approval of
the order, an invoice is created and forwarded to the accounting department while the order
information is forwarded to the shipping company.
Q4 [65 pts]
Consider the following problem description:
A private neighborhood health clinic wants to automate management of their operations by implementing an
interactive web-based software system using the html5 standard, which should make the system run on
tablets and smart phones as well as desktop and laptop machines. The Clinic Management System (CMS) is to
be used by both patients and the clinic personnel (doctors, nurses, and administrative staff).
A patient will be able to make on-line appointments for an examination, cancel an existing appointment,
inspect lab results, check their outstanding balance and make payments using their credit cards.
A doctor will be able to record their schedules including the time periods they are busy and periods they have
time-off. They will also be able to browse their schedules for any appointments for examinations. The doctors
could also ask to cancel appointments during a specified period, in case they become unavailable for
unexpected reasons, subject to approval by clinic director, who is also a doctor with management
responsibilities. A doctor may browse a list of his/her patients, including past patients. Initially only some
brief information is displayed for each patient but the doctor may ask for details (including picture and
patient records in chronological order).
A nurse will be able to request time-off using CMS, subject to approval by the head nurse (head nurse
herself/himself reports to the clinic director).
The administrative staff can also help patients, doctors and nurses to perform operations on their behalf, in
situations where such a user does not have access to the Internet.
The accounting of the clinic for both customers (balances due) and clinic personnel (their salaries and other
compensation) are to be managed by an existing software module put in place by the clinic when they first
started operation.
User authentication is especially critical for such a system with sensitive information for both patients and
clinic personnel. In addition, clinic currently has only about a couple of hundred active patients but as time
goes by, especially after the automated system is in place, the clinic management expects to have at least
thousands of patients if not more.
To attract more customers, the clinic management has also decided to put two types (silver and gold) of
memberships in place with varying privileges. One can become a silver customer if they have used clinic
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facilities pretty regularly for at least two years. A customer who has been a silver customer for at least two
years gets to be a gold customer, assuming they have never failed to make payments past their due dates.
Both silver and gold customers are provided with more flexible time slots for making appointments. Gold
customers get additional privileges such as getting an SMS notification when their lab results are ready.
a) [5 pts] List and justify two non-functional requirements for this system.
Response time (web-based) and scalability (simultaneously used by many)
b) [20 pts] Identify actors and use cases for the system described above and show them on a UML Use
Case Diagram.
c) [20 pts] Perform a quick application domain analysis to come up with an object model for the above
system. Express your findings with a UML Class Diagram, making sure to identify any critical
operations of classes.
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d) Consider the following use case scenario:
Mr. Smith is a registered patient of a clinic using CMS. Lately he is feeling back pain and decides to go to
the clinic for an examination on upcoming Monday (March 31, 2014). Among the doctors available he
prefers Dr. Clark. Since he is not very computer friendly, he prefers to call the clinic and ask Mrs. Black
(clinic staff) to help him set up an appointment. As he is a morning person, he asks to get the first
morning appointment (8:30) but Dr. Clark doesn't seem to be available at this hour. He then asks for the
following day and successfully books an appointment with Dr. Clark. The system displays Mr. Smith's
current address ("123 York Ave, NY") and health insurance information ("FirstHealth",456) and asks
whether or not an update would be needed. Mr. Smith tells Mrs. Black that there is no change in this
information, and Mrs. Black completes the task. You may skip any authentication steps.
[2 pts] First, identify the use case that this scenario belongs to.
The scenario looks like an instance of the "MakeAppointment" use case.
[18 pts] Then, draw a UML Sequence Diagram for this particular scenario. You may use any
software/solution domain objects if needed as well.
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Mini Dictionary:
To authenticate Doğrulamak
To approve Onaylamak
Available Uygun, mevcut
Business logic İşleme mantığı
Customer representative Müşteri temsilcisi
Balance due Borç
Compensation Tazminat/maaş/telafi
To convey Taşımak, iletmek
Examination Muayene/tetkik
Flexible Esnek
Head nurse Başhemşire
To inspect İncelemek
To justify Doğrulamak, haklı göstermek
Mail order Posta ile yapılan mal siparişi
Outstanding balance Ödenmemiş bakiye
To place an order Bir sipariş vermek
Privilege Ayrıcalık/imtiyaz
To report to Karşı sorumlu olmak/rapor etmek
To return a product Bir ürünü iade etmek
Salary Maaş
Sensitive Duyarlı/hassas
Skeletal iskelet gibi, çatısal
Staff Çalışan
Time-off İzin, çalışılmayan zaman
Time period/slot Süre/zaman aralığı
I hereby affirm that the work submitted in this examination is my own exclusively.
Name & Signature: Uğur Doğrusöz Section:
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