1802/159.251代写、代做Java编程、Java程序语言调试

日期：2020-11-23 11:22

Page 1 of 9 COS

1802/159.251

MTUI DISD

MASSEY UNIVERSITY

MANAWATU AND DISTANCE CAMPUSES

EXAMINATION FOR

159.251 SOFTWARE ENGINEERING DESIGN AND CONSTRUCTION

SEMESTER TWO 2018

_________________________________________________________________________________________________________

Time allowed is THREE (3) Hours.

This paper contains EIGHT (8) questions

Candidates must answer ALL EIGHT (8) questions

Questions are not of equal marks

Write your answers to all applicable questions in the Blue Answer Book supplied

Students may NOT remove any part of this question paper from the exam room.

The exam paper will be made available on the University Library website.

Page 2 of 9 COS

Question 1 – Design and DRY [8 marks]

Assume you have to design a student registration system for an university. In this system,

students are represented as instances of a class Student with several properties (id,

firstName, lastName, dob). A desktop graphical user interface (GUI) for this application is

provided by the class StudentEditor, and instances of Student are stored as xml

documents using a structure defined by the XML schema students.xsd.

a) For this kind of application, a design based on tiers (layers) is often used. Name the

tiers (layers) you would here, and describe the dependencies between these tiers !

[3 marks]

b) At some stage, a new boolean attribute isExtramural must be added to the Student

class. This will also require changes to the schema and the editor (form)

StudentEditor (a new text field must be added). Discuss the DRY principle using

this example, and which technologies can be used to facilitate this kind of change.

[3 marks]

c) Later, your client decides to change the application by providing a web-based user

interface. Using your answer to a) , describe the benefits of the tiered (layered)

design to facilitate this.

[2 marks]

Page 3 of 9 COS

Question 2 – Logging and Orthogonality [6 marks]

a) Explain the concept of orthogonality using log4j loggers, levels and appenders as an

example! Discuss which language features in Java are used in order to achieve

orthogonality in log4j !

[4 marks]

b) What will be printed on the console if the following script is executed?

[2 marks]

Logger logger = Logger.getLogger("mylogger");

Appender appender = new ConsoleAppender(new SimpleLayout(),ConsoleAppender.SYSTEM_OUT);

logger.addAppender(appender);

logger.setLevel(Level.ERROR);

logger.error("error1");

logger.info("info1");

logger.warn("warn1");

logger.debug("debug1");

logger.setLevel(Level.DEBUG);

logger.error("error2");

logger.info("info2");

logger.setLevel(Level.INFO);

logger.warn("warn2");

logger.debug("debug2");

Page 4 of 9 COS

Question 3 – Testing [8 marks]

Assume you build a tax calculator library that has a method double distance(Point,Point)

that computes the distance between two points in space. The algorithm used only works

for points with non-negative coordinates, otherwise, an IllegalArgumentException is

thrown.

a) Let’s assume you have created test cases for 1,000 different input values using a

spreadsheet. All tests succeed, i.e., they calculate the expected value. Can you

conclude from this that distance(Point,Point) is correctly implemented ?

[2 marks]

b) Describe how you would use junit features to efficiently implement such a large

number of tests. Explain how this feature(s) works !

[2 marks]

c) The handling of negative input values is part of the specification of the

distance(Point,Point) method. How would you test this?

[2 marks]

d) An alternative to testing negative input values is to exclude them from all tests by

adding a precondition that the input values must be non-negative. Which junit

feature can be used to implement this, and how does this work ?

[2 marks]

Page 5 of 9 COS

Question 4 - Organising Code [4 marks]

Explain the advantages of convention over configuration using the Java getter and setter

convention !

Page 6 of 9 COS

Question 5 - Shell and Scripting [8 marks]

a) In a shell session, when you enter the command:

grep "abc" file.txt

It produces no output, indicating the command found no matches. How would you

determine if the same command was successful in a shell script?

[2 marks]

b) What are environment variables used for? List some commonly used environment

variables.

[1 marks]

c) With examples, explain the concepts of redirection and piping in the Unix shell.

[3 marks]

d) Permissions are used to control access to files. Describe the permissions for script.sh

in the following listing.

[2 marks]

cd ~

ls -l

-rw-rw-r-- script.sh

Page 7 of 9 COS

Question 6 - Source Code Management [8 marks]

a) What is the purpose of using a linter such as Checkstyle or a code formatter (e.g.

google-java-format) in collaborative software development?

[1 mark]

b) What is the key difference between an older version control system such as CVS

and Git?

[1 mark]

c) A development team has released the first version of a software, tagged the release

as v1 and it has been built and shipped to a set of customers. The developers are

now working on features for version 2. Meanwhile, a customer reports a bug for

version 1.

Explain how the developers would use Git (with git commands and commit graph)

during development, and to contribute a bugfix for version 1 and also to apply the

fix on version 2, release a patched version and ship to customer as v1.1 without the

newer features in v2

[6 marks]

Page 8 of 9 COS

Question 7 - Issue Tracking and Licensing [4 marks]

a) Describe how you would use an issue tracker in collaborative software

development and what information it records and tracks.

[3 marks]

b) What is the main difference between permissive licenses such as the BSD/MIT

license and the GPL, a copyleft license?

[1 marks]

Page 9 of 9 COS

Question 8 - Metrics [6 marks]

a) Discuss how lines of code metrics can be misleading in assessing developer

productivity

[2 marks]

b) Define logical, physical lines of code and cyclomatic complexity. For the sorting

method listed below in Java, calculate these metrics.

[4 marks]

public void bubbleSort(int[] arr) {

boolean swapped = true;

int j = 0;

int tmp;

while (swapped) {

swapped = false;

j++;

for (int i = 0; i < arr.length - j; i++) {

if (arr[i] > arr[i + 1]) {

tmp = arr[i];

arr[i] = arr[i + 1];

arr[i + 1] = tmp;

swapped = true;

}

}

}

}

+ + + + + + + +