Assignment 2- Bounce: part I/III 

COMPSCI 230 Assignment 
Bounce: part I/III 
Introduction  
The aim of this assignment project (named Bounce) is to develop and reinforce skills in object‐oriented 
programming. The context of this project is similar to what you handled in A1, which should help you 
get going with the rest of the assignments. You will develop an application of some complexity that is 
designed around design patterns and which leverages the JDK library classes. The assignment project 
is split into three parts, and each part has a number of tasks. You will generally need to complete 
one part before continuing on to the next.  
This very assignment (A2 or Bounce‐I) requires you to complete the first iteration of this project. In 
completing  the  assignment,  you  will  further  develop  the  Bounce  application  introduced  to  you  in 
lectures.  Essentially,  Bounce  involves  an  animation  comprising  an  extensible  set  of  shape  types. 
Shapes have in common knowledge of their position, velocity, direction and bounding box, while each 
kind of special shape has a specific way of painting itself.  
You  will  need  to  refer  to  JDK  API  when  completing  this  assignment.  Browsing  the  online  JDK  API 
documentation should be sufficient for the needs of this assignment.  
The source code for this assignment is available from Canvas. You will probably have lots of questions 
when looking through the source code, as there will be references to JDK entities that you have not 
seen before along with use of design techniques yet to be covered. For this part of the assignment, 
however, you are essentially constrained to building and testing the Shape class hierarchy. As the 
course progresses, you will learn about the other aspects. 
Assessment criteria 
Each task is associated with assessment criteria. To test that you have met the criteria, each task is 
associated with CodeRunner tests. The tests include a mix of: 
 tests that run your compiled code to check that it is functionally correct and, 
 other tests that examine your source to ensure that conforms to object‐oriented principles. 
CR3 submissions carry 85% of the marks, whereas the ADB submission carry the rest 15%. 
Marking scheme  for CR3 questions is mentioned against each task. ADB submission will be marked 
based on whether your entire submitted code compiles and runs successfully to show the expected GUI 
as per  specifications given in assignment brief. As such, if your code passes all CR3  tests  for all  six 
questions, and your code is showing the expected GUI in your IDE, submitting the full iteration code 
should  work  fine  at  marker’s  end  too.  You  can  ensure  this  by  carefully  packaging,  zipping  and 
submitting the verified code to ADB as per the submission instructions given below. 
Submission 
For part 1 of the assignment (A2 – Bounce I), you must: 
 (8.5 marks) pass the CodeRunner3 tests by Week 8 (Friday 9:00pm, 15 May 2020).  
o visit coderunner3.auckland.ac.nz.
o under ‘Assignments’, you should access ‘A2 – Bounce I’ Quiz. 
o the  quiz  has  a  total  of  6  questions, each  of which  would  require  you  to  paste  the 
source code of one of your classes’ that you wrote in your IDE to complete each task. 
o each  assignment  task  has  two  CR  questions  (one  question  for  passing  tests  and 
another for static analysis of class code) 
o You may click on ‘Check’ for each question multiple times without any penalty. 
o You may however make only one overall CR submission for the whole quiz. 
 (1.5  marks)  submit  your  entire source  code  (including  the  original  Canvas  code)  to  the 
Assignment Drop Box (ADB – adb.auckland.ac.nz) by Week 8 (Friday 10:00pm, 15 May 2020).  
o The code submission must take  the  form of one zip  file  that maintains the Bounce 
package structure. 
o You must name your zip file as “YourUPI_230a2_2020.zip”. 
o You may make more than one ADB submission, but note that every submission that 
you make replaces your previous submission.  
o Submit ALL your files in every submission.  
o Only your very latest submission will be marked.  
o Please double check that you have included all the files required to run your program 
in  the  zip  file  before  you  submit  it.  Your  program must  at  least  compile  and  run 
(through Java 1.8) to gain any marks.
NOTE: It would be ideal  to  first complete all  tasks  (that you are able  to complete) in an IDE like 
Eclipse, and  then only proceed  to answer CR3 questions once you have  finished writing working 
code for this iteration in your IDE. 
Constraints 
For all three parts of the assignment project, any changes you make to the Shape class hierarchy must 
not break existing code (e.g. the AnimationViewer class). In particular, class Shape must provide 
the following public interface (note this is not the Java “interface”; here the term “interface” refers to 
the set of public methods in a class that may act as entry points for the objects of other classes) at all 
times: 
 void paint(Painter painter)
 void move(int width, int height)
Task 1: add class OvalShape 
An OvalShape is a special kind of Shape that moves like other shapes but which paints itself as an 
oval that fits within its bounding box. 
Specific requirements 
 Class OvalShape must be a subclass of Shape. 
 It must be possible to create an OvalShape object using the same set of creation options as 
offered  by  class  Shape.  In  other  words,  class  OvalShape must  provide  4  constructors, 
similarly to class Shape. 
 An OvalShape should use Painter’s drawOval() method when painting itself. 
Once created, edit the AnimationViewer class to add an instance of OvalShape to your animation. 
Testing 
From the CodeRunner quiz named Bounce I, complete the first two questions: 
 (1.5 marks) Bounce I OvalShape, which runs a series of tests on your OvalShape class.  
 (1  mark)  Bounce  I  OvalShape  (static  analysis),  which  examines  the  source  code  for  your 
OvalShape class.  
Your code will need to pass all tests. 
Task 2: add class DynamicRectangleShape 
A  DynamicRectangleShape is  a  new  kind  of  Shape that  paints  itself  similarly  to  a 
RectangleShape.  At construction time, a fill color may be specified that is used when painting a 
DynamicRectangleShape. Depending on how it bounces, a DynamicRectangleShape alters its 
appearance. 
Specific requirements 
 Class DynamicRectangleShape must be a subclass of RectangleShape. 
 Class DynamicRectangleShape must provide two constructors: 
public DynamicRectangleShape(int x, int y, int deltaX, int deltaY,
int width, int height)
public DynamicRectangleShape(int x, int y, int deltaX, int deltaY,
int width, int height, Color color)
 If a DynamicRectangleShape object is created without specifying a color, it should default
to red. 
 Prior  to any  bouncing, a DynamicRecantangle paints itself as a  solid  figure, in  the color 
specified at construction time or the default red color. After bouncing off the left or right wall, 
a DynamicRectangleShape always paints itself as a solid shape. After it bounces off the top 
or bottom wall, it switches its appearance to that of a RectangleShape, i.e. painting itself 
with a black outline. If it bounces off both walls, the vertical (left or right) wall determines its 
appearance.  
 In  implementing  DynamicRectangleShape’s  movement/bouncing  behaviour,  use  the 
object‐oriented programming technique of overriding method move() for refinement. 
 After making any calls to a Painter to effect a color change, a DynamicRectangleShape
object should restore the painting color to what it was before it made the change. 
 Make only necessary calls to Painter’s setColor() method. 
Implement class DynamicRectangleShape and include such a shape in your animation. 
Testing  
From the CodeRunner quiz named Bounce I, complete the following questions: 
 (2  marks)  Bounce  I  DynamicRectangleShape,  which  runs  a  series  of  tests  on  your 
DynamicRectangleShape class. 
 (1 mark) Bounce I DynamicRectangleShape (static analysis), which examines the source code 
for your DynamicRectangleShape class. 
Your code will need to pass all tests. 
Task 3: add class ImageRectangleShape 
ImageRectangleShape is a special type of Shape that displays an image. At construction time, an 
ImageRectangleShape takes a java.awt.Image parameter  that  represents an  image, e.g. in a 
format such as  JPEG, PNG or GIF. In an animation, an ImageRectangleShape objects displays its 
image as it moves and bounces. 
Specific requirements 
 Class ImageRectangleShape must be a subclass of RectangleShape. 
 Class ImageRectangleShape must provide one constructor: 
public ImageRectangleShape(int deltaX, int deltaY, Image image)
 Class ImageRectangleShape must provide a static factory method: 
public static Image makeImage(String imageFileName, int
shapeWidth)
This method loads the image specified by imageFileName and scales it. Specifically, if the 
width  of  the  image  is  greater  than  shapeWidth,  which  is  the  desired  width  of  the 
ImageRectangleShape object that will display the image, the image must be scaled so that 
its width equals shapeWidth. 
Implement class ImageRectangleShape and include such a shape in your animation. 
Testing 
Complete the CodeRunner quiz named Bounce I by working through the remaining questions: 
 (2  marks)  Bounce  I  ImageRectangleShape,  which  runs  a  series  of  tests  on  your 
ImageRectangleShape class. 
 (1  mark)  Bounce  I  ImageRectangleShape,  which  examines  the  source  code  for  your 
ImageRectangleShape class. 
Your code will need to pass all tests. 
Hints 
 To implement the static makeImage()method, you will need to use image processing classes 
from  the  JDK:  java.awt.Image, java.awt.Graphics2D,
java.awt.image.BufferedImage and  java.io.File.  Consult  the  JDK  API 
documentation. 
 Download a suitable image file, in JPEG, PNG or GIF format, from the Internet that you can 
use for this task.  
 The  image  file  should  be  stored  in  a  directory  that  is  accessible  to  the  AnimationViewer
application.  You  may  want  to  use  your  login  directory.  On  Windows  machines,  this  is 
C:/Users/<username,  where  <username  is  replaced  with  your  username.  The  following 
code shows how you can generate the full path name for an image named Holden.jpg that is 
stored in your login directory. 
String path = System.getProperty("user.home");
String imageFileName = path + “/” + “Holden.jpg”
The  imageFileName  variable  can  then  be  suppled  as  the  first  argument  to 
ImageRectangleShape’s static makeImage() method, and should be a fully qualified path
to the image file. 
 A possible algorithm for makeImage() is as follows: 
variables: 
  sw  width of new shape (int) 
  sh  height of new shape (int) 
  f  instance of File (java.io.File) 
  b  instance of BufferedImage (java.awt.image.BufferedImage) 
  w  width of loaded image (int) 
  h  height of loaded image (int) 
  sf  scale factor (double) 
  g  instance of Graphics2D (java.awt.Graphics2D) 
algorithm: 
1. Let f = new java.io.File object, supplying a string whose value represents the name of 
the image file 
2. Let b = new BufferedImage object, using javax.imageio.ImageIO’s read() method with 
f as a parameter 
3. Let w = b’s width, obtained using b’s getWidth() method 
4. Let h = b’s height, obtained using b’s getHeight() method 
5. If w sw: 
a. Let sf = sw / w 
6. Let sh = h * sf 
7. Let b = new BufferedImage object, supplying sw and sh as parameters 
8. Let g = new Graphics2D object by calling method createGraphics() on b 
9. Draw the image onto g by calling g’s drawImage() method 
10. Return b 
 With the above algorithm, note: 
o When calculating sf and h, you will need to use casting to type double. 
o Graphics2D inherits a six‐argument drawImage() method that is suitable to use. 
The last parameter is an ImageObserver that can be used to track the loading of an 
image; you can simply provide a null value for this parameter.  
Debugging 
I strongly recommend that you use Eclipse for all assignments, and use Eclipse debugging feature for 
your assistance.