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Instructions
This design task requires you to produce a class design for a game of space
invaders, see Figure 1. The class design is to be submitted as code only (no UML is
required). Each component of the game shown in the Figure must be modelled to a
class. The implementation of the game does NOT need to include rendering of the
game, so it does not have to be playable (your code should be model only – no view
controller). However, you should have stubs in place where you would 1) expect an
object to be drawn to the screen, 2) receive input from the player, 3) Make a sound.
The game does NOT have to work to score well, but does have to be a good design
which shows relevant use of the patterns required. All classes should be used and
have some relationship with other classes in the design.
To help you understand how the game works play it here
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You are expected to demonstrate the use of the following OO techniques and
patterns.
Factory
Chain of responsibility
Singleton
Open closed principle
Single responsibility
The code must be written in Java™
Responsibilities
You should make a list of the relevant responsibilities for each class and determine
what data should be modelled.
Code style and commenting
Please follow the coding style guidelines given here.
Provide the public interface with each class with Java documentation comments.
This can be done in Eclipse by typing /** then hitting the return key.
Each public method of the class should have a comment and also the class itself
should have a class comment.
Deliverables
The deliverable will be a zip file containing all the source code for your game,
including all Java source class, interface and other files.
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Marking
Relevant use of factory class for the problem given 10%
Relevant use of the chain of responsibility for the problem given 30%
Good application of open/closed principle within the code 15%
Relevant use of Singleton for the problem given 10%
Good coverage of game functionality 10%
Single responsibility conformance 5%
Overall code readability and quality 20%
Note you must use the patterns given to solve the problem given, so not just have
for example a piece of factory code which is to solve a different problem.
Compile errors and marking
The code must compile, you will lose marks for compile errors. The more compile
errors the more marks you will lose.
Code entry point
Provide a class called Main.java, this should be the entry point for your game and
contain a static main method for allow to code to start.
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Hints
To help you get started here are some hints. You do not have to follow this method,
and you do not need to submit any related documentation however this will help you
getting going. To get started write up a description of the game. Include as many
details as you can remember to think up a name for the relevant components on the
screen, e.g. player, sprite or high score. Once this is written use the noun
identification technique to identify candidate classes.
Now start to think the responsibilities (associated methods) that the classes will have
to support (for example drawing themselves on the screen, rendering). Also think of
the relationships between the classes, aggregation, inheritance, interface
implementation etc. This will give you a good start on how to code the game.
