Description
Part 2: Programming (55 points)
This assignment is intended to explore inheritance, abstract classes, and patterns.
Please recall that all programs must compile, so keep a working version of each part before your
proceed to the next. Please also note that soft-copy Javadoc output is required, including class
comments, constructor comments (with @param) and method comments (with @param and @return, as
appropriate). You also need to provide some test examples: make sure you turn in some screen shots to
show the functionality of your system.
Step 1 (20 points): Getting started. Implement the code in section 6.3, pages 232 to 234. The source
code can be downloaded from the book’s on-line companion. Make sure you properly attribute the source
of this code!
However, you will find that by itself it won’t compile, as it needs the interface on page 228, the abstract
class on page 229, and the concrete classes on page 229, most of which happens to be implemented
using the Template pattern on pages 238 and 239. But, you will probably need to modify some of the
code from pages 168 to 169 to get CarShape (which you used in Assignment 3). Some of this code is
available in a related form as the answer to Exercise 6.17 in the on-line companion, although the code
that you will find there answers a somewhat different question and is not quite what you need.
Then, just as you did in Assignment 3, you should rearrange the code and remove any magic numbers
so that whatever you import is easier to understand and is more self-documenting. If you wish, you can
redesign the look and feel for both car and the house to personalize them or to make them look more
attractive, but you won’t get extra credit for doing so. Test the code and submit some evidence of your
testing.
Step 2 (17 points): Using Step 1, do Exercise 10.8. That is, using the Action pattern, and the code on
pages 405 and 406, change the buttons you used in Step 1 so they can be enabled and disabled. You
must decide with each action when they should be enabled or disabled: you should have both a lower
limit and an upper limit on the number of houses and cars–either separately for each, or their number in
total taken together–that can be drawn or removed. Note that these buttons can therefore interact with
each other: for example, a disabled button can be re-enabled by the action of a different button. These
decisions should be documented in your design and code.
If you do this Step, you do not have to submit separate output from Step 1.
Step 3 (18 points): Creativity Step. Add an enhancement similar to those if Exercise 6.14, except that
your enhancement can’t be a truck or a stop sign. You only need to do one new extension of
3
SelectableShape, and it can be simple and small–but it must have at least two primitive shapes that make
it up (that is, it must use GeneralPath). It should also have its own Action pattern “Add Me” button, and
be controllable by the “Remove” button. And, it should establish and/or affect the minimum and maximum
limits on how many of these shapes, as well as the existing shapes, the buttons can control. For
example, it could be that this new shape is a kind of car, so the total number of cars permitted obeys one
rule but houses are independent. Or maybe it is so complicated that it counts as two shapes. Or maybe
it can’t be drawn unless some other condition is met, like, the number of houses exceeds the number of
cars. Whatever you decide, you must document it clearly.
But in addition: this new shape must have an extra property different from the House and Car shapes.
It can be drawn anywhere at all, even in a fully random location, except that it should not overlap any
existing shape. Note that sometimes this means you cannot draw the shape at all(!), and your testing
should show this.
There are many ways to do this, and most of them require looking at all the existing shapes and using
the GeneralPath method “contains”. And, some of these algorithms are not going to give exact results all
the time, depending on how the algorithm represents the new figure and how it compares this
representation to the existing shapes using “contains”. Not that “contains” is required in the Shape
interface in several forms, and that therefore it has been actually implemented for each specific shape(s)
in the API.
Make sure you clearly specify in a comment what ever algorithm you have chosen, and explain
whether it is exact (that is, whether it is guaranteed to work always) or only approximate (that is, it
depends on a heuristic or on an approximation, and may occasionally fail as the frame fills up). If it is
approximate, clearly explain what can cause it to fail. Note that you do not have to use an exact
algorithm as long as you clearly indicate the strengths and weaknesses of an approximate one.
If you do this Step, you do not have to submit separate output from Step 1 or Step 2.
General Notes:
For each step, design the system using whatever CRC, UML, or other technology you find helpful; we
do not require you to submit the results of these tools, but you should find that them make the Javadoc
easier. Then, write the documentation and the system, and text edit its classes into files. Compile them,
execute them on your own test data, and debug them if necessary. When you are ready, submit a hard
copy of the text of the code and your testing (use appletviewer or some other screen capture tool), and
whatever additional documentation is required; submit an electronic copy of the your class and javadoc
files. Make sure that the source code is clear and its user interface is comprehensive and informative.
Write your classes clearly, with a large block comment at the beginning describing what the class does,
how it does it (i.e. in some form, talk about its CRC and UML), and how it will be tested. Describe the test
data in the comment, also. Document each constructor and method, using javadoc tags and other
commentary as necessary. Clear programming style will account for a substantial portion of your grade
for the programming part of this assignment.
4
Checklist for submission:
For theory: Hard copy, handed in to Prof or TA by the beginning of class. No extra points for using a
text editor. Neatly stapled, separately from programming hard copy! Name and UNI attached.
For programming: Hard copy, handed in to Prof or TA by the beginning of class. All code, all testing
runs (cut and pasted from console, and/or captured screenshots). Neatly stapled, separately from theory
hard copy! Name and UNI attached.
Also for programming: Soft copy, submitted to the Course Files Shared Folder on courseworks by the
beginning of class, in a tarball created by CUIT Unix tar command (“tar -cvzf uni_HW4.tar.gz
whateverMyDirectoryIs”). Please use “uni_HW4” as the name of your Courseworks submission. Include
softcopy of javadoc html. Name and UNI should be included as comments in every class. The code must
compile. Last submission before deadline is the official one that will be executed if needed.
