A local pharmacy would like to keep a small database of its clients and a list of the medications that each patient is currently taking. For now, it is confined to local residents, but the
pharmacy is hoping to tap into the larger region and include communication with the hospitals. We are tasked with supporting a basic system that will monitor medication lists to
later attach to patient files. Since most people are not taking large numbers or medications,
we decide to use the basic List ADT to manage each patient’s medication information.
We haven’t decided whether to use an array-based list or a reference-based list, so we will
implement both. That way we can plug in whichever one suits the client’s needs, without
having to alter the client’s handling of the lists. The array-based medication list has already
been completed and tested. We need to complete the reference-based list.
In this assignment you will:
• Develop the MedListRefBased class that implements the standard List interface
approved by the client.
• Use the doubly-linked list as the primary data field in this class; it is described in
the textbook’s Chapter 5, beginning on page 280.
(1) Create a fresh directory to contain this assignment: CSC115/assn2 is a recommended name. Download this pdf file and the .java files to this directory.
(2) Download and extract the docs.zip and javafiles.zip in the same directory.
A docs directory will be created to store the specifications for the public classes.
The following links will work if the documents are stored in the docs directory
local to this pdf file.
• List specifications
• MedListArrayBased specifications
• Medication specifications
(3) Examine the List specification document. It is similar to the ADT description in the
textbook, page 204. The List.java file contains all the method headers required
of any class that implements a List. Note that each method does not contain a body;
the implementation is never part of the ADT. Note also that the description uses
Java generics, described in the textbook, page 291. This allows the developer of a
List to decide the particular data type of the elements stored in the list.
(4) Examine the completed source code for the MedListArrayBased class. Note
that it implements List
MedListArrayBased implements every method of the List interface. The main
method is used as the test harness for MedListArrayBased and tests every
method, including the private methods. Use this test harness as a model for the
tests that you will create in MedListRefBased.
(5) Examine the completed source code for MedListListTester. This is an example
of an external tester. It is the tester that is run once the completed class is ready for
its final assessment, before submitting it to the client. Note that it can only test the
methods that are listed in the List interface. It tests the list for functionality from
the perspective of a user, the pharmacy, in this case.
(6) Compile all the given Java files. You can run MedListArrayBased to examine
the internal tester results. You can also run the MedListTester to examine the
external test results.
(7) Your job is to create a class called MedListRefBased that implements
information on the doubly-linked list.
(8) Once the code for MedListRefBased is completed and internal testing is done,
you can make a very small change to the external tester and perform the external
test on your code.
There are several files supplied in this assignment. Examine them many times; their purpose makes sense as you work on the implementation of the linked list version of the
medication list. You only need to create one class. Once that is done, you will need to alter
the external tester class so that it calls the MedListRefBased constructor instead of the
You are to create, implement and test the MedListRefBased class. Make sure of the following:
(1) The main data structure you use to store the medications is a doubly-linked list, that
you create yourself (no classes that extend the java.util.List data structure are
to be used in your source code).
(2) The class implements List
(3) Any private methods are properly commented (follow the MedListArrayBased
source code as a guide). Note that comments are not required for any method that
implements a method required by the List interface. Those methods are already
commented and the methods you implement will follow those specifications. During the labs, you will be introduced to javadoc, a tool to create proper documentation.
(4) The main method inside your source code tests each of your methods. Create your
own internal tester for MedListRefBased to thoroughly check the code you write,
including the private helper methods. You do not need to comment out the main
method and you must not delete it. The marker will be looking for evidence of
(5) Once you you are satisfied that all the internal testing works, then you can make
a final check, using the external tester that is provided. If the external tester fails,
then you must go back to the internal tester and take the necessary steps to debug
and fix your code. The external tester will test your program when you alter the
one line in MedListTester.java that declares the list variable by initializing it
to a MedListRefBased object∗
. You should see exactly the same output as when
it tests the MedListarrayBased class.
Submit the following completed file to the Assignment folder on conneX.
Please make sure you have submitted the required file(s) and conneX has sent you a confirmation email. Do not send [.class] (the byte code) files. Also, make sure you submit
your assignment, not just save a draft. Draft copies are not available to the instructors, so
they are not collected with the other submissions. We can find your draft submission, but
only if we know that it’s there.
A note about academic integrity
It is OK to talk about your assignment with your classmates, and you are encouraged to
design solutions together, but each student must implement their own solution.
∗Note the use of inheritance here. The list variable is of type List but the actual declaration calls the
correct constructor of the implementing subclass.
Marks are allocated for the following:
• Proper programming style is demonstrated, as per the coding conventions on CSC115
– In this assignment, all public methods that implement List methods do not
need header comments, although internal programmer comments are welcome
where needed within the method.
• All methods are implemented exactly to the specifications.
– Note that the external tester may be used as an indicator of success or failure
with respect to the specifications being met. However, external tester success
is not the definitive indicator that the program works completely as specified.
• Use of private helper methods where applicable: if similar code is used in more
than one method, then a separate private method should be created that is then
called by the methods using similar operations. See the array based version of the
list as an example.
• Internal testing in the main method that demonstrates clearly that each method was
• Marks will be withheld for code that makes use of any other data type other than a
You will receive no marks for any Java files that do not compile.