Description
DESCRIPTION:
It’s time to try a little functional programming. In this case, your job will be to
develop a very simple Sales Order application using the Clojure language. REALLY simple. In fact,
all it will really do is load data from a series of three disk files. This data will then form your Sales
database. Each table will have a “schema” that indicates the fields inside.
So your DB will look like
this:
cust.txt: This is the data for the customer table. The schema is
<custID, name, address, phoneNumber>
An example of the cust.txt disk file might be:
1|John Smith|123 Here Street|456-4567
2|Sue Jones|43 Rose Court Street|345-7867
3|Fan Yuhong|165 Happy Lane|345-4533
Note that no error checking is required for any of the data files. You can assume that they have been
created properly and all fields are present. Each field is separated by a “|” and contains a non-empty
string. All text is case-sensitive so “John” and “john” are different people. Finally, there are no
duplicate records/customers.
prod.txt: This is the data for the product table. The schema is
<prodID, itemDescription, unitCost>
An example of the prod.txt disk file might be:
1|shoes|14.96
2|milk|1.98
3|jam|2.99
4|gum|1.25
5|eggs|2.98
6|jacket|42.99
Again, the data is valid – no duplicates and text is case sensitive.
sales.txt: This is the data for the main sales table. The schema is
<salesID, custID, prodID, itemCount>
An example of the sales.txt disk file might be:
1|1|1|3
2|2|2|3
3|2|1|1
4|3|3|4
The first record (salesID 1), for example, indicates that John Smith (customer 1) bought 3 pairs of
shoes (product 1). Again, you can assume that all of the values in the file (e.g., custID, prodID) are
valid.
So now you have to do something with your data. You will provide the following menu to allow the
user to perform actions on the data:
*** Sales Menu ***
——————
1. Display Customer Table
2. Display Product Table
3. Display Sales Table
4. Total Sales for Customer
5. Total Count for Product
6. Exit
Enter an option?
The options will work as follows
1. You will display the contents of the Customer table. The output should be similar to the
following:
1: [“John Smith” “123 Here Street” “456-4567”]
2: [“Sue Jones” “43 Rose Court Street” “345-7867”]
3: [“Fan Yuhong” “165 Happy Lane” “345-4533”]
Note that exact formatting does not matter. You can use commas as separators or round
brackets instead of square brackets. The important thing is that each record lists the ID,
followed by the data associated with the ID. Records should be sorted by ID.
Note that the records are NOT guaranteed to be sorted in the data file (as they are in the
illustration above). In addition, ID numbers are not guaranteed to be consecutive numbers
(e.g., the IDs could be 7, 3, 2, 9, 14)
2. Same thing for the prod table – it will be sorted by Product ID (again, the data file may not
be sorted)
3. The sales table is a little different. ID values aren’t very useful for viewing purposes, so the
custID should be replaced by the customer name and the prodID by the product description,
as follows:
1: [“John Smith” “shoes” “3”]
2: [“Sue Jones” “milk” “3”]
3: [“Sue Jones” “shoes” “1”]
4: [“Fan Yuhong” “jam” “4”]
Again, the list should be sorted by Sales ID (the data file may not be sorted)
4. For option 4, you will prompt the user for a customer name. You will then determine the
total value of the purchases for this customer. So for Sue Jones you would display a result
like:
Sue Jones: $20.90
This represents 1 pair of shoes and 3 cartons of milk (in our simple example).
5. Here, we do the same thing, except we are calculating the sales count for a given product. So,
for shoes, we might have:
Shoes: 4
This represents three pairs for John Smith and one for Sue Jones.
Note that if a given customer or product does not exist when using menu option 4 or 5, an
appropriate response is given (either a “cust/prod not found” message or total sales/count
= 0 )
6. Finally, if the Exit option is entered the program will terminate with a “Good Bye” message.
Otherwise, the menu will be displayed again.
So that’s the basic idea. There are a few final points to keep in mind:
1. You do not want to load the data each time a request is made. So before the menu is
displayed the first time, your data should be loaded and stored in appropriate data
structures (you can do this any way that you like).
2. This is a Clojure assignment, not a Java assignment. So Java should not be embedded in the
Clojure code for any important functionality. It might be necessary to use Java classes, for
example, to convert text to numbers in order to do the sales calculations. That’s OK, but Java
should not be used for much more than that.
3. You can not use while loops in your program. Clojure provides a while, but the purpose of
this assignment is to program in a functional style. So any iteration/looping must be done
with either recursion or application of the apply-to-all style functions (e.g, map, reduce,
filters). The apply-to-all functions are particularly powerful – use them!
4. The I/O in this assignment is trivial. While it is possible to use complex I/O techniques, it is
not necessary just to read the text files. Instead, you should just use “slurp”, a Clojure
function that will read a text file into a string. For the input from the user, the “read-line”
function can be used.
5. Do not worry about efficiency. There are ways to make this program more efficient (both
the data management and the menu), but that is not our focus here. I just want you to use
basic functionality to try to get everything working.
6. For production level Clojure development, many programmers use a build automation
framework called leiningen (similar to ant and maven with Java). However, leiningen is
overkill for this assignment and will complicate your life and possibly that of the grader as
well. So I suggest that you do NOT use it for this assignment.
Instead, just create your code and test it directly from the command line. This is what the
graders will be doing. Something like repl.it is likely more than enough for this. If you do
use leiningen, or any other development tools, however, you must still make sure that your
final submission can run from the command line with no additional configuration required.
DELIVERABLES: Ordinarily we would organize our code into multiple source files. However, this
can complicate the grading slightly as Clojure relies on the Java Classpath to locate additional
modules. We don’t want to have to deal with inconsistencies between student configurations, so
you will just use a single source file for your code. It will be called sales.clj. This is all you will
submit. The markers will provide the text files for testing, which will be stored in the same folder as
your source file.
Once you are ready to submit, place the sales.clj file into a zip file (I know that you don’t need a zip
file for one source file but it makes the submission process easier). The name of the zip file will
consist of “a2” + last name + first name + student ID + “.zip”, using the underscore character “_” as
the separator. For example, if your name is John Smith and your ID is “123456”, then your zip file
would be combined into a file called a3_Smith_John_123456.zip”. The final zip file will be submitted
through the course web site on Moodle. You simply upload the file using the link on the assignment
web page.
Good Luck
