CS 280 Spring 2009 Assignment 8 – Looping, Nested Loop and Reading from Files 100 “Assignment” points

Assigned: 03/26/2009

Due: 04/02/2009 at the start of class (after break)

Pre-Lab (Do Before Lab): Bring materials – a USB for a take home copy. If you have a chance, plan out your GUI, tasks, objects, and events needed for program. Plan out how you will solve the problem. There is at least one part of this assignment that will take some thought!

Main Assignment:

Imagine you are writing a simplified program to help State U explore what their application pool looks like. Since State U receives enormous numbers of applications, they do not have time to read essays and will only look at SATs and high school GPA. We are still a bit away from being able to do the full job, so pay attention to what I’m asking for. Also note that you will need to gain an understanding of the provided Applicant class. The provided class will be in a zip file on Blackboard, along with documentation for the class. A quick introduction is included below. You will need to

· declare an ArrayList object as an instance variable in your GUI class so that it is available from all of your buttons (and from start up code). You should also instantiate it as an empty ArrayList when you create it.

· Write a method (general in your GUI class) to read info from a file, creating Applicant objects and adding them to the ArrayList. Please see hints and details below.

· Call that method upon start up (after GUI components are initialized), so no buttons have to be clicked in order for applicant information to be available.

You should create buttons in your GUI to:

· Determine how many applicants meet a given total SAT threshold (that score or higher). Get the given threshold from the user via a text field.

· Determine how many applicants meet a given high school GPA threshold (that GPA or higher). Get the given threshold from the user via a text field.

· Determine how many applicants meet both a given total SAT and a given high school GPA threshold (given values or higher). Get the given thresholds from the user via text fields.

· Determine how high a target Math SAT score has to be in order to get the percent of applicants below a given threshold (entered as a decimal please! – i.e. 20% is expressed as 0.20). Get the given percent threshold from the user via a text field.

· Quit

Background Knowledge:

SAT scores range from 200-800 on each test, with values always divisible by 10 (i.e. 620 occurs, 621 does not). Total SAT adds the Math and Verbal scores together, so the total SAT can range from 400-1600. We’re ignoring the new writing section.
GPA’s are assumed to range from 0.0-4.0 (anything outside that range is converted)
Percentages entered as a decimal range from 0.00 (0%) to 1.00 (100%) – at least when we are talking about percentage of a total.
The applicant names are actually (made-up) initials in my file.

User Interface:

· You’re just a beginning at setting up GUIs in NetBeans. Don’t worry too much about making the interface nice. See my simple sample interface below – Don’t let that constrain your creativity. I know that mine can be improved upon!!! Use it to help understand what I see as inputs and outputs. The version of the assignment on my www site includes more pictures (“screen shots”). The version on Blackboard may not include any.

· If you prefer to display answers in the form itself instead of using message boxes, feel free to do so.

· Format outputs of GPAs and percents to have reasonable number of decimal places. Let’s avoid using real percents in favor of decimal equivalents (saves a little bit of effort)

· Include your name in a label or the title bar on your GUI form

Miscellaneous Details:

Make sure you read the documentation on the Applicant class. It is provided as Javadoc documents, which are html files that can be found inside the project folder included in the zip.
In general, you would make your class in a different project than the Applicant project, because the Applicant class might be useful in a lot of projects besides yours. However, as beginners, you may well be better off taking the expedient path and just including your GUI class file in the same project and package as my code. It’s not what you will be wanting to do for later bigger projects, but for getting started …
You probably have to get the reading from a file to work before you can test any other part of your program.
The file contains one line for every applicant. If you read in a line at a time (as done with DVDs in class on 3/25), you are well on your way to creating the ArrayList of Applicants. There is an Applicant constructor that will be very valuable for creating an Applicant object. Adding applicant objects to an ArrayList is no different than adding Integer objects (which was seen in class on 3/23).
In reading the file, catch exceptions involving the file not being found and display a message (as done in class on 3/25). A data file will be available on Blackboard and my www site. It is (obviously) shorter than real life data and is made up data. Any file with the same format (name, school, math SAT, verbal SAT, GPA) should work.
We’re no longer going to assume that the clerk enters valid and reasonable values. Ensure that the SAT total, high school GPA, and Percent threshold values entered are reasonable values when relevant buttons are clicked. (DO NOT check them when irrelevant buttons are clicked (e.g. when SAT button is clicked, don’t check GPA threshold)). This does not have to be done via looping (as we probably have done in class). In an event-driven world – you can display a one-time message and give control back to the user. See background knowledge above for reasonable values.
Don’t try to calculate anything if the inputs are bad – only display a message and let the user back into control.
If the user enters letters instead of numbers in text fields, the parse commands will crash. We’re still going to ignore these types of problems. (No need to catch and complain about this). (NOTE also that no entry in a text field is like having non-numeric)
Use any kind of loop that works for you for looping through the ArrayList of Applicants. I suggest a “foreach” though.
For the SAT Total search, you do NOT have to check that the user specified SAT is divisible by 10. If the user specified an SAT of 1133, you can test how many Applicants have that SAT or higher exactly as you would if they specified 1130.
In doing the percentage threshold search, find the lowest Math SAT score for which the user specified percentage OR LESS obtained that score. If you have questions about what I’m after here, ask me!
For looping through possible Math SAT scores, you don’t have to consider impossible SAT scores – you can loop through … , 540, 550, 560, etc

Good Programming Practices:

o MAKE SURE YOUR PROGRAM WORKS! (i.e. gets correct results). It must provide all of the requested capabilities AND provide them in the expected way.

o We are now branching – so the program must be tested on more inputs to ensure that all paths through the program code work!

· Add YOUR NAME, e-mail address, and purpose of the program in comments at the beginning of your file (the date should already be there – which is also a very good practice). The purpose should be what the program is supposed to do, not the learning goals.

· Name all variables and constants meaningfully.

· Name meaningfully all jbuttons, jtxtfields, jlabels, etc that will be referred to in code. Use conventions for the start of their names.

· If you provide any outputs on the form itself, make the results read-only. (not editable)

· Define numbers (especially those that could change sometime in the future) as named constants (i.e. they should be ‘final’). You can use public constants from the Applicant class via the class name (e.g. Applicant.MAX_GPA)

· Only variables that need to be accessed from more than one button should be declared as instance variables for the GUI class. Others should be declared local to the methods they are used in.

· Indent to show any structure of the program (The IDE usually does this well if you don’t go back and change things – probably not much to worry about on this basic of a program)

o You MUST include some comments that explain your program in order to get full credit; any complexity should have comments – if you had to stop and think about how to do something, it needs a comment.

Red Tape to Aid Grading:

· Please set the name of the project to something other than the default name (JavaApplication1, …).

· Add your name in a jlabel on the GUI form or on the title bar.

Name your zip file so that it identifies you as well as the assignment (e.g. yourlastname assignment8.zip). This is very important for my grading!!!!

Hand in:

Compressed (zipped) folder with your entire assignment containing all files related to the assignment, including your code and mine – submitted to Blackboard. Please submit one zip file.
Printed copy of your code – To get just that, paste into Word, WordPad, NotePad etc. Please don’t double space.

Do your own assignments !!!! Work that is copied or done with somebody (when not assigned to a group) will be punished. If programs are copied, both students will receive a zero for the assignment. If significant sections of programs are copied, points will be taken off. Changing small aspects of a copied program does not make it not a copy. Asking another for help on a step or two in a many-step assignment is acceptable; looking at another person’s program is temptation for cheating; handing in a near duplicate program is cheating

Sample Interface:

On Startup if data file isn’t found: