OPS435: Assignment #2

HAND-IN REQUIREMENTS:

OVERVIEW / GENERAL REQUIREMENTS:

You have been approached by the "purchasing department" to write a portable Bash shell script called makePayments.bash to use graphical method of viewing purchasing information, and making payments against outstanding vendor balances. Vendors are companies that we have purchased goods and services from and may owe them money. In order to make the shell script graphical, you need to study how to use the Zenity command. Refer to the HINTS / TIPS section below to learn how to use the Zenity command.

The purchasing department already has an employee that records vendor purchases into a purhchases file, so we don't have to worry about recording vendor purchases. What we need to do is create a graphical program that reads the purchases file to generate reports, and record payments towards outstanding vendor balances. You can assume that if there are multiple purchases for the same vendor, the outstanding balance grows for that one vendor record.

The layout for the purchases file will always consist of the same format: a four-field, colon-separated database file containing the following field sequence:

• Customer Number
• Full Customer Name
• Date of Most Recent Purchase
• Purchase Amount

Your shell script will only accept one argument: a valid 4 field, colon-separated purchases database file pathname. This filename could be ANY filename, as long as it is a valid database. If your shell script is issued without exactly one argument, then the shell script will display a graphical USAGE error message, and exit the shell script with a false value. If the file is not valid (i.e. doesn't exists), or is not a four-field database (separated by colon), then the shell script will display a graphical error message, and exit the shell script with a false value. Since the error messages are graphical, you are NOT required to redirect stdout as stderr. If the shell script is issued correctly, then the following graphical menu will appear. This menu will continue to loop until the user selects "Exit". In the menu, the user clicks on a button, and then clicks OK or presses ENTER. This is a fairly fool-proof system, and no error-checking is involved. Please view the picture on the right-side for reference.

Diagram of Main Menu for Making Selections

DETAILED REQUIREMENTS:

DISPLAY PURCHASES:

When this menu item is selected, the purchases database file is read in order to graphically display the vendor's full name, and the outstanding balance. Also, a grand total of the outstanding balance will be displayed at the bottom, along with a message that a copy of this file is contained in the file pathname ~/purchaseReport.txt. NOTE: The report should be properly aligned for the ~/purchaseReport.txt file, but does NOT have to be aligned for the graphical display. There is an ongoing issue with how the Zenity command handles whitespace characters generated from the printf command.

Sample Report for Displaying Purchases. Click to Enlarge."

Sample Hard-copy Report Saved as a file (not related to graphical display report on left-side). Click to Enlarge.

MAKE A PAYMENT:

When this menu item is selected, the user will be prompted for a full vendor name. The user MUST enter a vendor name that matches (including case sensitivity and exact full vendor name), otherwise, another dialog box will indicate "no matches", and request that the user re-enter a vendor name.

Dialog box prompting for full Vendor Name.

Dialog box prompting to re-enter Vendor Name if no match.

Dialog box requesting amount of payment against outstanding balance.

If there is a vendor name match, then the vendor name and outstanding vendor balance will be displayed, and the user can enter a payment against that outstanding balance. You can assume that your program only works with dollars (i.e. no decimal places), therefore your shell script will only accept valid integers; otherwise, the user will have to re-enter the payment. Also, if the payment is greater than the outstanding balance, your program will indicate that the "payment exceeds the outstanding balance", and that the user must re-enter the payment amount. An example of this is shown in the YouTube SAMPLE RUNS.

If the partial payment was successful, then the vendor record's balance is updated in the database file.

If a complete payment has been made against the outstanding balance, then the vendor record is to be removed from the purchases database file.

NOTE: Please refer to the HINTS / TIPS for help and suggestions...