File Hierarchy And Download
Application	Client Side	Server Side
Source Code	ClientCP.java ClientCustomized.java CCProperty.java LuhnCheck.java	ServerCP.java CCProperty.java
Documentation	ClientCP.html ClientCP.WindowHandler ClientCustomized.html CCProperty.html LuhnCheck.html	ServerCP.html CCProperty.html
Supplementary Files	cc.properties amex.gif master.gif visa.gif visadebit.gif masterdebit.gif	cc.properties
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Package	Client Side	Server Side
Source Code	Client Side Application Source Code Client Side Application Online Source Code Server Side Application Source Code Server Side Application Online Source Code Full Application Source Code Full Application Online Source Code

Ducumentation

Client Side Application Documentation Server Side Application Documentation Full Application Documentation

Binary Package

Client Side Application Binary Package Server Side Application Binary Package Full Application Binary Package

Full Package

Client Side Application Package Server Side Application Package Full Application Package Full Application Package Without Report

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Requirements and Pre Installation :

First of all, this program requires JDK1.4 and above or JRE1.4 in order to execute the program. Please refer to Sun Java website (http://www.java.sun.com) to download the lastest JDK or JRE. Beware, any JDK or JRE which the version below 1.4 will not execute the program properly and maybe get error while compile or executing the class file.

Program Installation and Execution :

After downloaded the package, just unzip the package to folder . There will be binary files inside the package , if you want to compile again then just open the command prompt windows and open directory till the specific folder. There will be 2 folders which are Client and Server .

To start up the server, open the command prompt windows and type
cd server
java ServerCP

** NOTE: 'cc.properties' must with ServerCP.class
** The Server successfully started if no error message that address the error start server.

To run client application, open the command prompt windows and type
cd client
java ClientCP

** NOTE: 'cc.properties' must with ClientCP.class
** A GUI of Credit card Transaction will appear at screen that indicate the client application is running now.

System Overview :

The Credit Card Transaction Interface

Assume from the program installation and execution part, the server(ServerCP) and client(ClientCP) application already running. Therefore, we just discuss about the flow of the system.
The System Flow :

• At ServerCP, the server is running and always ready for clients's transaction information.[Screenshot]
• At the ClientCP, GUI of client side application already ready for users to inputs value. By default, radio button of Credit Card and Visa Card is selected.[Screenshot]
• First , you need to select which card that you held. The official card logo will changed according to the following card.[Screenshot]
• Then , select the transaction type of Credit Card or Debit Card. The official card logo will changed according to the following service and card.[Screenshot][Screenshot]
• After that, just fill in all the fields at the screen. You can reset the value by clicking the Reset Button .
• Once you ready to make a transaction, click Validate Button to validate all the entries's data. The client application will check for all entries's data for any errors. Once error detected, error message with full detail will be shown to users as well as highlighted those errors. Users just need to based on the error message to input again the value.[Screenshot][Screenshot][Screenshot][Screenshot]
• After all the data are validated true without errors, an information message will pop-up to inform users that they are ready to submit the transaction. Now, Send Button will be active and Validate Button and all the fields are inactive . Used to pending transaction.[Screenshot]
• Once the Send Button is clicked, the system will prompt users whether to continue or cancel. Once users continue, transaction's information will send to server that always awaiting for the client's information.[Screenshot]
• Before that , client application try to establish connection with server. Information will be sent to server once the connection established. At the server, once the transaction's approved, the information will be logged and also printed at the console window screen. Meanwhile, a comfirmation message will be sent back to inform users everything done. Finally , everything set to normal and await for another transaction. [Screenshot][Screenshot][Screenshot]

Validation Algorithm :

All the fields that appeared at client application must be filled. The basic textfield validation algorithm is below : First of all, client application will check the blank field of that particular textfield. Once blank field detected, users will be prompted to enter that particular field. After that, the input of that particular textfield will be validated (Discuss the details below). Again, users will be prompted to input and error will be highlighted when error detected.
** Note : Check blank field validation and input validation for each textfield before the following textfield.

1) Date validation :
For both the date that needed to input (Date Valid To and Date Valid From), the format is fitted to MM-YYYY. On the other ,MM-YY/MM-YYY format also accepted, system will parse that date to december of year 999 when 12-999 inserted. Any other data type not from numeric will be thrown exeption and error message will pop up. Besides, comparison between both date and current date also had been done to avoid any expiration card also use the credit card transaction and vice versa .

2) Number validation :
For amount and security code textfield, validation will be made for digit checking only. Any data inserted that contain any non-digit data will be thrown exeption and error message will pop up.

3) Luhn Check Algorithm :
Luhn Check Algorithm is used to check/validate the card number. This algorithm written in Java and obtained from http://www.merriampark.com/anatomycc.htm using mod 10 calculations. The algorithm used to arrive at the proper check digit
All card can be checked using this Algorithm.
The Issuer Identifier is the main idea of the appearance of Luhn Check Algorithm. For example, Issuer Identifier Card Number Length table

Issuer	Identifier	Card Number Length
American Express	33xxxx, 37xxxx	15
VISA	4xxxxx	13, 16
MasterCard	51xxxx-55xxxx	16

Luhn Check Algorithm used those Issuer Identifier to validate the card number .
Below taken from the website :

Thanks to Aleksandar Janicijevic for directing me to information about H.P. Luhn. The most succint description of the Luhn algorithm I have found comes from the hacker publication phrack 47-8: "For a card with an even number of digits, double every odd numbered digit and subtract 9 if the product is greater than 9. Add up all the even digits as well as the doubled-odd digits, and the result must be a multiple of 10 or it's not a valid card. If the card has an odd number of digits, perform the same addition doubling the even numbered digits instead."

The idea is certain cards have certain card number format like Visa card number first digit starts with a 4, Mastercard first digit starts with a 5 and American Express card number starts with 3 at the first digit. Validation is done to the card number format as well as the length of the card number as different card varies in different card number length.

Critcal Appraisal

Overall, all the sections mentioned had been done. Section 1 which involves GUI that conttribute most of the problem that faced along the assignment. The main point is which layouts used to design the client side application interface ? Finally, pure GridBagLayout layout from Java.AWT had been chosen and constraints of GridBag had been declared to design a pure GridBagLayout based interface instead of using JPanel. Although using JPanel is good but pure GridBagLayout layout give an extra control of designing interface and become a good practice to explore GridBagLayout layout.

Beside, some components, object and methods from Java Swing had been used. First of all, Input Mask that used at Date To and Date From field is taken from Java Swing (JDK1.4 only) which fit the Mask into MM-YYYY format. Numerous methods had been used to validate data includes format the input that fit the current Decimal Formatter as did for Amount and Security Code field to avoid unwanted data. Besides, highlighter had been used for highlighting the errors that detected which error message . Key Adapter and Key Event had been used for limiting some characters that can be inserted only.

Section 2 and 3 for this assignment just simply involves socket programming in Java. This is just a simple method for client and server technology at Java language . Therefore, the source code for socket programming easier to get any references from book or internet source. However, there are others technologies like RMI which is much stable and safer. Socket is facing risk of losing data while communicating or bad packets. For the current trend at Java World, RMI already used to replace socket in client and server technology and the technology now slowly migrated to another technology called JiniTM technology which believed to be more stable and realiable.

Although this assignment just ignore the security issues of online credit card transaction, but security issues also a hard issues to settle especially policy permission that faced by java application or applet when running live at internet. Therefore , this not a important issues for this critcal appraisal. However, this is a global issue that online credit card transaction will exposed the credit card number if the digital security certificates not standardized for credit card.

References :

• Websites
1. Java APIs and Development Kit (JDK) references from http://www.java.sun.com
2. LuhnCheck.java algorithm is obtained from http://www.merriampark.com/anatomycc.htm
• Books
1. Java Programmers's Reference, Grant Palmer 2000, Wrox Press Ltd.