comp3021_pos_system

Enhanced POS Application (Knowledge of GUI and Simple Threads included)

1. OBJECTIVE You are required to implement a graphical user interface (GUI) version for the point of sale (POS) application similar to that in assignment 1. The objective of assignment 2 is to practice skills in GUI and multi-threaded programming.
2. TASKS There are three implementation tasks in this assignment, which are the logic, GUI and multi-thread part. The details are listed as follows. LOGIC Part: In addition to the basic functionalities mentioned in Assignment 1, the POS application allows a store to offer discounts to its customers. There are four types of discounts:
3. Event discount: The store may offer an event discount on a special day. All purchases on that day can enjoy a specified discount.
4. Customer discount: Purchases made by a customer who is a club member of the store can enjoy a specified discount.
5. Product discount: Purchases of a product under promotion can enjoy a specified discount.
6. Sales discount: Purchases of products may enjoy a specified discount if their total amount (before discount) is greater than a certain value. Let’s mark the event discount ratio as e, the customer discount ratio as c, the product discount ratio as pi for a purchased product Pi and the sales discount ratio as s when total payment exceeds R, then the total amount of payment is calculated by: (1) If the total payment exceeds R (Price1*(1-p1) + Price2*(1-p2) + Price3(1-p3)…..) * (1-c) * (1-e)(1-s). (Pricei is the corresponding price of the purchased product Pi.) (2) If the total payment does not exceed R (Price1(1-p1) + Price2*(1-p2) + Price3(1-p3)…..) * (1-c) * (1-e). The enhanced POS system reads various discount information from the file conf.xml. For example, you can find the following contents in the file conf.xml under the directory “configure”:

The file defines various discounts as follows: Event discount with ratio 5% Customer discount with ratio 10% Sales discount with ratio 20% when total payment exceeds 103 Product discounts: ID Name Ratio ID002 basketball 15% ID005 doll 5% ID009 shoe 25% Users of the POS system can adjust different discount ratios by changing the value field in the XML records. For example, by adding a row with under the product strategy, you can add a new discount ratio y to a specific product with id xxx ,which should be unique. (You may try different discount values and observe the changes in the fields “discounted” and “total sum” in the payment interface introduced below.) The system can also display different currency symbol according to the file conf.xml. You can see there is a line in the file. HK It can also be set to US The system will show the corresponding currency symbol in the payment window shown below. You may also try it out in the demo program we have provided. You can find the prices of each product in the file itemListFile.txt under directory configure. (Please be aware that do not change the files under this directory; otherwise you may not be able to run the demonstration correctly.) Since the prices and the discounts are non-negative real numbers, you will need to use double or float in your logic. GUI Part: In this task, you should design the GUI interface of the POS application. 1). Log in A log in window for cashier authentication will pop up when the POS starts. It should contain two text fields for a cashier to enter username and password respectively. It also contains a “Sign In” button for confirming the sign-in procedure. Below is one example used in our demo program. The system displays a sales screen after successful authentication. Invalid input detection: The cashier receives a failure message of “Invalid username or password!” upon unsuccessful authentication. 2). Sales. The cashier’s user name will be displayed at the top of the screen. The POS system should support that the cashiers can input a sales record in two ways: 1. They can add the products to the shopping cart by directly entering the product ID and corresponding amount; or 2. They can select the product in the product list at the left hand side, enter the amount in the middle and click the “-->” button to add it to the shopping cart. Cashiers can check the entered products and their prices at the shopping cart. Cashiers can select a product item at the shopping cart, and click the “<--” button to remove it. If cashiers click the “Clear” button, the shopping cart will be emptied. The cashier can check the “Is VIP?” box before pressing the “Pay” button at the bottom of the interface if the current customer is a club member of the store. If the box is not checked, the customer does not enjoy the customer discount. When the shopping cart is non-empty, the cashier can press the “Pay” button (whether the customer is a club member or not) to proceed to the payment screen. Invalid input detection: 1. If the cashier enters a non-existing product ID XXX, a message “Prodcut XXX does not exist” will be displayed. 2. If the shopping cart is empty but the cashier presses the ”Pay” button, a message “Invalid sales information” will be displayed. 3). Payment: In this screen, all items and their corresponding amounts entered at the sales screen will be displayed in the list at the left hand side. Detailed information of the sale is displayed, including: Total price: the sum of the purchased products’ prices before any discount Discounted: total discount of the sale Total sum: the total money the customer should pay Paid: the amount of received money Refund: the amount of money that the cashier should return to the customer when paid money is greater than total sum. It is obvious that when paid money is not enough or is empty, this field should have no value. The cashier can press the “submit” button, and return to the sales screen after successful payment. Invalid input detection: If the paid money is not enough, a message “Not enough money!” will be displayed. After a sale is submitted, corresponding purchased record will be recorded in the file salesRecord.txt under the directory “configure” in your program execution path. The format of the record is: OperatorName VIP Price Discount Paid Refund Product1 amount, Product2 amount... Threading Part: In order to control the GUI part and the application logic part independently, you are required to use a thread to control the GUI part and another thread for the POS part. In addition, the POS should support the creation of multiple Cashiers, each uses an individual GUI. You should use concurrent threads serving these GUIs so that they can respond timely to multiple Cashiers’ inputs simultaneously. These multiple Cashiers, however, share the same sales record file. Therefore you should carefully program the concurrency to prevent multiple Cashiers from writing the sales record file simultaneously. You can run the demo program to better understand the requirements. Testing Part Finally, please also include your test suite and test cases for unit testing when you submit your program. You are required to obtain 100% statement coverage to all public methods and the main routine of the POS program that you completed for assignment 1. Statement coverage of exception handling blocks is not required. Your test classes and test methods should strictly follow their naming regulations as introduced in the lab session. That is: Test class should be named as xxxTest such that xxx is the name of the tested class. E. g: Class name: DateHelper, Test class name: DateHelperTest. Test method should be named as testXxx in which Xxx is the name of the tested method. You can use a sequential number as the identifier of different test cases for the same method. E. g: Method name: MatchDate(), Test method name: testMatchDate01(). It is strongly recommended that you organize all your test cases in a package separated from your program, so that our TAs may check the code of your test cases quickly. When you submit your assignment, make sure that you have included a test suite which executes all of your tests. How to start: (1) Download assignment2.zip package from the course website and unzip it. Use Eclipse to import the Enhanced_POS project(click the menu File->Import, select General/Existing Projects into Workspace, choose the folder “Enhanced_POS” you got from the package as the root directory, and click finish) (2) We’ve already implemented several parts for you. a) Enhanced POS settings and product information. Packages “conf”, ”conf.currency”, ”conf.discount”, ”core.entities” are used to load Enhanced POS settings and product information from the files in the “configure” folder and store them in the pre-defined data structures such as the user list, product information, currency symbol and discount strategy. You are recommended to use these data structures in your own implementation but you are also allowed to define your own data structures to store these information. GlobalConfiguration.java contains the logic of the loading process and you are recommended to read and understand it but not modify it. You can modify other files we provided by adding more functions to simplify your implementation. Again, please use all the provided classes if you find them useful. You are NOT required to use them. Please try to understand them by yourself and the course will not provide special sessions to explain them to you. b) The process of loading configuration files. We provide you an example of how to using GlobalConfiguration to load the Enhanced POS settings in LoadConfExample. You can add similar code anywhere in your own implementation to load all the configuration files to certain data structures. (3) If you have any problems about importing the project or running the LoadConfExample, please check your JDK version and the build path of the project in Eclipse first. Just in case some of you still don’t know how to start, we will arrange a lab session to demonstrate you the process and you can also ask questions if you’ve already started. 3. GRADING Grading will be based on functionalities. The breakdown of grades is as follows: 1. All GUI interfaces introduced above: 30% 2. Thread control part: 20% 3. Invalid input detection (refer to each interface, 2.5 points for each): 10% 4. Final result saving (in the file salsesRecord.txt): 10% 5. Computation correctness (for 4 test cases we prepared, your program can compute correct price, discount, sum and refund, 5 points for each): 20% 6. Code quality (design and documentation): 10% 7. Good design (e.g. overall design, reusable classes, portability (some of the classes will be used in a extended version later), clear classes design... etc.): 3% 8. Good documentation (Brief but meaningful comments for each class and function, appropriate use of javadoc tags): 3% 9. Good coding style (e.g. appropriate indentation, meaningful variable and method names, explanatory comments for difficult parts ... etc.): 4% 10. Test Quality : 10% a. Good naming regulations (Strictly follow the naming regulation introduced above. If you fail to follow test naming regulation, your score of test quality will be under 2): 3 b. Test suite availability (You need to include a test suite containing all tests you’ve written, and include a test runner implementation so that all tests are executed with a single execution of that runner): 2 c. Test adequacy (You are required to obtain 100% statement coverage for all public method and the main method of the whole program. Coverage of exception handling codes is not required. If you fail to achieve this requirement, your score will be based on the actual coverage level: 1 for coverage level 0%~50%, 3 for coverage level between 51%~99%. The coverage level will be evaluated by EclEmma report of your tests): 5 Note: 1. If your program could not be compiled, we may give you partial credits (normally under 20% points). 2. This is an individual assignment. Please acknowledge the resources (books, web sites and so on) that you have consulted and the people whom you have discussed with. Please be reminded that plagiarism is a serious offence. Students who are involved in plagiarism could fail the course assignments. 4. SUBMISSION Due date: May 17, Assignment grading will be based on the full version. • The assignment is due at 11:59pm on the due date and you may use Course Assignment Submission System (CASS) to submit your assignment. To use CASS, you may first go to https://course.cs.ust.hk/cass/submit.html. Then choose Comp3021 for the course and select the files you would like to submit. Please submit the file named assignment2.zip. • Considering that it is possible you cannot reuse the implementation in assignment 1 in this assignment, please zip your assignment 1 together with the test cases that you create as assignment1.zip and submit it as well. • Please ensure your submitted program is self-completed, that is, can be compiled and run by itself. For fairness, we will not supply more files to compile and run your program during grading. And also provide us a readme file to tell us how to run your program. • Please submit your assignments by the due date. Late submission will not be accepted. • You are recommended to use JDK 6 to compile and run your program.