Objectives

Other objectives include:

• Use of nested loops.
• Call and write methods with parameters and return values.
• Use the DrawingPanel, Graphics, Color classes, and mouse events such as Click.
• Use while loops and if statements to validate input and control code.
• Use arrays to store and process information.

Hand-in Requirements

All projects will be submitted electronically through Blackboard.  Zip up your entire lab directory to submit as the source.  (Right click on the lab folder and follow the 7-Zip > Add to "abc123_project3.zip" or follow Send To > Compressed (zipped) Folder.)  The lab folder should include the following:

• SupermarketDynamicWindow.java
• DrawingPanel.java

Introduction

The goal of this project is to code the missing parts (methods) of a program that allows the user to process a supermarket transaction in a graphical way.   This version will be programmed as if the application was going to be deployed for a tablet.   The most interesting part of this project is experiencing the re-use of code.   Calling methods with different parameters allows the programmer (a.k.a. the student) write programs with less lines of code while also organize the funtionalities.  

This project is similar to the project 2.   For instance, the method getValueList performs the same functionality than getValidInput in Project 2.   Moreover, both methods are in charge of getting values from the user.   The difference now is that we need to get the information in a graphical way.   That said, the program will not send anything to display in text mode rather than through the DrawingPanels.

Just like for the project 2, in this exercise you act as if you were part of a software development team.   In other words, when working in that environment, you need to use/code each and every method provided as method stubs.   The reason for that is that if you don't work with the methods provided the complete team project will fail when tests will take place. 

Note: Do not pay attention to the tittle of the DrawingPanels.   Specifically where it says "@fox05".

As a recommendation, try to start working with enough time in advance given that this project may take a good amount of time to accomplish it.

Details

The program will start with the method genTransaction, which will perform the following tasks.

• Ask the user for a customer via a method call such as customer = (int) getValueList(customerName, "Customer", true);.
• Repeatedly ask the user for actions via a method call such as action = (int) getValueList(actions, "Action", true);.   According to the action returned from the call, it will perform one of the following tasks. 
  • Add to cart.
    
    • Check if the cart is full using the method isCartFull and perform the following actions according to the returned Boolean value.
      
      • True: Do nothing.
      • False:
        • Let the user select an item to add to the cart via a method call item = (int) getValueList(itemDesc, "Item", true);
        • Let the user input a quantity via a method call  quantity = getValueList(numbers, "Quantity", false);. Note that here the third parameter is set to false to indicate that the returned quantity is expected to be a true double value  (with digits and a decimal point ".").   This would require the getValueList method to assemble a String with the digits and period to represent a valid double value. The method isNumeric(temporalString) should be used to validate such a string. If the quantity is valid and after the user clicks the OK button on the panel, the getValueList method should use the Double.parseDouble(valueString) method to convert the string representation of the valid quantity into a double value and return it.  If the value returned is 0.0 the action "adding to the cart" should be cancelled.
        • Add the itemID and quantity information to the cart by calling the method addToCart
        • Calculate and revise the subtotal, discount, tax, and grand total.
        • Display the grand total in the panel by calling the method showTotal.
  • Remove from cart.
    
    • Verify that the cart contains at least one item by calling the method isCartEmpty and perform the following tasks according to the returned Boolean value.
      • True: Do nothing.
      • False:
        • Let the user select the item to delete.   For that, the program will:
          • Create an array with the description of the items in the cart by calling the method getCartItemNames.
          • Let the user select the item to delete via a method call such as itemCart = (int) getValueList(cart, "Cart", true);, where the first parameter cart is the array returned by getCartItemNames. 
            
        • Obtain the item "ID" by calling the method getItemAtCart.
        • Remove the item from the cart by calling the method remItem which will return the quantity of that item in the cart.
        • Calculate and update the subtotal, discount, tax, and grand total.
        • Display the grand total in the panel by calling the method showTotal.
  • Finish transaction.
    
    • Let the user enter the dollar amount (to pay for the items in the cart) via a method call such as cash = getValueList(numbers, "Cash", false);.
    • If the value returned is greater than or equal to the grand total, calculate the change and show the change by calling the method showMessage. Otherwise, keep asking the user for another cash value.
  • Cancel transaction.
    • Clear the cart by calling the method clearCart.
    • Reset the subtotal, discount, tax, and grand total.
    • Display grand total which should be 0.00 by calling the method showTotal.
    • Display the message "cart is empty" by calling the method showMessage.

The Cart

In the previous project, all the arrays were static.   In other words, they did not change in size or values throughout all the program execution. Nonetheless, in this project we introduce the concept of a shopping cart.   The cart  stores information in two arrays cartItem and cartQty.   These arrays have a capacity to hold MAX_ITEMS items.   However, the actual number of items can be less than  MAX_ITEMS  and will be recorded in the variable cartSize.

Initial Zip File

You should start your project by downloading abc123_project3.zip.  This file contains DrawingPanel.java file and a template SupermarketDynamicWindow.java file.

DrawingPanel.java

The DrawingPanel.java has been updated to include two additional methods for getting mouse click positions.  Here are the methods you may use.

Method Name	Description
getGraphics( )	returns a Graphics object that the program can draw on
setBackground(color)	sets the background color
sleep(milliseconds)	pause for a given number of milliseconds (1000 milliseconds equals one second)
close( )	closes the window
getClickX( )	returns the X position of the last mouse click
getClickY( )	returns the Y position of the last mouse click

See the provided getDecision() method in the SupermarketDynamicWindow class for more details on how to use these methods. You should model your implementation of your getValueList method after the sample code provided in the getDecision().

SupermarketDynamicWindow.java

The template version of SupermarketDynamicWindow.java already implements the following pseudocode which you should not change:

In the main method:

1. Asks to the user to confirm if a new transaction should be started.
2. If yes, it will call the genTransaction method.

In the genTransaction method:

1. Asks to the user to confirm if a new transaction should be started.
2. If yes, it will call the genTransaction method.

You should study the code in SupermarketDynamicWindow.java to gain an understanding of how the code implements the aforementioned behavior. Pay attention to the description of what is stored in each variable. For the getClickRowExample and getClickColExample methods, determine the correspondence between the return values and locations of the mouse clicks.   Figure out how the program knows which rectangle is selected in a particular cell labeled by "Yes" and "No".

You should then start coding the functionality described in the section Details.   Study the detailed documentation of what is each method purpose (functionality) and the details about parameters and their possible values, and what will be returned by the method.

Change to receive an array of options

For this project, you need to code the missing parts in all the code which intends to work with dynamic windows which will change size and options possible toselect based on the array that will be received as parameter.

The program should be modified to ensure that it implements the behavior that will be seen in the videos provided in the next link.

Rubric

Your program should compile without any errors.  A program with more than one or two compile errors will likely get a zero for the whole assignment.

The following criteria will also be used to determine the grade for this assignment:

• [10 points] If your submission includes the following:
• The program draws the string "Project 3 written by [...]". with your specifics.
• Your submission was a Zip file named abc123_project3.zip containing a folder named abc123_project3, which contains the other files.   Note that you should change abc123 to your own.
• If your submission contains files named SupermarketDynamicWindow.java and DrawingPanel.java.
• If your program contains a comment that describes what the program does and contains a comment describing each method and big portions of the program.
• If your program is indented properly.
• [20 Points] The genTransaction method was implemented following the process described in the Details section.
• [25 Points] The getValueList method was implemented and called correctly.
  • [15 Points] Correctly working to get the index of the array received when returnInt parameter is true.
  • [10 Points] Correctly working to get the double value assembled by the sequence of numbers and "." selected by the user when returnInt parameter is false.
• [5 Points] The method getClickRow was coded and called correctly, using as example the method getClickCol.
• [15 Points] All the methods pertaining to the operations with the cart were implemented correctly.
  • [3 Points] The method addToCart
  • [3 Points] The method removeItemCart
  • [1 Points] The method getCartItemNames
  • [1 Points] The method getItemAtCart
  • [1 Points] The method clearCart
  • [1 Points] The method isCartFull and isCartEmpty
• [15 Points] Correct implementation of the graphical methods.
  • [10 Points] The method drawOptions was implemented with nested loops.
  • [3 Points] The method showMessage.
  • [2 Points] The method showTotal.
• [10 Points] The program shows the right output as presented in the videos provided.