Tutorial 4

Due Sunday, June 1 at 6 am.

For this tutorial, you will add to the project that you created in Tutorial 3. If you did not do Tutorial 3, then review the steps for creating the project and adding files to it.

Activity One

Download these files to the ProgrammingActivitiesFiles directory that you created in Tutorial 3.

Before you modify the files, I want you to move them to a directory inside the Source Packages folder. Reivew these steps in Tutorial 3 for screen shots.

Right-click the Source Packages and select New -> Java Package.
Create a package that is named username.ch6.one (replace username with your webmail user name). Click Finish.
While holding down the control key, select all the files that are in the default package. Right-click on one of the highlighted files and select Cut.
Right-click on the new package that you created and select Paste -> Refactor Move. It is very important that you select Refactor Move and not just Move. When you refactor, it changes all the files that are affected by the move.
You will be asked to confirm what is to be refactored. Click Refactor.
When you are done, you will see that all the files are in the new package.

Only edit the Cashier.java file.

Create a while loop that will process all the items at a grocery store. The person checking out is placing items from the shopping cart onto the conveyor belt.
Declare a double that will accumulate the price of all the items in the person's cart.
Call the getNext method to retrieve the next item on the conveyor belt.
- This method always returns an Item.
- You don't know the type of the item, but you can get its price by calling the items getPrice method.
After each it is retrieved, add its price to your total and call the animate method with the total.
You will know that the cart is empty when you retrieve an item whose price is negative (there could be some free items in the cart).

Run the program several times.

It is okay if it ends right away, it just means that the cart is empty.
If there are items in the cart, verify that you total matches the total generated by the program.
If your total does not match, then you have a logical error that you must find and fix.

Activity Two

Download these files to the ProgrammingActivitiesFiles directory that you created in Tutorial 3.

Before you modify the files, I want you to move them to a directory inside the Source Packages folder. Reivew these steps in Tutorial 3 for screen shots.

Right-click the Source Packages and select New -> Java Package.
Create a package that is named username.ch6.two (replace username with your webmail user name). Click Finish.
While holding down the control key, select all the files that are in the default package. Right-click on one of the highlighted files and select Cut.
Right-click on the new package that you created and select Paste -> Refactor Move. It is very important that you select Refactor Move and not just Move. When you refactor, it changes all the files that are affected by the move.
You will be asked to confirm what is to be refactored. Click Refactor.
When you are done, you will see that all the files are in the new package.

Only edit the Cashier.java file.

This is very similar to the first part of the activity. The only difference is that the checkout method has an integer parameter that is the number of items in the cart.
Declare a double that will accumulate the price of all the items in the person's cart.
You will be asked to enter the number of items that are in the cart. Do not create a variable to store this, other parts of the program will store the number.
Use the parameter to the checkout method to control how many times the loop iterates.
Call the getNext method to retrieve the next item on the conveyor belt.
- This method always returns an Item.
- You don't know the type of the item, but you can get its price by calling the items getPrice method.
After each it is retrieved, add its price to your total and call the animate method with the total.

Run the program several times.

It is okay if it ends right away, it just means that the cart is empty.
If there are items in the cart, verify that you total matches the total generated by the program.
If your total does not match, then you have a logical error that you must find and fix.
Be sure that the loop iterates the correct number of times.

Submitting the Tutorial

To submit the tutorial, perform a Clean and Build on for the project. Be sure that you have followed the instructions for adding .java files to the JAR file before you do this step. If you are not sure, then review the steps in the Creating a NetBeans Project from Existing Sources page; it is in the section on Submitting Assignments.

You can verify that the JAR files are correct by clicking on the Files tab in NetBeans; open the project folder; open the dist folder; expand the JAR file. You should see the .class and .java files in the JAR. If you only see the .class files, then you need to review the instructions for adding the .java files. This is the same for NetBeans 5.5 and 6.

Using the operating system, not NetBeans, navigate to the dist directory for the project and upload the JAR file to me: Submit Assignment.