Your Task

NOTE: This lab will require a significant effort, and you should start on it as soon as possible.

See Lab02: Web Applications I Lab for instructions on how to download the two archive components for Lab02 and then import them into Eclipse. This version of the lab (Lab02a: Web Applications II) assumes that you have downloaded and completed Lab02 and builds upon the AddNumbers and GuessingGame examples from that lab.

Lab02a will “force” you to investigate, explore, and learn the structure of a standard WebApp, from Web.xml, the servlets, the controllers, the model, all the way through the JSPs. You will need to have this kind of familiarity with the WebApp architecture in order to get started on your team project, as well as to be able to make significant technical contributions to any and all aspects of your team project.

NOTE: You must work individually on this lab. It is imperative that everyone on your team be able to fully comprehend, design, implement, toubleshoot, and debug the complete architecture of a standard client-server application. This WILL come up on the exam.

NOTE: You are allowed to use ChatGPT to assist you with this lab. If you do use ChatGPT, you must mention it prominently in your comments.

NOTE: This lab will require a significant effort, and you should start on it as soon as possible.

You have six tasks:

First, make a copy of the CS320_Lab02_username project, and then refactor (rename) that copy to CS320_Lab02a_username. YOU MUST DO THIS BEFORE YOU EXPORT YOUR SOLUTION AND SUBMIT IT TO MARMOSET. Example: I would refactor (rename) the copy of my CS320_Lab02_djhake2 project to CS320_Lab02a_djhake2 as soon as I imported the project into Eclipse. Submissions that DO NOT adhere to that guideline will not be graded until they are refactored and resubmitted.

Add a third number to the AddNumbers example, such that a third number field shows up on the AddNumbers web page, and the returned result is the sum of all three numbers. Your code should check for the same errors as the existing AddNumbers example does. This problem will require changes to the AddNumbers servlet, controller, and JSP.
Create a new WebApp based on the AddNumbers example, called MultiplyNumbers. This WebApp should accept two numbers from the user and return the product of those numbers. It should check for all of the same errors that the existing AddNumbers example does. This problem will require changes to Web.xml, and the controller (modify the existing AddNumbersController and refactor it to NumbersController, rather than creating a new controller). You will also need to create a new MultiplyNumbers servlet and new MultiplyNumbers JSP file, both of which can be based off the AddNumbers versions of those files.
After you have modified AddNumbers and created MultiplyNumbers and have them both completely working, modify the existing Index JSP file so that you can access all three of the servlets (AddNumbers, MultiplyNumbers, and GuessingGame) from the Index page. Implement this as a collection of three “submit” buttons, each labelled with one of the three functions. Each button will result in IndexServlet issuing a doGet to the appropriate JSP.
After all of the above are working, create a common model class (Numbers.java) for AddNumbers and MultiplyNumbers, such that the numbers submitted through the HTTP request are stored in the model, along with the result. You will need get and set accessor methods for all model fields, along with a constructor for the model class. Look at the model for the GuessingGame WebApp as a template - and how that model is instantiated, initialized, and accessed. The corresponding JSP’s should pull the data directly from the Numbers model, rather than from the HTTP request. Again you can look at the GuessingGame implementation to see how this is done.
As part of this exercise, implement a complete set of test cases for the controller and model classes. Implement those test cases as you develop each of the above tasks. A significant portion of the effort on your team project will be creating an extensive and comprehensive set of JUnit test cases - WHILE YOU ARE DEVELOPING YOUR TEAM PROJECT.

NOTE: I HIGHLY recommend that you save your work after you have each of the above steps working. To that point, I also highly recommend that you use this lab as a means for learning how to use git to store your changes on GitHub.

At a minimum, archive the project at each stage, and submit it to Marmoset. That will provide a back-up in case you lose your work, or if you need to revert to a previous version of your work.
If you want to keep your previous work accessible to you, make copies of your project in Eclipse after the completion of each step, and then rename that copy to indicate the completed step. Continue your effort in the existing project.
I still strongly suggest regularly storing your archives to Marmoset (preferably to GitHub) so that you can restore your work if your PC dies.

Submitting

NOTE: You must also get this lab signed off by a tutor/mentor or your instructor in order to get credit for it. Simply submitting the lab to Marmoset without a lab sign-off will NOT result in any credit. You must get a lab sign-off.

Here is the complete set of tests that will be used to sign-off on your lab.

Here is a PDF version of the complete sign-off criteria that you can download, print, and use as a checkoff list when you get the sign-off for the lab.

Although you should strive to satisfy all of the above tests, a minimum passing submission must have the following:

An operational Index page that links to all 3 applications
The Add Numbers page must allow entry of three numbers
A Numbers.java model file
AddNumbers.JSP and MultiplyNumbers.JSP must pull their field data directly from Numbers.java and NOT from the original parameter values passed in through the HTTP POST received by the Servlet.
There will be at least some test cases for the methods in NumbersController.java and Numbers.java

When you are done, submit the lab to the Marmoset server using the method below.

From a web browser

Save your project (CS320_Lab02a_username) to a zip file by right-clicking it and choosing

Export → General → Archive File

Make sure to choose an appropriate location and archive name before saving the archive, or you might unintentionally overwrite an archive that you previously saved.

Upload the saved zip file to the Lab02a project on the Marmoset server. The server URL is

https://cs.ycp.edu/marmoset/