Language: Java
Version: Java 11.0.2 - JDK 10.0.2
Project Type: Java Maven
Created with IDE: IntelliJ 2020.1
- Open the project folder Bowling using an IDE that can compile and run Java Applications (Ex: Netbeans or IntelliJ)
- Make sure the IDE is pointing on the Main-java.
- Alternative, right click on the Main-file (should be located Bowling/src/main/java/com.company/main.java) and select the "Run Main.main()"
- Run the application
- Important Note: By default, the app will use the API/URL provided by SKAT ( apiConn.getSkatBackendApi() )
- To switch API/URL to be used when running the app, open Main.js and change the method being used from apiConn
- The app, by default, has 2 API/URL
- apiConn.getSkatBackend()
- apiConn.getCeoBackend()
- The following processes are being shown in the console when the application is run:
- Displays the scores retrieved from the server to be calculated
- Displays the calculated results and the token, to be send to the server for verification
- Displays the servers response, both if the received results were correct and what results were sent
Original project Description found here
The project was part of an assignment for a job interview with SKAT (the danish IRS).
The assignment tasked me to create a program and algorithm, that could retrieve a collection of scores from a bowling game from a server provided by SKAT, correctly calculate the scores, and finally send the calculated scores back to the SKAT servers to verify the calculations.
Furthermore, the program also needed to show "a substantial amount of Test", in which I decided to use JUnit 5.4 for Testing.
I chose to tackle the assignment using Java, due to the job-description specifying SKAT was looking for a JAVA-developer, and I added the MAVEN framework to easier add external libraries and dependencies.
My first crack at a solution, and the one that would be handed in before deadline, can be found in the Calculations-folder. I was by no way satisfied, proud or happy about my first attempt at the assignment, which suffered from a lot of simple mistakes and my excitement and rush to deliver a solution.
To be honest, I had not programmed in JAVA for some time, having mainly programmed in C# and JavaScript during my last project, which at the time of writing this project, was back in December of 2019.
Combining my lack of programming the past couple of months, needing to quickly get back into JAVA and the excitement of having been given a project to work on and present, was a perfect cocktail for disaster.... And it showed.
Work on the assignment proceeded right up until deadline, and despite my feelings regarding my work, I handed-in my work as it was at the time, and continued to work on it through the night, to get it to a somewhat stable state.
The handed-in version was able to get the scores from the servers, perform calculations and send the results back for verification. But the code was clunky, messy, hard-to-read and in general bad. The calculation was insufficient and did not cover all the possible scoring scenarios, and there was a clear lack of Testing.
Having handed-in my solution for review by SKAT, I was left with a feeling of huge disappointment by my performance, so much so, that in my email with my Github-repo link to the person at SKAT that was going to review my work, I wrote that if they wanted to cancel the interview based on my solution, I would be totally ok with that.
My first solution can still be found in the folder Calculations, though note that the program will not run the methods from that folder atm.
Having digested my frustration and disappointment after having sent my Github-repo link to SKAT, I decided to redo the assignment from (almost) scratch, because I had to prove to myself that I could do better.
Despite only having a few days before my interview, I decided to take another crack at the assignment, learning from my mistakes from the first go-around and try to avoid letting the excitement and adrenaline take over and make me rush-code.
I decided to re-use my work on the GET- and POST-classes, since my main gripe was with the way I handled the Calculation-folder and -classes, and these two performed their function ok,
but they both did receive a few tweaks and additions during development of this second solution.
I also decided to not delete/remove the first solution from the project, so that I could see the difference.
The new solution, its folders and its subsequent classes and files, was named with VerTwo at the end of the [Classname], to avoid clashes with existing classes with similar names in the first solution-folder.
The first iteration of this second version of the assignment was worked on for 2 days, in between having handed-in the first version for review and my interview with SKAT. It was pushed to Github just 3 hours before my interview, around 04 in the morning...
Despite the second solution not being totally complete before my interview, I was a lot more satisfied and happy with it. The solution worked better, better calculations, was more readable, better comments, better doc, had more Test, and was in general a HUGE improvement from my first solution.
Because of the timing and me not informing about a new updated version of the solution on Github before my talk with SKAT, my interview was based on my first solution, which I had previously stated I was fine with. At the beginning of my interview and before we went through SKAT's feedback of my solution, I did inform them that I had created and pushed a new version to Github, which they could look through if they wanted to later.
Despite my interview and review being based on the first solution that I provided, which I had no issues with, I enjoyed working with the assignment, since it provided me with a great project to get my programming back into gear. I therefore continued to work on my second solution, to use it as a project in which I could improve my problem solving and general programming capabilities, and show my programming-style for future opportunities.
This second solution has greatly improved since the version that I managed to create in under 2 days and pushed to Github, just 3 hours before the interview, and is vastly better in all areas than the first solution.
The current iteration of my solution can be found in the CalculationsVerTwo-folder. When running the application, this is also the solution that is being run and executed.
A new aspect of the project that I came up with for this project, was creating my own API on my own personal Node JS/Express JS backend-server, in case the one provided by SKAT ever got shutdown or if the API-specifications of their end changed.
I therefore have created a /bowling/api/points on my own backend-server, combined with a No-SQL database that I have populated with scores, so that the GET- and POST-calls to my backend performs exactly same as SKAT does when I worked on the assignment. The user is able to manually switch between which API the application is going to use (see the "How to Run"-section at the top of the readme for more information). While these API's was developed using the same JSON-structure and GET- and POST-routes as SKAT's, development of these API's was done with no access or knowledge of SKAT's source-code.
For more information regarding my own developed API, please click here to see the repo containing the source code for the bowling-api.
While developing these API's and testing them with the application, a lot of updates, changes, bug fixing and improvements has been made.
- I've updated the application to use the more modern httpclient to perform GET and POST to the backend, rather the outdated httpurlconnection
- By populating my database with scores and testing those scores on my application, those scores actually helped me to identify bugs and incorrect calculations in the application
- Created a lot of new Test to help me identify and fix the bugs that was showing up, when testing the application with my own backend and scores
- Application now has over 50 test
- Database has 20+ scores, scores that are designed to really challenge the application's ability to correctly calculate them
- A lot of refactoring for better code-layout and readability
- Better documentation
Overall, I'm really proud of my work on this new addition to the project! It has especially future proofed my own application, in case SKAT closes or make changes to their own setup.
The following is a list of features and work that I still need to complete in this project, and a few general thoughts/notes about the project :
- Because this was a one-person project, I did not use Branches during development, which in retrospective would have been preferred, since it would have made it easier to go back and more elegantly look at various snapshots/stages of the project during development.
- Apply and enforce the SOLID principles to the entire project
- Refactoring of variable- and method-naming needs to be performed, for better readability
- Refactoring of the CalculationsVerTwo.java-file, since it seems a tad too big and a bit bloated
- Refactoring of individual methods to be more and easilier Test-able
- Continue updating Documentation of method- and Test-descriptions
- More Testing of individual methods
- Outside of Test, make it possible to manually provide a list of scores to be calculated.