Number Validator - Code Assignment

This is my solution to a code assignment where the task was to, in Java, with an OOP approach, write a program that tests the validity of Swedish personnummer (social security numbers) and two other types of "governmental numbers" - organisationsnummer and samordningsnummer. The checks to be performed should extend a fictive class/interface ValidityCheck and a method that takes such checks should be implemented. The specifications of all three number types were provided. The program should take the numbers to be checked as strings. The project should also have a build script.

The program is adapted for demo purposes (see "Run" section) but the code could also be used as part of something bigger. The basic idea is: To validate a nummer, create a Nummer object of corresponding type and pass the number to be validated as a string to the constructor, then execute the object's method checkValidity(), which will update the isValid and failingTests fields of the Nummer object. These fields can then be accessed to make printouts/logging or whatever one needs them for. In App.java, a few such methods are implemented for the demo. All important classes also have unit tests (see "Unit tests" section).

Dependencies

• Java 19

Build

• The project uses Gradle for build and running (built with Gradle 8.0)
• The gradlew script ensures that the right version is used and because of it you don't need to have gradle installed to run the project.
• To build and run the project, just use the following command, while in the project folder.

On Windows:

$ gradlew.bat run

On Linux/Mac:

$ ./gradlew run

Run

The program has two modes:

1. testing example numbers - pass no arguments
2. testing a single number - pass number to test as argument

Mode 1: Test example numbers

With no arguments, the program tests example numbers from all three classes of numbers and prints if they're valid or not and list failing tests if invalid.

$ ./gradlew run
> Testing VALID personnummer:
> 900118+9811 is a valid personnummer
> 201701102384 is a valid personnummer
> ...
> Testing INVALID organisationsnummer:
> 17556614-3185 is not a valid organisationsnummer
> 1 out of 4 ValidityChecks failed:
> YearDigitCheck: Year digit is not 16.

Mode 2: Test one number

Specific numbers can be tested by passing them as arguments to the program. The type of number must be passed as an argument (p, o or s).

$ ./gradlew run --args="900118+9811 p"
> 900118+9811 is a valid personnummer

$ ./gradlew run --args="556614-3185 o"
> 556614-3185 is a valid organisationsnummer

$ ./gradlew run --args="s 190910799824"
> 190910799824 is a valid samordningsnummer

$ ./gradlew run --args="17556614-3185 o"
> 17556614-3185 is not a valid organisationsnummer

If you want to see what tests failed, pass the argument v or verbose.

$ ./gradlew run --args="17556614-3185 o v"
> 17556614-3185 is not a valid organisationsnummer
> 1 out of 4 ValidityChecks failed:
> YearDigitCheck: Year digit is not 16.

Unit tests

The project is tested with JUnit Jupiter tests. To execute the tests run:

$ ./gradlew test