OOP Kata

A code kata is an exercise that will help you to train a very specific skill. This one will help you train your Object-Oriented approach. Feel free to over-engineer solution. Below you will find general information about the project that you will work on.

Warm up

You can jump straight to the code, or you might look at the article explaining the approach.

Initial project

Code on main branch simulates some washing machine. There are a few requirements, that it needs to fulfil.

• Must provide dedicated programs for a different type of fabric; supported ones are wool, cotton and silk
• Programs for fabrics must be adjustable in the matter of temperature and spin speed
  • Wool can be washed only in temperature up to 40°C, with spin speed between 100 and 400 rounds per minute
  • Cotton can be washed in temperature between 30 and 95°C, with spin speed up to 1200 RPM
  • The maximum temperature for silk is 30°C and up to 300 RPM
• The washer should have protection for putting over 7 kilograms of laundries
• The default value for temperature and spin speed will be its maximum value

Sample solution

You can find a sample solution on sample-solution branch. If you need guidance on start, you can follow these steps:

• make a class for each type of Laundry Elements and remove enum
• do not use setters for an update of laundry dirty flag, make dedicated, explicit methods that will mark laundry as dirty or clean
• create a class that will group Laundry Elements into Laundry object. Use this object in communication between classes
• create a Basket class that will handle the logic of sorting laundry by its type
• create a class for Program that will store spin speed and temperature
• rename Washing Machine methods so they will reflect real-world operations that you perform on it
• try to remove all direct passing of List as method parameter - List should be only used internally inside of a class
• extend Programme class so it will contain behaviours to adjust parameters
• temperature can be changed only every 5 degrees
• the spin speed can be changed only every 100
• the programme can be set up to perform an additional rinse
• create dedicated classes for temperature and spin speed
• move check if the value is in a valid range to Temperature and SpinSpeed classes
• laundry, that does not fit into Washing Machine should be put back into Basket
• try to remove Service class or name it properly - naming class with 'Service' suffix promotes adding all, barely connected code into this class instead of splitting responsibilities

Another languages

Thanks to the community, this Kata is available also for another languages. Check them out!

• Swift by @ytyubox