Exercises in Programming Style–Abstract Things

NOTE : read the rest of the series, or check out the source code.

If you enjoy read­ing these exer­cises then please buy Crista’s book to sup­port her work.

Fol­low­ing on from the last post, we will look at the Abstract Things style today.

 

Style 13 – Abstract Things

Constraints

• Larger problem is decomposed into abstract things that make sense for the problem domain
• Each abstract thing is described by what operations the things of that abstraction can do
• Concrete things are then bound to the abstractions
• The rest of the application uses the things not by what they are but by what they do in the abstract

 

First, let’s define our abstractions:

Unfortunately, after this point the implementation are basically identical to the Things style (except the relevant members in each type is defined as part of the corresponding abstraction rather than as a member of the type):

Finally, remember we need to “use the things not by what they are but what they do in the abstract”, so call the WordFrequencyController via its abstraction:

 

You can find the source code for this exer­cise here.