R Programming By Example

Easily allowing new database integration with a factory

We know at this point that we will only use the CSVFiles Database implementation for this example, but we can easily imagine cases where new database implementations come into play. For example, the reader will create an implementation of the MySQL database, and will want it to substitute the CSVFiles implementation. Isn't that right? When you expect some change in the future where you will likely need to switch one interface implementation for another, factories is a great tool to facilitate that change for yourself in the future.

Our database_factory() function receives a db_setup and table_names objects, both of which will come from our centralized settings file. It then takes the ...