This last chapter of the book takes up the issue of how to separate a program’s computation-related responsibilities from its presentation-related ones. You may recall that Chapter 1 first addressed this issue when it created version 2 of the banking demo. Version 2 contained the new classes BankClient, which embodied the presentational responsibilities, and Bank, which embodied the computational ones.
It turns out that Chapter 1 didn’t go far enough. This chapter argues that programs should also isolate the computation classes from the presentation classes, and for this you need classes ...
