Practical Object-Oriented Design: An Agile Primer Using Ruby

by Metz Sandi

There is design detail that must be captured at this level, but an object-oriented application is more than just classes. It is made up of classes but defined by messages. Classes control what’s in your source code repository; messages reflect the living, animated application. Design, therefore, must be concerned with the messages that pass between objects. It deals not only with what objects know (their responsibilities) and who they know (their dependencies) but also with how they talk to one another. The conversation between objects takes place using their interfaces; this chapter explores creating flexible interfaces that allow applications to grow and to change.

Oop vs classes