B7 Informatik 2 Summer 2024

Lab 03 Handout: A Note on the Notation of CRC Cards

We’ve discussed the relationship between the Classes “Student” and “Course” (aka Module, Class) in last week’s lab and lecture.

I’ve pointed out that if you change the syntax of the representation, e.g. because you use some kind of diagramming tool, you have to be careful not to loose any information.

if you consider these two CRC cards below, a CRC card contains information about these three things¹:

• Class Name
• Responsibilities
• Collaborators Dependencies (see below)

CRC-Cards

Consider these two CRC-Cards:

Class Diagram

This class diagram contains the same information: class names, responsibilities (in the form of method names) and a dependency: Course depends on Student. Note that this relationship has a direction!

Why I use the term “Dependencies” instead of “Collaborators” to describe Dependencies between Objects

The german term “Kollaborateur” should not be used to describe dependencies between Objects, as its sole meaning is in the sense of “someone who cooperates traitorously with an enemy”, “traitor”.² According to the Pons and Collins Dictionaries, the English term “Collaborator” is primarily used in the sense of “Colleague”, “Co-Worker” (“Mitarbeiter_in”), and only secondarly in the sense of “Traitor” – someone who cooperates traitorously with an enemy. The Pons Dictionary also list the translation “Nazi collaborator”/“Nazispitzel”.

Thus, “Kollaborateur” is not a good choice to translate the word “Collaborator” to German, as “Mitarbeiter/in” or “Kollege/in” would be more accurate translations. And even if it was a correct translation, the above mentioned negative connotations are enough reason not to use it. I’ve never seen the terms “Mitarbeiter/in” or “Kollege/in” used for collaborating Objects³.

The most common – and useful – term for this relationship seems to me to be “Dependency”. We say that a Class “A” depends on another Class “B” if the source code of “A” contains the name “B”.