Yes, you are right. Judith uses what are probably the official standards for UML notations, and we use the same notations as the Gang of Four. I like the fact that GoF use arrowheads and have the same notation for inheritance and implementation, which are non-standard but I believe more useful for design patterns.

Take care,
Bill

Thank you very much. Checked out your site—very nice indeed!

Kindest regards,
Bill

The IBM UML is pretty official–I think it’s the one that Judith Bishop uses in her book on C# design pattern. However, GoF had lots of meanings for the same symbol—like “..holds a reference…” (Line and arrow) By keeping it general (and loose!), there’s more latitude in how you can construct a relationship. Sometimes (probably a lot of times) we end up worrying about the wrong thing. If we keep the principles in mind and have a general sense, I think we can do better than trying to nail down what is broad.

Where you have ‘dependency’ I think the term needs to be set in a specific context. If you say that a Client class, whose primary task is to make requests, depends of the structure of the pattern, I’d agree, but then all you have is dependency, and you’re worrying about the wrong thing.

It’s better to think composition and delegation than dependency. The Client uses the structure of the the design pattern and is sometimes part of the pattern itself. One could make an argument that they’re all interdependent, but I think that too may be a moot point. The focus needs to be on reuse and loose relations—just like Carnaval!

Deixe-nos ir ao carnaval!
Bill

This topic always confuses me when I’m doing an UML diagram. For instance, when you say “When one class holds a reference to another class…” isn’t the same as “In UML, a dependency relationship is a relationship in which one element, the client, uses or depends on another element, the supplier. You can use dependency relationships in class diagrams, component diagrams, deployment diagrams, and use-case diagrams to indicate that a change to the supplier might require a change to the client.” from IBM UML Help. There fore, you should use as a dashed line with an open arrow that points from the client to the supplier.

My point is: it is still not clear when it is a dependency or acquaintance. Or is an acquaintance a dependency relationship?
I hope I get your answer!

Tot ziens!

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