Re: 'withing' problem

[Ted Dennison<dennison@telepath.com>]

In article <3be65f4c$0$237$ed9e5944@reading.news.pipex.net>, David Crocker
says...
>
>OK, so if you think cross-dependency reflects bad design when the
>implementation language is Ada, can you tell me how you would redesign the
>Doctor/Patent/Insurer example in
>http://home.bluemarble.net/~jvolan/WithingProblem/FAQ.html ?

Make a new class called "symptom", which the doctor treats, and the patient has.
Make another new class called "insurer", which the doctor bills and the patient
has (and periodicly pays into). When a patient calls Visit_Doctor, they pass in
their symptom(s) and their insurer.

Circular dependancies are just as bad an idea in OO control flows as they are in
traditional logic control flows. Think about what used to result back when
people made their own loops using all sorts of interrelated goto's. When
designing you should be looking for hierarchy and structure, not just any old
path through your objects that seems to work.

I understand that in early OO, objects each had their own control (like
threads). If this were the case today we wouldn't even be having this
conversation. You are trying to make multiple objects both servers and clients
with each other, which is a perfect design for deadlock.

---
T.E.D.    homepage   - http://www.telepath.com/dennison/Ted/TED.html

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