David A. Scott

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Recent posts by David A. Scott

oh don't get me wrong, I'm not going to lose any sleep, I'm just mildly curious.
General Considerations (maximum = 100): 99
Documentation (maximum = 70): 70
O-O Design (maximum = 30): 30
GUI (maximum = 40): 31
Locking (maximum = 80): 44
Data store (maximum = 40): 40
Network server (maximum = 40): 40

I'm afraid I haven't much of an idea how/why I gained/lost marks in any section.

I went for a three tier design and RMI networking. I've already posted some rudimentary class diagrams which give some idea of the structure.

I can usually write quite clear english which is maybe why my documentation did well, I spent a lot of time reading and re-reading my choices document and I got my wife to test drive the user guide. I also included some ascii class diagrams in the choices.txt, though I suspect this was overkill.

The mysterious 44/80 for locking, I thought my locking code was rock solid!

99/100 for general considerations??

My networking code was (ahem) "heavily influenced" by the demo project in the Monkhouse book (so cheers Andrew).

I thought my GUI looked splendid so no idea why I dropped marks there.

I wish you could get a bit more info on why you dropped marks. I suppose the danger is that it would all get posted here and make it too easy for everyone else. Anyway that's as much thought as I'm prepared to give it, a pass is a pass after all.

With regard to the essay exam - don't sweat it. Give your choices document a good read through the night before and you'll be ok. I was in the exam for 30 minutes.

Thank you all for your help.


p.s. I got my result exactly two weeks after the essay exam. Not bad.
The only thing I can think is that the SecurityException is declared in the supplied interface which is not necessary for unchecked exceptions. But this doesn't mean it's invalid to do so.

I just used the one from java.lang.

It's there to be used surely.

Can anyone give a reason why this was wrong?


Originally posted by Timothy Frey:
Seems like a very reasonable and easy to understand diagram to me. As a matter of fact, it looks like your database server is EXACTLY the same as mine (with a few method names changed here and there). I passed the exam with this design, by the way, so it looks like you're in good shape!

That's great! I just wanted the diagram to make sense.

Thanks Timothy.

Originally posted by John Stone:
(but I think you are doing unnecessary work)

I'm starting to arrive at the same conclusion...

Originally posted by Rajah Nagur:

1. Does Data class composed of FileManager & LockManager?

Yes. Data HAS-A FileManager and Data HAS-A LockManager

2. From the above diagram, it seems there is inverse package dependency. i.e. Data is dependent on DBServicesImpl? What is the exact relationship between two?

DBServicesImpl HAS-A Data object. Or, more accurately, it HAS-A object that implements DB. Data has no dependancy on DBServicesImpl.

I thought <>------ represented composition.
Mark -

Sorry, perhaps I should have made it clear.

I'm not really asking about class structure I've chosen. I'm too far down the road to change my mind about that!

All I'm really asking is if this is a valid class diagram that might make sense to the examiner. I don't have much(/any!) experience of UML so I don't really know what I'm doing.

I wanted to include class diagrams in my choices.txt which is an approach that some forum users have taken.

John -

How did I do it? The hard way I'm afraid - typing lots of ascii characters into a text editor.

I'm not especially proficient at UML but this is what I've cobbled together based on a few tutorials I've read. Does it seem reasonable or am I just way out of my depth!

I just want to represent the structure of the key classes in my data layer and business layer.

Also : Does anyone know of a good text editor that lets you do stuff like this? e.g. cut a whole block of text and paste it to the right of another block? (Windows suggestions only please.)
I'm afraid I haven't touched my project for a month and I can't remember the specifics(!) but when I utilised my wifes laptop as a "server", I discovered a problem with my RMI implementation which was not apparent when running both client and server on the same machine.

So what I'm saying is it's definately worth testing them on seperate machines.
My project states that there should only be one server or one standalone client accessing the datafile so this should work in theory.

I suppose the problem comes if the application crashes unexpectedly and you have potentially lost hundreds of user updates. Also the same is true if the shutdown write fails. If you are writing the data out constantly and there are I/O problems you will probably only lose a handful of updates but if you are writing the data out once and there are I/O problems then you lose everything.

I'm sure you can think of clever ways to code around this and make it safer but I'd worry about the complexity of such an application. The oft-repeated mantra on this forum is "keep it simple".

My question really is - does that book serve well as an introduction to UML for the complete beginner?

Sometimes books written specifically for certifications are geared purely towards cramming the exam content and aren't much good for learning.

I'm currently trying to get my SCJD project ready for submission and I'm thinking about the next certification challenge.

I've found working towards a particular certification to be an excellent way to learn a subject (e.g. the Java platform) if it's not something I necessarily use on a day-to-day basis.

So I'm looking at the UML Fundamental exam next. I don't have much UML knowledge beyond being able to (more-or-less) understand class diagrams when they are presented in a book.

There is only one book available specifically for the OMG exam and I've read some discussion of it's pros and cons on this forum. But what I want to know is whether this book is suitable for a newbie like myself or is there a book which would better serve a complete beginner? Sadly there is no "Head First UML 2.0" - perhaps there is an equivalent?
Since you're not "breaking" the interface contract by adding a RuntimeException I don't think there's a problem.

And declaring it in Data.java is good manners for any (theoretical) client programmers using your class.
[ May 14, 2007: Message edited by: David A. Scott ]