Tomi Tuomainen

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Recent posts by Tomi Tuomainen

Harbo,

In Cade's system data is persisted into legacy systems and entity beans won't help much there. Although it seems that you could use an entity bean instead of customer DAO for creating and maintaining account. Maybe Cade assumes that container managed security will be used, so details of creating accounts will be specified later (will LDAP or database table hold user names/passwords etc.)

Shopping cart will probably be maintained with HTTP session, so it is not actually a component to be shown in the Catalog component diagram.

The assigment tells us to show all J2EE components in the component diagram, so also entity beans should be there. But of course, you don't have to use entity beans, this is your decision. Also you could use stateful session beans, or just let the web or Java application maintain the state...

Tomi
[ August 24, 2004: Message edited by: Tomi Tuomainen ]
Hello friends

I had a couple of free days and of course this was a great opportunity to finish my assigment. Three long days and I got everything ready for upload. In overall drawing diagrams and writing assumptions won't take that long, but research work was more time consuming. Maybe 60-80 hours totally...

I'm still feeling a little uncertain about my TransMaster solution with just stateless session bean and DAO... and I'm not sure that creating user account via entity bean was that a good idea with container managed security... And one extra object in a corner of a sequence diagram (which I noticed after upload) .

Anyway, thanks guys (especially Parag), this forum has been a big help. If I fail I just have to get back to you for more second opinions.

Tomi
Parag,

That means we should identify design classes based on domain classes (or objects). So I don't think any method (RUP etc.) recommends drawing implementation specific classes "blindly". Anyway, it's important that there's some kind of link between implementation specific elements (in component and sequence diagrams) and implementation independent elements (in class diagram). But we don't have to use same classes in all diagrams since perspective changes.

I hope I'm making some sense here... (feel free to correct if I'm not).

Tomi
Parag,

The way I see it, domain object is purely conceptual, "analysis object model". The domain object might be implemented as an entity bean or it might correspond to VO created by DAO. I would just model VO's and EJB's the way it seems best for J2EE architecture and check later traceability. (This is probably not preferred way in any method, but the point is that don't model "domain objects" in diagrams after business analysis -> model design or implementation objects).

Tomi
I don't think it's necessary to go into details. For example showing FlightListVO should be enough, I'm not planning to show any FlightVO's. There's just 12 points to gain.. (somebody correct me if I sound too lazy ).

Tomi

Originally posted by Parag Doshi:
Might sound like a dumb question. Does Dia work on windows?



Yep. Just try it, won't take long to check the features. Dia is just a simple drawing tool with some UML support.

Tomi

Originally posted by D. Rose:
Hi Tomi,

Is DIA good enough for our purpose? Does it have good export function as well?


Dia is good enough for me, but I haven't passed yet . Export function has some bugs, but I think all the tools I tried have. Anyway, exporting seems good enough, Dia supports many formats.


How about component diagrams?


With Dia I can model a component inside a component by using just "ordinary" boxes. This is somehow impossible with most of tools, although it's shown in UML standard.

If you have problems with your current tool and haven't drawn all the diagrams, I recommend trying Dia. But I think every modeller has his/her own favourite and there's no perfect tool for everyone.

Tomi
Parag,

I'm glad if I helped. Yes, you can add "..." attribute in a Dia class. And if existing UML elements don't fit, you can always freely add boxes, lines and text with Dia.

Tomi
I'm thinking to use DAO with query statements for read only data. As I "modeled" the database (in my head), I figured out that searching data with complex criteria would be quite tricky with entity beans. So I'm thinking to use entity beans only for data that needs to be inserted/updated. Though I'm not sure, if I'm following any "official" best practise...

Tomi
[ August 18, 2004: Message edited by: Tomi Tuomainen ]
Parag,

Unfortunately I can't help you with Jude, but if things get too complicated and you need a free, flexible tool, you might want to try Dia.

Tomi

Originally posted by Parag Doshi:

As for the web container, I have a need to show the interaction between the client request coming in and the web container intercepting it (for container managed security), so was wondering how to show it. I could show an object and add the <<web container>> stereotype..thats one possibility..


I just added an UML note with a text "container handles authentication" in suitable places. So I didn't actually model authentication or anything that happens after customer sends logIn message (until log in succeeds). I'm not sure if that's the best solution but I hope it's good enough for my examiner.

Tomi

Originally posted by Parag Doshi:
I had a few sequence diagram questions:

1. How are web containers and ejb containers shown in a sequence diagram? I wanted to show interception of message call by web/ejb containers in the seq diagrams. Do I attach a note or show it as an actor or is there a different way to show it?


From my point of view it's not necessary to show containers in a sequence diagram if a component diagram shows them. In a component diagram you can use a package, or preferrably outer container-component. In a sequence diagram you could use of course notes, but I don't know if there's any other reasonable way...?


2. If a DAO returns a VO, do we have to show the return through all the layers or just attach a note that the DAO operation returns a VO?
For example. if a FlightDAO returns a FlightVO, do I show the return of the VO to the Facade, then from Facade to the Delegate, from delegate to the Action etc or just attach a note stating that a VO is returned?


I would show that DAO creates VO object but not any return arrows or notes. Client could then call getData of this same VO object. (check Transfer Object pattern sequence diagram). In practise client's VO is not the same instance, but I don't think we should stress about that. Cade is not showing different copies of VO's in his example.

I hope my opinions help...

Tomi
Don't show EJB's or maybe just facades. Keep it simple. (my opinion)

Tomi

Originally posted by D. Rose:
For authentication, can I use third party tool (like LDAP) than container security?


Hi D,

The idea of container managed security is that container can be mapped to an extra resource like LDAP or a database table, which holds users and roles. This means that both servers (Web and Application) can use a common resource. This way also both clients will finally access the same user data.

I don't think it's necessary to worry about network security in diagrams, but we should understand and explain shortly how security will be implemented. (I hope I'm not wrong in this one!)

I hope that answers the question...

Tomi
Thanks Gavin, I think get your point now. You we're talking about common presentation tier all along...

My point just was that if this common GUIFrontController is running in an application server, there's a "container-preferred", secured way to access it from different clients. If common GUIFrontController is running in a web server, we surely need SOAP or some other way to communicate with a Swing application client.

Tomi