Larr Goneg

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since Jul 02, 2003
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Recent posts by Larr Goneg

Originally posted by Billy Tsai:
how much documentation do you have?
my design is heavily based on the petstore architecture so it has many many classes and looks complex so I have like 10 pages of documentation.

I have 8 pages doc. Don't worry about the number of pages, just ensure you explain your design completely and clearly.
Actually there are many post discuss this issue in this forum.
I don' think the role of Front Controller and BD are overlapped, because they are put into different purpose. The front controller is used to mediate with the GUI and provides the data(in petstore, it uses viewhelper to get the data). But the BD is used to encapsulate the underlying business logic from the client. Only BD will interact with serverside EJB. From the implementation point of view, it should be something like that
class FrontController {
public void processRequest(){
class BD{
public getDisplayData(){
ejb1 = ServiceLocator.getEJB1();
ejb2 = ServiceLocator.getEJB2();
Off course you can put this processing into front controller. But I think it make more flexible and extendable to make it independent with the client.
anyway, I don't think it will affect your score if you combine both together, since it's your design choice. We all know there is no absolute right design. The important thing is you can defend them.
[ September 09, 2003: Message edited by: Larr Goneg ]
Billy, yes, I use some of the stereotype, but not many.

dbala, I submited on 30th July, and got the result on 10th Sept. I think you have to wait for some more time.
Ahoo, I have 1 class diagram, 1 component diagram, and 7 sequence diagram(including one for MVC and one for login)
Billy, though I spent a lot of time to study petstore, but my design is not totally based on it, since I think it's a little complex.
So,my class digram didn't show any similar classes from petstore, only show the domain classes, it has nothing to do with the J2ee.
sh, yes, I used BD, Front Controller, which are mainly shown in seq diagram, as well as in component diagram.
I'm very glad to know that I passed. Thanks everyone for your helpful posts in this forum.
Sun Certified Enterprise Architect for Java 2 Platform Enterprise Edition Technology Part II (310-061)
Grade: P
Score: 93
Comment: This report shows the total points that could have been awarded in each section and the actual amount of points you were awarded. This information is provided in order to give you feedback on your relative strengths on a section basis. The maximum number of points you could have received is 100, minimum to pass is 70. Class Diagram (44 maximum) .......................... 42 Component Diagram (44 maximum) ...................... 39 Sequence/Colloboration Diagrams (12 maximum) ........ 12 jar is less than 200k(with gif images), so the size doesn't matter.
2.Make it simple, it's mentioned by most of candidates, I think once you get a solid understanding about it, the rest of work will be very easy, and you will feel confidence.
3.Explore the petstore before doing the assignment is very helpful, especially for those who don't have much experience. Ask the questions that need to be taken care all the time when you study the petstore, such as the how it addresses the security, how it manages the session status, how transaction is handled, etc.. I ever saw a post advertise their product, in their homepage, there are a list of those kind of questions, after you can go through each of them in petstore, it should be easy to finish the assignment. But I can not find the post now.
4.I also get the feeling that the correctness of your design doesn't affect your score if you it make sense to yourself, and you can defend it in all the aspects. So go ahead to draw your design first, then review it yourself, and to make changes untill you think you cover all the aspects.
5.Don't get yourself entrangled into UML syntax, think about how to show your design idea. In most time, a piece of note can help a lot.
6.I must tell that it's hard on the way, but once you finish it, it will become very easy. So be patient, and record every decision and every improvement you made in the process. And enjoy yourself for the hard working on the way to the goal.
Ok, I found this post is helpful
but still didn't get a clear understanding! Some one kind enough to show some light for me?
according to BluePrint
As of version 1.3 of the J2EE platform, a J2EE product is required to support access within a single transaction to:
• A single JDBC database (multiple connections to the same database are
• A single Java Message Service (JMS) provider, and
• Multiple Enterprise Information Systems (EISs) through resource adapters
(Connectors) specifying the XATransaction transaction level
Access to multiple JDBC databases within a single transaction is not required

But in case of
1. I want to have a unit-of-work, which should be executed in one transaction, but there are data update from different Database.
2. If in the transaction, I also want to include a transaction with external system through http protocol. What should I do to make it participating the whole transaction? Do I need to write the ResourceManager to support XATransaction from the ground?
Thank you very much if you can show some light!
most sample applications in ejb books are using declarative security, but I am wondering how it is happen in real project. Because in that case, Your users will be managed by the Application Server, all users have to be configured in the deploy descriptor, how are you going to add users programmically?
In petstore, it doesn't use any J2EE security feature(HTTP basic authentication, SSL authentication, or form-based login), instead, it uses EJB and SignOnFilter to handle this. Why doesn't it use declarative security to handle login, etc.?
anyone show some light on it? thanks!
Normally if you use CMT to manage transaction in EJB, the container will take care of all the commit and rollback job(which is the same as commit of rollback in Database, I think), but what if the EJB's change is not a database update? For example, a EJB PaymentEJB access external creditcard service using special protocol, I'd like following in one transaction,
in this case, how to control the transaction? Do I have to write something like commit and rollback myself in accessExternalservice()?
First, Thank you very much for your helpful reply.

Originally posted by Ajith Kallambella:

Use of BD decouples your clients from the enterprise tier and hides details such as JNDI lookups for the session facade(ServiceLocator) and in some implementations, can actually store the home reference to the session facade. BDs are also very handy if you have non-web based clients. In such a scenario, you may not have the controller which is typically a Servlet. Bundling BDs with stand-alone client jars is a very popular practice.

if I have non-web based clients, for example, using RMI to access EJB tier directly, can I still reuse the same business delegator?

BDs normally have the same set of methods as the SFacade, but nothing precludes you from adding more behavior to BDs. For instance, a BD can act as a "business controller" and selectively choose an appropriate facade to service the requiest. For instance, a BankingServiceBD can look at the request parameters and select either a TellerFacade or a CustomerFacade to service the request. In this case, although the BD exposes just one method to the client, there is some business intelligence involved in how the request is processed and such nuances are neatly hidden from the clinet.
Hope this helps,

So, in an application, the number of BD should always less than the number of session facade. normally there should be only one BD, for ext., in this Banking applicaiton, there maybe only one BD that is BankingServiceBD, am I right?
thanks again!

Originally posted by Anil Vupputuri:
According Service-to-Design Pattern, the flow something looks like,
Client -> Controller -> Dispatcher -> Session Facade -> Business Service (EJB)


But in this case, what's the benefit of BD(dispatcher), since every BD only deal with one Session Facade, actually both BD and session facade has the exactly same methods, why not call session facade directly from controller?
1.When I want to draw a line between a note and a message in sequence diagram. it only allow me to draw the line between the vertical bar and the note, it doesn't highlight when I put mouse on the message.
2.In component diagram, how to show the external subsystem? In Mark Cade, he shows an interface, which then have a dot-line to Subsystem, But Together doesn't allow to draw such a line beteen the interface and the subsystem.
thanks for your reply!
did you show the class diagram in conceptual perspective(which is only to show the concept in the domain)
or in specification perspective(which will show the resposibility of the classes that participate in the software)
Can you tell us what's your secret of success? (besides "simple and clear")
what do you think you have learnt from this process?
how do you understand class diagram?
when we model normal application, there are inheritance relationship, for example, in <<Apply UML and pattern>>, there is
how should we model this in our class diagram, should we model in the same way?
but actually in J2ee, you won't have CreditCardPaymentEJB, CashPaymentEJB,CheckPaymentEJB, but you only have one EJB that is PaymentEJB because it's correspondent to only one table. In this context, should we show only the payment in the class diagram, if so, how should we show there are different kinds of payment?(just an attribute?)

Originally posted by Jitender Bhatia:
Debjoyoti >
Document this. Say that by using so-and-so i get to achieve so-and-so. This will go a long way in ensuring that the examiner does not miss it.
Perhaps it is alright not to have a perfect solution (what is a perfect solution after all ? There are so many), but it is not alright not dealing with a requirement at all.

yes, meeting the requirement is a must, but where is the requirement? I think the assignment doesn't give you one precise requirement to meet, rather you have to make assumption to "make" a requirement. That brings a question, will our assumption affect the score, I mean, is there any "good" or "bad" assumption?
btw., in real world, as an architect, will you be allowed to make assumption on requirement?