calvin zhu

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Recent posts by calvin zhu

My opinion is they focus on different aspect. While in SCEA u don't have to do the testing and coding, but the material u need to read and learn is much more than SCJD.
So it doesn't make too much sense to compare them, it varys from people to people.
How about FastLaneReaderSessionBean<<stateless>> -> DAO ?
How can I move the starting point of a FOC? (Focus of Control, is portrayed through narrow rectangles that adorn lifelines.)

When I create an Object in the sequence diagram, it will have a default FOC, which is started just under the object. And I have no way to move it. Even I move the message between 2 objects lower, it will only create 2 seperated FOC on the object's lifeline. And the first FOC still attach to the oject's rectangle.

If I can't move this starting point of FOC, then it means every object is created at the same time. That's no good. So please help me if you have this experience.

I read the help and search on the internet, just find somebody with the same problem:
"Moving the top and bottom of focus-of-control rectangles. Sometimes I manage to move them by moving some messages. I've tried the business of holding down the Alt key while moving a message. I'm still in the dark about this. In particular, I'd like to get rid of the dangling tail of the FoC rectangle that always hangs down below the last outgoing message from that object."
I agree with Ajith.
The truth is I did think about which approach to take for facade after reading Parag's approach few days ago. Then I looked at pet store's example, found it also use SFSB as facade, which makes me think is using SFSB as facade such a bad choice?

Allow me do a simple calculation here:
Using SFSB as facade, that's is enough for keeping session.
Using SLSB as facade, u still have to create a SFSB to keep the session. So it's SLSB + SFSB vs SFSB.

Using SFSB as facade, when serving more user than the instance limits, container will do the serialization for u under necessary situation.

Using SLSB as facade, everytime the reference pass in and out need to be serialized.

So I will go for the SFSB facade choice.
I think the second should work too, why not? As long as your local reference implements Serializable interface.

I didn't test it and would like to know the answers too. Maybe you can ask Parag Doshi, seems to me he is taking the same approach in assignment.

Originally posted by Richard Duglora�:
- Is RMI-IIOP over SSL possible and if yes is it common ?

- If I have 2 EJBs A and B, is it possible to transmit to a (remote) client a local (EJBLocalObject) ref to B, then have the client pass to A the local ref to B (as an argument in a call), and make A call B via this ref ?


The first one is yes. I'm not sure if it's common. I find this on IBM website.

Overview: WebSphere Application Server's use of Secure Socket Layer
Secure Socket Layer (SSL) provides secure communication for several WebSphere Application Server components. In particular, SSL is used between:

The Web server WebSphere Application Server plug-in acting as an SSL client, and an application server Web container acting as an SSL server using HTTPS.
Am EJB client acting as an SSL client, and an application server acting as an SSL server using RMI/IIOP over SSL.
A Web component, including servlets and Java Server Page (JSP) files, acting as an SSL client, and an external SSL secured Web site acting as an SSL server using HTTPS.
An enterprise bean in an application server acting as an SSL client, and an external SSL secured EJB server acting as an SSL server using RMI/IIOP over SSL.
Internal administrative and application server processes using RMI/IIOP over SSL on WebSphere Application Server Advanced Edition.
Administrative clients, including the administrative console, XMLConfig, and WSCP, acting as an SSL client, and the administrative server acting as an SSL server using RMI/IIOP over SSL on WebSphere Application Server Advanced Edition.
Administrative and application servers acting as an SSL client, and an SSL secured Lightweight Directory Access (LDAP) server acting as an SSL server over LDAPS on WebSphere Application Server Advanced Edition.

Originally posted by Richard Duglora�:
I'm confused about the sequence diagrams:
Among the top scores for part 2/3, some recommend to stay at an abstract business level and show only objects from the class diagram, while others recommend to describe interactions at the component level. Personally, I lean toward the former (to stay at an abstract level).

Since these people all succeeded, I'm wondering if it matters that much?


Man, I don't know why u would worry at all. Since like you said, they all succeeded, then just following one path.
I looked at the pet store 1.3.1 design documents. Actually it has 3 SFSB:

ShoppingCartEJB�(Stateful) maintains the contents of an individual user�s virtual shopping cart
ShoppingControllerEJB�(Stateful) provides access to the Shopping Client Facade; extends the WAF EJB controller (EJBControllerLocalEJB)
ShoppingClientFacadeEJB�(Stateful) caches references and provides unified access to customer, shopping cart, and user ID

I would like to know the reason why pet store need 3 SFSB too. Too bad there is no clear explaination about this, and I searched old topics, somebody asked the same question about "why EJB controller is a SFSB in pet store", no answer.

I guess the reason is to clear divide the responsibity by put the function into 3 module. Otherwise using one stateful session controller hold the reference to customer and shopping cart is good enough.

About your design, I don't see any flaws myself. I think as long as you pass the SFSB's reference around should be fine. The only thing I will think about SLSB facade is that SLSB's method is atomic, so will this method become too complicate in the end?
Ben, maybe the support you mentioned was about software installation?
The support I mentioned is for answering the questions about mock questions.
Parag, why do you still need to consider a shopping cart should be stateful or stateless if you already have a stateful session object for user? Can't you just have an object array as shopping cart and let this SFSB hold the reference?

I must admit I haven't think about this shopping cart yet, and didn't study the pet store sample. So please point out this model's shortcoming.
[ September 16, 2004: Message edited by: calvin zhu ]
Parag, I would think using here HTTPConnection is screen scrapers -- without changing any code on destination and form a http string to emulate the GUI's result. Right?

Originally posted by Parag Doshi:

Can you elaborate on it? How can we use connectors if we are not able to change any part of the CGI system? Am I missing something?


Screen scraper, just like Annie said. Passing 1st exam, I'm sure you know the way, right?

Originally posted by Rick Portugal:
The question is not whether Sun will release a new version of the exam. The question is when. That has not been addressed in the "old topics."

Well Rick, if you really read those old topics about "When a update version will come..." You will see lots of them has addressed the "When" already, like 2002, 2003 spring, end of 2003, 2004, etc. Just none of them become true.
That's why I said I don't care for "When" anymore, because even somebody answers right not, it might be push back as usual.
Just do a google search u will find out how to use this class.