Katrin Perry

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since Mar 07, 2007
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Recent posts by Katrin Perry


Something else which wasn't mentioned above. Another reason why MDB is a much more reliable option is that it can be transaction aware:

"A message can be delivered to a message-driven bean within a transaction context, so all operations within the onMessage method are part of a single transaction. If message processing is rolled back, the message will be redelivered. " From Oracle Java EE 6 tutorial on MDB


I didn't create alternative sequence diagrams for failure scenaros.
I did where possible create one sequence diagram per use case. In some cases though, the use case was long and inluded 2 different logical scenarios (i.e. Buy at current price / Buy at set price) In those case I had 2 sequence diagrams.

I hope this helps.

I put the design considerations under Assumptions.

My Assumptions had sub-titles:
- Domain model (assumptions)
- Use Cases (assumptions)
- Design decisions
- Java EE Version and frameworks

I hope this helps. Good luck!

Oracle advise that waiting times are 4-8 weeks.
I received my results few weeks ago, I waited exactly 4 weeks.

I received my assignment results about 4 weeks after I did the essay. I am pleased to say that I am now a certified Java Architect with surprisingly high results of 151 points out of 160. I say surprising because I had doubts about my deployment diagram and I suspect this is where I lost 9 points. Not that it really matters.
Thank you for all your postings. This forum & the kind people that answered my questions really helped me.

Good luck to you all!

This is what I did, too. I haven't submitted my assignment yet, but I see no problem with doing this.

Thanks for making a valuable point Guru. I suppose this and other external systems the SUD relies on are a major risk.
How would one mitigate such risk?
- if I need to rely on a external JMS interface to get prices and it is down... I can't think of anything else but persist all request to buy and sell (price needs to checked first) and attempt to fulfill them once pricing is up and running again.
Similarly if the we need to rely on External Web Services to execute the requests to buy and sell. This would be a major risk. Any hints on how to mitigate? Again persist and attempt to fulfill later perhaps?

Thanks Amritendu.

I think I would need to use the JMS queue that provides me with prices in both synchronous and asynchronous manner.

If I just need to pick up a price for the purpose of displaying to the user yes synchronous would be the way, as you suggest. (1 sec response time is OK)
But I would also need to monitor prices and act if the price has reached a certain level. In this case I am planning to send requests for prices every say 10 sec and use MDB to process the response (if not the right price discard, otherwise act on it)

Congratulations on going over the first hurdle successfully Sandeep.

UML Distilled by Martin Fowler is a good guide on UML.

Good luck with your assignment
Hi Amritendu,

Thanks for your reply. The interpretation you propose would be one way to interpret the requirements.

As you know the requirements in the Assignment are vague. Mine states: (I made small alterations to the original text)
The SUD will take advantage of the Java Message Service (JMS) interface to "Pricing" to retrieve the current price for any asset. "Pricing" has committed to a 1 second response time.

does this suggest "synchronous JMS point-to-point architecture"? or could it be interpreted as topic that SUD could subscribe to in order to receive price updates, that could then be stored in the DB, cached... so that the SUD always has the current price?
Please could you let me know if my question is not clear and I would try to clarify?
I would appreciate your opinions on my question

My application should take advantage of Java Message Service interface in order to retrieve some type of data. The service provider has committed to 1 sec. response time.
I am trying to interpret the above.
Do you think the above information suggests that there is a provider queue that we send a request to and it takes 1 sec. for a response to be posted back to my JMS client. Or could one interpret it as meaning that my application has subscribed to a topic and it takes 1 sec from the time the data has been posted to the topic (by the provider) to to the time when the data reaches my application JMS client.

Your views are appreciated.


This is something I have been wondering about.
Is submitting the assignment a prerequisite to registering for the essay? I wasn't sure weather it is is possible to register for the essay for a date sometimes in the future and carry on working on my assignment. From what I have read here it sounds like this is not possible, but could someone that has already been through confirm what is the process?

I just logged into Pearson Vue to try and work out what the process is. I selected testing center, then date/time and reached the point of payment. At that point I didn't continue .... but up to this point there was no check whether I have submitted an assignment or not (i haven't yet)

Could someone clarify this?