Can Synchronous messaging provide instant reponse?

[Zhixiong Pan]

Hi all,

Please take a look at the below question. The answer provided is A.

You are designing an online shopping application to make it easier for customers to order products from your company. The aim is that the majority of customers buying over the phone will start using the web instead. When customers purchases goods online they will use credit cards and will require an instant response as to whether the sale has been approved or not. (Note the credit card validation is carried out by another very powerful system.) What type of messaging should be used?

A Synchronous messaging
B Asynchronous messaging
C You shouldn't be using messaging at all as it's not transactional.
D You could use messaging because it is transactional however it's not advised, as the system would never perform well enough for an instant response.

But I don't think so, and my reason is as below. And I think a session bean is better to deal with instant response.
If you need an instant response you probably wouldn't use messaging. The idea of messaging is that you can send messages to other applications and let them process the messages in their own time.

How about your idea? Thanks.

[satheesh krishnaswamy]

Hi,

I agree to your point. The Quesiton is little tricky here. From what I get from the question is if we want to use messaging which type we will use. The answer should be obviously "Synchronous". But if the question is put in a different way(may be much clear way) then we should choose "We should not use messaging".

I presume these kind of confusing questions will not be asked in the real exam.

Anyone who has cleared the test, can you please help us?

Thanks,
Satheesh.K
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[Jason Marston]

Zhixiong Pan wrote:

A Synchronous messaging
B Asynchronous messaging
C You shouldn't be using messaging at all as it's not transactional.
D You could use messaging because it is transactional however it's not advised, as the system would never perform well enough for an instant response.

This is one of the Whizlabs questions and the clue is in the phrasing of the answers.

B is obviously wrong as you would not get an instant response
C is wrong because messaging can be transactional
D is wrong because you have just been told the card validations system is VERY POWERFUL. So the statement that is will "NEVER perform well enough for an instant response" is wrong.

So the process of elimination leaves us A.

Syncronous messaging CAN indeed give an instant response. I think you are confusing messaging with asynchronous messaging (fire and forget).

Regards,

Jason.

Edit: I got 100% in this part of the Part 1 exam. I do actually agree that given a choice you would not use messaging, but many existing systems do use syncronous messaging as their interface. If use session beans had been one of the answers it would have been correct.