Async vs Sync processes

["Brian Lee" <brian_a_lee@hotmail.com>]

I've been wondering a bit about a problem we have and I propose it to the 
group for your suggestions.

I'm working on an app where we have a process that needs to be completed. 
Certain portions are asynchronous. I.e. We send off a request for an id and 
continue working on other stuff until it comes back.

Now the problem I'm encountering is that we don't have a good way to restart 
the process once it's gone async. The current proposal is to store state in 
the db and then have a process that polls or sweeps the db looking for stati 
and reinitiating the process.

Now I am against pollers for many, many reasons but can't think of a good 
way to restart the process flow after I've dropped something off async 
(because I want the whole thing to persist if my app server goes down).

We're forced to use WebSphere so if there's any cool workflow apps out there 
I'd love to hear about it.

Semi-detail of process
1. User Creates Order
2.1 If valid customer id exists then send order on to fraud check
2.2 If invalid customer id then wait for external process to update customer 
id
2.2.1 Reinitiate process once customer id comes in
3.1 If pass fraud check then proceed
3.2 If fail fraud check then wait for manual processing
3.2.1 Reinitiate process once manually processed
4. Send order to fulfillment

There is some thought of having the processes that receive the async 
responses (2.2 and 3.2) reinitiate the processes manually. But if there are 
errors then we will need something that resubmits the orders after a certain 
amount of time.

Any thoughts or books or web sites are appreciated.

Thanks,
BAL





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