Syncrhonous and Asynchronous calls

[Morgan Duchène]

Great document, thank you!

Morgan

Todd Wright a écrit :
>
> This design issue is discussed in the "Mandelbrot" demo:
>   http://cougaar.org/docman/view.php/17/201/cougaar_mandelbrot.ppt
>
> The code is included in the Cougaar 12.4 release, in:
>   demo-mandelbrot.zip
>
> Three design options are discussed:
>
>   v1) Servlet is self-contained
>
>   v2) Servlet invokes a synchronous Service, e.g. a service advertised
>       by another plugin.
>
>   v3) Servlet publishes a blackboard "Job" request and waits for a
>       synchronized "notify()" event or subscription change.
>
> Similar to design v3, your servlet could publish a blackboard request 
> and then poll the blackboard for the result, or have the client poll 
> the servlet. Polling is easy to implement but can be inefficient.
>
> Todd
>
> Morgan Duchène wrote:
>> Hi,
>>
>> I have a basic architecture question about the development model with 
>> Cougaar.
>> * Developments with Cougaar and plugins are based on blackboard 
>> registrations to events (objects, tasks, ...). So it is an 
>> asynchronous model where plugins are awaken when new events they are 
>> interested in are published.
>> * Cougaar also offers to interact with "the outside world" with 
>> servlets to receive commands for example. When a browser sends a 
>> requests for a page to and http server, it's a synchronous call as it 
>> waits for the answer.
>>
>> So my simple question it this one: if we don't have the data 
>> available on the blackboard as the servlet is sending the search 
>> parameters (database, files, ...), what is the best way to have 
>> plugins give the answer to the servlet?
>>
>> Thanks,
>> Morgan
>>
>> _______________________________________________
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>> Cougaar-developers at cougaar.org
>> http://cougaar.org/mailman/listinfo/cougaar-developers
>>
>
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