Re: [Springframework-developer] SWF - Creating HTTP sessions - Feedback needed

[J. E. R. <er...@di...>]

Hi all,

We think it is a great idea that contributes to do SWF more independent 
from
the framework used, Portlets, Struts, etc.

The biggest problem that we have encountered to use a unique 
FlowExecutionManager
from Spring PortletMVC has been the manner to store/load the FlowExecution.

With this new interface should be easy to implement an 
AbstractFlowExecutionManager, or a FlowExecutionManager that delegates on
FlowExecutionStorage strategy (depends on the design pattern used).

Regards.

> +1
>
> We'll have to look into how difficult this would be to implement.
>
> Storing the flow execution state in the request could also make web 
> flows usable in situations
> where you have back-button/refresh-button issues.
>
> This would also allow us to implement a "continuation like" flow 
> execution system: clone the
> flow execution for every request, generate a unique id for each clone 
> and put that id in the request and
> the flow execution clone is some storage somewhere. That way the flow 
> execution effectively
> becomes a continuation! This would also solve most 
> back-button/refresh-button issues, but
> is ofcourse memory intensive.
>
> Erwin Vervaet
> erw...@er...
> ----- Original Message ----- From: "Keith Donald" <ke...@in...>
> To: <spr...@li...>
> Sent: Friday, April 01, 2005 2:46 AM
> Subject: RE: [Springframework-developer] SWF - Creating HTTP sessions 
> - Feedback needed
>
>
>> Seth,
>>
>> Excellent idea.
>>
>> If we extract an interface from the HttpServletExecutionManager, we get
>> something like:
>>
>> public interface FlowExecutionStorage {
>>    public FlowExecution loadFrom(Event inputEvent);
>>    public void saveOrUpdate(FlowExecution flowExecution);
>>    public void remove(FlowExecution flowExecution);
>> }
>>
>> Or something like that.  Erwin what do you think? Need to think about it
>> more.  I imagine here the FlowExecutionStack would have to be 
>> reconstructed
>> from the Event parameters, for example: http request parameters, in 
>> an http
>> servlet environment.  It also has to be rehydrated with services on
>> deserialization as well, including the FlowLocator and its
>> FlowExecutionListenerList.
>>
>> Keith
>>
>> -----Original Message-----
>> From: spr...@li...
>> [mailto:spr...@li...] On 
>> Behalf Of
>> Seth Ladd
>> Sent: Thursday, March 31, 2005 6:21 PM
>> To: spr...@li...
>> Subject: Re: [Springframework-developer] SWF - Creating HTTP sessions -
>> Feedback needed
>>
>> On Thu, 31 Mar 2005 17:49:24 -0500, Keith Donald <ke...@in...>
>> wrote:
>>
>>> Just thinking out loud here, but no, I don't think this would be too
>>> difficult to implement.  There is potentially lot to serialize out 
>>> on each
>>> request, though, particularly if you a flow execution that has spawned
>>
>> many
>>
>>> nested subflows.
>>>
>>> Methinks we could have custom tag that serializes the 
>>> FlowExecutionStack
>>
>> on
>>
>>> each request.  This would include serializing:
>>> - The ID of the flow execution (randomly generated guid)
>>> - The stack of IDs of all spawned flows, the top being the active 
>>> flow and
>>> the rest any suspended parent flows (if the active flow is a subflow)
>>> - For each flow in the stack, everything in 'flow scope'.
>>
>>
>> Keith,
>>
>> Sounds like there might be two Strategies here for storing the
>> FlowExecutionStack: HttpSession Strategy and HttpRequest Strategy.
>> The developer can then choose the strategy for their needs, as there
>> are good use cases for not requiring a session.
>>
>> Seth
>>
>>
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>
>
>
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Tel +34 655 407 965
Email: er...@di...