Re: [scxml] Questions on Multiple Instances

[Rahul Akolkar <ra...@gmail.com>]

On Mon, Oct 25, 2010 at 12:19 PM, Christopher Dragert
<ch...@mail.mcgill.ca> wrote:
> The scenario:  I have many different classes (call them type A) each with their own unique SCXML state chart. Though designed to work together, type A classes are necessarily separate because we need them to be used modularly. Another set of classes (call these type B), each instantiate a subset of the available type A classes.  Inside a type B class, events are manually passed between the state charts in a broadcast arrangement.  Thus, there are many different type B classes, each containing their own instances of several type A classes that essentially operate as parallel state charts.
>
>  I am having problems with the efficiency of this arrangement.  I have two questions:
>
> 1)  When a state chart is parsed and loaded, one of the steps is to create an SCXML engine.  Is it possible to clone the engine?  In my scenario, each type A class may be instantiated many times.  This means that the associated SCXML file is parsed and loaded many times, causing a significant slow down at load time.  Cloning an engine seems to offer a way around this.
>
<snip/>

As already mentioned, Commons SCXML uses a parse to model once,
instantiate any number of executors approach. This will require not
using the AbstractStateMachine helper class, which is a very simple
pattern (that re-parses).


> 2)  Is it possible to create an engine, then add a new state chart to the engine, treated as though it was part of the first state chart but enclosed in <parallel> tags?  In my scenario, this would allow my type B classes to only have one execution environment for all of its instantiated type A classes.  Since we don't know what type As will be contained in a type B, it seems hard to do this by prebuilding scxml files that actually contain the <parallel> sections.  All this could be done before the state chart begins execution.
>
<snap/>

Type B could "generate" the SCXML just before executor instantiation,
including the type As as needed either via XML includes or via the now
deprecated src attribute of the <state> element.

-Rahul


> Any other advice regarding running large number of SCXML files would be appreciated!  Thanks for any help.
>
> Regards,
> Chris Dragert
>

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