[rules-users] Dynamic JavaBeans

[Yuri de Wit]

In my specific case, PropertyChangeListeners are useful even with the
new MVEL update dialect (which is a great feature, btw) because I am
dealing with a tree/graph where updates to an tree/graph object may
internally update related nodes. Sometimes a single object model
change may even update many other objects (in many cases multiple
properties for multiple objects). It becomes cumbersome to have to
track all that in the consequence and individually and manually modify
them.

thanks,
-- yuri

On 6/28/07, Mark Proctor <mproctor at codehaus.org> wrote:
> If it can be done cleanly I'm not averse to it. however there is
> something else...
> In the new MVEL dialect you no longer need propertychangelisteners if
> you don't want to call update()
>
> modify ( cheese ) { price = 25, quality = premium }
>
> This will modify all the setters and notify the engine at the end of the
> block setter. Is that good enough for you?
>
> Mark
> Yuri de Wit wrote:
> > Mark,
> >
> > btw, If this is a feature that makes sense from Drools pov I wouldnt
> > mind giving a shot at implementing it and contributing it back to
> > Drools.
> >
> > -- yuri
> >
> > On 6/28/07, Yuri de Wit <ydewit at gmail.com> wrote:
> >> Sure. The solution I am taking right now is dont use dynamic
> >> properties, which is not optimal (depending on the problem property
> >> changes not being batched defeats the purpose of dynamic beans).
> >>
> >> The bottom line is that I was hoping that this feature would (1)
> >> either already be taken care of in 4.0 or (2) become a feature request
> >> for future releases.
> >>
> >> -- yuri
> >>
> >> On 6/28/07, Mark Proctor <mproctor at codehaus.org> wrote:
> >> > No we don't do anything to batch property change listener results. But
> >> > maybe you can do this yourself.
> >> > instead of calling modify, add it to a transaction list (that you make
> >> > available in the current context). Then at the end of the consequence
> >> > you can iterate that list and call modify on each object. Or
> >> > alternatively don't use dynamic properties.
> >> >
> >> > Mark
> >> > Yuri de Wit wrote:
> >> > > I am not talking about assert, but modify. I have a dynamic fact
> >> > > already asserted but now I need to perform N changes on N different
> >> > > properties on the same object on the same consequence. Drools is
> >> going
> >> > > to traverse the RETE network N times once for each time the
> >> > > PropertiesListener is called (each setProperty called).
> >> > >
> >> > > -- yuri
> >> > >
> >> > > On 6/28/07, Mark Proctor <mproctor at codehaus.org> wrote:
> >> > >> Why would doing the assert work at the end of the consequence be
> >> any
> >> > >> quicker than doing it during the consequence?
> >> > >>
> >> > >> Mark
> >> > >> Yuri de Wit wrote:
> >> > >> > I noticed that changes performed on facts asserted dynamically
> >> causes
> >> > >> > the fact to be modified right away and therefore triggering a
> >> RETE
> >> > >> > network traversal and rule schedulings.
> >> > >> >
> >> > >> > For apps with a large number of facts this could be a significant
> >> > >> > scalability problem. At least in my case, I would like to be
> >> able to
> >> > >> > use dynamic facts and perform any number of updates and have
> >> those
> >> > >> > updates commited to working memory only when the rule
> >> consequence is
> >> > >> > completed.
> >> > >> >
> >> > >> > Looking at the code, it seems that it would not be a major
> >> effort to
> >> > >> > collect the facts received by the
> >> ReteooWorkingMemory.propertyChange
> >> > >> > and perform the actual modifyObject() only when the consequence
> >> > >> > evaluation is actually completed.
> >> > >> >
> >> > >> > Does that makes sense? Or are there side effects I am not
> >> seeing? Is
> >> > >> > this a problem that 4.0 already resolves?
> >> > >> >
> >> > >> > thanks in advance,
> >> > >> >
> >> > >> > -- yuri
> >> > >> > _______________________________________________
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> >> > >> > https://lists.jboss.org/mailman/listinfo/rules-users
> >> > >> >
> >> > >>
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