[rules-users] Why are MVEL rules compiled on first access?

[Greg Barton]

If I recall correctly the HashMap churn issue I pointed out with mvel on the dev list was due to mvel expressions being repeatedly compiled.  I'll have to double check, but if that's the case and it can be avoided it would be awesome. :)

--- On Thu, 6/4/09, Edson Tirelli <tirelli at post.com> wrote:

> From: Edson Tirelli <tirelli at post.com>
> Subject: Re: [rules-users] Why are MVEL rules compiled on first access?
> To: "Rules Users List" <rules-users at lists.jboss.org>
> Date: Thursday, June 4, 2009, 1:40 PM
> 
>    Sobhana, 
> 
>    This is very important feedback. Would you be able to
> create an isolated test case showing this problem? This
> would be the quickest way for us to fix it.
> 
>    On a related note, everything should be compiled at
> compile time, including MVEL stuff. If that is not
> happening, we need to check what mvel is doing internally.
> 
> 
>    Thanks,
>       Edson
> 
> 2009/6/4 Sobhana <sobhanarich at yahoo.com>
> 
> 
> 
> hi,
> 
> 
> 
> Our application uses Drools 4.0.7 and Hibernate 3.x. We use
> the BRMS to
> 
> compile the rules from drl files (using java dialect) into
> rule packages
> 
> which are updated into the rule base using the rule agent.
> 
> 
> 
> We have seen that MVEL rules are compiled when the rules
> are fired for the
> 
> first time. If the fact passed at the first run contains a
> Hibernate proxy
> 
> (subclass of the original object) and we later re-use the
> compiled rule on
> 
> the fact containing the original object, we get a
> ClassCastException.
> 
> However, if we pass the fact containing the original object
> in the first
> 
> run, there is no problem for further runs.
> 
> 
> 
> Why are the rules not compiled when we create the package
> using the BRMS?
> 
> How can we enable precompilation so that the type is taken
> as the original
> 
> object itself?
> 
> 
> 
> Thanks,
> 
> Sobhana
> 
> 
> 
> --
> 
> View this message in context: http://www.nabble.com/Why-are-MVEL-rules-compiled-on-first-access--tp23874950p23874950.html
> 
> 
> Sent from the drools - user mailing list archive at
> Nabble.com.
> 
> 
> 
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> 
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> 
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> 
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> 
> 
> 
> 
> -- 
>   Edson Tirelli
>   JBoss Drools Core Development
>   JBoss, a division of Red Hat @ www.jboss.com
> 
> 
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