[rules-users] How to set drools.dialect.mvel.strict = false?
Jeet Singh
jeetcyb at gmail.com
Thu Jul 25 15:44:06 EDT 2013
Thanks a lot, this helps alot. now all the errors gone.
On Thu, Jul 25, 2013 at 1:24 AM, Wolfgang Laun <wolfgang.laun at gmail.com>wrote:
> @Mark: There's really no need to claim additional bugs ;-)
>
> @Jeetendra: Within a pattern (such as "ProposalLight(...)") you may
> write bindings and constraints, which are boolean expressions. Older
> versions had a much more restricted syntax for constraints, and
> general (Java-style) expressions were only peremitted by enclosing
> them in "eval(...)". In 5.5.0, as soon as you open a parenthesis, you
> have to stick to plain old Java (or MVEL) syntax, and "eval" is a name
> like any other. Recognizing "eval(...)" as the legacy marker for
> introducing an expression has to be kept, but only at the outermost
> parenthesis nesting level of constraint expressions. See example #1
> below:
>
> ### 1 ###
> function boolean positive(int a){ return a > 0; }
>
> // legacy style constraint, use eval() to wrap boolean expression
> $msg: Message( eval(positive($msg.getText().length())) )
>
> // modern style: boolean expression
> $msg: Message( positive($msg.getText().length()) )
>
> // modern style: boolean expression with redundant parentheses
> $msg: Message( ( positive($msg.getText().length()) ) )
>
> The next example demostrates that eval is a "soft" keyword, with
> recognition restricted to certain places:
>
> ### 2 ###
> function boolean eval(int a){ return a > 0; } // Why not call a
> function "eval"?
>
> // modern style: boolean expression, parentheses required to bypass
> soft "eval" recognition
> $msg: Message( ( eval($msg.getText().length()) ) )
>
> So, the answer to your question "How can I make it work?" is quite
> simple: add a declaration of a boolean function eval, like this:
>
> function boolean eval( boolean b ){ return b; }
>
>
> And, please, do not use terms like "throws an exception" when a simple
> syntax error is reported.
>
> -W
>
>
> On 25/07/2013, Mark Proctor <mproctor at codehaus.org> wrote:
> > It shouldn't do, and could be a bug. Can you try 5.6.0.SNAPSOT and see
> if it
> > is still a problem.
> >
> > Mark
> > On 24 Jul 2013, at 18:22, Jeet Singh <jeetcyb at gmail.com> wrote:
> >
> >> Alright, I kinda found out the cause of the exception I am getting,
> >> however I am still struggling the reason behind the exception.
> >>
> >> So DRL_1, this works perfectly fine.
> >> package drools;
> >> import drools.ProposalLight;
> >> import function drools.DateUtil.compareDatesWithTime;
> >> rule "Date Rule"
> >> when
> >> $obj : ProposalLight(eval(compareDatesWithTime(endDateTime, -2, 6,
> >> \"<\")))
> >> then
> >> $obj.addFailedRule("Date Rule");
> >> end;
> >>
> >> DRL_2, this doesn't work. and throws [Error: unable to resolve method
> >> using strict-mode: myObject.eval(boolean)] [Near : {...
> >> (eval(compareDatesWithTime(star ....}] ...
> >>
> >> package drools;
> >> import drools.ProposalLight;
> >> import function drools.DateUtil.compareDatesWithTime;
> >> rule "Date Rule"
> >> when
> >> $obj : ProposalLight((eval(compareDatesWithTime(endDateTime, -2, 6,
> >> \"<\"))))
> >> then
> >> $obj.addFailedRule("Date Rule");
> >> end;
> >>
> >> Notice that extra paranthesis around eval(). This is where Drools 5.5
> >> throws exception. Can someone please explain why this extra paranthesis
> >> throws exception and how can I make it work.
> >>
> >> Thanks,
> >> Jeetendra.
> >>
> >>
> >> On Wed, Jun 5, 2013 at 1:27 AM, Wolfgang Laun <wolfgang.laun at gmail.com>
> >> wrote:
> >> The error message suggests that you have made a syntactic error in a
> >> rule which is not the one you have posted, or you have modified the
> >> rule too much to be of any help. Post again, taking great care not to
> >> omit anything or to change the cause of the problem. Also, indicate
> >> precisely the declaration of the function compareDatesWithTime().
> >>
> >> -W
> >>
> >>
> >> On 04/06/2013, jeetendray <jeetcyb at gmail.com> wrote:
> >> > Hi,
> >> >
> >> > Snippet of my DRL .
> >> >
> >> > rule "Rev: Start Time < 2 Hours in Future"
> >> > when
> >> > $obj : eval(compareDatesWithTime(startDateTime, -2, 2,
> >> > "<"))
> >> > then
> >> > $obj.addFailedRule("Rev: Start Time < 2 Hours in
> >> > Future");
> >> > end
> >> >
> >> > This fails during compilation and throws error:
> >> >
> >> > org.drools.rule.InvalidRulePackage: Unable to Analyse Expression
> >> > (eval(compareDatesWithTime(startDateTime, -2, 2, "<")) ):
> >> > [Error: unable to resolve method using strict-mode:
> >> > myObject.eval(boolean)]
> >> > [Near : {... (eval(compareDatesWithTime(star ....}]
> >> > ^
> >> > [Line: 6, Column: 2] : [Rule name='Proposal - Start time is after
> >> > current +
> >> > 2 hour']
> >> >
> >> >
> >> > I am using Drools 5.5 and I found the cause that my code runs in
> strict
> >> > mode.. so If I set strict mode to false then this would work. Now I am
> >> > not
> >> > sure how to make it to false.
> >> >
> >> > Here's the code I am using:
> >> >
> >> > PackageBuilderConfiguration packageBuilderConfiguration = new
> >> > PackageBuilderConfiguration();
> >> > PackageBuilder packageBuilder = new
> >> > PackageBuilder(packageBuilderConfiguration);
> >> > packageBuilder.addPackageFromDrl(drl.getCharacterStream());
> >> >
> >> > Can someone please suggest me how to do that??
> >> >
> >> > Thanks!!!
> >> >
> >> >
> >> >
> >> > --
> >> > View this message in context:
> >> >
> http://drools.46999.n3.nabble.com/How-to-set-drools-dialect-mvel-strict-false-tp4024122.html
> >> > Sent from the Drools: User forum mailing list archive at Nabble.com.
> >> > _______________________________________________
> >> > rules-users mailing list
> >> > rules-users at lists.jboss.org
> >> > https://lists.jboss.org/mailman/listinfo/rules-users
> >> >
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> >>
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