[rules-users] Calling a function from When part

[Stephen Masters]

Hi Sam,

Probably your best bet would be to create a separate rule, which evaluates the function in the RHS and inserts a fact encapsulating the results into working memory. That can be set to no-loop or to have a negative match on the fact it creates.

rule "eval function"
	no-loop
when
	$request : RequestFact()
then
	FunctionResult result = functionCall();
	insertLogical(result);
end

rule "business rule"
when
	$request : RequestFact()
	$functionResult : FunctionResult()
then
	// do something
end

… or something vaguely similar. This way your function call is only evaluated once, and the business rule does not fire until the function has been evaluated.

Steve

On 6 Aug 2012, at 08:34, RulesUsers wrote:

> Hey laune, I think we are mixing up the things.
> My requirement is to call a method in an helper class, that in turn accesses
> the db. 
> 
> 
> Currently i have done with 
>  */evel(functionCall() )/* //The return type of the method is boolean
> 
> *But the problem is, once the control enters WHEN part of the rule it making
> multiple calls to this method ( checked by putting in SYSO statements). But
> i want this call to take place once.*
> 
> 
> So it will be very helpful, if any once can suggest me any other way to make
> function call from when part.
> Also tried with 
> 
> /*$A : Boolean() from functionCall( )
> eval( $A )*/
> 
> 
> But the result is same.
> 
> Also please provide your inputs if it is not possible to handle the problem,
> where in it make multiple function call.
> 
> 
> Regards,
> Sam
> 
> 
> 
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