[rules-users] Drools templates header arguments

[Alexander Wolf]

afaik that's not possible. 
Basically the templates replace the value for @{param} with param.toString()  (that's why your approach is not working).
Regarding your concerns about performance: the templates are translated into rules once -> afterwards there is no connection between the variables and the rules in KnowledgeBase.

You could instead write a module that replaces the @{param} fields with values from your arrayList within your rules (e.g. loading the rules from a file into string, then use regex or whatever suits you best).
Then just insert the rules somewhat like this:

String myRules = "rule "test" when @{arr[1]}>x... then ... ";
String parameterizedRules  =MyTemplateBuilder.build(myRules, yourParams);

Reader rdr = new StringReader(parameterizedRules);
kbuilder.add(ResourceFactory.newReaderResource(rdr), ResourceType.DRL);

- Alex


On 25 Nov 2013, at 11:43, petert <peter.j.troelsen at gmail.com> wrote:

> I am working on a project, using templates to generate all my rules. I have
> one problem though, I wanna parse my arguments to the template as a
> ArrayList, and do somthing like this:
> 
> template header
> 
> ruleId
> args
> 
> package dk.prks 
> import com.poc.entity.Bill;
> import com.poc.entity.BillLine;
> import com.poc.entity.Description;
> import java.util.ArrayList;
> 
> template "01"
> 
> 
> rule "@{ruleId}_@{row.rowNumber}"
>  dialect "mvel" 
>    when 
>      $bill : Bill ($line : lines) and
>      BillLine( service == @{args.get(0)}, $lineNr : lineNr) from $line and
>      BillLine( service == @{args.get(1)}, lineNr < $lineNr) from $line          
>    then
>      $bill.setColor(1);
> 
> end
> 
> end template
> However, this is not possible. Furthermore I want to stretch that
> performance is an issue, and i want the generated file to only contain the
> values from the list, and not make any look ups in the array when running my
> rules
> 
> 
> 
> --
> View this message in context: http://drools.46999.n3.nabble.com/Drools-templates-header-arguments-tp4026908.html
> Sent from the Drools: User forum mailing list archive at Nabble.com.
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