Re: [rules-users] Rule Templates - Conditionally Generate Rule based on Values in Data
A *rule template *is a text (file) intended to be expanded repeatedly using
different sets of template parameters, similar to a macro processor. Each
expansion will generate - more or less - the same rule, unless you put the
flexibility into the parameter, which just passes the buck to the code
driving the expansion.
Let's say that you want to be alerted if one of your lucky numbers becomes
a fact. You can write a template, create a collection of your lucky numbers
and run the expander to create one rule for each of your lucky numbers.
This is explained in section "Expanding a Template".
Most of the time, sets of almost identical rules can be avoided if facts
containing parameter sets are inserted and rules are written to match the
values from a ParameterSet fact rather than literals, as would be done by
generated rules. Consider
when
Integer( valueOf == 7 )
when
Integer( valueOf == 13 )
as opposed to
when
Parameter( $n: number )
Integer( valueOf == $n )
with appropriate Parameter facts (7, 13).
-W
On 18 June 2013 16:58, Jason Allen <jason.allen(a)data-sign.com> wrote:
All,
I saw this question was asked a couple of months ago with no reply, but
thought I would try again.
In using a Rule Template, I'm trying to determine a way to dynamically
generate rules based on a value in the data.
There is a data set, that has various pieces data, depending on a column
value, the rule that is generated is relatively different. Different
enough that I wouldn't want the generated a rule for each row of data,
because many of the rules generated would never fire.
In the drools expert docs, it lists under 6.1.7 Rule Templates the ability
to "conditionally generate rules based on the values in the data", but I
can't seem to find the syntax for how to do that.
Does anyone know the answer to this?
I would picture it looking something like this
if ("@{RevenueCode}" == "NR")
rule "RevenueMapperRule_1"
when
claim1 : ClaimFact (ProgramType in ("FC", "FCP", "FALSE",
"FALSE"),
ProcedureCode == "NR",
(serviceBegin >= "01-Oct-2003" && serviceBegin <=
"31-Dec-2030"),
modifier1 in ("U"),
typeofBill == "3");
then
claim1.setResultSPCCode("507.11");
list.add(claim1);
end
end if
Essentially, the only time this rule would be generated is if RevenueCode
in the Rules Spreadsheet had a value of "NR".
If this is not possible, how should I be thinking about this problem?
Feels weird to generate a bunch of rules that will never fire, simply
because there is no way to conditionally generate a rule. Maybe the answer
is to create separate rule files and template definitions? That also feels
like an over complication.
Thoughts?
Thanks in advance!
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