4:29 a.m.
I hope you're not going through all of that trouble just to get the functionality from
that concrete example. You get that for free with Drools' default conflict
resolution, which includes "specificity." Specificity means that rules with the
more specific conditions, and all else equal, are fired first. So between these two
rules, only the CheeseSausagePepperoniPepper one fires:
rule "CheeseOnly"
when
p : Pizza( )
t1: Topping( pizza == p, name == "cheese" )
then
System.out.println( "Eating cheese pizza" );
retract( t1 );
retract( p );
end
rule "CheeseSausagePepperoniPepper"
when
p : Pizza( )
t1: Topping( pizza == p, name == "cheese" )
t2: Topping( pizza == p, name == "sausage" )
t3: Topping( pizza == p, name == "pepperoni" )
t4: Topping( pizza == p, name == "pepper" )
then
System.out.println( "Eating cheese sausage pepperoni pepper pizza" );
retract( t4 );
retract( t3 );
retract( t2 );
retract( t1 );
retract( p );
end
See the attached project.
--- On Tue, 9/1/09, Bill Tarr <javatestcase(a)yahoo.com> wrote:
From: Bill Tarr <javatestcase(a)yahoo.com>
Subject: [rules-users] Trouble getting Dynamic Salience working
To: rules-users(a)lists.jboss.org
Date: Tuesday, September 1, 2009, 7:28 PM
We have a winner! Many thanks
Michal, hope I can return the favor one day.
salience ( return getSalience4() )
for the record, my function looks something like (after
tempate evaluation):
<pre>
function int getSalience4(){
int salience = 0;
if("VALUE"=="VALUE") salience += 1000;
return salience;
}
</pre>
I think the combination activation-group and dynamic
salience for rule-template projects are pretty useful.
Just for anyone interested, the tempate code looks
something like this:
<pre>
rule "Some Rule_(a){row.rowNumber}"
activation-group "@{PARAM1}-@{PARAM2}"
salience ( return getSalience(a){row.rowNumber}() )
</pre>
where PARAM1 and PARAM2 make up a kind of key. I only want
to execute one rule that matches that key, no matter how
many options there are.
Rules that have additional parameters get higher salience
than rules with less parameters, so here is my function.
<pre>
function int getSalience(a){row.rowNumber}(){
int salience = 0;
if("@{PARAM3}"=="@{PARAM3}") salience += 1000;
if("@{PARAM4}"=="@{PARAM4}") salience += 1000;
return salience;
}
</pre>
A concrete example could be pizza. So there are 3 types
of pizza, all are grouped in the same activation-group.
cheese, pepperoni
cheese, pepperoni, sausage
cheese, pepperoni, meatball, pepper
Any cheese and pepperoni pizza should could match all these
rules, but more toppings is always better for me.
So cheese, pepperoni, onion, pepper getts a salience of
2000, and is the only rule evaluated.
On Tue Sep 1 18:39:13 EDT 2009, Michal Bali michalbali at
gmail.com wrote:
does this work?
salience ( return getSalience() )
or this:
salience ( getSalience();)
On Tue, Sep 1, 2009 at 6:50 PM, Bill Tarr <javatestcase
at yahoo.com> wrote:
> Possibily just a simple MVEL error, but I've been
struggling for a while
> and thought I'd see if anyone could help.
>
> I just want to run a logic test to determine salience
for some rules I am
> generating with rules-templates. Even after making
the logical test "true"
> I can't get any of variation to compile.
>
> (true ? "1000" : "0")
> **produces**
> Unable to build expression for 'salience' : not a
statement, or badly
> formed structure
>
> ( true ? 1000 : 0)
> **produces**
> Unable to build expression for 'salience' : invalid
number literal: 1000
>
> salience ( getSalience() )
> ...
> function int getSalience(){return 0;}
> **produces**
> Unable to build expression for 'salience' :
org.mvel2.util.MethodStub
> cannot be cast to java.lang.Class'(
getSalienceNONCDW() )'
>
> Seems like I am missing something simple, but I've
tried many variations on
> the above, and have been unable to find any working
examples of using a
> logical test in salience, so if anyone has any
direction it would be greatly
> appreciated.
>
> Thanks!
>
> Bill
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