Hi,

  I am using agenda groups to  pick sets of rules to fire based on an attribute value. The presence or absence of other attributes  is dependent on the value of this attribute based on which I select  a particular agenda group.

Here is an example

rule "ABC"
  when 
    Shape( type = "rectangle" )
  then
    drools.setFocus("twodimensional")
end


rule "PQR"
  when 
    Shape( type = "cube" )
  then
    drools.setFocus("threedimensional")
end

rule "area threshold"
agenda-group "twodimensional"
  when 
    Shape( area > 20 )
  then 
    System.out.println ("large object" );
end
 
rule "volume threshold"
agenda-group "threedimensional"
  when 
    Shape( volume > 20 )
  then 
    System.out.println ("large object" );
end
 

Suppose if my shape object is a rectangle, then it wouldnt have the volume attribute. In this case when we try to run these rules it would throw a  NoSuchElementException.

Is there a way to avoid this? Agenda groups help us fire the RHSs conditionally, Is there a way by which I can conditionally fire LHS of certain sets of rules ?


Thanks


Jai

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