[rules-users] How to traverse a hierarchy?
Charles Binford
Charles.Binford at Sun.COM
Mon Apr 13 17:56:35 EDT 2009
All, I'm trying to figure out a better way to solve this problem. I
have a batch of objects that I want matched against a hierarchy of
rules. I check the rules in order, and as soon as I find a match I'm
done for that level of the hierarchy. In other words, If the object
matches a rule, we'll check the rules children, but not the siblings.
Example:
rule 1
rule 1.1
rule 1.2
rule 1.2.1
rule 1.2.2
rule 1.3
rule 2
If an object matches rule 1, check for a match at level "1.*", but rule
2 will never be checked. If an object matches 1, 1.2, and 1.2.1, we're
done as 1.2.1 has no children.
My current implementation with drools works, but is very inefficient. I
have a "level" string in the objects and whenever I find a match I
update the level of the object and force an object update. Each rule
tests that the level string is correct, e.g. rule 1.2.1 works as follows:
rule "1.2.1"
when
obj(level matches "1.2.*",.....)
...
then
objSetLevel("1.2.1.*");
....
end
I'm also using saliance to keep the evaluation order like I want it.
Changing the contents of the object and doing the update is not good for
drools performance as I understand it so I'm looking for a better way.
The hierarchy and the order of the matching is key to my application so
I'm not wanting to redesign that part of things.
I tried using activation-groups. That worked great as long as I only
had a single object to run through the hierarchy, but given the way the
rest of the system is design I need to load up 10-100 objects before
each call to fireallrules() for performance purposes.
Any suggestions are appreciated.
Charles Binford
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