Adding this rule attribute will fire the rule only once. Still, you won't be able to tell from the two titles which one is the odd-man-out. Also, if there are two or more violations, it won't show either.
rule "check-same"
activation-group "one-shot"
when
...
Otherwise, duplicate firings for a pair can be eliminated by adding a constraint that reduces activations to a specific order of a pair; for this you'll need an attribute in your Fact that can be compared with '<', to wit:
$p1 : Fact( $n1 : num, $t1 : title, $g1 : groupNames, $p1 : propNames )
$p2 : Fact( num > $n1, $t2 : title, ( groupNames != $g1 || propNames != $p1 ) )
As for your question ("comparing sets"), I suggest that you write a simple wrapper class, say, class PropNameSet, with a single attribute Set<String> names. Then you might write rules such as
rule "make set"
when
$f1 : Fact( $p1 : propNames )
not PropNameSet() // not Set()
then
insert( new PropNameSet( $p1 ) ); // insert( $p1 );
end
rule "check-names"
when
PropNameSet( $names : names ) // $names : Set()
$f1 : Fact( $t1 : title, propNames != $names )
then
System.out.println( "mismatch " + $t1 );
end
You could also use the indicated alternative with the raw Set as a fact, but there is a fairly obvious disadvantage: not Set() is a very general condition.
Note that the PropNameSet will be derived from an arbitrary Fact; thus the mismatch might occur repeatedly, and for the good ones.
-W2009/5/15 Ian Spence <ianspence@gmail.com>Wolfgang and all,
Your suggestion did work. Thank you for that. I am learning more as I go along.
I am thinking of another approach now. To populate working memory with a Set of all names "allNames"; call fireAllRules; then in the DRL, for each Title compare Proprietor names (set) with "allNames".
How can I compare 2 sets like this in a DRL ?
Ian Spence2009/5/14 Wolfgang Laun <wolfgang.laun@gmail.com>
Assuming that your facts are structured as the indentation suggests, I would solve this using a technique you could call "virtual field". So, if a fact object has fields
String title
List<PropGroup> pgList
and a PropGroup has fields
String name
List<String> pList
I would not try to get at the embedded data from the objects contained within List<PropGroup>. Rather, I'd add a couple of getters to your Fact class, each of which would return a Set<String> computed from the contained List<PropGroup>. Then the rule simply becomes
rule "check-same"
when
$p1 : Fact( $t1 : title, $g1 : groupNames, $p1 : propNames )
$p2 : Fact( this != $p1, $t2 : title, ( groupNames != $g1 || propNames != $p1 ) )
then
System.out.println( "mismatch " + $t1 + " and " + $t2 );
end
Notice that this won't find the odd-man-out; it will fire twice for each unequal pair.
-W2009/5/14 Ian Spence <ianspence@gmail.com>_______________________________________________Regards,Hello all,--I am new to Drools…
I have a scenario
Each fact object will have the structure:
Title
Proprietor Group
Proprietor Name
E.g.
2100-100
J2 ½ share
SMITH, JOHN
JONES, FRED
T ½ share
BROWN, CHARLIE
2100-101
J2 ½ share
BROWN, CHARLIE
JONES, FRED
T ½ share
SMITH, JOHN
2100-102
T ½ share
BROWN, CHARLIE
J2 ½ share
JONES, FRED
SMITH, JOHN
The group names and the proprietor names must be the same across each Title. The scenario above is a valid case. A failed case would result for Title 2100-100 if we add an extra Proprietor name e.g. WHITE, MARY.
I anticipate having one rule to cater for this. I am hedging towards the ‘collect’ operator but cannot get a clear picture on how to implement it.
Ian Spence
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--
Regards,
Ian Spence
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