[rules-users] Comparing multiple instances of the same object

[Brian Enderle]

I have 3 Rfrnc objects that I would like to compare and return a message if 
the firstNm, middleNm and lastNm of two objects match.  I set up the Rfrnc 
objects with the names "Brian A Enderle", "Brian B Enderle" and "Brian C 
Enderle" and created the following rule (with the intent of building up to 
checking first, middle and last name).

rule "LevelTwo: Duplicate Reference check"
	agenda-group "LevelTwo"
	when
		$i : Rfrnc($firstNm : firstNm, $middleNm : middleNm, $lastNm : 
lastNm)
		$j : Rfrnc(this != $i, firstNm == $firstNm) 
	then
		System.out.println("Duplicate refernce found: " + 
$i.getMiddleNm() + $i.getLastNm() + ":" + $j.getMiddleNm() + $j.getLastNm());
end	

This produces the following output (which is what I would expect):
Duplicate refernce found: CEnderle:BEnderle
Duplicate refernce found: BEnderle:CEnderle
Duplicate refernce found: CEnderle:AEnderle
Duplicate refernce found: AEnderle:CEnderle
Duplicate refernce found: AEnderle:BEnderle
Duplicate refernce found: BEnderle:AEnderle

While doing some testing I changed "Brian B Enderle" to "Brian A Enderle" so 
that now I have two Rfrnc objects with the name of "Brian A Enderle".  When I 
rerun the same rule from above I get the following output:

Duplicate refernce found: CEnderle:AEnderle
Duplicate refernce found: AEnderle:CEnderle
Duplicate refernce found: AEnderle:CEnderle
Duplicate refernce found: CEnderle:AEnderle

What I don't understand is why do I not have any return statements 
of "Duplicate reference found AEnderle:AEnderle".  I would expect 2 of these 
messages, one for when the first "Brian A Enderle" object is compared to the 
second and vice versa.

Is the "$i == this" condition checking values within the object itself?  Am I 
missing something here as to how this rule should work?

Thanks in advance,
Brian Enderle