All,

I'm having a problem using memberOf combined with a collect statement. My test includes 3 rules each written to output the same results (I think), but I get different results (depending on which version of Drools I use).

The rules are:

rule "TestMemberOf"
    salience 10
    when
        $messages: ArrayList() from collect (Message(status == 100))
        $wrappers: ArrayList() from collect (Wrapper(message memberOf $messages))
    then
        System.out.println("TestMemberOf: " + $wrappers.size());
end

rule "TestEval1"
    salience 9
    when
        $messages: ArrayList() from collect (Message(status == 100))
        $wrappers: ArrayList() from collect (Wrapper($message: message, eval($messages.contains($message))))
    then
        System.out.println("TestEval1: " + $wrappers.size());
end

rule "TestEval2"
    salience 8
    when
        $wrappers: ArrayList() from collect (Wrapper($message: message, eval($message.getStatus() == 100)))
    then
        System.out.println("TestEval2: " + $wrappers.size());
end

The output is (by version):

4.0.0

TestMemberOf: 0
TestEval1: 0
TestEval2: 2

4.0.1

TestMemberOf: 0
TestEval1: 2
TestEval2: 2

4.0.2.SNAPSHOT (taken 9/18/07)

TestMemberOf: 0
TestEval1: 2
TestEval2: 2

The correct output should be:

TestMemberOf: 2
TestEval1: 2
TestEval2: 2

Am I using memberOf correctly? Is there some issue using an eval to test conditions on a list created by a collect?

Any help would be appreciated.

Attached is the full example.

Thanks,
-Chris West