Jitting Exception when using Collections or HashSet in DRL

[sascha.s...@signavio.com]

I am currently trying to use Lists in my DRL files.

In order to check equality without duplicates, I am trying to create a new HashSet from my List and then compare it to another new HashSet made from another list.

The DRL looks like this:

package com.signavio.droolsexport 

import java.util.List

import java.util.Arrays

import java.util.HashSet

import java.util.Collections

declare  ListDecision 

    textList : List  

    booleanList : List  

    numberList : List  

    textOutput : String  

end

rule "listDecision_rule_1"

    no-loop 

when

    $listDecision : ListDecision( textList.equals(Arrays.asList("hallo", "welt")), booleanList.equals(Arrays.asList(true)), numberList.equals(Arrays.asList(1.0, 2.0, 3.0)) )  

then

    modify( $listDecision ){ 

        setTextOutput("EQUALS"); 

    };

end

rule "listDecision_rule_2"

    no-loop 

when

    $listDecision : ListDecision( !textList.equals(Arrays.asList("hallo", "welt")), !booleanList.equals(Arrays.asList(true)), !numberList.equals(Arrays.asList(1.0, 2.0, 3.0)) )  

then

    modify( $listDecision ){ 

        setTextOutput("NOT EQUALS"); 

    };

end

rule "listDecision_rule_3"

    no-loop 

when

    $listDecision : ListDecision( new HashSet(textList).containsAll(new HashSet(Arrays.asList("hallo", "welt"))), new HashSet(booleanList).containsAll(new HashSet(Arrays.asList(true))), new HashSet(numberList).containsAll(new HashSet(Arrays.asList(1.0, 2.0, 3.0))) )  

then

    modify( $listDecision ){ 

        setTextOutput("ELEMENTS OF"); 

    };

end

rule "listDecision_rule_4"

    no-loop 

when

    $listDecision : ListDecision( !new HashSet(textList).containsAll(new HashSet(Arrays.asList("hallo", "welt"))), !new HashSet(booleanList).containsAll(new HashSet(Arrays.asList(true))), !new HashSet(numberList).containsAll(new HashSet(Arrays.asList(1.0, 2.0, 3.0))) )  

then

    modify( $listDecision ){ 

        setTextOutput("NOT ELEMENTS OF"); 

    };

end

rule "listDecision_rule_5"

    no-loop 

when

    $listDecision : ListDecision( !Collections.disjoint(textList, Arrays.asList("hallo", "welt")), !Collections.disjoint(booleanList, Arrays.asList(true)), !Collections.disjoint(numberList, Arrays.asList(1.0, 2.0, 3.0)) )  

then

    modify( $listDecision ){ 

        setTextOutput("CONTAINS ANY OF"); 

    };

end

rule "listDecision_rule_6"

    no-loop 

when

    $listDecision : ListDecision( new HashSet(textList).equals(new HashSet(Arrays.asList("hallo", "welt"))), new HashSet(booleanList).equals(new HashSet(Arrays.asList(true))), new HashSet(numberList).equals(new HashSet(Arrays.asList(1.0, 2.0, 3.0))) )  

then

    modify( $listDecision ){ 

        setTextOutput("CONTAINS ONLY"); 

    };

end

rule "listDecision_rule_7"

    no-loop 

when

    $listDecision : ListDecision( Collections.disjoint(textList, Arrays.asList("hallo", "welt")), Collections.disjoint(booleanList, Arrays.asList(true)), Collections.disjoint(numberList, Arrays.asList(1.0, 2.0, 3.0)) )  

then

    modify( $listDecision ){ 

        setTextOutput("CONTAINS NONE OF"); 

    };

end

I'm getting the following output on the console:

2015-06-24 15:28:40,512  WARN (MvelConstraint.java:312) - Exception jitting: booleanList.equals(Arrays.asList(true)) This is NOT an error and NOT prevent the correct execution since the constraint will be evaluated in intrepreted mode

2015-06-24 15:28:40,515  WARN (MvelConstraint.java:312) - Exception jitting: numberList.equals(Arrays.asList(1.0, 2.0, 3.0)) This is NOT an error and NOT prevent the correct execution since the constraint will be evaluated in intrepreted mode

2015-06-24 15:28:40,519  WARN (MvelConstraint.java:312) - Exception jitting: new HashSet(booleanList).containsAll(new HashSet(Arrays.asList(true))) This is NOT an error and NOT prevent the correct execution since the constraint will be evaluated in intrepreted mode

2015-06-24 15:28:40,520  WARN (MvelConstraint.java:312) - Exception jitting: new HashSet(numberList).containsAll(new HashSet(Arrays.asList(1.0, 2.0, 3.0))) This is NOT an error and NOT prevent the correct execution since the constraint will be evaluated in intrepreted mode

2015-06-24 15:28:40,522  WARN (MvelConstraint.java:312) - Exception jitting: !Collections.disjoint(booleanList, Arrays.asList(true)) This is NOT an error and NOT prevent the correct execution since the constraint will be evaluated in intrepreted mode

2015-06-24 15:28:40,571  WARN (MvelConstraint.java:312) - Exception jitting: !Collections.disjoint(numberList, Arrays.asList(1.0, 2.0, 3.0)) This is NOT an error and NOT prevent the correct execution since the constraint will be evaluated in intrepreted mode

2015-06-24 15:28:40,574  WARN (MvelConstraint.java:312) - Exception jitting: new HashSet(booleanList).equals(new HashSet(Arrays.asList(true))) This is NOT an error and NOT prevent the correct execution since the constraint will be evaluated in intrepreted mode

2015-06-24 15:28:40,576  WARN (MvelConstraint.java:312) - Exception jitting: new HashSet(numberList).equals(new HashSet(Arrays.asList(1.0, 2.0, 3.0))) This is NOT an error and NOT prevent the correct execution since the constraint will be evaluated in intrepreted mode

This actually causes the execution to never finish. How can I work around that?

Thanks!

- Sascha

[sascha.s...@signavio.com]

Oh and as for the components:

I am using  drools core, compiler, kie-api and kie-internal 6.2.0 Final as well as mvel2.2.4Final.

[Davide Sottara]

I didn't check the logic in detail, but it seems that your rules are loop-prone. "Modify" will cause the reevaluation of the rules, no-loop is not sufficient in this case.

Second, I wonder about the performance impact, having to manipulate all those collections. MVEL has list literals, you might want to consider custom operators / static helper functions as well

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[sascha.s...@signavio.com]

Hi Davide,

yes, I know about this issue but currently have other priorities. I will however change the style of rules to avoid loops.

My workaround to at least get it to compile is ugly as hell and not performant at all, but works for now:

new HashSet(Arrays.asList(new String[]{"hello", "world"}))

Do you have any pointers as to where I can read more about the MVEL list literals or maybe even an example?

Thanks,

- Sascha

[Davide Sottara]

You can look here, for example:

https://en.wikipedia.org/wiki/MVEL_Language_Guide

To view this discussion on the web visit https://groups.google.com/d/msgid/drools-usage/ebbe0752-4d9c-492d-92e6-808ce835359e%40googlegroups.com.

[sascha.s...@signavio.com]

Davide,

thanks for the input.

I tried inlining the lists but still got Jitting exceptions sometimes for some rules.

Here is an example, maybe you can tell me where I went wrong?

DRL:

package com.signavio.droolsexport 

import java.util.List

import java.util.Arrays

import java.util.HashSet

import java.util.Collections

declare  ListDecision 

    textList : List  

    booleanList : List  

    numberList : List  

    textOutput : String  

end

rule "listDecision_rule_1"

    no-loop 

when

    $listDecision : ListDecision( textList.equals(["hallo", "welt"]), !booleanList.equals([true]), new HashSet([1.0, 2.0, 3.0]).containsAll(new HashSet(numberList)) )  

then

    modify( $listDecision ){ 

        setTextOutput("RULE 1"); 

    };

end

rule "listDecision_rule_2"

    no-loop 

when

    $listDecision : ListDecision( !textList.equals(["hallo", "welt"]), booleanList.equals([true]), !new HashSet([1.0, 2.0, 3.0]).containsAll(new HashSet(numberList)) )  

then

    modify( $listDecision ){ 

        setTextOutput("RULE 2"); 

    };

end

rule "listDecision_rule_3"

    no-loop 

when

    $listDecision : ListDecision( new HashSet(["hallo", "welt"]).containsAll(new HashSet(textList)), booleanList.equals([true]), !numberList.equals([1.0, 2.0, 3.0]) )  

then

    modify( $listDecision ){ 

        setTextOutput("RULE 3"); 

    };

end

rule "listDecision_rule_4"

    no-loop 

when

    $listDecision : ListDecision( !new HashSet(["hallo", "welt"]).containsAll(new HashSet(textList)), !booleanList.equals([true]), !Collections.disjoint(numberList, [1.0, 2.0, 3.0] )  

then

    modify( $listDecision ){ 

        setTextOutput("RULE 4"); 

    };

end

rule "listDecision_rule_5"

    no-loop 

when

    $listDecision : ListDecision( !Collections.disjoint(textList, ["hallo", "welt"], !new HashSet([true]).containsAll(new HashSet(booleanList)), numberList.equals([1.0, 2.0, 3.0]) )  

then

    modify( $listDecision ){ 

        setTextOutput("RULE 5"); 

    };

end

rule "listDecision_rule_6"

    no-loop 

when

    $listDecision : ListDecision( new HashSet(["hallo", "welt"]).equals(new HashSet(textList)), new HashSet([true]).equals(new HashSet(booleanList)), Collections.disjoint(numberList, [1.0, 2.0, 3.0] )  

then

    modify( $listDecision ){ 

        setTextOutput("RULE 6"); 

    };

end

rule "listDecision_rule_7"

    no-loop 

when

    $listDecision : ListDecision( Collections.disjoint(textList, ["hallo", "welt"], !booleanList.equals([true]), numberList.equals([1.0, 2.0, 3.0]) )  

then

    modify( $listDecision ){ 

        setTextOutput("RULE 7"); 

    };

end

Inputs are:

List<String> stringInput = Arrays.asList("wurst", "schmeckt", "wurst", "neckt");
List<Boolean> booleanInput = Arrays.asList(false, false);
List<Double> numberInput = Arrays.asList(1d, 2d, 3d);
String expected = "RULE 7";

With the following console Output in IntelliJ using the Janino 2.5.16 compiler:

2015-07-01 10:00:02,838  WARN (MvelConstraint.java:312) - Exception jitting: booleanList.equals([true]) This is NOT an error and NOT prevent the correct execution since the constraint will be evaluated in intrepreted mode

2015-07-01 10:00:02,869  WARN (MvelConstraint.java:312) - Exception jitting: !booleanList.equals([true]) This is NOT an error and NOT prevent the correct execution since the constraint will be evaluated in intrepreted mode

2015-07-01 10:00:02,884  WARN (MvelConstraint.java:312) - Exception jitting: !Collections.disjoint(numberList, [1.0, 2.0, 3.0]) This is NOT an error and NOT prevent the correct execution since the constraint will be evaluated in intrepreted mode

2015-07-01 10:00:02,903  WARN (MvelConstraint.java:312) - Exception jitting: !booleanList.equals([true]) This is NOT an error and NOT prevent the correct execution since the constraint will be evaluated in intrepreted mode

2015-07-01 10:00:02,906  WARN (MvelConstraint.java:312) - Exception jitting: numberList.equals([1.0, 2.0, 3.0]) This is NOT an error and NOT prevent the correct execution since the constraint will be evaluated in intrepreted mode

The rule that was supposed to fire was rule "listDecision_rule_7".

Is this a problem with my rules (overlap) or is there something I am not seeing?

Thanks already for your help!

[Davide Sottara]

The messages you're seeing are not real exceptions, it's just a warning that the engine can't optimize some of the constraints like it would with more traditional "==" or ">".

If you are not getting the expected behavior, it should be for a different reason.

To view this discussion on the web visit https://groups.google.com/d/msgid/drools-usage/c94a73e8-0169-480c-84cb-8d8779a41b7d%40googlegroups.com.

[sascha.s...@signavio.com]

So my rule produced an infinite loop there?
At least my test seems to not stop any more with these inputs. Might be a bad choice of inputs then.

Thank you

[Davide Sottara]

"no-loop" is not enough to avoid infinite recursion in your rules. 

You can find possible solutions in this ever-green classic : https://ilesteban.wordpress.com/2012/11/16/about-drools-and-infinite-execution-loops/

To view this discussion on the web visit https://groups.google.com/d/msgid/drools-usage/b95fe315-1dc0-496c-86b6-271477069f52%40googlegroups.com.

[sascha.s...@signavio.com]

One question that I am still not entirely sure on though:

Why do the rules produce an infinite loop when inlining the lists with MVEL but terminate when I use the ugly new HashSet(Arrays.asList(new String[]{})) approach?
Shouldn't these be interchangeable?

[Davide Sottara]

The actual question is: do the same rules fire in both versions, given the facts you insert? 

Can you replace the "modify" with e.g. a printout and compare them?

To view this discussion on the web visit https://groups.google.com/d/msgid/drools-usage/002280a6-d5f3-4855-8ce4-efeca245cf5a%40googlegroups.com.