[rules-users] confusing behaviour of enum comparison

[Wolfgang Laun]

Given your enum, this .drl

declare Step
   id: String
   status: Status
end

rule insertion
salience ( 10 )
when
then
  Step step = new Step();
  step.setId( "One" );
  step.setStatus( Status.PENDING );
  insert( step );
end

rule testPending
when
    $step: Step( status == Status.PENDING )
##    $step: Step( status != Status.ACTIVE )
##    $step: Step( status.active == false )
then
    System.out.println( "testPending " + $step.getId() );
end

and Drools 5.2.0 Final, all three patterns result in a firing of rule
testPending.

-W


On 26 October 2011 19:38, lhorton <LHorton at abclegal.com> wrote:

> 5.2.0.Final
>
> I am seeing some confusing behaviour in enum comparisons in LHS rule
> conditions.  I have an enum class, "Status" (full source below) that is an
> attribute on several of our domain objects.  I'm comparing the enum in
> several ways, and the rule fires differently when I use syntax that AFAIK
> ought to have the same result.
>
> for example, say there is a Step with status of Status.PENDING.  if I
> write:
>
> $step : Step(status.active == false)    // rule DOES fire
>
> $step : Step(status != Status.ACTIVE)    // rule does NOT fire, but should
>
> I am testing this with the same objects and same test each time.  can
> anyone
> explain why the two comparisons do not get the same result?
>
> here is the definition of Status:
>
> public enum Status {
>
>        PENDING("Pending"),
>        ACTIVE("Active"),
>        COMPLETE("Complete");
>
>        private final String label;
>
>        private Status(String label) {
>                this.label = label;
>        }
>
>        public String getLabel() {
>                return label;
>        }
>
>        public boolean isPending(){
>                return label.equals("Pending");
>        }
>
>        public boolean isActive(){
>                return label.equals("Active");
>        }
>
>        public boolean isComplete(){
>                return label.equals("Complete");
>        }
>
>        public static boolean isPending(Status status) {
>                return (status == null) ? false : status.isPending();
>        }
>
>        public static boolean isActive(Status status) {
>                return (status == null) ? false : status.isActive();
>        }
>
>        public static boolean isComplete(Status status) {
>                return (status == null) ? false : status.isComplete();
>        }
>
>        public static Status fromString(String name) {
>                if (name != null) {
>                        Status types[] = Status.values();
>                        for(Status s : types) {
>                                if (name.equalsIgnoreCase(s.toString())) {
>                                        return s;
>                                }
>                        }
>                }
>                return null;
>        }
> }
>
>
> --
> View this message in context:
> http://drools.46999.n3.nabble.com/confusing-behaviour-of-enum-comparison-tp3455245p3455245.html
> Sent from the Drools: User forum mailing list archive at Nabble.com.
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