[jboss-jira] [JBoss JIRA] (DROOLS-1227) Drools cannot be configured to expire Events properly

[Cristobal Arellano (JIRA)]

Cristobal Arellano created DROOLS-1227:
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             Summary: Drools cannot be configured to expire Events properly
                 Key: DROOLS-1227
                 URL: https://issues.jboss.org/browse/DROOLS-1227
             Project: Drools
          Issue Type: Feature Request
    Affects Versions: 6.2.0.Final
         Environment: Windows, Java SE 1.8
            Reporter: Cristobal Arellano
            Assignee: Mark Proctor
            Priority: Critical


Hello,

I want to configure Drools (CEP) to expire events when no longer needed. There are two scenarios:

==SCENARIO A==
I configured Event with no explicit expires. In this scenario, if there is a rule with temporal constraints, the expiration is automatically calculated based on the constrains.  If there is a rule with no temporal constraints, the expiration is INFINITE. The following example shows the scenario:

dialect "mvel"
declare Event
@role(event)
end
rule "ExampleRule1"
when
( $a : Event(name == "event a") 
then
System.out.println("ExampleRule1Triggered");
end
rule "ExampleRule2"
when
( $a : Event(name == "event a") ) and
( $b : Event((name == "event b") && (this after [1ms, 15s] $a)) )
then
System.out.println("ExampleRule2Triggered");
end

With the previous Event definition:
* If only ExampleRule1 loaded, expires INFINITE. Expected expires 0. ERROR?
* If ExampleRule1 loaded and ExampleRule2 loaded, expires 15s. Expected expires 15. OK!

To solve this situation a tried the following scenario:
== SCENARIO B==
I configured Event with explicit expires. In this scenario, if there is a rule with temporal constraints, the expiration is not taken into account because it is overriden by the explicit expires. The following example shows the scenario:

dialect "mvel"
declare Event
@role(event)
@expires(0s)
end
rule "ExampleRule1"
when
( $a : Event(name == "event a") 
then
System.out.println("ExampleRule1Triggered");
end
rule "ExampleRule2"
when
( $a : Event(name == "event a") ) and
( $b : Event((name == "event b") && (this after [1ms, 15s] $a)) )
then
System.out.println("ExampleRule2Triggered");
end

With the previous Event definition:
* ExampleRule1 is triggered and event removed. OK!
* ExampleRule2 is not triggered inserting two events because the first one expires. ERROR?

I suppose that SCENARIO B is not factible because explicit expires overrides implicit expires (according to issue DROOLS-586).

Could you please help me to solve this situation? Should Drools set inferred expiration time to 1ms when there are rules with no temporal constraints?




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