Re: [rules-users] ClassCastException
Hi Shannon,
yes all eventtypes inherit from a base class, but the superclass doesn't
include all the attributes I want to acces in the rules. Unfortunately I
can't modify the classes since they're part of a library that i'm using.
Here is my intention:
I get a bunch of different events and have to extract some data.
Every event has a field with EPC's to which all the rest of the data
belongs. I want to extract all the single EPC's with its related data.
With pure Java the solution would be somethin like that:
void handleObjectEvent(ObjectEventType p_objEvent){
List<EPC> epcs = p_objEvent.getEPC();
if(epc!=null){
for(EPC e : epcs){
if(p_objEvent.getBizLocation() !=null){
doSomething(e, p_objEvent.getBizLocation());
}
if(p_objEvent.getBizStep() !=null){
doSomething(e, p_objEvent.getBizStep());
}
if(p_objEvent.getDisposition() !=null){
doSomething(e, p_objEvent.getDisposition());
}
...
...
}
}
}
For the other types of Events there would similar functions. Since there
are a lot of if-statements in the functions I thougt that it would be
nice to use rule engine instead.
Greetings,
Christoph
Shannon Lal wrote:
Christoph,
I am not sure that this is a rules problem as it seems to be more of a
Java problem. Do you Event types all inherit from a base class?
Could you not just check to see on the base class is present? Also,
you might want to add in SMALL example of what you are trying to do in
pure Java code (outside of Rules) as it might be easy to translate.
Shannon
On Thu, May 14, 2009 at 6:35 AM, Christoph Kramer <amrod(a)gmx.de
<mailto:amrod@gmx.de>> wrote:
Hi all,
i've some problems with a ClassCastException when using the
"or"-conditional element.
I have different Java-Beans which all have some string-values. Now
I want to create one rule which is able to handle every type of my
classes because it would be a lot of work to create one rule for
every class.
Depending on the type of beans in the working memory the programm
is crashing with an ClassCastException.
Here is a snippet of my drl-file with the "crashing-rule":
rule "BizLocation"
when
$epc : EPC()
QuantityEventType(epcClass == $epc.value ,$bizLoc:
bizLocation !=null ) or AggregationEventType(childEPCs.epc
contains $epc, $bizLoc : bizLocation != null) or
ObjectEventType(epcList.epc contains $epc, $bizLoc : bizLocation
!= null)
then
System.out.println("BizLocation: " +$bizLoc.getId());
end
There are some EPC's in the working memory and some Events (which
might be of type QuantityEventType, AggregationEventType or
ObjectEventType). When there are only ObjectEventType in the
working memory, everything works fine, but wenn there is an
QuantityEventType this rule crashes with
"org.fosstrak.epcis.model.QuantityEventType cannot be cast to
org.fosstrak.epcis.model.ObjectEventType".
I've lot of other, similar rules some of them crashing, others don't.
Can anyone give me a hint where is the error?
Thanks,
Christoph
PS: Sorry for the bad english :(
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