Re: [rules-users] How to check if a property IS null ?
Thank you.
Here's a very simple use case : https://github.com/ceefour/droolsnull
Running this on Drools 5.4.0 will output:
00:29:34.122 [main] INFO c.h.droolsnull.BookingService - getNullQty()
called!
00:29:34.125 [main] INFO c.h.droolsnull.BookingService - getFilledQty()
called!
00:29:34.139 [main] INFO c.hendyirawan.droolsnull.DroolsNull - Notify has
filled sentTime: Thu Aug 16 00:29:34 WIT 2012
00:29:34.139 [main] INFO c.hendyirawan.droolsnull.DroolsNull - Notify has
NULL sentTime
00:29:34.140 [main] INFO c.hendyirawan.droolsnull.DroolsNull - You've got a
filled booking with qty 5.0
00:29:34.140 [main] INFO c.hendyirawan.droolsnull.DroolsNull - You've got a
NULL booking
00:29:34.140 [main] INFO c.hendyirawan.droolsnull.DroolsNull -
BookingService can return filled qty: 10.0
Expected is one more:
BookingService can return NULL qty
BookingService.getNullQty() is called by the Drools rule but then ignored.
How to capture this?
The rules :
package com.hendyirawan.droolsnull
dialect "mvel"
import org.slf4j.*;
import com.hendyirawan.droolsnull.*;
global Logger log;
global BookingService bookingService;
rule "Booking data with not null qty exists"
when
$booking : Booking( $qty : qty != null )
then
log.info("You've got a filled booking with qty {}", {$qty});
end
rule "Booking data with null qty exists"
when
$booking : Booking( qty == null )
then
log.info("You've got a NULL booking");
end
rule "BookingService can return null qty"
when
Double( this == null ) from bookingService.getNullQty()
then
log.info("BookingService can return NULL qty");
end
rule "BookingService can return filled qty"
when
$qty : Double() from bookingService.getFilledQty()
then
log.info("BookingService can return filled qty: {}", {$qty});
end
rule "Notify has null sentTime"
when
$notify : Notify( sentTime == null )
then
log.info("Notify has NULL sentTime");
end
rule "Notify has filled sentTime"
when
$notify : Notify( $sentTime : sentTime != null )
then
log.info("Notify has filled sentTime: {}", {$sentTime});
end
The rule that isn't working :
rule "BookingService can return null qty"
when
Double( this == null ) from bookingService.getNullQty()
then
log.info("BookingService can return NULL qty");
end
Thank you.
Hendy
(I also once had a criteria like " $notify : Notify( sentTime == null ) "
not working but can't reproduce it again yet. if I can find it I'll post
again)
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