RE: JESS: dealing with shadow facts having null properties
Well, I'm really sorry...JFL
> From: [EMAIL PROTECTED]> Subject: Re: JESS: dealing with shadow facts having
> null properties> Date: Fri, 3 Aug 2007 15:23:03 -0400> To:
> jess-users@sandia.gov> > Look closely at your stack trace: it says "Message:
> Called method > threw an exception." If you called getCause() on the
> JessException, > it would return a NullPointerException, and if you looked at
> that > NPE's stack trace, you'd see it was thrown by the getA() method of >
> your Test class. Here are the relevant lines from your code:> > private
> Integer a = null;> ...> public int getA() {> return a;> }> > Note that the
> type of variable "a" is Integer, but getA() is > returning an int. That means
> that, due to auto-unboxing, the Java > compiler is going to emit code as if
> you had written something like> > public int getA() {> return a.intValue();>
> }> > > and since "a" is null, this line throws a NullPointerException. It's >
> not Jess's fault if your getter methods throw NPEs when called!> > > > > > On
> Aug 3, 2007, at 2:51 PM, Skeptic 2000 wrote:> > >> > Hi and thanks a lot for
> helping, the details are here :> >> > That's the ShadowFact :> >> > public
> class Test {> >> >> >> >> > private Integer a = null;> >> > private Integer b
> = 4;> >> >> >> >> > public Test() {> >> >> >> > }> >> >> >> >> > public int
> getA() {> >> > return a;> >> > }> >> >> >> >> > public int getB() {> >> >
> return b;> >> > }> >> >> > }> >> > That's the .CLP file :> >> > (defclass
> Test xxx.yyy.zzz.Test)> >> >> > (defrule testrule> >> > (Test (a ?a) (b ?b))>
> >> > =>> >> > (printout t "testrule ok")> >> > )> >> > That's the java code
> :> >> > void functionX() {> > ...> > jessEngine.add(new Test());> > ...> > }>
> >> > That's the exception :> >> > Jess reported an error in routine
> DefinstanceList.updateMultipleSlots.> >> > Message: Called method threw an
> exception.> >> > at
> jess.DefinstanceList.getSlotValueFromObject(DefinstanceList.java: > > 371)>
> >> > at jess.DefinstanceList.setAllSlotValuesFromObject > >
> (DefinstanceList.java:353)> >> > at
> jess.DefinstanceList.createNewShadowFact(DefinstanceList.java:332)> >> > at
> jess.DefinstanceList.definstance(DefinstanceList.java:111)> >> > at
> jess.Rete.definstance(Rete.java:1903)> >> > at
> jess.Rete.definstance(Rete.java:1883)> >> > at jess.Rete.add(Rete.java:2023)>
> > ...> >> >> > JFL> >> >> >> >> >> > > From: [EMAIL PROTECTED]> > > Subject:
> Re: JESS: dealing with shadow facts having null properties> > > Date: Fri, 3
> Aug 2007 10:48:15 -0400> > > To: jess-users@sandia.gov> > >> > > I can't
> reproduce anything like this; can you show me a stack trace> > > (run
> jess.Main with -stacktrace to see a full error trace).> > >> > > On Aug 2,
> 2007, at 6:12 PM, Skeptic 2000 wrote:> > >> > > >> > > > When I add a shadow
> fact with a property having a null value, I > > get> > > > an exception (in
> updateMultiSlot IRRC).> > > >> > > > JFL> > > >> > > > > From: [EMAIL
> PROTECTED]> > > > > Subject: Re: JESS: dealing with shadow facts having null
> > > properties> > > > > Date: Thu, 2 Aug 2007 15:57:55 -0400> > > > > To:
> jess-users@sandia.gov> > > > >> > > > > Jess has been able to handle null
> properties for a long time; > > 6.1p8> > > > > can handle them, as can the
> current versions. What problem > > are you> > > > > having, exactly?> > > >
> >> > > > > On Aug 2, 2007, at 2:19 PM, Skeptic 2000 wrote:> > > > >> > > > >
> >> > > > > > Hi,> > > > > >> > > > > > I need to add in the working memory
> some shadow facts with> > > > > > properties whose values are null.
>
Re: JESS: dealing with shadow facts having null properties
Look closely at your stack trace: it says "Message: Called method
threw an exception." If you called getCause() on the JessException,
it would return a NullPointerException, and if you looked at that
NPE's stack trace, you'd see it was thrown by the getA() method of
your Test class. Here are the relevant lines from your code:
private Integer a = null;
...
public int getA() {
return a;
}
Note that the type of variable "a" is Integer, but getA() is
returning an int. That means that, due to auto-unboxing, the Java
compiler is going to emit code as if you had written something like
public int getA() {
return a.intValue();
}
and since "a" is null, this line throws a NullPointerException. It's
not Jess's fault if your getter methods throw NPEs when called!
On Aug 3, 2007, at 2:51 PM, Skeptic 2000 wrote:
Hi and thanks a lot for helping, the details are here :
That's the ShadowFact :
public class Test {
private Integer a = null;
private Integer b = 4;
public Test() {
}
public int getA() {
return a;
}
public int getB() {
return b;
}
}
That's the .CLP file :
(defclass Test xxx.yyy.zzz.Test)
(defrule testrule
(Test (a ?a) (b ?b))
=>
(printout t "testrule ok")
)
That's the java code :
void functionX() {
...
jessEngine.add(new Test());
...
}
That's the exception :
Jess reported an error in routine DefinstanceList.updateMultipleSlots.
Message: Called method threw an exception.
at jess.DefinstanceList.getSlotValueFromObject(DefinstanceList.java:
371)
at jess.DefinstanceList.setAllSlotValuesFromObject
(DefinstanceList.java:353)
at jess.DefinstanceList.createNewShadowFact(DefinstanceList.java:332)
at jess.DefinstanceList.definstance(DefinstanceList.java:111)
at jess.Rete.definstance(Rete.java:1903)
at jess.Rete.definstance(Rete.java:1883)
at jess.Rete.add(Rete.java:2023)
...
JFL
> From: [EMAIL PROTECTED]
> Subject: Re: JESS: dealing with shadow facts having null properties
> Date: Fri, 3 Aug 2007 10:48:15 -0400
> To: jess-users@sandia.gov
>
> I can't reproduce anything like this; can you show me a stack trace
> (run jess.Main with -stacktrace to see a full error trace).
>
> On Aug 2, 2007, at 6:12 PM, Skeptic 2000 wrote:
>
> >
> > When I add a shadow fact with a property having a null value, I
get
> > an exception (in updateMultiSlot IRRC).
> >
> > JFL
> >
> > > From: [EMAIL PROTECTED]
> > > Subject: Re: JESS: dealing with shadow facts having null
properties
> > > Date: Thu, 2 Aug 2007 15:57:55 -0400
> > > To: jess-users@sandia.gov
> > >
> > > Jess has been able to handle null properties for a long time;
6.1p8
> > > can handle them, as can the current versions. What problem
are you
> > > having, exactly?
> > >
> > > On Aug 2, 2007, at 2:19 PM, Skeptic 2000 wrote:
> > >
> > > >
> > > > Hi,
> > > >
> > > > I need to add in the working memory some shadow facts with
> > > > properties whose values are null. Currently, my workaround
is to
> > > > use a "NullObject" to prevent Jess from crashing upon
finding a
> > > > null value.
> > > >
> > > > Is it the recommended way to do it ?
> > > >
> > > > JFL
> > > >
> > > > Soyez parmi les premiers à essayer Windows Live Mail.
> > >
> > > -
> > > Ernest Friedman-Hill
> > > Advanced Software Research Phone: (925) 294-2154
> > > Sandia National Labs FAX: (925) 294-2234
> > > PO Box 969, MS 9012 [EMAIL PROTECTED]
> > > Livermore, CA 94550 http://www.jessrules.com
> > >
> > >
> > > To unsubscribe, send the words 'unsubscribe jess-users
> > [EMAIL PROTECTED]'
> > > in the BODY of a message to [EMAIL PROTECTED], NOT to the
list
> > > (use your own address!) List problems? Notify owner-jess-
> > [EMAIL PROTECTED]
> > >
> > >
> >
> >
> > Soyez parmi les premiers à essayer Windows Live Mail.
>
> -
> Ernest Friedman-Hill
> Advanced Software Research Phone: (925) 294-2154
> Sandia National Labs FAX: (925) 294-2234
> PO Box 969, MS 9012 [EMAIL PROTECTED]
> Livermore, CA 94550 http://www.jessrules.com
>
>
> To unsubscribe, send the words 'unsubscrib
RE: JESS: dealing with shadow facts having null properties
Hi and thanks a lot for helping, the details are here :
That's the ShadowFact :
public class Test {
private Integer a = null;
private Integer b = 4;
public Test() {
}
public int getA() {
return a;
}
public int getB() {
return b;
}
}
That's the .CLP file :
(defclass Test xxx.yyy.zzz.Test)
(defrule testrule
(Test (a ?a) (b ?b))
=>
(printout t "testrule ok")
)
That's the java code :
void functionX() {
...
jessEngine.add(new Test());
...
}
That's the exception :
Jess reported an error in routine DefinstanceList.updateMultipleSlots.
Message: Called method threw an exception.
at jess.DefinstanceList.getSlotValueFromObject(DefinstanceList.java:371)
at jess.DefinstanceList.setAllSlotValuesFromObject(DefinstanceList.java:353)
at jess.DefinstanceList.createNewShadowFact(DefinstanceList.java:332)
at jess.DefinstanceList.definstance(DefinstanceList.java:111)
at jess.Rete.definstance(Rete.java:1903)
at jess.Rete.definstance(Rete.java:1883)
at jess.Rete.add(Rete.java:2023)
...
JFL
> From: [EMAIL PROTECTED]> Subject: Re: JESS: dealing with shadow facts having
> null properties> Date: Fri, 3 Aug 2007 10:48:15 -0400> To:
> jess-users@sandia.gov> > I can't reproduce anything like this; can you show
> me a stack trace > (run jess.Main with -stacktrace to see a full error
> trace).> > On Aug 2, 2007, at 6:12 PM, Skeptic 2000 wrote:> > >> > When I add
> a shadow fact with a property having a null value, I get > > an exception (in
> updateMultiSlot IRRC).> >> > JFL> >> > > From: [EMAIL PROTECTED]> > >
> Subject: Re: JESS: dealing with shadow facts having null properties> > >
> Date: Thu, 2 Aug 2007 15:57:55 -0400> > > To: jess-users@sandia.gov> > >> > >
> Jess has been able to handle null properties for a long time; 6.1p8> > > can
> handle them, as can the current versions. What problem are you> > > having,
> exactly?> > >> > > On Aug 2, 2007, at 2:19 PM, Skeptic 2000 wrote:> > >> > >
> >> > > > Hi,> > > >> > > > I need to add in the working memory some shadow
> facts with> > > > properties whose values are null. Currently, my workaround
> is to> > > > use a "NullObject" to prevent Jess from crashing upon finding a>
> > > > null value.> > > >> > > > Is it the recommended way to do it ?> > > >>
> > > > JFL> > > >> > > > Soyez parmi les premiers à essayer Windows Live
> Mail.> > >> > > -> >
> > Ernest Friedman-Hill> > > Advanced Software Research Phone: (925) 294-2154>
> > > Sandia National Labs FAX: (925) 294-2234> > > PO Box 969, MS 9012 [EMAIL
> PROTECTED]> > > Livermore, CA 94550 http://www.jessrules.com> > >> > >
> > > > To
> unsubscribe, send the words 'unsubscribe jess-users > > [EMAIL PROTECTED]'> >
> > in the BODY of a message to [EMAIL PROTECTED], NOT to the list> > > (use
> your own address!) List problems? Notify owner-jess- > > [EMAIL PROTECTED]> >
> > > > >>
> >> >> > Soyez parmi les premiers à essayer Windows Live Mail.> >
> -> Ernest
> Friedman-Hill> Advanced Software Research Phone: (925) 294-2154> Sandia
> National Labs FAX: (925) 294-2234> PO Box 969, MS 9012 [EMAIL PROTECTED]>
> Livermore, CA 94550 http://www.jessrules.com> >
> > To
> unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]'> in
> the BODY of a message to [EMAIL PROTECTED], NOT to the list> (use your own
> address!) List problems? Notify [EMAIL PROTECTED]>
> >
_
Soyez parmi les premiers à essayer Windows Live Mail.
http://ideas.live.com/programpage.aspx?versionId=5d21c51a-b161-4314-9b0e-4911fb2b2e6d
Re: JESS: dealing with shadow facts having null properties
I can't reproduce anything like this; can you show me a stack trace (run jess.Main with -stacktrace to see a full error trace). On Aug 2, 2007, at 6:12 PM, Skeptic 2000 wrote: When I add a shadow fact with a property having a null value, I get an exception (in updateMultiSlot IRRC). JFL > From: [EMAIL PROTECTED] > Subject: Re: JESS: dealing with shadow facts having null properties > Date: Thu, 2 Aug 2007 15:57:55 -0400 > To: jess-users@sandia.gov > > Jess has been able to handle null properties for a long time; 6.1p8 > can handle them, as can the current versions. What problem are you > having, exactly? > > On Aug 2, 2007, at 2:19 PM, Skeptic 2000 wrote: > > > > > Hi, > > > > I need to add in the working memory some shadow facts with > > properties whose values are null. Currently, my workaround is to > > use a "NullObject" to prevent Jess from crashing upon finding a > > null value. > > > > Is it the recommended way to do it ? > > > > JFL > > > > Soyez parmi les premiers à essayer Windows Live Mail. > > - > Ernest Friedman-Hill > Advanced Software Research Phone: (925) 294-2154 > Sandia National Labs FAX: (925) 294-2234 > PO Box 969, MS 9012 [EMAIL PROTECTED] > Livermore, CA 94550 http://www.jessrules.com > > > To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' > in the BODY of a message to [EMAIL PROTECTED], NOT to the list > (use your own address!) List problems? Notify owner-jess- [EMAIL PROTECTED] > > Soyez parmi les premiers à essayer Windows Live Mail. - Ernest Friedman-Hill Advanced Software Research Phone: (925) 294-2154 Sandia National LabsFAX: (925) 294-2234 PO Box 969, MS 9012 [EMAIL PROTECTED] Livermore, CA 94550 http://www.jessrules.com To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' in the BODY of a message to [EMAIL PROTECTED], NOT to the list (use your own address!) List problems? Notify [EMAIL PROTECTED]
RE: JESS: dealing with shadow facts having null properties
When I add a shadow fact with a property having a null value, I get an exception (in updateMultiSlot IRRC). JFL > From: [EMAIL PROTECTED]> Subject: Re: JESS: dealing with shadow facts having > null properties> Date: Thu, 2 Aug 2007 15:57:55 -0400> To: > jess-users@sandia.gov> > Jess has been able to handle null properties for a > long time; 6.1p8 > can handle them, as can the current versions. What problem > are you > having, exactly?> > On Aug 2, 2007, at 2:19 PM, Skeptic 2000 > wrote:> > >> > Hi,> >> > I need to add in the working memory some shadow > facts with > > properties whose values are null. Currently, my workaround is > to > > use a "NullObject" to prevent Jess from crashing upon finding a > > > null value.> >> > Is it the recommended way to do it ?> >> > JFL> >> > Soyez > parmi les premiers à essayer Windows Live Mail.> > > -> Ernest > Friedman-Hill> Advanced Software Research Phone: (925) 294-2154> Sandia > National Labs FAX: (925) 294-2234> PO Box 969, MS 9012 [EMAIL PROTECTED]> > Livermore, CA 94550 http://www.jessrules.com> > > > To > unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]'> in > the BODY of a message to [EMAIL PROTECTED], NOT to the list> (use your own > address!) List problems? Notify [EMAIL PROTECTED]> > > _ Soyez parmi les premiers à essayer Windows Live Mail. http://ideas.live.com/programpage.aspx?versionId=5d21c51a-b161-4314-9b0e-4911fb2b2e6d
Re: JESS: dealing with shadow facts having null properties
Jess has been able to handle null properties for a long time; 6.1p8 can handle them, as can the current versions. What problem are you having, exactly? On Aug 2, 2007, at 2:19 PM, Skeptic 2000 wrote: Hi, I need to add in the working memory some shadow facts with properties whose values are null. Currently, my workaround is to use a "NullObject" to prevent Jess from crashing upon finding a null value. Is it the recommended way to do it ? JFL Soyez parmi les premiers à essayer Windows Live Mail. - Ernest Friedman-Hill Advanced Software Research Phone: (925) 294-2154 Sandia National LabsFAX: (925) 294-2234 PO Box 969, MS 9012 [EMAIL PROTECTED] Livermore, CA 94550 http://www.jessrules.com To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' in the BODY of a message to [EMAIL PROTECTED], NOT to the list (use your own address!) List problems? Notify [EMAIL PROTECTED]
