[rules-users] unmarshal global variable

[Wolfgang Laun]

I suppose you might use the classic Singleton design pattern, insert
the object as a fact (so it'll get marshalled) but access its fields
via classname.staticmethod, which is not much different from a
globalname.staticmethod.
-W

On 07/01/2013, Ormond, Alex C. (GDLP) <ACOrmond at greatdanetrailers.com> wrote:
> Many thanks to all who responded.
>
> Wolfgang, I assume you provided the answer.  Thank you, I'll give it a
> shot.
>
> Yes, the rule works separate of marshalling.  I can believe there's a
> better way to get constants into the session from a spreadsheet, but
> this is the only way I could get to work.
>
> Yes, I did declare "variables" in the spreadsheet.
>
> Cheers to all,
>
> Alex
>
>
> -----Original Message-----
> From: rules-users-bounces at lists.jboss.org
> [mailto:rules-users-bounces at lists.jboss.org] On Behalf Of Wolfgang Laun
> Sent: Monday, January 07, 2013 12:44 PM
> To: Rules Users List
> Subject: Re: [rules-users] unmarshal global variable
>
> A DRL global is not marshalled /unmarshalled along with the session.
> You'll have to marshal/unmarshal this object separately, and setGlobal
> it again in the restored session.
> -W
>
> On 07/01/2013, Ormond, Alex C. (GDLP) <ACOrmond at greatdanetrailers.com>
> wrote:
>> Thanks for the response.  The first rule table in the spreadsheet
>> (kinda) looks like this:
>> 				
>> RuleTable Constants					
>> NAME	CONDITION	ACTION	ACTION		
>> 					
>> 	eval(! productPricer.isConstantsSet($1) )
>> productPricer.setConstant($1, $2);
>> productPricer.setConstantsSet($1);		
>> Rule Name	Set?				
>> ProductName	TRUE	"NAME", "Champion CL"			
>> DefaultCost	TRUE	"COST", "80000"			
>> DefaultPrice	TRUE	"PRICE", "100000"			
>> DefaultLength	TRUE	"LENGTH", "53"			
>> Done	TRUE		TRUE		
>> 					
>>
>> The first rule generated looks like this:
>>
>> rule "ProductName"
>> 	when
>> 		eval(! productPricer.isConstantsSet() )
>> 	then
>> 		productPricer.setConstant("NAME", "Champion CL");
>> end
>>
>>
>> Alex
>>
>>
>> -----Original Message-----
>> From: rules-users-bounces at lists.jboss.org
>> [mailto:rules-users-bounces at lists.jboss.org] On Behalf Of Wolfgang
> Laun
>> Sent: Monday, January 07, 2013 11:22 AM
>> To: Rules Users List
>> Subject: Re: [rules-users] unmarshal global variable
>>
>> The crucial info is: what is in the first table, how do you insert
> this
>> data?
>> Is it a DRL global? A fact? How does the (generated) rule look like?
>> -W
>>
>> On 07/01/2013, acormond <acormond at greatdanetrailers.com> wrote:
>>> Gentlepeople,
>>>
>>> I am fairly new to Drools and have what I hope is a simple question.
>> I am
>>> attempting to marshal (serialize) a Drools knowledge session and then
>>> unmarshall it.  The marshalling works but the unmarshalling fails
> with
>> a
>>> null pointer exception.  The error is apparently with unmarshalling a
>>> global
>>> variable in the session.
>>>
>>> The session is created from a spreadsheet (decision table).  This
>>> spreadsheet
>>> has two RuleTables.  The first of these exists solely so that I can
>> enter
>>> some
>>> constants into the session, specifically the name and price of the
>> product
>>> the
>>> spreadsheet is dealing with.  The second ruletable is where the rules
>> are
>>> specified.  The exception occurs when unmarshalling the first rule in
>> the
>>> first
>>> rule table.  If, as a test, I eliminate the first rule table, then I
>> can
>>> successfully marshal and unmarshall the session.
>>>
>>> The marshalling is done using the following, simplified, code:
>>>
>>>   Marshaller marshaller = MarshallerFactory.newMarshaller(kbase);
>>>   File droolsSessionFile = new File(MARSHAL_FILE);
>>>   foStream = new FileOutputStream(droolsSessionFile);
>>>   baos = new ByteArrayOutputStream();
>>>   marshaller.marshall(baos, ksession);
>>>   baos.writeTo(foStream);
>>>
>>> and the unmarshalling is done like this:
>>>
>>>   Marshaller marshaller =
>>> MarshallerFactory.newMarshaller(pricingProcessor.getKnowledgeBase());
>>>   FileInputStream fis = new FileInputStream(MARSHAL_FILE);
>>>   StatefulKnowledgeSession ksession = marshaller.unmarshall(fis);
>>>
>>>
>>> So, where did I go wrong?  Perhaps I need to deal with the global
>> variable
>>> differently, perhaps by putting it in the knowledgeBase before I
>> unmarshall
>>> the session?
>>>
>>> Thank you for any help.
>>>
>>> Alex Ormond
>>>
>>>
>>>
>>>
>>> --
>>> View this message in context:
>>>
>>
> http://drools.46999.n3.nabble.com/unmarshal-global-variable-tp4021375.ht
>> ml
>>> Sent from the Drools: User forum mailing list archive at Nabble.com.
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