[rules-users] Caching results in temperory variables

[Manav]

Great stuff. Things are very clear now . It raised some more questions though :-

-- Say we use the one shot insert at the very start of the rule. And i am using 
this rule to validate some 

     100,000 User facts . Will these inserts be done only once or as many times 
as new facts are inserted
     in WM.  Is there something that we can use to determine this as per the 
need.

-- As done in the example below there will be as many UserResult objects 
inserted in the memory as there are User facts. We insert them in the WM at the 
start and update them as the rule executes . At the very end should we retract 
them as well from the WM . Is that a suggested practice or doesn't really matter 
. 


-- Does WM automatically remove objects if they have not been used for long time 
or it's the responsibility of the application developer to keep track of what's 
goes in and out.

-- Instead of inserting one fact at a time if we insert a collection at one go 
in the WM how does this rule get applied . Sequentially to all the objects or in 
parallel ?

Regards,
Manav



________________________________
From: Wolfgang Laun <wolfgang.laun at gmail.com>
To: Manav <manav7574 at yahoo.com>
Cc: rules-users at lists.jboss.org
Sent: Fri, August 13, 2010 11:41:53 PM
Subject: Re: [rules-users] Caching results in temperory variables

On 13 August 2010 18:36, Manav <manav7574 at yahoo.com> wrote:

Your explanation is absolutely superb.  I modified my drl as per your 
suggestions and it's just been completely transformed. Just one question 
regarding one suggestion below :
>
>-- is this something like a for each loop in java . This is the first example i 
>have seen in drl 
>

In a way, yes. Since
   Foo( ... )   # match any Foo according to constraints, if any
   Bar( ... )   # match any Bar according to constraints, if any
these two patterns produce the Cartesian product, such as a nested loop does. 
BUT, the order of the pairings is indeterministic, and changes in WM might 
influence this loop, even make it infinitive. Therefore, "in a way".  



-- will this automatically iterate over as many languages as have been inserted 
? 


That's the whole idea :-)
 
-- the inserts .. don't they have to be within a rule block ? or did you just 
omit other things to keep it simple
>

You can do it in the Java application framework. You can also write a 
high-salience one-shot rule such as

rule "1st shot"
when
then   

insert( new Language( "Japanese" ) ); 
>insert( new Language( "French" ) ); 
>// more of the same
>
end

Cheers
Wolfgang 


      
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