[rules-users] rule using sliding window

[Bhushan Bhangale]

Thanks Edson

 

I read about "from" CE and understand that it can call any external method.
In the external method I can write the code to extract the data from
database.

 

I googled and found this, where its using hibernate session and that way
giving complete flexibility in writing rule on any data set. Do you think
it's a good idea?

 

global org.hibernate.Session hibernateSession;

 

rule "hibernate_from"

            when

                        game:Game() from
hibernateSession.createQuery("select games from Player p where p.age >=
:age").setProperties( {"age" : 18 }).list()

            then

                        System.out.println("The game "+game.getName() +"is
owned by "+game.getPlayers());

end

 

 

-----Original Message-----
From: rules-users-bounces at lists.jboss.org
[mailto:rules-users-bounces at lists.jboss.org] On Behalf Of Edson Tirelli
Sent: Monday, June 01, 2009 6:48 PM
To: Rules Users List
Subject: Re: [rules-users] rule using sliding window

 


   Hi

   The description you have bellow is ambiguous, so I can't give you a
definitive answer. But it seems to be that you don't need sliding windows
for that. Simple temporal operators will do.

> Secondly if the window is large and number of records coming in is high
then could there be a memory issue?
   Yes, Drools does not manages persistence by itself. So, if your design
must support more data than it would fit in your running environment memory,
you need to design a solution that comprises persistence.

> Also since every record is getting stored in database, can I not use the
database directly instead of sliding window?
   Yes, you can fetch data on demand from external sources, be it databases
or anything else. Look at the "from" CE.

    []s
    Edson



2009/6/1 Bhushan Bhangale <bhushan_bhangale at kaleconsultants.com>

I am using Drools 5. I am struggling to write rule for this logic -

If a stock price changes more than 10% within an hour then report the
change.

I understand I have to use sliding window feature but unable to write the
rule.

For example I got an update for IBM stock @ 12:30 for price 100 and then
another update IBM stock @ 12:35 for price 111. Since the time difference is
within an hour and the change is also greater than 10% I want to report this
price change.

 

Stock class -

 

Public class Stock {

   Private String stock;

   Private double price;

   Private Date time;

   Private double priceChange;

   Private Boolean highlight;

}

 

 

rule "Stock Price change more than 10% within an hour"

 

when

 

then

set the priceChange attribute of Stock object

set highlight to true     

end

 

 

Secondly if the window is large and number of records coming in is high then
could there be a memory issue?

 

Also since every record is getting stored in database, can I not use the
database directly instead of sliding window?

 

Thanks

 


Mr. Bhangale Bhushan
Associate Manager
Kale Consultants Ltd.
 <mailto:bhushan_bhangale at kaleconsultants.com>
bhushan_bhangale at kaleconsultants.com
tel:
<http://www.plaxo.com/click_to_call?lang=en&src=jj_signature&To=%2B91+%280%2
9206+608+3777&Email=bhushan_bhangale at kaleconsultants.com> +91 (0)206 608
3777
 <http://www.kaleconsultants.com> http://www.kaleconsultants.com 

 


 


 

 

 

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-- 
 Edson Tirelli
 JBoss Drools Core Development
 JBoss, a division of Red Hat @ www.jboss.com




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