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@lists.jboss.org [mailto:rules-users-bounces@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@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. bhushan_bhangale@kaleconsultants.com tel: +91 (0)206 608 3777 http://www.kaleconsultants.com

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