[rules-users] How to use for loop in drools!!!!
Hello Everybody,
I am not getting, on how to do for loop functionality in drools.
Like for instance, my functionality has :
for(i = 0; i10; i++)
{
c.setCustomerCount(c.getCustomerCount() + 1);
}
How to translate this code into rule language (.drl).
It would be helpful if anybody could guide me on this.
Thanks and Regards,
Sumeet Karawal
Mailto: sumeet.kara...@tcs.com
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Re: [rules-users] Dynamic updates of stateful sessions
Hi!
Yes, I have already implemented a KnowledgeAgentEventListener acts on
KnowledgeBaseUpdatedEvent and ResourceCompilationFailedEvent. I use this to
update my knowledgebase reference in my class that wraps the KnowledgeBase and
KnowledgeAgent. Below is the code for this class (DynamicDecisionService). I
suspect that I have missed something vital since I'm actually not getting my
knowledgebase to update itself either but I do it myself in the listener when
I receive a KnowledgeBaseUpdatedEvent.
Here is the code that handles the KnowledgeAgent and KnowledgeBase (I have
stripped out some labels and comments since this belongs to the client).
Best regards
Mattias Avelin
package com.x.service;
import java.util.ArrayList;
import org.apache.log4j.Logger;
import org.drools.KnowledgeBase;
import org.drools.KnowledgeBaseConfiguration;
import org.drools.KnowledgeBaseFactory;
import org.drools.agent.KnowledgeAgent;
import org.drools.agent.KnowledgeAgentConfiguration;
import org.drools.agent.KnowledgeAgentFactory;
import org.drools.builder.KnowledgeBuilderError;
import org.drools.builder.KnowledgeBuilderErrors;
import org.drools.conf.EventProcessingOption;
import org.drools.event.knowledgeagent.KnowledgeBaseUpdatedEvent;
import org.drools.event.knowledgeagent.ResourceCompilationFailedEvent;
import org.drools.event.rule.DefaultKnowledgeAgentEventListener;
import org.drools.io.ResourceChangeScannerConfiguration;
import org.drools.io.ResourceFactory;
/**
* {@inheritDoc}
* p
* This implementation of DecisionService updates the knowledgebase dynamically
* when the underlying rules (drl-files) are updated. Therefore each call to the
* createSession() method will return a session based on the most resent version
* of the rules (allowing for some lag due to the intervals of the
* resource scanner).
* /p
* p
* For statefull sessions the session needs to be updated manually when the
* KnowledgeBase has been updated.
* /P
* @author Mattias Avelin - mattias.ave...@netlight.se
*/
public class DynamicDecisionService implements DecisionService
{
private static Logger LOG = Logger.getLogger(DynamicDecisionService.class);
// Repository of all the application's knowledge definitions
private KnowledgeBase kBase;
// The agent that monitores the rule files (resources) for changes
private KnowledgeAgent kAgent;
// Decision service type
private DecisionSessionType type;
// When the current knowledgebase was created
private long kbaseLastUpdated;
/**
* Create a DynamicDecisionService using a ChangeSet.
*
* @param changeSet - The ChangeSet referencing the rule-files to use
*for this service. Expects a classpath reference
*
* @throws IllegalArgumentException if changeSet is not a valid ChangeSet.
*/
public DynamicDecisionService(
String changeSet,
DecisionSessionType type)
{
this.kBase = createKnowledgeBase(type);
// the method could reference kBase itself but I thought it
// more more clear if I actually supply it in the method invocation
this.kAgent = createKnowledgeAgent(changeSet, this.kBase);
// This should not be neccesary according to all sources I've found
// but without re-assigning the reference it doesn't work!?!?
this.kBase = kAgent.getKnowledgeBase();
this.kbaseLastUpdated = System.currentTimeMillis();
}
/**
* {@inheritDoc}
*/
public DecisionSession createSession ()
{
return new DecisionSession(kBase.newStatefulKnowledgeSession());
}
/**
* {@inheritDoc}
*/
public DecisionSession updateSession (DecisionSession oldSession)
{
// Create a new session from the current KnowledgeBase
DecisionSession newSession =
new DecisionSession(kBase.newStatefulKnowledgeSession());
if(oldSession != null)
{
// Clean the old session of all stateless facts before update
oldSession.removeAllStatelessKnowledge();
// Copy all remaining facts to the new session
newSession.uploadKnowledge(new ArrayList(oldSession.getAllFacts()));
}
return newSession;
}
/**
* {@inheritDoc}
*/
public boolean isSessionStale(DecisionSession decisionSession)
{
if(decisionSession.getCreationTime() this.kbaseLastUpdated)
{
return true;
}
else
{
return false;
}
}
/**
* Create a KnowledgeBuilder from a ChangeSet.
*
* @param changeSet - The ChangeSet
* @return A KnowledgeBuilder
* @throws IllegalArgumentException if changeSet is not a valid ChangeSet.
*/
private KnowledgeAgent createKnowledgeAgent(
String changeSet,
KnowledgeBase kbase)
{
// Configure KnowledgeAgentFactory
configureAgentFactory();
//
[rules-users] Fw: Some Querries on Drools
Hi Everybody, I had posted this earlier. It would be very greatful if anybody could help me on these queries, any suggestions or any document that I can refer to. Thanks and Regards, Sumeet Karawal Mailto: sumeet.kara...@tcs.com From: Sumeet Karawal/MUM/TCS To: rules-users@lists.jboss.org Date: 04/18/2011 06:58 PM Subject:Some Querries on Drools Hello All, I have some queries regarding use of drools as rule engine for my Application. It would be very helpful if I get some guidance regarding these: 1) I have an application in which a user logs in, and according to his profile he is provided with some benefits, and rule engine check for the eligibility criteria. But if hundreds of thousands of user will log in at same time, then what will be the performance accordingly. Like, these concurrent users hitting the server, and so many threads will be generated and many number of rules will be fired in the session. Will this hamper the performance of Rule Engine. 2) Suppose I have an application using drools. I create EAR / WAR file of that application and deploy it on some other system. Would it be still possible for me to change the rules on the fly. Or some dependencies might have to be managed. 3) How can we manage sessions in drools? Suppose we are having different stateful sessions in our application, but time consumption when we fireAllRules() exceeds the expected time. So is there a mechanism to kill, restart the session in drools. Could I get some help/document regarding session Management on drools. Thanks Regards, Sumeet Karawal Mailto: sumeet.kara...@tcs.com =-=-= Notice: The information contained in this e-mail message and/or attachments to it may contain confidential or privileged information. If you are not the intended recipient, any dissemination, use, review, distribution, printing or copying of the information contained in this e-mail message and/or attachments to it are strictly prohibited. If you have received this communication in error, please notify us by reply e-mail or telephone and immediately and permanently delete the message and any attachments. Thank you ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] how to get a list of incomplete workitems after e.g server/process crash?
i tried to load the session from a store like below and then query it for
work items/nodes but it doesn't give me an access to e.g. workItem
parameters as this value is empty.
Is there any API that would provide this information or should i somehow
duplicate drools flow and try to use NodeListeners? I'm sure there must be
some way of querying crashed process where it was so it could be resumed
using workItem.complete api
StatefulKnowledgeSession session = kbase.loadStatefulKnowledgeSession()
for (NodeInstance n : ((WorkflowProcessInstance)
getKnowledgeSession().getProcessInstance(1)).getNodeInstances()){
WorkItem w = ((WorkItemNodeInstance)n).getWorkItem();
//w is null here so i don't have an access to its parameters
}
--
View this message in context:
http://drools.46999.n3.nabble.com/how-to-get-a-list-of-incomplete-workitems-if-one-of-them-crashed-e-g-server-restart-tp2835230p2838237.html
Sent from the Drools: User forum mailing list archive at Nabble.com.
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[rules-users] Problem in compiling each rule separately
Hi sir , I have 10 rules . rules are created dynamically .Now if any of them is causing problem so none of them runs so I want to compile each rule separately , so that i can create knowledge base with rules which have no errors but can i do this ? I am not finding the way how i can do it . is it possible ? thanks , Saurabh Maheshwari ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
[rules-users] Trying to compare int and String objects
Hello everybody:
I'm trying to write rules in which fact int attributes and fact String
attributes should be compared in condition elements. When I compare them,
let's say from int to String,
rule
when
Fact1($intAttr : attrInt1)
Fact2(attrString == $intAttr)
the rule seems to behave OK, whereas when I compare them from String to int,
rule
when
Fact1($stringAttr : attrString1)
Fact2(attrInt == $stringAttr)
I get a RuntimeDroolsException( Conversion to long not supported from
java.lang.String).
I've taken a look at the code which throws the exception,
BaseObjectClassField.getLongValue() and found that it only accepts Number
and Date objects to be converted to long.
...
if ( value instanceof Number ) {
return ((Number) value).longValue();
} else if ( value instanceof Date ) {
return ((Date) value).getTime();
}
...
Is it possible to add String to long conversion via Long.parseLong(str) or
is there any reason not to allow this conversion?.
Thank you again for your time.
Best regards,
Manuel Ortiz.
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Re: [rules-users] Dynamic updates of stateful sessions
There is no need to update your kbase in the listener. The agent will apply
all the changes to the provided kbase. If you already have a stateful
ksession from that kbase, then the changes in the kbase should be
reflected immediately.
Could you please post the log output of the kagent?
Best Regards,
Esteban Aliverti
- Developer @ http://www.plugtree.com
- Blog @ http://ilesteban.wordpress.com
On Tue, Apr 19, 2011 at 4:24 AM, Mattias Avelin
mattias.ave...@netlight.sewrote:
Hi!
Yes, I have already implemented a KnowledgeAgentEventListener acts on
KnowledgeBaseUpdatedEvent and ResourceCompilationFailedEvent. I use this to
update my knowledgebase reference in my class that wraps the KnowledgeBase
and KnowledgeAgent. Below is the code for this class
(DynamicDecisionService). I suspect that I have missed something vital
since I'm actually not getting my knowledgebase to update itself either but
I do it myself in the listener when I receive a KnowledgeBaseUpdatedEvent.
Here is the code that handles the KnowledgeAgent and KnowledgeBase (I have
stripped out some labels and comments since this belongs to the client).
Best regards
Mattias Avelin
package com.x.service;
import java.util.ArrayList;
import org.apache.log4j.Logger;
import org.drools.KnowledgeBase;
import org.drools.KnowledgeBaseConfiguration;
import org.drools.KnowledgeBaseFactory;
import org.drools.agent.KnowledgeAgent;
import org.drools.agent.KnowledgeAgentConfiguration;
import org.drools.agent.KnowledgeAgentFactory;
import org.drools.builder.KnowledgeBuilderError;
import org.drools.builder.KnowledgeBuilderErrors;
import org.drools.conf.EventProcessingOption;
import org.drools.event.knowledgeagent.KnowledgeBaseUpdatedEvent;
import org.drools.event.knowledgeagent.ResourceCompilationFailedEvent;
import org.drools.event.rule.DefaultKnowledgeAgentEventListener;
import org.drools.io.ResourceChangeScannerConfiguration;
import org.drools.io.ResourceFactory;
/**
* {@inheritDoc}
* p
* This implementation of DecisionService updates the knowledgebase
dynamically
* when the underlying rules (drl-files) are updated. Therefore each call
to the
* createSession() method will return a session based on the most resent
version
* of the rules (allowing for some lag due to the intervals of the
* resource scanner).
* /p
* p
* For statefull sessions the session needs to be updated manually when
the
* KnowledgeBase has been updated.
* /P
* @author Mattias Avelin - mattias.ave...@netlight.se
*/
public class DynamicDecisionService implements DecisionService
{
private static Logger LOG =
Logger.getLogger(DynamicDecisionService.class);
// Repository of all the application's knowledge definitions
private KnowledgeBase kBase;
// The agent that monitores the rule files (resources) for changes
private KnowledgeAgent kAgent;
// Decision service type
private DecisionSessionType type;
// When the current knowledgebase was created
private long kbaseLastUpdated;
/**
* Create a DynamicDecisionService using a ChangeSet.
*
* @param changeSet - The ChangeSet referencing the rule-files to use
*for this service. Expects a classpath reference
*
* @throws IllegalArgumentException if changeSet is not a valid
ChangeSet.
*/
public DynamicDecisionService(
String changeSet,
DecisionSessionType type)
{
this.kBase = createKnowledgeBase(type);
// the method could reference kBase itself but I thought it
// more more clear if I actually supply it in the method
invocation
this.kAgent = createKnowledgeAgent(changeSet, this.kBase);
// This should not be neccesary according to all sources I've found
// but without re-assigning the reference it doesn't work!?!?
this.kBase = kAgent.getKnowledgeBase();
this.kbaseLastUpdated = System.currentTimeMillis();
}
/**
* {@inheritDoc}
*/
public DecisionSession createSession ()
{
return new DecisionSession(kBase.newStatefulKnowledgeSession());
}
/**
* {@inheritDoc}
*/
public DecisionSession updateSession (DecisionSession oldSession)
{
// Create a new session from the current KnowledgeBase
DecisionSession newSession =
new DecisionSession(kBase.newStatefulKnowledgeSession());
if(oldSession != null)
{
// Clean the old session of all stateless facts before update
oldSession.removeAllStatelessKnowledge();
// Copy all remaining facts to the new session
newSession.uploadKnowledge(new
ArrayList(oldSession.getAllFacts()));
}
return newSession;
}
/**
* {@inheritDoc}
*/
public boolean isSessionStale(DecisionSession decisionSession)
{
Re: [rules-users] Fw: Some Querries on Drools
Hi, I am quite new to drools but I will try to answer your questions. I don't think Drools will cause your application to crash if you ensure 1. You develop rules that will not result in infinite loops. 2. Dispose sessions if you are using Stateful sessions. Basically, you would want to create the Knowledge base once i.e. during application startup. You will create a new Session (not an expensive operation) for every request. In this scenario it will be better to use stateless sessions as you do not have to worry about disposing them. However, if you want to use statefull sessions, you might want to write a set of wrapper classes that provide api's to manage the statefull session and execute rules. Developers will only be allowed to access api's that execute rules and will not have access to api's that create and dispose a session. To you next question on making changes to rules, You have to create a KnowledgeAgent that checks if the rule resource has been modified at configured intervals. The rule resource (drl,pkg etc) can exist on the file system or you want to try to configure rules in guvnor. Guvnor is a GUI tool that allows you to manage rules. Regards, Randhish -Original Message- From: rules-users-boun...@lists.jboss.org [mailto:rules-users-boun...@lists.jboss.org] On Behalf Of Sumeet Karawal Sent: Tuesday, April 19, 2011 2:53 PM To: rules-users@lists.jboss.org Subject: [rules-users] Fw: Some Querries on Drools Hi Everybody, I had posted this earlier. It would be very greatful if anybody could help me on these queries, any suggestions or any document that I can refer to. Thanks and Regards, Sumeet Karawal Mailto: sumeet.kara...@tcs.com From: Sumeet Karawal/MUM/TCS To: rules-users@lists.jboss.org Date: 04/18/2011 06:58 PM Subject:Some Querries on Drools Hello All, I have some queries regarding use of drools as rule engine for my Application. It would be very helpful if I get some guidance regarding these: 1) I have an application in which a user logs in, and according to his profile he is provided with some benefits, and rule engine check for the eligibility criteria. But if hundreds of thousands of user will log in at same time, then what will be the performance accordingly. Like, these concurrent users hitting the server, and so many threads will be generated and many number of rules will be fired in the session. Will this hamper the performance of Rule Engine. 2) Suppose I have an application using drools. I create EAR / WAR file of that application and deploy it on some other system. Would it be still possible for me to change the rules on the fly. Or some dependencies might have to be managed. 3) How can we manage sessions in drools? Suppose we are having different stateful sessions in our application, but time consumption when we fireAllRules() exceeds the expected time. So is there a mechanism to kill, restart the session in drools. Could I get some help/document regarding session Management on drools. Thanks Regards, Sumeet Karawal Mailto: sumeet.kara...@tcs.com =-=-= Notice: The information contained in this e-mail message and/or attachments to it may contain confidential or privileged information. If you are not the intended recipient, any dissemination, use, review, distribution, printing or copying of the information contained in this e-mail message and/or attachments to it are strictly prohibited. If you have received this communication in error, please notify us by reply e-mail or telephone and immediately and permanently delete the message and any attachments. Thank you ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users http://www.mindtree.com/email/disclaimer.html ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
[rules-users] Drools-Guvnor – question about build and deploy packages
I am using Drools-Guvnor 5.1 release in an enterprise application. The rules created are separated per packages, and for each package there is a snapshot package called LATEST. The KnowledgeAgent polls the snapshot packages to get the latest data and load into the rule engine. Whenever there is a new rule, or updates to an existing one, the application triggers the process of re-creating the package snapshot: builds all the rules within the package, and creates a new snapshot for the package. The main problem with this approach is that the time to build the package rules, increases quite a lot as the number if rules gets higher. This creates a serious performance hit in the real-time app whenever there is a change to the rules. I sneaked a bit to the source code, and noticed that when build package is called, Guvnor builds a new binary for all the rules within a package even though not all of them are modified. Would it be possible to incrementally create/update the package binary? This would speed up things a lot when the package has lots of rules but only one rule changes at the time. What is the best approach for creating the package snapshots? The approach we've taken is to build all the rules within a package into one snapshot, and we ran into this performance issue. Any ideas/suggestions is much appreciated. Thanks, Patricia___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Drools-Guvnor question about build and deploy packages
Patricia, My understanding (which is certainly open to being corrected) is that in general there is no way to do an incremental compilation of rules. The entire package is analyzed together and significant optimizations are performed to combine common items between rules (which is one of the big reasons why the engine executes so well!). So, generally, what you are doing is the best practice. When you say that you are experiencing a performance hit, are you talking about a delay in seeing the updates appear in your production application, or something else? Generally, the compilation is a one-time step, and even during compilation your enterprise application that is actually using the rules should continue to perform quite reasonably, since the compilation is going on in a separate application. David From: Patricia Bogoevici patriciabogoev...@yahoo.commailto:patriciabogoev...@yahoo.com Reply-To: Rules Users List rules-users@lists.jboss.orgmailto:rules-users@lists.jboss.org Date: Tue, 19 Apr 2011 10:45:59 -0500 To: Rules Users List rules-users@lists.jboss.orgmailto:rules-users@lists.jboss.org Subject: [rules-users] Drools-Guvnor – question about build and deploy packages I am using Drools-Guvnor 5.1 release in an enterprise application. The rules created are separated per packages, and for each package there is a snapshot package called LATEST. The KnowledgeAgent polls the snapshot packages to get the latest data and load into the rule engine. Whenever there is a new rule, or updates to an existing one, the application triggers the process of re-creating the package snapshot: builds all the rules within the package, and creates a new snapshot for the package. The main problem with this approach is that the time to build the package rules, increases quite a lot as the number if rules gets higher. This creates a serious performance hit in the real-time app whenever there is a change to the rules. I sneaked a bit to the source code, and noticed that when build package is called, Guvnor builds a new binary for all the rules within a package even though not all of them are modified. Would it be possible to incrementally create/update the package binary? This would speed up things a lot when the package has lots of rules but only one rule changes at the time. What is the best approach for creating the package snapshots? The approach we've taken is to build all the rules within a package into one snapshot, and we ran into this performance issue. Any ideas/suggestions is much appreciated. Thanks, Patricia ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] How to use for loop in drools!!!!
Thanks Esteban!!. I got you point. But how to make the rule to run
according to a condition, in a loop.
Also, how can we trigger the firing of one rule from another rule. Like
when the Condition part of a rule satisfies then, in the Action part a
particular rule is triggered and after that the control resumes to the
previous rule, just as we do in nested if else statement.
Thanks Regards,
Sumeet Karawal
Mailto: sumeet.kara...@tcs.com
From: Esteban Aliverti esteban.alive...@gmail.com
To: Rules Users List rules-users@lists.jboss.org
Date: 04/19/2011 05:41 PM
Subject:Re: [rules-users] How to use for loop in drools
Sent by:rules-users-boun...@lists.jboss.org
Drools is an inference engine and it let you express your knowledge using
rules.
A rule has 2 parts: CONDITION par and ACTION part.
The CONDITION part is expressed in a drools' proprietary syntax, but in the
ACTION part you can use plain java code.
What you have described looks like an action that needs to be executed when
certain constraints are meet.
So, in your case, you can just write those lines in you action part. They
should work fine.
I recommend you to read the documentation:
http://downloads.jboss.com/drools/docs/5.1.1.34858.FINAL/drools-expert/html_single/index.html
Best Regards,
Esteban Aliverti
- Developer @ http://www.plugtree.com
- Blog @ http://ilesteban.wordpress.com
On Tue, Apr 19, 2011 at 3:13 AM, Sumeet Karawal sumeet.kara...@tcs.com
wrote:
for(i = 0; i10; i++)
{
c.setCustomerCount(c.getCustomerCount() + 1);
}
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Notice: The information contained in this e-mail
message and/or attachments to it may contain
confidential or privileged information. If you are
not the intended recipient, any dissemination, use,
review, distribution, printing or copying of the
information contained in this e-mail message
and/or attachments to it are strictly prohibited. If
you have received this communication in error,
please notify us by reply e-mail or telephone and
immediately and permanently delete the message
and any attachments. Thank you
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Re: [rules-users] Fw: Some Querries on Drools
Thanks a lot Randhish!!! Stateful sessions will have to be disposed. But what if the sessions are taking too long, same with the case of stateless sessions, then what to do in that case. Also in the multi- threaded environment, if I have 10 - 100 Ks of threads, will the rule engines performance be still better. Thanks Regards, Sumeet Karawal Mailto: sumeet.kara...@tcs.com From: Randhish Raghavan randhish_ragha...@mindtree.com To: Rules Users List rules-users@lists.jboss.org Date: 04/19/2011 08:51 PM Subject:Re: [rules-users] Fw: Some Querries on Drools Sent by:rules-users-boun...@lists.jboss.org Hi, I am quite new to drools but I will try to answer your questions. I don't think Drools will cause your application to crash if you ensure 1. You develop rules that will not result in infinite loops. 2. Dispose sessions if you are using Stateful sessions. Basically, you would want to create the Knowledge base once i.e. during application startup. You will create a new Session (not an expensive operation) for every request. In this scenario it will be better to use stateless sessions as you do not have to worry about disposing them. However, if you want to use statefull sessions, you might want to write a set of wrapper classes that provide api's to manage the statefull session and execute rules. Developers will only be allowed to access api's that execute rules and will not have access to api's that create and dispose a session. To you next question on making changes to rules, You have to create a KnowledgeAgent that checks if the rule resource has been modified at configured intervals. The rule resource (drl,pkg etc) can exist on the file system or you want to try to configure rules in guvnor. Guvnor is a GUI tool that allows you to manage rules. Regards, Randhish -Original Message- From: rules-users-boun...@lists.jboss.org [ mailto:rules-users-boun...@lists.jboss.org] On Behalf Of Sumeet Karawal Sent: Tuesday, April 19, 2011 2:53 PM To: rules-users@lists.jboss.org Subject: [rules-users] Fw: Some Querries on Drools Hi Everybody, I had posted this earlier. It would be very greatful if anybody could help me on these queries, any suggestions or any document that I can refer to. Thanks and Regards, Sumeet Karawal Mailto: sumeet.kara...@tcs.com From: Sumeet Karawal/MUM/TCS To: rules-users@lists.jboss.org Date: 04/18/2011 06:58 PM Subject:Some Querries on Drools Hello All, I have some queries regarding use of drools as rule engine for my Application. It would be very helpful if I get some guidance regarding these: 1) I have an application in which a user logs in, and according to his profile he is provided with some benefits, and rule engine check for the eligibility criteria. But if hundreds of thousands of user will log in at same time, then what will be the performance accordingly. Like, these concurrent users hitting the server, and so many threads will be generated and many number of rules will be fired in the session. Will this hamper the performance of Rule Engine. 2) Suppose I have an application using drools. I create EAR / WAR file of that application and deploy it on some other system. Would it be still possible for me to change the rules on the fly. Or some dependencies might have to be managed. 3) How can we manage sessions in drools? Suppose we are having different stateful sessions in our application, but time consumption when we fireAllRules() exceeds the expected time. So is there a mechanism to kill, restart the session in drools. Could I get some help/document regarding session Management on drools. Thanks Regards, Sumeet Karawal Mailto: sumeet.kara...@tcs.com =-=-= Notice: The information contained in this e-mail message and/or attachments to it may contain confidential or privileged information. If you are not the
Re: [rules-users] How to use for loop in drools!!!!
Hi Samarat, as Esteban suggested, please read the documentation as for
example your question is answered there very early on in chapter 2.2.1.
Methods versus Rules.
Tihomir
On 4/19/11 12:06 PM, Sumeet Karawal wrote:
Thanks Esteban!!. I got you point. But how to make the rule to run
according to a condition, in a loop.
Also, how can we trigger the firing of one rule from another rule. Like
when the Condition part of a rule satisfies then, in the Action part a
particular rule is triggered and after that the control resumes to the
previous rule, just as we do in nested if else statement.
Thanks Regards,
Sumeet Karawal
Mailto: sumeet.kara...@tcs.com
From: Esteban Alivertiesteban.alive...@gmail.com
To: Rules Users Listrules-users@lists.jboss.org
Date: 04/19/2011 05:41 PM
Subject:Re: [rules-users] How to use for loop in drools
Sent by:rules-users-boun...@lists.jboss.org
Drools is an inference engine and it let you express your knowledge using
rules.
A rule has 2 parts: CONDITION par and ACTION part.
The CONDITION part is expressed in a drools' proprietary syntax, but in the
ACTION part you can use plain java code.
What you have described looks like an action that needs to be executed when
certain constraints are meet.
So, in your case, you can just write those lines in you action part. They
should work fine.
I recommend you to read the documentation:
http://downloads.jboss.com/drools/docs/5.1.1.34858.FINAL/drools-expert/html_single/index.html
Best Regards,
Esteban Aliverti
- Developer @ http://www.plugtree.com
- Blog @ http://ilesteban.wordpress.com
On Tue, Apr 19, 2011 at 3:13 AM, Sumeet Karawalsumeet.kara...@tcs.com
wrote:
for(i = 0; i10; i++)
{
c.setCustomerCount(c.getCustomerCount() + 1);
}
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Re: [rules-users] How to use for loop in drools!!!!
Sorry about the name typo in my previous reply Sumeet.
On 4/19/11 12:14 PM, Tihomir Surdilovic wrote:
Hi Samarat, as Esteban suggested, please read the documentation as for
example your question is answered there very early on in chapter 2.2.1.
Methods versus Rules.
Tihomir
On 4/19/11 12:06 PM, Sumeet Karawal wrote:
Thanks Esteban!!. I got you point. But how to make the rule to run
according to a condition, in a loop.
Also, how can we trigger the firing of one rule from another rule. Like
when the Condition part of a rule satisfies then, in the Action part a
particular rule is triggered and after that the control resumes to the
previous rule, just as we do in nested if else statement.
Thanks Regards,
Sumeet Karawal
Mailto: sumeet.kara...@tcs.com
From: Esteban Alivertiesteban.alive...@gmail.com
To: Rules Users Listrules-users@lists.jboss.org
Date: 04/19/2011 05:41 PM
Subject:Re: [rules-users] How to use for loop in drools
Sent by:rules-users-boun...@lists.jboss.org
Drools is an inference engine and it let you express your knowledge using
rules.
A rule has 2 parts: CONDITION par and ACTION part.
The CONDITION part is expressed in a drools' proprietary syntax, but in the
ACTION part you can use plain java code.
What you have described looks like an action that needs to be executed when
certain constraints are meet.
So, in your case, you can just write those lines in you action part. They
should work fine.
I recommend you to read the documentation:
http://downloads.jboss.com/drools/docs/5.1.1.34858.FINAL/drools-expert/html_single/index.html
Best Regards,
Esteban Aliverti
- Developer @ http://www.plugtree.com
- Blog @ http://ilesteban.wordpress.com
On Tue, Apr 19, 2011 at 3:13 AM, Sumeet Karawalsumeet.kara...@tcs.com
wrote:
for(i = 0; i10; i++)
{
c.setCustomerCount(c.getCustomerCount() + 1);
}
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Re: [rules-users] Drools-Guvnor question about build and deploy packages
Thanks David for your reply. To clarify: the performance problem is specifically related to the build package. This task takes longer as the package has more and more rules. The build package process is complex, and performs also rule validation. That's why I asked if there is a way to incrementally update the package binary. The app I am working on, we streamlined the process of creating a new rule, including building and deploying a new snapshot package to propagate the changes quick. Because the build task takes longer (as the package has more and more rules), it is a problem for the end user, as it feels that nothing happens for a while when saves a rule. Once the new snapshot package is created, the KnowledgeAgent propagates the updates into the app without problems. So, coming back to the build package task: what is the best strategy to create snapshot packages, so that the build time does not take a long time when there are lots of rules in the package? One possible solution I see, is to create a snapshot package for each rule within a package, using a custom selector. I haven't tried it, but this approach will keep the build time short. However, it doesn't seem natural to me to have so many snapshot packages... thanks,Patricia --- On Tue, 4/19/11, David Faulkner david.faulk...@amentra.com wrote: From: David Faulkner david.faulk...@amentra.com Subject: Re: [rules-users] Drools-Guvnor question about build and deploy packages To: Rules Users List rules-users@lists.jboss.org Date: Tuesday, April 19, 2011, 11:51 AM Patricia, My understanding (which is certainly open to being corrected) is that in general there is no way to do an incremental compilation of rules. The entire package is analyzed together and significant optimizations are performed to combine common items between rules (which is one of the big reasons why the engine executes so well!). So, generally, what you are doing is the best practice. When you say that you are experiencing a performance hit, are you talking about a delay in seeing the updates appear in your production application, or something else? Generally, the compilation is a one-time step, and even during compilation your enterprise application that is actually using the rules should continue to perform quite reasonably, since the compilation is going on in a separate application. David From: Patricia Bogoevici patriciabogoev...@yahoo.com Reply-To: Rules Users List rules-users@lists.jboss.org Date: Tue, 19 Apr 2011 10:45:59 -0500 To: Rules Users List rules-users@lists.jboss.org Subject: [rules-users] Drools-Guvnor – question about build and deploy packages I am using Drools-Guvnor 5.1 release in an enterprise application. The rules created are separated per packages, and for each package there is a snapshot package called LATEST. The KnowledgeAgent polls the snapshot packages to get the latest data and load into the rule engine. Whenever there is a new rule, or updates to an existing one, the application triggers the process of re-creating the package snapshot: builds all the rules within the package, and creates a new snapshot for the package. The main problem with this approach is that the time to build the package rules, increases quite a lot as the number if rules gets higher. This creates a serious performance hit in the real-time app whenever there is a change to the rules. I sneaked a bit to the source code, and noticed that when build package is called, Guvnor builds a new binary for all the rules within a package even though not all of them are modified. Would it be possible to incrementally create/update the package binary? This would speed up things a lot when the package has lots of rules but only one rule changes at the time. What is the best approach for creating the package snapshots? The approach we've taken is to build all the rules within a package into one snapshot, and we ran into this performance issue. Any ideas/suggestions is much appreciated. Thanks,Patricia -Inline Attachment Follows- ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] How to use for loop in drools!!!!
Sumeet Karawal wrote:
Thanks Esteban!!. I got you point. But how to make the rule to run
according to a condition, in a loop.
Also, how can we trigger the firing of one rule from another rule. Like
when the Condition part of a rule satisfies then, in the Action part a
particular rule is triggered and after that the control resumes to the
previous rule, just as we do in nested if else statement.
You're thinking procedural. You won't go far this way.
Rules based engined require a different way of approaching problems.
Familiarize yourself with these differences and you will find out that in
most cases you do not need loops or nested conditions.
The keyword here is predicate logic.
-Stathis
Thanks Regards,
Sumeet Karawal
Mailto: sumeet.kara...@tcs.com
From: Esteban Aliverti esteban.alive...@gmail.com
To: Rules Users List rules-users@lists.jboss.org
Date: 04/19/2011 05:41 PM
Subject:Re: [rules-users] How to use for loop in drools
Sent by:rules-users-boun...@lists.jboss.org
Drools is an inference engine and it let you express your knowledge using
rules.
A rule has 2 parts: CONDITION par and ACTION part.
The CONDITION part is expressed in a drools' proprietary syntax, but in
the
ACTION part you can use plain java code.
What you have described looks like an action that needs to be executed
when
certain constraints are meet.
So, in your case, you can just write those lines in you action part. They
should work fine.
I recommend you to read the documentation:
http://downloads.jboss.com/drools/docs/5.1.1.34858.FINAL/drools-expert/html_single/index.html
Best Regards,
Esteban Aliverti
- Developer @ http://www.plugtree.com
- Blog @ http://ilesteban.wordpress.com
On Tue, Apr 19, 2011 at 3:13 AM, Sumeet Karawal sumeet.kara...@tcs.com
wrote:
for(i = 0; i10; i++)
{
c.setCustomerCount(c.getCustomerCount() + 1);
}
___
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Re: [rules-users] Dynamic updates of stateful sessions
I have recently looked into Knowledge Agent and I don't think that this will
update the
Knowledge Base of an existing Stateful Knowledge Session.
For a Stateful KS you do a kAgent.getKnowledgeBase() to get the new KBase
and start a new KS from it.
For a Stateless KS that has been created with
kAgent.newStatelessKnowledgeSession(), the KBase is updated automatically
and the next kSession.execute() will reflect the new KBase.
If this is not correct, I'd appreciate pointers where it is documented
otherwise.
I haven't tested this exhaustively, but what I did test did not contradict
the above.
-W
2011/4/19 Esteban Aliverti esteban.alive...@gmail.com
There is no need to update your kbase in the listener. The agent will apply
all the changes to the provided kbase. If you already have a stateful
ksession from that kbase, then the changes in the kbase should be
reflected immediately.
Could you please post the log output of the kagent?
Best Regards,
Esteban Aliverti
- Developer @ http://www.plugtree.com
- Blog @ http://ilesteban.wordpress.com
On Tue, Apr 19, 2011 at 4:24 AM, Mattias Avelin
mattias.ave...@netlight.se wrote:
Hi!
Yes, I have already implemented a KnowledgeAgentEventListener acts on
KnowledgeBaseUpdatedEvent and ResourceCompilationFailedEvent. I use this to
update my knowledgebase reference in my class that wraps the KnowledgeBase
and KnowledgeAgent. Below is the code for this class
(DynamicDecisionService). I suspect that I have missed something vital
since I'm actually not getting my knowledgebase to update itself either but
I do it myself in the listener when I receive a KnowledgeBaseUpdatedEvent.
Here is the code that handles the KnowledgeAgent and KnowledgeBase (I have
stripped out some labels and comments since this belongs to the client).
Best regards
Mattias Avelin
package com.x.service;
import java.util.ArrayList;
import org.apache.log4j.Logger;
import org.drools.KnowledgeBase;
import org.drools.KnowledgeBaseConfiguration;
import org.drools.KnowledgeBaseFactory;
import org.drools.agent.KnowledgeAgent;
import org.drools.agent.KnowledgeAgentConfiguration;
import org.drools.agent.KnowledgeAgentFactory;
import org.drools.builder.KnowledgeBuilderError;
import org.drools.builder.KnowledgeBuilderErrors;
import org.drools.conf.EventProcessingOption;
import org.drools.event.knowledgeagent.KnowledgeBaseUpdatedEvent;
import org.drools.event.knowledgeagent.ResourceCompilationFailedEvent;
import org.drools.event.rule.DefaultKnowledgeAgentEventListener;
import org.drools.io.ResourceChangeScannerConfiguration;
import org.drools.io.ResourceFactory;
/**
* {@inheritDoc}
* p
* This implementation of DecisionService updates the knowledgebase
dynamically
* when the underlying rules (drl-files) are updated. Therefore each call
to the
* createSession() method will return a session based on the most resent
version
* of the rules (allowing for some lag due to the intervals of the
* resource scanner).
* /p
* p
* For statefull sessions the session needs to be updated manually when
the
* KnowledgeBase has been updated.
* /P
* @author Mattias Avelin - mattias.ave...@netlight.se
*/
public class DynamicDecisionService implements DecisionService
{
private static Logger LOG =
Logger.getLogger(DynamicDecisionService.class);
// Repository of all the application's knowledge definitions
private KnowledgeBase kBase;
// The agent that monitores the rule files (resources) for changes
private KnowledgeAgent kAgent;
// Decision service type
private DecisionSessionType type;
// When the current knowledgebase was created
private long kbaseLastUpdated;
/**
* Create a DynamicDecisionService using a ChangeSet.
*
* @param changeSet - The ChangeSet referencing the rule-files to use
*for this service. Expects a classpath reference
*
* @throws IllegalArgumentException if changeSet is not a valid
ChangeSet.
*/
public DynamicDecisionService(
String changeSet,
DecisionSessionType type)
{
this.kBase = createKnowledgeBase(type);
// the method could reference kBase itself but I thought it
// more more clear if I actually supply it in the method
invocation
this.kAgent = createKnowledgeAgent(changeSet, this.kBase);
// This should not be neccesary according to all sources I've found
// but without re-assigning the reference it doesn't work!?!?
this.kBase = kAgent.getKnowledgeBase();
this.kbaseLastUpdated = System.currentTimeMillis();
}
/**
* {@inheritDoc}
*/
public DecisionSession createSession ()
{
return new DecisionSession(kBase.newStatefulKnowledgeSession());
}
/**
* {@inheritDoc}
*/
public DecisionSession updateSession (DecisionSession oldSession)
{
Re: [rules-users] Fw: Some Querries on Drools
100K concurrent threads tends to be a problem, with or without Drools. There are several strategies for limiting this, but this is not a Drools topic. Hint 1: You can limit connects on sockets. Hint 2: Java thread pool, a design pattern. -W On 19 April 2011 18:13, Sumeet Karawal sumeet.kara...@tcs.com wrote: Thanks a lot Randhish!!! Stateful sessions will have to be disposed. But what if the sessions are taking too long, same with the case of stateless sessions, then what to do in that case. Also in the multi- threaded environment, if I have 10 - 100 Ks of threads, will the rule engines performance be still better. Thanks Regards, Sumeet Karawal Mailto: sumeet.kara...@tcs.com From: Randhish Raghavan randhish_ragha...@mindtree.com To: Rules Users List rules-users@lists.jboss.org Date: 04/19/2011 08:51 PM Subject:Re: [rules-users] Fw: Some Querries on Drools Sent by:rules-users-boun...@lists.jboss.org Hi, I am quite new to drools but I will try to answer your questions. I don't think Drools will cause your application to crash if you ensure 1. You develop rules that will not result in infinite loops. 2. Dispose sessions if you are using Stateful sessions. Basically, you would want to create the Knowledge base once i.e. during application startup. You will create a new Session (not an expensive operation) for every request. In this scenario it will be better to use stateless sessions as you do not have to worry about disposing them. However, if you want to use statefull sessions, you might want to write a set of wrapper classes that provide api's to manage the statefull session and execute rules. Developers will only be allowed to access api's that execute rules and will not have access to api's that create and dispose a session. To you next question on making changes to rules, You have to create a KnowledgeAgent that checks if the rule resource has been modified at configured intervals. The rule resource (drl,pkg etc) can exist on the file system or you want to try to configure rules in guvnor. Guvnor is a GUI tool that allows you to manage rules. Regards, Randhish -Original Message- From: rules-users-boun...@lists.jboss.org [ mailto:rules-users-boun...@lists.jboss.org] On Behalf Of Sumeet Karawal Sent: Tuesday, April 19, 2011 2:53 PM To: rules-users@lists.jboss.org Subject: [rules-users] Fw: Some Querries on Drools Hi Everybody, I had posted this earlier. It would be very greatful if anybody could help me on these queries, any suggestions or any document that I can refer to. Thanks and Regards, Sumeet Karawal Mailto: sumeet.kara...@tcs.com From: Sumeet Karawal/MUM/TCS To: rules-users@lists.jboss.org Date: 04/18/2011 06:58 PM Subject:Some Querries on Drools Hello All, I have some queries regarding use of drools as rule engine for my Application. It would be very helpful if I get some guidance regarding these: 1) I have an application in which a user logs in, and according to his profile he is provided with some benefits, and rule engine check for the eligibility criteria. But if hundreds of thousands of user will log in at same time, then what will be the performance accordingly. Like, these concurrent users hitting the server, and so many threads will be generated and many number of rules will be fired in the session. Will this hamper the performance of Rule Engine. 2) Suppose I have an application using drools. I create EAR / WAR file of that application and deploy it on some other system. Would it be still possible for me to change the rules on the fly. Or some dependencies might have to be managed. 3) How can we manage sessions in drools? Suppose we are having different stateful sessions in our application, but time consumption when we fireAllRules() exceeds the expected time. So is there a mechanism to kill, restart the session in drools. Could I get some help/document regarding session Management on drools. Thanks Regards, Sumeet Karawal Mailto: sumeet.kara...@tcs.com =-=-= Notice: The information contained in this e-mail message and/or attachments to it may contain confidential or privileged information. If you are not the intended recipient, any dissemination, use, review, distribution, printing or copying of the information contained in this e-mail message and/or attachments to it are strictly prohibited. If you have received this communication in error, please notify us by reply e-mail or telephone and immediately and permanently delete the message and any attachments. Thank you ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users http://www.mindtree.com/email/disclaimer.html ___
[rules-users] Sequential mode and partial propagations
Hi All This post is to continue an interresting (to me) discussion started there : https://issues.jboss.org/browse/JBRULES-46 This was about my remark about a backward-chaining mode that could be used to allow sequential mode to handle some kind of RETE updates (first rules could then trigger subsequent rules). There are some number of answers after that, but I am not sure if I can answer them in the JIRA, so this post ... To Mark : Currently our sequential mode works as single pass, but it has no inference as rete join memory is turned off. So it produces all the conflict set more efficiently, and then it uses rule order for the execution order of the conflict set. However changes in the current rule are not recognised by the later rules. That is planned though by partinioning the sequential engine around the modify statements. The advantage to this is we keep a single algorithm that is just configured slightly to provide different behaviours. Rather than two competely different engines. I think this is a very good solution, far much better (more efficient and far more clear to predict how rules will fire) than handling propagation for each individual rule's update. But I did not understand if it is already done in trunk in some way, or if it is something planned for future. And if so, the question after that is do you have an idea of when this could be done ? ... or if is quite affordable for someone not involved directly in drools developement? (like me for instance, as you speak of sligth configuration ). To Michael : You propose some new rules, by binding the something field in condition rather than calling getSomething() in action (and you change the object to which is applied the update, which is an error I think). To me that changes nothing, the rule will loop as one of its binded value is changed ($value, and now $something..). And a no-loop property won't change this too ... To summarize a bit, the use-case I present in the JIRA (create counters, fill them, validate them) could really take advantage (perfs, simplicity in authoring/design) of a sequential mode that could handle a partial inference (driven by a flow for instance, which seems quite natural for everyone (dev or BA)). ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
Re: [rules-users] Sequential mode and partial propagations
On 19/04/2011 18:58, Vincent LEGENDRE wrote: Hi All First : sorry for the misplaced reply to another thread This post is to continue an interresting (to me) discussion started there : https://issues.jboss.org/browse/JBRULES-46 This was about my remark about a backward-chaining mode that could be used to allow sequential mode to handle some kind of RETE updates (first rules could then trigger subsequent rules). There are some number of answers after that, but I am not sure if I can answer them in the JIRA, so this post ... *To Mark :* /Currently our sequential mode works as single pass, but it has no inference as rete join memory is turned off. So it produces all the conflict set more efficiently, and then it uses rule order for the execution order of the conflict set. However changes in the current rule are not recognised by the later rules. That is planned though by partinioning the sequential engine around the modify statements. The advantage to this is we keep a single algorithm that is just configured slightly to provide different behaviours. Rather than two competely different engines./ I think this is a very good solution, far much better (more efficient and far more clear to predict how rules will fire) than handling propagation for each individual rule's update. But I did not understand if it is already done in trunk in some way, or if it is something planned for future. And if so, the question after that is do you have an idea of when this could be done ? ... or if is quite affordable for someone not involved directly in drools developement? (like me for instance, as you speak of sligth configuration). Sequential mode as in that text above is done. What is not done is the modify partitioning such that later constraints see the updated values in the single pass - similar to what other products do. there are advantages and disadvantages to modify partitioning, but it's good to allow the user to have both :) To Michael : You propose some new rules, by binding the something field in condition rather than calling getSomething() in action (and you change the object to which is applied the update, which is an error I think). To me that changes nothing, the rule will loop as one of its binded value is changed ($value, and now $something..). And a no-loop property won't change this too ... To summarize a bit, the use-case I present in the JIRA (create counters, fill them, validate them) could really take advantage (perfs, simplicity in authoring/design) of a sequential mode that could handle a partial inference (driven by a flow for instance, which seems quite natural for everyone (dev or BA)). ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
[rules-users] First Order Logic - METHODS in Drools
According to First order Logic, (from a rule perspective), one can represent their statements using: PREDICATES, METHODS, CONNECTORS (including existential quantifiers) ..while PREDICATES can be synonymous with Object and Object expressions; the only way of using methods has been via eval (AFAIK, as per my outdated knowledge); and this is discouraged for the fact that evals perhaps dont fit in the RETE-OO scheme of things. Please note: By methods I dont bean Bean getter/setters; but work horse service layer methods. ..however, to be true to FOL, using methods directly should be supported. Q1) If it is, can one show or state an example? Q2) If not, for METHODS that return a specific type of Object, cant they be useful in RETE-OO evaluation? Q3) I've used from for DAO's , conceptually does from address this fully? In FOL (imo) PREDICATES METHODS can be exchanged freely, not sure if from gives that freedom. thanks -- View this message in context: http://drools.46999.n3.nabble.com/First-Order-Logic-METHODS-in-Drools-tp2841531p2841531.html Sent from the Drools: User forum mailing list archive at Nabble.com. ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
[rules-users] Encrypt password in repository.xml
We use mysql to store the data, hence mysql db credentials are mentioned in repository.xml The DB user password in repository.xml is not encrypted currently. What are the options available to place encrypted password in repository.xml? -- View this message in context: http://drools.46999.n3.nabble.com/Encrypt-password-in-repository-xml-tp2841654p2841654.html Sent from the Drools: User forum mailing list archive at Nabble.com. ___ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users
