Typecasting problem
by hsherlock
I have a following scenario in which a complex logic (distributed over
multiple .DRL files) need to process incoming jobs as fast as possible. A
job definition looks something like describing what to do (type), what to
process (item) with some additional data supplied (args).
enum JobType
{
VALIDATE,
SEND
}
class Job
{
String type;
Object item;
Object[] args;
}
In order to implement the processing I need to put the business logic into
rules which fire depending on the kind of processing requested and type of
the item passed:
rule "process [VALIDATION] on [Document]"
when
$job: Job(type==JobType.VALIDATE)
$doc: Document(issued==true) from $job.item
then
insert(new DocumentAlreadyIssuedFact());
end
rule "process [SENDING] on [Message]"
when
$job: Job(type==JobType.SEND)
$msg: Message() from $job.item
then
//do the sending
end
Unfortunately this does not work and results in ClassCastException being
thrown, because it looks that Drools tries to cast any passed item to the
class expected by the particular rule. In my opinion behaviour one can
expect from Drools here is to first match the item class to the one expected
by the rule and on success to perform the type casting.
Is it a Drools bug or a missing feature?
So after stidying the documention and example code I found only one way to
workaround this – by using eval and instanceof which should have its
performance implications due to extensive use of the eval.
rule "process [VALIDATION] on [Document]"
when
$job: Job(type==JobType.VALIDATE)
eval(($job.item instanceof Document))
$doc: Document(issued==true) from $job.item
then
insert(new DocumentAlreadyIssuedFact());
end
rule "process [SENDING] on [Message]"
when
$job: Job(type==JobType.SEND)
eval(($job.item instanceof Message))
$msg: Message() from $job.item
then
//do the sending
end
Such an implementation works, but I see it as some form of workaround as my
feeling is that it will not allow the optimizations of Drools to shine.
Please recommend more effective and elegant way of implementing this.
Thank you in advance
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15 years
Guvnor - Operations with snapshots
by Demian Calcaprina
Hi everyone. I am using Guvnor 5.2, and I need to make some operations from
my application.
Specifically, I need to make two operations remotely:
- List Snapshots, as it is possible to list packages.
- Create a new snapshot from a package.
Is this possible to make these operation through rest API?
Thanks,
Demian
15 years
EXTENDED Deadline October 18th - Semantic Web Applications and Tools for the Life Sciences (SWAT4LS 2011)
by Adrian Paschke
++++ Extended Submission Deadline is - October 18th, 2011 ++++
Call for Papers
4th International Workshop on
Semantic Web Applications and Tools for the Life Sciences
SWAT4LS 2011
<http://www.swat4ls.org/2011/> http://www.swat4ls.org/2011/
Dec 7th-9th, 2011, London, UK
In cooperation with ACM SIG Bioinformatics, W3C
News:
*********************************************************************
* Extended Full Paper Submission Deadline is October 18th *
* Proceedings will be published and listed in the ACM ICP Series *
* SWAT4LS in cooperation with the ACM SIG Bioinformatics *
* SWAT4LS supported by W3C *
* Journal Special Issue for extended and revised accepted papers *
* Program includes Hackathon, Tutorials, Keynotes, Demos, Panel *
* http://www.swat4ls.org/workshops/london2011/scientific-programme/ *
* Sponsored by BBSRC, NCBO, BioMed Central *
*********************************************************************
Deadlines
======================================================
- EXTENDED Abstract submission deadline: 14th October
- EXTENDED Papers submission deadline: 18th October 2011
- Posters and demo submission deadline: 31 October 2011
- Communication of acceptance: 7 November 2011
- Camera ready: 21 November 2011
Instructions
======================================================
All papers and posters must be in English, formatted according to ACM IPCS
guidelines (http://www.acm.org/sigs/publications/proceedings-templates) and
submitted in pdf format.
- Submissions for papers should report original research, and should be
between 4 and 8 pages.
- Submissions for position papers should report qualified opinions,
recommendations or conclusions, and should be between 1 and 3 pages.
- Submissions for posters should be between 1 and 2 pages.
- Submissions for software demo proposals should also be between 1 and 2
pages.
Submission
======================================================
All submissions are handled via the EasyChair submission system (
https://www.easychair.org/conferences/?conf=swat4ls2011).
To ensure high quality, submitted papers will be carefully peer-reviewed by
at least three members of the Scientific Committee.
15 years
NPE on fact insertion if rule has sliding window
by John
Hello,
I've been messing with this for days now and can't get to the bottom of
this. I'm using drools 5.2.0 Final and setting up my KnowledgeBase with a
KnowledgeAgent which is pulling a package from guvnor (also 5.2.0 Final). I
do NOT get this error if I use a KnowledgeBuilder and add the exact same drl
file as a resource.
If the DRL in guvnor has a rule that uses a sliding window, i get an NPE
when trying to insert an object and the following stack trace:
java.lang.NullPointerException
at
org.drools.reteoo.ReteooFactHandleFactory.newFactHandle(ReteooFactHandleFactory.java:56)
at
org.drools.common.AbstractFactHandleFactory.newFactHandle(AbstractFactHandleFactory.java:80)
at
org.drools.common.AbstractFactHandleFactory.newFactHandle(AbstractFactHandleFactory.java:65)
at org.drools.common.NamedEntryPoint.createHandle(NamedEntryPoint.java:705)
at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:282)
at
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:905)
at
org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:864)
at
org.drools.impl.StatefulKnowledgeSessionImpl.insert(StatefulKnowledgeSessionImpl.java:255)
at john.DroolsError.runRules(DroolsError.java:48)
at john.DroolsError.main(DroolsError.java:40)
Here is the DRL:
1. | package drools
2. | import simple.SimpleType
3. |
4. |
5. |
6. |
7. |
8. |
9. | import simple.SimpleType;
10. |
11. | declare SimpleType
12. | @role(event)
13. | end
14. |
15. | rule "timer"
16. | timer (cron:5/5 * * * * ?)
17. | when
18. | $newest : Number()
19. | from accumulate( SimpleType ($num : number) over
window:time(5s),
20. | max($num) )
21. | $st : SimpleType( number == $newest.intValue )
22. | then
23. | System.out.println("SimpleType: " + $st.number);
24. | end
(note: the first import of simple.SimpleType comes from the package
configuration in guvnor, the second is in the drl file itself. the file will
not validate without the import explicitly listed there, saying the type is
not declared as an event...)
Here is the Java code:
ResourceChangeScannerConfiguration sconf = ResourceFactory
.getResourceChangeScannerService()
.newResourceChangeScannerConfiguration();
sconf.setProperty("drools.resource.scanner.interval", "20");
ResourceFactory.getResourceChangeScannerService().configure(sconf);
KnowledgeBaseConfiguration config = KnowledgeBaseFactory
.newKnowledgeBaseConfiguration();
config.setOption(EventProcessingOption.STREAM);
KnowledgeAgentConfiguration aconf = KnowledgeAgentFactory
.newKnowledgeAgentConfiguration();
aconf.setProperty("drools.agent.scanDirectories", "true");
aconf.setProperty("drools.agent.scanResources", "true");
aconf.setProperty("drools.agent.newInstance", "false");
KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase(config);
KnowledgeAgent kagent = KnowledgeAgentFactory.newKnowledgeAgent(
"drools agent", kbase, aconf);
String urlString =
"http://localhost:8080/drools-guvnor/org.drools.guvnor.Guvnor/package/droo...";
try {
URL url = new URL(urlString);
UrlResource urlResource = (UrlResource) ResourceFactory
.newUrlResource(url);
urlResource.setBasicAuthentication("enabled");
urlResource.setUsername("John");
urlResource.setPassword("");
kagent.applyChangeSet(urlResource);
} catch (Exception e) {
System.out.println("Caught exception: " + e.getMessage());
e.printStackTrace();
}
ResourceFactory.getResourceChangeNotifierService().start();
ResourceFactory.getResourceChangeScannerService().start();
StatefulKnowledgeSession ksession = kbase.newStatefulKnowledgeSession();
System.out.println("Initialize drools complete");
SimpleType simp = new SimpleType();
simp.setNumber(5);
ksession.insert(simp);
Thanks,
John
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15 years
best design pattern for fusion stream
by slyfox
I have a trading application that currently handles a fair amount of messages
per second, generally in the thousands. Soon it will handle 10s and perhaps
hundreds of thousands of messages.
I have not done any load testing yet but while I am here I figured I should
ask if there are any known limitations that I may run in to?
Presently my trading app handles price quotes by consuming an amqp queue
bound to a topic:
try {
q = quotes.poll(100, TimeUnit.MILLISECONDS);
if (q != null)
handleIncomingQuote(q);
} catch ...
I would like to use fusion so that I can get the code infrastructure done
and then hopefully never have to deal with code again for writing my
strategies, ideally all of that will be in the form of rules.
So I am at a point where I need to learn the camel integration piece so that
fusion will consume the amqp feed.
However, and this is my question, general practice is not to immediately do
any work on incoming message, currently I add to a LinkedBlockingQueue and
then pick up from another thread (shown above). So should I even worry
about the AMQP/Camel integration? It would seem to me that if fusion is
acting on each event this could become an eventual bottleneck. I wonder if
I would be better off manually inserting my incoming quotes into the entry
point in the manner that I have above, essentially by replacing
handleIncomingQuote(q) with EntryPoint.insert(q)?
Or does the working memory handle the buffering for me? Looking at the
Stream and Entry point doc I would say there is a chance but I am not
certain.
Thanks
Bobby
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15 years
rule limit
by Bobby Richards
Is it possible to limit the number of rules in a drl file?
Thanks,
Bobby
15 years
The database returned no natively generated identity value
by vanrobstone
Hi,
I am trying to get a webapp ported from oracle to db2. I managed to get all
the sql loaded in but it is now failing with the above error. After a day's
searching (I am not a web-developer by trade so please bear with me) I
managed to do a DB2 Driver trace and possibly narrow down my problem to a
table drools appears to create
SessionInfo
One of the columns is an id field that hibernate appears to be populating
with the following sql
Shortly after I am receiving the following stack trace (apppended to the
foot of this query).
I feel like there ought to be a trigger or something that would actually
populate the id field but hibernate seems to have problems. For all the
tables we have created we have created sequence numbers where appropriate
and are used by annotations in the code
I am not sure how to do the same for this generated table
Cheers for looking.
As promised the stack
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15 years
