JSR94- Drools Integration newbie question

[codySpringMan]

Hey all,

I am a newbie to jsr94 and I'm looking for resources. Specifically related to drools integration using the drools-brms. I have downloaded the latest version of spring-modules (0.9) and I have read the documentation regarding drools-integration. (what little there is...)

Anyway, I would be very appreciative if ANYONE could give me a few pointers, at least with the JNDI setup.

I'm really stoked about getting this setup, but I can't seem to get things started.

Thanks ahead of time.

-CodySpringMan

[codySpringMan]

Hello again,

I would appreciate any feedback. I have tried many variations but I am still unsuccessful.

Any reply is appreciated...

[Fiouz]

Hi,

Not using JNDI but plain Spring IoC, here is a working setup:

XML bean factory:

    <bean id="ruleAdministrator" class="org.springmodules.jsr94.factory.RuleAdministratorFactoryBean">
        <property name="serviceProvider" ref="droolsRuleServiceProvider"/>
    </bean>

    <bean id="ruleRuntime" class="org.springmodules.jsr94.factory.RuleRuntimeFactoryBean">
        <property name="serviceProvider" ref="droolsRuleServiceProvider"/>
    </bean>

    <bean id="droolsRuleServiceProvider" class="org.drools.jsr94.rules.RuleServiceProviderImpl"/>

Retrieve a RuleExecutionSetProvider:

LocalRuleExecutionSetProvider ruleExecutionSetProvider;
ruleExecutionSetProvider = ruleAdministrator.getLocalRuleExecutionSetProvider(null); // Drools JSR-94 integration ignores the argument

Create a RuleExecutionSet:

// optional: Drools PackageBuilder config
Map<String, Object> config = new HashMap<String, Object>();
config.put(Constants.RES_PACKAGEBUILDER_CONFIG, packageBuilderConfiguration);

RuleExecutionSet ruleExecutionSet;
ruleExecutionSet = ruleExecutionSetProvider.createRuleExecutionSet(source, config); // source can be a Reader, InputStream or Object (Drools Package)

Register the RuleExecutionSet:

ruleAdministrator.registerRuleExecutionSet("someName", ruleExecutionSet, null); // Drools JSR-94 ignores the third argument

Client side

Create a stateful RuleSession:

StatefulRuleSession ruleSession;
ruleSession = (StatefulRuleSession) ruleRuntime.createRuleSession("someName", null /* or a Map of parameters to WorkingMemory.setGlobal() */, RuleRuntime.STATEFUL_SESSION_TYPE);

Add objects to the RuleSession:

ruleSession.addObjects(someObjects);

Trigger rules processing:

ruleSession.executeRules();

Release resources:

ruleSession.release();

Regards

[codySpringMan]

So you are able to execute rules even though the ruleServiceProvider has NULL arguments?

Where are your .drl files located?

Thank you for the reply.

[Fiouz]

Hi,

So you are able to execute rules even though the ruleServiceProvider has NULL arguments?

Yes, have a look at the source code of org.drools.jsr94.rules.admin.RuleAdministratorImpl / org.drools.jsr94.rules.RuleRuntimeImpl, you'll see that Drools JSR-94 integration does ignore some arguments.

Where are your .drl files located?

The rule definition is referenced here under the "source" variable:

RuleExecutionSet ruleExecutionSet;
ruleExecutionSet = ruleExecutionSetProvider.createRuleExecutionSet(source, config); // source can be a Reader, InputStream or Object (Drools Package)

You can declare source either ways:

Reader source;
InputStream source;
Object source; // but the actual value has to be a org.drools.rule.Package

Actually, I don't use plain .drl files since I generate my rules from a Excel spreadsheet (using Drools decision table API). My rules are generated into a String which is given to the createRuleExecutionSet() method using a StringReader.

Regards

[codySpringMan]

Excellent,

Thank you for the clarification.

I will attempt to use this config. for my needs.

I will keep you updated.

Thanks again!!

[codySpringMan]

Do you know where I can find a sample packageBuilderConfiguration to reference?

How is it optional? I thought it was mandatory for Drools.

[Fiouz]

Do you know where I can find a sample packageBuilderConfiguration to reference?

How is it optional? I thought it was mandatory for Drools.

The simplest configuration is the default one:

        PackageBuilderConfiguration packageBuilderConfiguration;
        packageBuilderConfiguration = new PackageBuilderConfiguration();

It is optional as mentioned at http://downloads.jboss.com/drools/docs/4.0.7.19894.GA/apidocs/org/drools/compiler/PackageBuilder.html#PackageBuilder(org.drools.rule .Package, org.drools.compiler.PackageBuilderConfiguration)

[codySpringMan]

Fiouz,

Thank you for you help in this matter. However I am still confused as to how this configuration can be used in a J2EE environment. It seems that this configuration can only be used by having the decision tables / .drl files stored locally, which is NOT what I need.

I wish to deploy the drools-brms application on an application server, and be able to execute the rules stored there from another server. (does this make sense?)

Do you know where I might find an example configuration of this?

( JNDI - ???)

Thank you again for your help.

[Fiouz]

There is no mandatory usage of local files with Spring since you can make usage of the resources infrastructure in order to retrieve data from filesystem/classpath/war archive/...
Using classpath resources with Spring is a common usage in JEE environments.

As for JNDI retrieving, Spring has support classes too http://static.springframework.org/sp...ee-jndi-lookup and I mainly use it to retrieve JDBC datasources.
I'm not too used to app server custom JNDI binding/remoting, but I guess you just have to figure out what to bind (the rule definition itself? the service that generates it?), bind it and refer to it from Spring.