topic Re: BusinessRuleTask // icon + implementation in Alfresco Archive

BusinessRuleTask // icon + implementation

skay — Sat, 01 Nov 2014 14:45:48 GMT

Hi,This topic is actually for both forums : designer and engine.I would like to keep the bpm icon semantic of BusinessRuleTask, but we have our own RuleEngine implementation / not a drools 5.5 lib directly in the classpath, but rather a kind of remote executor.This is currently possible / User Guide

Re: BusinessRuleTask // icon + implementation

jbarrez — Mon, 03 Nov 2014 10:50:35 GMT

* I need to put the drools library within my classpath just for having the visual representation of "BusinessRuleTask" BPMN component in my process

I don't get that. It shouldn't be needed.

All behaviours are instantiated by the org.activiti.engine.impl.bpmn.parser.factory.ActivityBehaviorFactory. You can extends the default one and return your own implementation for the business rule task.

* A new feature of the designer/modeler would be to let the user link the freedom of bpmn tasks icons (why not custom icon?!).

That is possible with custom elements in the designer. See http://activiti.org/userguide/index.html#eclipseDesignerCustomizingPalette

Re: BusinessRuleTask // icon + implementation

skay — Mon, 03 Nov 2014 21:23:50 GMT

OK, this is the exercpt of my bpmn
<businessRuleTask id="businessruletask1" name="Business rule task" activiti:class="messagein.RuleEngineDelegate"></businessRuleTask>

Works OK if serviceTask instead of businessRuleTask.

Here is the ClassNotFound stack trace :

java.lang.NoClassDefFoundError: org/drools/runtime/rule/AgendaFilter
at org.activiti.engine.impl.bpmn.parser.factory.DefaultActivityBehaviorFactory.createBusinessRuleTaskActivityBehavior(DefaultActivityBehaviorFactory.java:232)
at org.activiti.engine.test.TestActivityBehaviorFactory.createBusinessRuleTaskActivityBehavior(TestActivityBehaviorFactory.java:239)
at org.activiti.engine.impl.bpmn.parser.handler.BusinessRuleParseHandler.executeParse(BusinessRuleParseHandler.java:37)
…

So it breaks out when parsing bpmn.
Seems like activiti:class="messagein.RuleEngineDelegate" is ignored ?

Finally, I tried those solutions :

<businessRuleTask id="businessruletask1" activiti:class="messagein.RuleEngineDelegate"></businessRuleTask>

<businessRuleTask id="businessruletask1" activiti:class="${messagein.RuleEngineDelegate"}></businessRuleTask>

<businessRuleTask id="businessruletask1" activiti:delegateExpression="${ruleEngineDelegate}" ></businessRuleTask>

But all are throwing the ClassNotFound ..

Re: BusinessRuleTask // icon + implementation

skay — Mon, 03 Nov 2014 21:44:58 GMT

I can fix the problem tweaking the source :

public class BusinessRuleParseHandler extends
AbstractActivityBpmnParseHandler<BusinessRuleTask> {

public Class<? extends BaseElement> getHandledType() {
return BusinessRuleTask.class;
}

@Override
protected void executeParse(BpmnParse bpmnParse,
   BusinessRuleTask businessRuleTask) {

ActivityImpl activity = createActivityOnCurrentScope(bpmnParse,
    businessRuleTask, BpmnXMLConstants.ELEMENT_TASK_BUSINESSRULE);
activity.setAsync(businessRuleTask.isAsynchronous());
activity.setExclusive(!businessRuleTask.isNotExclusive());
//FIXXX
if (businessRuleTask.getClassName()!=null) {
   ClassDelegate cd= new ClassDelegate(businessRuleTask.getClassName(), null);
   activity.setActivityBehavior(cd);
} else {
///ORIG
   activity.setActivityBehavior(bpmnParse.getActivityBehaviorFactory()
     .createBusinessRuleTaskActivityBehavior(businessRuleTask));
}
}

}

Re: BusinessRuleTask // icon + implementation

jbarrez — Wed, 05 Nov 2014 12:55:32 GMT

Which is why I said you need to change org.activiti.engine.impl.bpmn.parser.factory.ActivityBehaviorFactory implementation and indeed probably the handler. If you want to change the default behaviour (and keep using the businessRuleTask xml), it's the only way

Re: BusinessRuleTask // icon + implementation

skay — Thu, 06 Nov 2014 16:06:23 GMT

Hi,

This is the reason of the classCast :

<code>

<name>Activiti - Engine</name>
<artifactId>activiti-engine</artifactId>

<parent>
    <groupId>org.activiti</groupId>
    <artifactId>activiti-root</artifactId>
    <relativePath>../..</relativePath>
    <version>5.17.0-SNAPSHOT</version>
</parent>
…
    <dependency>
      <groupId>org.drools</groupId>
      <artifactId>drools-core</artifactId>
      <scope>provided</scope>
    </dependency>
<dependency>
      <groupId>org.drools</groupId>
      <artifactId>drools-compiler</artifactId>
      <scope>provided</scope>
    </dependency>

</code>

… And actually this lib is not present in activiti.explorer's distribution // supposed to be in the classpath

Re: BusinessRuleTask // icon + implementation

jbarrez — Mon, 10 Nov 2014 11:08:23 GMT

No, because the scope is 'provided'. Meaning, if you need it, you need to put it on the classpath yourself.

But in your case, it shouldn't be if you need Drools and replace the existing business rule logic yourself.

Re: BusinessRuleTask // icon + implementation

skay — Mon, 10 Nov 2014 23:34:25 GMT

" it shouldn't be if you need Drools and replace the existing business rule logic yourself"
-> This is the intention of the code / and User Guide notice :
http://www.activiti.org/userguide/#bpmnBusinessRuleTask

<code>
<businessRuleTask id="businessRuleTask" activiti:class="ch.ectropy.MyBusinessRule" />
</code>

Unfortunately, a hook over BusinessRuleTaskActivityBehavior is not working the because activiti:class value is not handled properly.
(no usage of BusinessRuleTask.getClassName() in the code !)

DefaultActivityBehaviourFactory is *always* creating a new instance of the BusinessRuleTaskActivityBehavior :

<code>
public BusinessRuleTaskActivityBehavior createBusinessRuleTaskActivityBehavior(BusinessRuleTask businessRuleTask) {
BusinessRuleTaskActivityBehavior ruleActivity = new BusinessRuleTaskActivityBehavior();
</code>

see pull request #427 for a simple fix proposal.
But maybe a harder refactoring is required here…

Re: BusinessRuleTask // icon + implementation

jbarrez — Tue, 18 Nov 2014 20:04:36 GMT

I'm not following here:

> DefaultActivityBehaviourFactory is *always* creating a new instance of the BusinessRuleTaskActivityBehavior :

Which is why you need to swap out the activityBehaviour so it doesn't do that, right?

To help this discussion: can you put your work in a unit test that demonstrates what you are tying to do?

Re: BusinessRuleTask // icon + implementation

skay — Tue, 18 Nov 2014 21:36:19 GMT

Yes, thats right;
Finally, the followings should be a good solution for a refactoring.
-> Camel task, mule task, and even mail task are built upon a Service Task pattern.
I think that the BusinessRule Task should move to that pattern / should be unified in order to inherit from the delegate expression, etc.
And the ServiceLocator-like parttern used for Camel Task should be applied the same for the BusinessRule Task.

Re: BusinessRuleTask // icon + implementation

jbarrez — Thu, 20 Nov 2014 08:13:49 GMT

> I think that the BusinessRule Task should move to that pattern / should be unified in order to inherit from the delegate expression, etc.

Why? We want to encapsulate the business rule task and only expose what is relevant for it.
If you don't like it, you can swap it out using the approach above with whatever implementation you want. Not many people have the use case of needing to do that.