SY Service Channel in Drools Service

[anikulin]

Hi guys

I'm using SY Drools Service and want to add Channel to it. I tried to expose already created SY Bean as a channel, but as a result neither the service operation was fired nor any exception occured. switchyard.xml configuration looks like this:

<sca:component name="TestRule">
  <rules:implementation.rules>
  <rules:channels>
  <rules:channel
  class="org.switchyard.component.common.knowledgMy e.service.SwitchYardServiceChannel"
  name="BeanService" operation="send" reference="BeanService" />
  </rules:channels>
  <rules:manifest>
  <rules:resources>
  <rules:resource location="testRule.drl" type="DRL" />
  </rules:resources>
  </rules:manifest>
  <rules:operations>
  <rules:operation name="init" type="FIRE_UNTIL_HALT" />
  <rules:operation name="insertFact" type="INSERT">
  <rules:inputs>
  <rules:input from="message.content" />
  </rules:inputs>
  </rules:operation>
  </rules:operations>
  </rules:implementation.rules>
  <sca:service name="DroolsService">
  <sca:interface.java
  interface="com.example.switchyard.switchyard_channel_example.DroolsService" />
  </sca:service>
  </sca:component>
  <sca:component name="BeanServiceBean">
  <bean:implementation.bean
  class="com.example.switchyard.switchyard_channel_example.BeanServiceBean" />
  <sca:service name="BeanService">
  <sca:interface.java
  interface="com.example.switchyard.switchyard_channel_example.BeanService" />
  </sca:service>
  </sca:component>

Please, let me know what I'm doing wrong. Thanks for help.

Regards, Anton

[dward]

Hi Anton,

Your problem is that you did not have a reference to the BeanService from your DroolsService.  Adding these lines corrects that:

            <sca:reference name="BeanService">

                <sca:interface.java

                    interface="com.example.switchyard.switchyard_channel_example.BeanService" />

            </sca:reference>

You should also update your DroolsService.java interface to include the data you are passing to it. So change this:

void insertFact();

to this:

void insertFact(TestModel fact);

Now, the question of why there was silently no error?  I'll look into that.

[dward]

Okay, there is a null reference check, which throws an exception, which is later caught and logged because Channels don't allow for checked exceptions.  I need to consider whether or not we want to actually throw a RuntimeException here instead. Same thing for WorkItemHandlers too.  As for why you didn't see the log, it's probably a logging configuration thing.

[dward]

I've opened a jira: [SWITCHYARD-2028] investigate using RuntimeException for fault propagation in SwitchYardServiceChannel - JBoss Issue Tra…

[anikulin]

Thanks a lot, David!