[rules-dev] Possible bug in looping ruleflows

[Shahad Ahmed]

I've been trying out the latest version of the ruleflow and I think I may
have found a bug when creating looping ruleflows. I think the bug is in
RuleFlowProcessInstance.getNodeInstance, where I suspect there is a return
in the wrong place in the if-then-else that deals with ISplit node.
I created a looping ruleflow that contains a Join and  Split node, where the
Split decides if we should enter the loop and the Join allows a flow to
re-enter the loop body. The issues is that the second time the same Split
node is re-entered I always get the following exception:

 java.lang.IllegalArgumentException: Illegal node type: class
org.drools.ruleflow.core.impl.Split
 at
org.drools.ruleflow.instance.impl.RuleFlowProcessInstance.getNodeInstance(
RuleFlowProcessInstance.java:121)
 at
org.drools.ruleflow.instance.impl.RuleFlowSequenceNodeInstance.triggerCompleted
(RuleFlowSequenceNodeInstance.java:38)
 at org.drools.common.RuleFlowGroupImpl$DeactivateCallback.execute(
RuleFlowGroupImpl.java:191)
 at org.drools.common.AbstractWorkingMemory.executeQueuedActions(
AbstractWorkingMemory.java:992)
 at org.drools.common.AbstractWorkingMemory.fireAllRules(
AbstractWorkingMemory.java:375)
 at org.drools.common.AbstractWorkingMemory.fireAllRules (
AbstractWorkingMemory.java:353)
 at org.drools.examples.SequentialTest.runTest4(SequentialTest.java:192)
 at org.drools.examples.SequentialTest.main(SequentialTest.java:27)

This exception is only thrown if the ruleflow contains an unknown node, but
org.drools.ruleflow.core.impl.Split is a valid node (i.e. an instance of
ISplit)! Looking at the body of RuleFlowProcessInstance.getNodeInstance   I
think the return in the following part of the if-then-else is in the wrong
place:

else if ( node instanceof ISplit ) {
            IRuleFlowNodeInstance result = getFirstNodeInstance( node.getId()
);
            if ( result == null ) {
                result = new RuleFlowSplitInstance();
                result.setNodeId( node.getId() );
                addNodeInstance( result );
                return result;
            }
}...

This code would mean that the second time the Split is entered, result is
not null, so "if ( result == null )" is never entered, which results in
dropping out of the if-then-else and activating the error exception above. I
suspect the return should be outside the "if ( result == null )"
if-statement just like the IJoin part of the if-then-else to give the
following (correct?) code:

else if ( node instanceof ISplit ) {
            IRuleFlowNodeInstance result = getFirstNodeInstance( node.getId()
);
            if ( result == null ) {
                result = new RuleFlowSplitInstance();
                result.setNodeId( node.getId() );
                addNodeInstance( result );
            }
          return result;
}...

Once I changed the return, looping seemed to work fine. I wasn't sure about
raising a JIRA about this, as this stuff is still under development.

Regards
Shahad
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