[rules-users] Updates with property change on facts. How???

[Jason Smith]

The Update command appears to be processed in org.drools.process.commands.UpdateCommand.   It's doing the update the same way I am.  

Why does this code work when Drools uses it, and it doesn't work for me?

package org.drools.process.command;
import org.drools.reteoo.ReteooWorkingMemory;
import org.drools.runtime.rule.FactHandle;
public class UpdateCommand
    implements
    Command<Object> {
    private FactHandle handle;
    private Object     object;
    public UpdateCommand(FactHandle handle,
                         Object object) {
        this.handle = handle;
        this.object = object;
    }
    public Object execute(ReteooWorkingMemory session) {
        session.update( handle,
                        object );
        return null;
    }
    public String toString() {
        return "session.update( " + handle + ", " + object + " );";
    }
}


Jason Smith
________________________________________
From: rules-users-bounces at lists.jboss.org [rules-users-bounces at lists.jboss.org] On Behalf Of Jason Smith [jsmith at infotrustgroup.com]
Sent: Friday, November 27, 2009 10:04 AM
To: Rules Users List
Subject: Re: [rules-users] Updates with property change on facts.  How???

Here is a twist.

If I call "update($fact)" explicitly in the rule, the rule is NOT called twice.

Can someone point me to the code used by "update($fact)"?  Maybe I can figure out what I did wrong to cause the rule to fire incorrectly a second time.


Jason Smith
________________________________________
From: rules-users-bounces at lists.jboss.org [rules-users-bounces at lists.jboss.org] On Behalf Of Jason Smith [jsmith at infotrustgroup.com]
Sent: Friday, November 27, 2009 9:54 AM
To: Rules Users List
Subject: [rules-users] Updates with property change on facts.  How???

I implemented the following listener for my bean and I am calling .update() directly on the StatefulKnowledgeSession.

QUESTION 1:  Is there a better way?  The old API supported .insert(fact,boolean).  The new one does not.  I am not finding any documentation that explains the new API (version 5.0.1).

QUESTION 2: Why is this calling my rule twice?  The rule is getting called twice, and the second time it's called, the entry conditions are invalid!  That is, I changed the bean in a way that invalidates the WHEN condition.  The rule still gets called twice.

How do I even begin to go about troubleshooting this?  This same behavior was happening with Drools 4 and the old API as well.



    private class InnerPropertyChangeListener implements PropertyChangeListener
    {
     private final InternalFactHandle factHandle;
     private final Object fact;
     private final StatefulKnowledgeSession session;

     public InnerPropertyChangeListener(InternalFactHandle factHandle, Object fact, StatefulKnowledgeSession session)
     {
      this.factHandle = factHandle;
      this.fact = fact;
      this.session = session;
     }

  @Override
  public void propertyChange(PropertyChangeEvent evt)
  {
   System.out.println("****** UPDATING " + evt.getPropertyName() + ": " +
     "\n        NEW:    " + StringUtil.indent(BeanUtil.printObject(evt.getNewValue()),16) +
     "\n        OLD:    " + StringUtil.indent(BeanUtil.printObject(evt.getOldValue()),16));
   if((evt.getNewValue() == null && evt.getOldValue() != null) || !evt.getNewValue().equals(evt.getOldValue()))
   {
    session.update(factHandle, fact);
   }
  }
    }





Jason Smith
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