Is it possible to determine what fields from an object changed within a rule.  

So I am using this to determine if any DataObject has changed:

//IDENTIFY ANY DATAOBJECT CHANGES

rule "identify any DATAOBJECT"

when

      $do : DataObject();

then

      System.err.println("ANY DataObject change detected:" + $do);

End

However this also fires when any new DataObject() is injected into the system and the rules are fired.  I would like to be able to only have a rule fire when  an object is first created

Vs. when it is modified and is there a way to detect what values of an object have changed if I don’t explicitly know what fields of DataObject changed ahead of time?

Thanks,

Chris