[rules-users] Extending objects in declared facts

[J Michael Dean]

When a fact is declared with propertyChangeSupport in Guvnor, such as  
following:

declare Hemodynamics
	@propertyChangeSupport
	systolicBP: Integer
	diastolicBP: Integer
	centralVenousP: Integer
	wedgeP: Integer
	status: Boolean
	alive: Boolean
end

then the following warning shows up in JBoss console:

  Warning: Method addPropertyChangeListener not found on the class  
class makeModelTest.Hemodynamics so Drools will be unable to process  
JavaBean PropertyChangeEvents on the asserted Object

I implement property changes in a model object so would like to be  
able to say something like:

declare Hemodynamics extends ModelObject
	@propertyChangeSupport
	systolicBP: Integer
	diastolicBP: Integer
	centralVenousP: Integer
	wedgeP: Integer
	status: Boolean
	alive: Boolean
end

The documentation refers to using Guvnor and declarative facts to  
extend an object that already exists, but not clear that this can  
actually be done.