// By setting dynamic to TRUE, Drools will use JavaBean
// PropertyChangeListeners so you don't have to call modifyObject().
boolean dynamic = true;
workingMemory.assertObject( a, dynamic );
workingMemory.assertObject( b, dynamic );
workingMemory.assertObject( c, dynamic );
workingMemory.assertObject( d, dynamic );
workingMemory.fireAllRules( );