oldEntities = myEntities;
Set<EOEntity> newEntities = new HashSet<EOEntity>();
newEntities.addAll(myEntities);
newEntities.add(entity);
myEntities = newEntities;
_modelEvents.addEvent(new EOEntityAddedEvent(entity));
firePropertyChange(EOModel.ENTITIES, oldEntities, myEntities);
} else {
myEntities.add(entity);
}
}