setExperimenters( new HashSet(grp.collectFromExperimenterLinks( block )));
setExperimenters( new HashSet(grp.eachLinkedExperimenter( block )));
    public void copy(IObject model, ModelMapper mapper) {    	if (model instanceof ExperimenterGroup) {			ExperimenterGroup grp = (ExperimenterGroup) model;            super.copy(model,mapper);            // Details            if (grp.getDetails() != null){                this.setOwner((ExperimenterData) mapper.findTarget(grp.getDetails().getOwner()));            }                        // Fields			this.setName(grp.getName());            // Collections            MapperBlock block = new MapperBlock( mapper );            setExperimenters( new HashSet(grp.collectFromExperimenterLinks( block )));    	} else {			throw new IllegalArgumentException(                    "GroupData can only copy from Group, not "+                    model.getClass().getName()); // TODO all errors like this.		}    }