public ObjectenOpslag(Group root, File file) {
            this.children=root.getChildren();
            
        try {
            JAXBContext jc = JAXBContext.newInstance(World.class);
            if(file == null){
            w = (World) jc.createUnmarshaller().unmarshal(ObjectenOpslag.class.getResource("Wereld.xml"));
            }else{
            w = (World) jc.createUnmarshaller().unmarshal(file);
            }
        } catch (JAXBException ex) {
            throw new RuntimeException("JAXB:" + ex);
        } 
        
        for(Building b : w.getBuildings()){
           buildings.add(b);
           children.add(b.getNode());
        }
        
        /*
         * persons
         */
        for(BoringPerson b : w.getPersons()){
            spatiesdingen.add(b);
            children.add(b.getNode());
        }
        
        for(ContainsPerson b : w.getContainsPersons()){
            spatiesdingen.add(b);
            children.add(b.getNode());
        }
        
        for(Item b : w.getItems()){
            spatiesdingen.add(b);
            children.add(b.getNode());
        }
        

    }