How a parent can catch an event of its child?

 public void onClose() {
    	Events.postEvent(EVENT_ON_CLOSE_SERVICE, this.self.getParent, null);
    }

<?page id="ServiceForm" title="Service form" cacheable="false" language="xul/html" zscriptLanguage="Java"?>
<?meta content="text/html; charset=UTF-8" pageEncoding="UTF-8"?>

<window closable="true" maximizable="true" sizable="true" height="400px" width="200px" contentStyle="overflow:auto" apply="org.chorem.bonzoms.ui.ServiceFormController">
<caption label="Service"/>

    <groupbox>
        <caption label="Service informations" />

        <vbox>

            <label value="Type" />
            <textbox value="@{composer.service.type, save-when='saveService.onClick'}" />

            <label value="Name" />
            <textbox value="@{composer.address.name, save-when='saveService.onClick'}" />

            <label value="Address 1" />
            <textbox value="@{composer.address.address1, save-when='saveService.onClick'}" />

            <label value="Address 2" />
            <textbox value="@{composer.address.address2, save-when='saveService.onClick'}" />

            <label value="Zip code" />
            <textbox value="@{composer.address.zipCode, save-when='saveService.onClick'}" />

            <label value="City" />
            <textbox value="@{composer.address.city, save-when='saveService.onClick'}" />

            <label value="Country" />
            <textbox value="@{composer.address.country, save-when='saveService.onClick'}" />

        </vbox>

    </groupbox>

    <button label="save" id="saveService" />

</window>

public class ServiceFormController extends GenericForwardComposer {

    protected Model model = new Model();

    protected Service service = new ServiceImpl();
    protected Address address = new AddressImpl();

    public static final String EVENT_ON_SAVE_SERVICE = "onSaveService";
	public static final String EVENT_ON_CLOSE_SERVICE = "onCloseService";
    
    @Override
    public void doAfterCompose(Component comp) throws Exception {
        super.doAfterCompose(comp);
        Window win = (Window) self;
        win.doModal();
        win.setPosition("center");
        String id = Executions.getCurrent().getParameter("serviceId");
        if (id != null) {
            initService(id);
        }
        DataBinder binder = new AnnotateDataBinder(comp);
        binder.bindBean("composer", this);
        binder.loadAll();
    }

    protected void initService(String id) {
    	service = model.retrieveServiceById(id);
        address = model.retrieveAddressById(service.getAddress());
    }

    /*
     * Events
     */
    public void onClose() {
    	Events.postEvent(EVENT_ON_CLOSE_SERVICE, this.self, null);
    }
    
    public void onClick$saveService() {
        address = model.createAddress(address);
        service.setAddress(address.getWikittyId());

        service = model.updateService(service);

        Events.postEvent(EVENT_ON_SAVE_SERVICE, this.self, service);

        self.detach();
    }

    /*
     * Getters
     */
    public Service getService() {
        return service;
    }
    
    public Address getAddress() {
    	return address;
    }
}