History.addValueChangeHandler(new ValueChangeHandler<String>() {
@Override
public void onValueChange(ValueChangeEvent<String> event) {
if ("login".equals(event.getValue())) {
AuthPresenter p = new AuthPresenter(bus, new AuthView());
p.go(RootPanel.get());
} else if ("app".equals(event.getValue())) {
ContactsView contactsView = new ContactsView(new GenericDataProvider(Module.Contact, bus));
ProductView productView = new ProductView(new GenericDataProvider(Module.Product, bus));
ProposalView proposalView = new ProposalView(new GenericDataProvider(Module.Proposal, bus));