Errai: Type-safe web apps in pure Java

Flexible HTML5 Templating

    
    
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Simple DOM Element Injection and Binding

@Templated @Page
public class CustomerForm extends Composite {

  @Inject @DataField TextBox name;
  @Inject @DataField TextBox phone;
  @Inject @DataField Button saveButton;

  @EventHandler("saveButton")
  public void onSave(ClickEvent event) {
    ...
  }
}

            

Bidirectional Model ↔ UI Binding

@Templated @Page
public class CustomerForm extends Composite {
  @Inject @Model Customer customer;
  @Inject @Bound @DataField TextBox name;
  @Inject @Bound @DataField TextBox phone;
  @Inject @DataField Button saveButton;

  @EventHandler("saveButton")
  public void onSave(ClickEvent event) {
    //customer already reflects form contents (two-way data binding)
    sendCustomerToServer(customer);
  }
}
            

Choice of JAX-RS or Bus RPC

@Path("/customers")
public interface CustomerEndpoint {
  @GET
  public long create(Customer customer);  
}

or

@Remote
public interface CustomerEndpoint {  
  public long create(Customer customer);  
}

            

Typesafe RPC Client

@Templated @Page
public class CustomerForm extends Composite {

  @Inject 
  Caller<CustomerEndpoint> customerEndpoint;

  private void sendCustomerToServer(Customer customer) { 
     RemoteCallback remoteCallback = ...     
     customerEndpoint.call(remoteCallback).create(customer);
  }
}
            

Bookmarkable Page Navigation

  @Templated
  public class MainMenu extends Composite {

    @Inject @DataField 
    private TransitionAnchor<CustomerForm> customerForm;
    ...
  }


            

Typesafe Distributed Events

@Stateless
public class CustomerEndpointImpl implements CustomerEndpoint {
  @Inject @New 
  private Event<Customer> customerEvent;

  public long create(Customer customer) {
    // fire an event on the server
    customerEvent.fire(customer); 
  }
}

@Templated
public class CustomerList extends Composite {
  // and simply observe the event on the client
  private void onNewCustomer(@Observes @New Customer customer) {...}
}
            

Integrated with Mobile hardware

@Templated @Page
public class CustomerForm extends Composite {

  @Inject 
  private Camera camera;

  private void onBatteryLow(@Observes BatteryLowEvent event) {
     ...
  }
}
            

Client-side JPA For Offline Storage

@Templated @Page
public class CustomerForm extends Composite {

  @Inject 
  private EntityManager em;

  public void save(Customer customer) {
    em.merge(customer);
    em.flush();
  }
}