how can i send information from composite to entrypoint class?

Question

my problem is about my GWT project. i got 2 files named Main.java(EntryPoint) and Registration.java(Composite) in my client package. Registration class is just user interface for registration.(it has text boxes and button)

There is a register button in Registration class which takes all information from registration form. My problem is here. how can i send this information from Registration class to EntryPoint class when user clicks button?

this is my onModuleLoad method;

....

Registration registration = new Registration();

     dockLayoutPanel.add(registration);

....

Answer 1

Use Command Pattern, for example I also have an Interface

public interface SuperPuperHandler<T> {
  public void onFire(T t);
}

and in your Registration class add save handler:

  public class Registration extends Composite{
       private SuperPuperHandler<MySavedObject> saveHandler;

       public void addSaveHandler(SuperPuperHandler<MySavedObject> saveHandler){
          this.saveHandler=saveHandler;
       }

       .....
       savebutton.addClickHandler(new ClickHandler() {
           public void onClick(ClickEvent clickEvent) {
              if(saveHandler!=null){
                  saveHandler.onFire(mysavedObject); 
              }               
          }
       });

}

So here is what to do in your EntryPoint

 public class Main implements EntryPoint {

       ....
       Registration registration =new Registration();
       registration.addSaveHandler(new SuperPuperHandler<MySavedObject>(){
          public void onFire(MySavedObject t){
              // here is saved objects in registration form
          }
        });

}