Question

I’m looking for someone to point me in the right direction (link) or provide a code example for implementing a drop down list for a many-to-one relationship using RequestFactory and the Editor framework in GWT. One of the models for my project has a many to one relationship:

@Entity
public class Book {

  @ManyToOne
  private Author author;
}

When I build the view to add/edit a book, I want to show a drop down list that can be used to choose which author wrote the book. How can this be done with the Editor framework?

Answer 1

For the drop-down list, you need a ValueListBox<AuthorProxy>, and it happens to be an editor of AuthorProxy, so all is well. But you then need to populate the list (setAcceptableValues), so you’ll likely have to make a request to your server to load the list of authors.

Beware the setAcceptableValues automatically adds the current value (returned by getValue, and defaults to null) to the list (and setValue automatically adds the value to the list of acceptable values too if needed), so make sure you pass null as an acceptable value, or you call setValue with a value from the list before calling setAcceptableValues.