Question

I am trying to figure out how to use GWT Editor when my model has a field that is a Set, List, etc.

I have this entity proxy:

public interface MyModel {
  void setSomeCollection(Set<String> c);
  Set<String> getSomeCollection();
}

Here is my multiselect field. I am extending ListBox so that I can change some of its behavior later.

public class DualListBox extends ListBox implements LeafValueEditor<Set<String>> {

    public DualListBox() {
        super(true);
    }

    @Override
    public void setValue(Set<String> values) {
        if (values == null) {
            return;
        }

        for (String value : values) {
            for (int i = 0; i < getItemCount(); i++) {
                if (getValue(i).equals(value)) {
                    setItemSelected(i, true);
                } else {
                    setItemSelected(i, false);
                }
            }
        }
    }

    @Override
    public Set<String> getValue() {
        Set<String> values = new HashSet<String>();
        for (int i = 0; i < getItemCount(); i++) {
            if (isItemSelected(i)) {
                values.add(getValue(i));
            }
        }

        // Debug shows that the set of values is populated correctly..
        return values;
    }
}

Basically I just cant figure out how to get fields with a Set (I have tried List as well) to work with GWTs Editor framework. Debugging so far shows that the values are coming out of the editor correctly.

I have looked at ListEditor but that looks like its used to edit a list of more complex that object types; not a single field with multiple possible values. I am implementing the wrong editor type? Is GWT Editor not able to handle fields that are collections yet?

Answer 1

Ooops! The code I have will work correctly. I simplified my actual scenario a bit and I ended up finding my error. My real entity proxy looked more like:

public interface MyModel {
  // BrokerType is an enum
  void setBrokerTypes(Set<BrokerType> brokerTypes);
  Set<BrokerType> getBrokerTypes();
}

ListBox always returns values as Strings! So the editor framework was probably having a hard time figuring out how to convert Set<String> to Set<BrokerType>. Would have rather seen an error instead of silent failure, but oh well.

This is the reason I was extending ListBox in the first place (to handle more complex types) so I guess I need to get that working before expecting the Editor framework to know what to do with the Set.