ListEditor with polymorphic types - gwt

Question

I have searched around and been trying to figure out if I can use the editor framework with polymorphic types. I found this post at Using GWT Editors with a complex usecase which is close to what I am trying to do.
I am fairly new to the editor framework, so any help would be much appreciated.
For example, here is some of the code,
Data Transfer Objects:
public class Employee{
public List<Contact> contacts
}
public class Contact {
public class ContactEmail extends Contact {}
public class ContactAddress extends Contact {}
public class ContactPhoneNumber extends Contact {}
Editors:
public interface ContactBaseEditor<T extends Contact> extends Editor<T> {}
public class AddressEditor extends Composite implements Editor<ContactAddress>, ContactBaseEditor<ContactAddress>{}
public class EmailEditor extends Composite implements Editor<ContactEmail>, ContactBaseEditor<ContactEmail>{)
public class PhoneNumberEditor extends Composite implements Editor<ContactPhoneNumber>, ContactBaseEditor<ContactPhoneNumber>{}
ContactEditor class:
public class ContactEditor extends Composite implements IsEditor<ListEditor<Contact, ContactEditorWrapper>> {
private class ContactEditorSource extends EditorSource<ContactEditorWrapper> {
#Override
public ContactEditorWrapper create(final int index) {
ContactEditorWrapper contactEditor = new ContactEditorWrapper();
communicationContactsPanel.add(contactEditor);
return contactEditor;
}
#Override
public void dispose(ContactEditorWrapper subEditor) {
subEditor.removeFromParent();
}
#Override
public void setIndex(ContactEditorWrapper editor, int index) {
communicationContactsPanel.insert(editor, index);
}
}
private ListEditor<Contact, ContactEditorWrapper> editor = ListEditor.of(new ContactEditorSource());
public ListEditor<Contact, ContactEditorWrapper> asEditor() {
return editor;
}
}
ContactEditorWrapper:
class ContactEditorWrapper extends Composite implements ContactBaseEditor<Contact>, ValueAwareEditor<Contact> {
private SimplePanel panel = new SimplePanel();
#Path("") ContactBaseEditor<Contact> realEditor;
public ContactEditor() {
initWidget(panel);
}
#Override
public void setValue(Contact value) {
if (value instanceof Address) {
realEditor = new AddressEditor();
panel.setWidget((AddressEditor)realEditor);
}
else if (value instanceof Email) {
realEditor = new EmailEditor();
panel.setWidget((EmailEditor)realEditor);
}
else if (value instanceof PhoneNumber) {
realEditor = new PhoneNumberEditor();
panel.setWidget((PhoneNumberEditor)realEditor);
}
else {
realEditor = null;
}
}
}
Main Editor class:
public class AddEmployeeEditor extends Composite implements Editor<Employee> {
#UiField
ContactEditor contacts;
interface Driver extends SimpleBeanEditorDriver<Employee, AddEmployeeEditor> {
}
public AddEmployeeEditor(final Binder binder) {
driver = GWT.create(Driver.class);
driver.initialize(this);
List<Contact> list = new ArrayList<Contact>();
list.add(new Address());
list.add(new Email());
list.add(new PhoneNumber());
list.add(new PhoneNumber());
Employee employee = new Employee();
employee.setContacts(list);
driver.edit(employee);
}
}
Can anyone tell me if this will work, am I going in the right direction or ?
Thanks in advance,
Mac
I have updated the code above to now contain the ContactEditorWrapper class that Thomas advised.

Answer 1

That code has good chances to break: there's no guarantee that an editor returned by the EditorSource won't be used to edit another value in the list.
You should create a wrapper editor implementing ValueAwareEditor and with the actual editor as a child editor with #Path(""); and create the appropriate ContactBaseEditor in the setValue method.
class ContactEditor extends Composite implements ValueAwareEditor<Contact> {
private SimplePanel panel = new SimplePanel();
#Path("") ContactBaseEditor realEditor;
public ContactEditor() {
initWidget(panel);
}
#Override
public void setValue(Contact value) {
if (contact instanceof ContactAddress) {
realEditor = new AddressEditor();
}
else if (contact instanceof ContactEmail) {
realEditor = new EmailEditor();
}
else if (contact instanceof ContactPhoneNumber) {
realEditor = new PhoneNumberEditor();
}
else {
realEditor = null;
}
panel.setWidget(realEditor);
}
Note however that only the field/sub-editors from ContactBaseEditor will be edited, whichever the actual implementation being used. If there are additional fields/sub-editors in some ContactBaseEditor subclass, you'd have to implement ValueAwareEditor and handle things by-hand in the setValue and flush methods.