GWT Request Factory and Editor Framework Exception

Question

When attempting to edit a new (proxy) entity using RequestFactoryEditorDriver.edit() I am getting the following error: "Exception caught: Attempting to edit an EntityProxy previously edited by another RequestContext". I am fairly sure that this is a result of my misunderstanding of the request factory/editor framework architecture. Here is the editor code that I think pertains to this problem:

public class OrgMaintenanceWidget extends Composite implements Editor<IOrgProxy> {
... other fields ...
private IOrgEditorDriver _orgEditorDriver;
interface IOrgEditorDriver extends RequestFactoryEditorDriver<IOrgProxy, OrgMaintenanceWidget> {}
public OrgMaintenanceWidget(final IClientFactory clientFactory) {
  ... widget initialization ...
  _orgEditorDriver = GWT.create(IOrgEditorDriver.class);
  _orgEditorDriver.initialize(_clientFactory.getRequestFactory().getEventBus(),
                              _clientFactory.getRequestFactory(), this);
}
@UiHandler("newButton")
public void onNewButtonClick(final ClickEvent clickEvent) {
  _org = _clientFactory.getCache().getOrgCache().newOrg();
  _orgEditorDriver.edit(_org, _clientFactory.getRequestFactory().orgRequestContext());
}
...
}

It's the "_orgEditorDriver.edit()" line that causes the exception. The "newOrg()" method is:

public IOrgProxy newOrg() {
  return _clientFactory.getRequestFactory().orgRequestContext().create(IOrgProxy.class);
}

The RequestFactory is simply:

public interface IRequestFactory extends RequestFactory {
IOrgRequestContext orgRequestContext();
}

I am sure that I'm missing something fundamental about editing a new entity. When I edit an existing entity everything is fine ... the UI components are populated automatically, and flushing the editor back to the entity works very nicely. Here's the code that initiates editing for an existing entity:

@UiHandler("newButton")
public void onNewButtonClick(final ClickEvent clickEvent) {
  _org = _clientFactory.getCache().getOrgCache().newOrg();
  _orgEditorDriver.edit(_org, _clientFactory.getRequestFactory().orgRequestContext());
}

Any help would be greatly appreciated, and I'll try to publish any lessons learned.

Answer 1

This code:

_clientFactory.getRequestFactory().orgRequestContext().create(IOrgProxy.class);

Means:

1. Create new orgRequestContext()
2. Create new IOrgProxy using this context
3. Edit new IOrgProxy using this context, because as docs say: "Returns a new mutable proxy that this request can carry to the server, perhaps to be persisted.", it means that the proxy is edited by this request.

This code:

_orgEditorDriver.edit(_org, _clientFactory.getRequestFactory().orgRequestContext());

Means:

1. Again, create new orgRequestContext() (because each invocation of getRequestFactory().orgRequestContext() provides new instance of orgRequestContext()

2. "Start driving the Editor and its sub-editors with data." as docs say. But as a part of it, use passed orgRequestContext() to edit passed IOrgProxy instance, so that the proxy is editable.

3. Because the proxy was already edited while created by other RequestContext, you get the exception, because there is fundamental rule in RequestFactory, that proxy can be edited only by one RequestContext.

   See also this thread.