I dug around a bit and discovered why the onFailure() handler was not being
called. The DynaTableRf sample that ships with GWT 2.1 uses the new Editor
framework. In the PersonEditorWorkflow.java class it initializes the editor and
keeps a copy of the RequestContext as follows:
PersonRequest context = requestFactory.personRequest();
context.persist().using(person);
When the user clicks the "Save" button, the onSave() click handler gets called,
which basically does:
context.fire(new Receiver<Void>() {
@Override
public void onSuccess(Void response) {
dialog.hide();
}
@Override
public void onViolation(Set<Violation> errors) {
dialog.setText("Errors detected on the server");
editorDriver.setViolations(errors);
}
});
For dealing with successes and violations, that works fine. The problem happens
when you want to deal with exceptions thrown on the server. The RequestContext
and Request objects seem to have their own Receiver() instances, but only the
Receiver instance for the Request (and NOT the RequestContext) gets parsed for
server-side exceptions (see
com.google.gwt.requestfactory.client.impl.AbstractRequest.handleResponseText()
for the error parsing code, and AbstractRequestContext.doFire() for
RequestContext code that ignores any errors). To briefly show what's going on,
below is a snippet from the TransportReceiver that gets created in the
AbstractRequestContext.doFire() method for handling the request:
public void onTransportSuccess(String payload) {
try {
// TODO: chained methods
assert invocations.size() == 1;
invocations.get(0).handleResponseText(payload);
if (receiver != null) {
if (errors.isEmpty()) {
receiver.onSuccess(null);
// After success, shut down the context
editedProxies.clear();
invocations.clear();
returnedProxies.clear();
} else {
receiver.onViolation(errors);
}
}
} finally {
postRequestCleanup();
}
}
What winds up happening is that if the payload contains errors, they get
processed in the handleResponseText() method call, but only if the request
instance has a Receiver set. The code below that does not handle errors at all,
so even on error the onSuccess() method of your receiver gets called.
Is such behavior intentional?
The workaround is to set the Request's Receiver instance and call
context.fire() instead, but still leaves the DynaTableRf sample a bit
misleading.
DK
On Nov 16, 2010, at 4:43 PM, DK wrote:
> I've encountered the same problem. Intuition says that throwing an
> error should trigger the onFailure() method, not the onSuccess()
> method with a SEVERE logging the exception. Is this a known bug?
>
> On Nov 6, 5:03 am, Henrique F M <fm.henri...@gmail.com> wrote:
>> Hi there,
>>
>> I didn't find the solution to this anywhere, so I'm creating this new
>> discussion.
>>
>> I want to be able to send errors from my RequestFactory to the client.
>> Let me give an example: let's say my app is a simple Person CRUD. My
>> Person class has a String name attribute and I don't want to have more
>> than two Persons with the same name. So i was thinking something like
>> this:
>>
>> ---------- RequestFactory Server Implementation --------
>> public static Person createNewPerson(String name){
>> ....
>> if( isThereAnotherPersonWithThisName(name) ){
>>
>> //do something HERE
>>
>> }else{
>> pm.makePersistent(person);
>> }
>> ...
>>
>> }
>>
>> ------ Client ---------------
>> (....).fire(
>> new Receiver<Person>() {
>> @Override
>> public void onSuccess(Person person) {
>> Window.alert("OK!");
>> //do stuff
>> }
>> @Override
>> public void onFailure(ServerFailure error) {
>> Window.alert("Fail!");
>> Window.alert(error.getMessage());
>> //do stuff
>> }
>> });
>>
>> --------------------
>> I don't know what I have to do on HERE to make my Receiver go to
>> onFailure. I've tried to throw Exceptions, RequestException, but it
>> only make my server log the error and the response never arrives to
>> the client.
>> Am I missing something here? What would you suggest?
>>
>> Thanks
>
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