Avoiding double form submission at server side

[Matias Blasi]

Hi!

I'am researching about the best way to avoid the double form submission at
the server side.
I was trying with a persistent flag

boolean onPrepareForSubmit() {
    return !this.processing;
}

Object onSuccess() {
    this.processing = true;
// do stuff
    this.processing = false;
return this;
}

I was disapointed when I saw that the 'Succes' event is fired even when the
prepareForSubmit handler returned false.

Any suggestion?

Regards,
Matías.