No way to cancel in SimpleFormController

[pearsons_11114]

How do you allow a user to cancel a form submission that has errors and fails validation? Some solutions that were suggested in an earlier post:

1. Override suppressValidation. However, since it's final and can't be overriden, I suspect nobody actually tried this. In any case, it only affects the validation not the workflow. There's still no way to capture the user's action and bail out of the form.

2. Separate form for the cancel button using a GET and a different ACTION. This works, but precludes the use of a generic button bar because the cancel ACTION is hardcoded.

3. Use Javascript to achieve the same effect as #2. Work great as long as the browser has Javascript and it's turned on, neither of which you have any control over.

All of the above soutions are pretty hacky, IMHO. The root issue is that the idea of cancelling a form submission isn't part of the workflow. Granted, HTML is brain-dead that way. Traditional forms have submit and reset, but the only way to bail is to have alternate links. My own hack is to derive from AbstractWizardFormController instead where the cancel action is explicitly trapped for.

Anyone have a clean solution to the problem? I may eventually create an alternate SimpleFormController that traps for cancel, but doesn't bring in all the rest of the Wizard machinery.

[irbouho]

You can override processFormSubmission as follows:

  public ModelAndView processFormSubmission(HttpServletRequest request,
                                            HttpServletResponse response,
                                            Object command,
                                            BindException errors) throws Exception {
    String action = request.getParameter(Globals.CANCEL);

    if (Globals.CANCEL.equalsIgnoreCase(action)) {
      return new ModelAndView("cancel");
    }

    return super.processFormSubmission(request, response, command, errors);
  }

Globals is a constants class.
HTH

[pearsons_11114]

And it was even right there in the documentation waiting for me, with this issue as the example use case. Duh. Thanks for the pointer.

[pearsons_11114]

However, it does have the drawback of doing a lot of unnecessary work in the case of a cancel. That was the original poster's objection in the other thread I mentioned. I've looked at the doc and source, but so far haven't figured out a way to bail from processing and redirect to another page before binding and vaildation. Not the end of the world, but would be cleaner to find a way to do this.

[gchanman]

However, it does have the drawback of doing a lot of unnecessary work in the case of a cancel. That was the original poster's objection in the other thread I mentioned. I've looked at the doc and source, but so far haven't figured out a way to bail from processing and redirect to another page before binding and vaildation. Not the end of the world, but would be cleaner to find a way to do this.

I'm new at this. I just ran into the same issue. For example: if the user changes his/her mind on editting the data. Seems a 'cancel' should be part of the form controller and all I would have to do is supply were to go on the cancel. Well I supplied a button (the dirty way):
<input name="cancel" type="submit" class="button" value=" Cancel " onclick="javascript:window.location.href=/wheretheyneedtogo.htm">

Or I could just expect them to use the 'Back Button'.

[smv]

Instead of subclassing SimpleFormController, just subclass CancellableFormController and override one of the onCancel methods or just set cancel view with the "setCancelView" method. This class subclasses SimpleFormController, so you won't have to change anything else in your class. If you're using session forms, this has the benefit of removing your form from the session.

smv