[seam-dev] Module reviews

[Lincoln Baxter, III]

> I don't see how or why it assumes that. Why could I not have multiple
> validators which all specified that they belonged to the same form?

I think I was having a bit of a dyslexic day all around...

On Mon, Jun 14, 2010 at 11:57 PM, Lincoln Baxter, III <
lincolnbaxter at gmail.com> wrote:

> Hehe :)
>
> I'm in favor of the @FormValidator(...) annotation. Sold, for an
> annotation.
>
> --Lincoln
>
>
> On Mon, Jun 14, 2010 at 8:19 PM, Gavin King <gavin.king at gmail.com> wrote:
>
>> P.S. shouldn't FormValidator be called ActionForm?
>>
>> *ducks*
>>
>> On Tue, Jun 15, 2010 at 2:17 AM, Gavin King <gavin.king at gmail.com> wrote:
>> > On Mon, Jun 14, 2010 at 5:23 PM, Lincoln Baxter, III
>> > <lincolnbaxter at gmail.com> wrote:
>> >
>> >> Unfortunately, this assumes the existance of only 1 FormValidator per
>> form,
>> >> which is likely not the case in many scenarios;
>> >
>> > I don't see how or why it assumes that. Why could I not have multiple
>> > validators which all specified that they belonged to the same form?
>> >
>> > Or are you trying to say that it encourages one form per form
>> > validator? (That's not what you wrote.)
>> >
>> >> It encourages breaking
>> >> separation of concerns (where now you have only 1 validator handling
>> >> multiple scenarios per form -- if you do have multiple scenarios-- and
>> many
>> >> different combinations of fields that may or may not be related.
>> >
>> > So the intention here is that you would create reusable form
>> > validators that would attach to common, repeated combinations of input
>> > fields that appear in many forms? This seems deeply, deeply doubtful
>> > to me. It seems that in this case you should be composing a reusable
>> > JSF component out of the smaller fields and attaching a single
>> > validator to it. Cross-field validation is usually something that is
>> > very specific to a single form in the application, in my experience.
>> >
>> >> This also
>> >> breaks re-use of FormValidators by hard-binding form field IDs to
>> validator
>> >> field names.
>> >
>> > Again, I don't see that cross-field validation is something that is
>> > often reusable. On the contrary, it's highly uncommon to see repeated
>> > combinations of fields in several different forms, and when you do see
>> > it, it's usually a case where you should factor out some higher-level
>> > control (like a datetime control or whatever).
>> >
>> > I'm not saying that it's unimaginable, just that it's not at all the
>> > common case.
>> >
>> >> There is also the danger of bleeding across views, where a
>> formValidator is
>> >> created that "accidentally" becomes attached to another form with the
>> same
>> >> name on a different page, or when you want to use the same form-name,
>> but
>> >> can't because you will automatically trigger form validation (that
>> would
>> >> likely fail (forcing you to disable it in some way, or choose a
>> different
>> >> name.)
>> >
>> > That all sounds totally trivial to solve via a combination of view id
>> > and form id.
>> >
>> > @FormValidator(view="login.jsf", form="loginForm")
>> >
>> >> This could also have the undesired effect of attaching validators that
>> are
>> >> not intended to be form validators (perhaps validators that were not
>> even
>> >> defined by the developer themselves -- e.g.: included in a JAR file.)
>> >
>> > huh?
>> >
>> >> Does this feature really buy us much?
>> >
>> > Well, it lets you encapsulate all the information about the form
>> > validator in exactly one place, saving you the need to add a special
>> > tag to your JSF page. And keeping all information about validation
>> > outside of the view definition (which is the case with single-field
>> > validation via bean validation annotations). Now, I would not argue
>> > that this is something super-important from a software engineering
>> > perspective, but it certainly looks clean and is convenient in the
>> > common case. When I looked at the <formValidator/> tag in the JSF
>> > view, it looked anything but clean. I'm talking pure aesthetics here.
>> >
>> >
>> > --
>> > Gavin King
>> > gavin.king at gmail.com
>> > http://in.relation.to/Bloggers/Gavin
>> > http://hibernate.org
>> > http://seamframework.org
>> >
>>
>>
>>
>> --
>> Gavin King
>> gavin.king at gmail.com
>> http://in.relation.to/Bloggers/Gavin
>> http://hibernate.org
>> http://seamframework.org
>>
>
>
>
> --
> Lincoln Baxter, III
> http://ocpsoft.com
> http://scrumshark.com
> "Keep it Simple"
>



-- 
Lincoln Baxter, III
http://ocpsoft.com
http://scrumshark.com
"Keep it Simple"
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