[jsr-314-open] [JSF2.NEXT] Converers on Input/Output components.

[Kito Mann]

+1

How does Seam implement this?
---
Kito D. Mann | twitter: kito99 | Author, JSF in Action
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On Thu, Dec 10, 2009 at 1:26 AM, Lincoln Baxter III <lincolnbaxter at gmail.com
> wrote:

>  Converters are a great tool, and I use them all the time -- problem is, I
> sometimes need to use more than one converter (rich text processing, for
> example) and that leaves me having to write my own converter chain class,
> instantiating that class in a bean, then binding it to my Facelet component
> through EL.
>
> This seems like a lot of work, when what I'd really like to see is chaining
> support out of the box. I see two potential issues to prevent this:
>
>     Object -> String
>
>     String -> Object
>
> Right now, chains only operate on strings. which could cause some
> confusion, potentially, but I see reasons to enable multiple converters per
> component, and convert (in list style) in the order in which the converters
> were added.
>
> We allow multiple validators, but not multiple converters. This caveat
> recently bit me as Kito found out, I was converting URLs into <a>  tags as
> part of a comment output component. In order to accomplish this, I was
> disabling encoding on the component itself, so that the converted output <a>
> tag would not be rendered as text. I had attached a converter prior to the
> link converter that was supposed to take care of the escaping. Problem is...
> the last converter added in the Facelets file wins because only one is
> allowed, so my site was (until I fixed it) vulnerable to XSS attacks - a BIG
> problem.
>
> I propose adding converter chaining, by default, to UIComponent. In effect,
> turning converters into filters. This isn't a hard change, doesn't add much
> complexity, but does fix one of those things that people end up having to do
> themselves (Seam provides a ConverterChain, and I did some Googling to find
> that many other people are doing this themselves.) This is low hanging fruit
> that we can pick.
>
> Thoughts?
>
> ---
> Lincoln Baxter, III
> http://ocpsoft.com
> http://scrumshark.com
> "Keep it Simple"
>
>
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