The Wiki is a good place for this discussion.

----- Original Message -----
From: "Joseph Panico" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>;
<[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Saturday, July 06, 2002 7:57 AM
Subject: Re: [Tapestry-developer] Assets stored in database


> The fact that there is widespread interest in such an Asset shows that the
> Tapestry design in the area of assets is under-generalized. I don't
believe
> that we should have to write a new class of asset for every new method of
> image (or any mime content for that matter) retrieval that comes along.
The
> dynamic charting demonstration application would not have required a
custom
> asset if Tapestry was properly generalized for image handling and neither
> would the problem of images in a database.

Tapestry uses the assets abstraction to handle a bunch of difficult cases
involving localization
and deployment. but the abstraction is flexible enough for more unusual
cases.

>
> In WebObjects I would not have to write special components and services
> depending on where my images come from or how they are generated.

In Tapestry you don't need new components; you do need a new definition of
asset for assets
that don't fall into the static types provided by Tapestry (external,
context or private).

>
> The retrieval or generation of images needs to be decoupled from the
vending
> of images. The image tapestry component should simply be passed an image,
> regardless of where that image came from. The logic for providing that
image
>   to the View layer should reside in the Control layer.

This is exactly what's going on, except its called "Asset" not "Image".

>
> In my mind, the very name "Asset" is not general enough. An asset implies
> that the resource somehow "belongs" to the application. And indeed, this
is
> true of the resources that Tapestry's asset system is currently designed
> for-- icons and style sheets. But images that are sitting "at large" on
the
> filesystem, and can be manipulated by many different applications, do not
> belong to the Tapestry application. The Tapestry asset system is biased in
> favor of resources that the application knows about at development time.
But
> a properly generalized design would assume that all knowledge of the
> resource would be provided dynamically, and the case where the resources
> "belong" to the application would be a specialization of that general
> system.

Yes, should have called it
"BlobOfPossiblyBinaryDataFromUndisclosedSourceForUseByComponentsAsTheySeeFit
" instead of "Asset". ;-<>

The asset system isn't exactly "biased"; its just that the specifications
allow for easy identification of static assets
and dynamic assets (from a database, generated using JFreeChart, etc.)
simply can't be specified statically.

The containing component Java class, which is the controller (within the MVC
pattern), fulfillls its role by providing the IAsset as a property to the
component it embeds.

Tapestry provides the IEngineService and Gesture mechanisms as an easy way
to provide content for those assets from within Tapestry; though it could
just as easily provide assets that provide content using URLs to servlets or
some other mechanism.

>
> I would really like to generate some discussion about a redesign in this
> area. It's clear from the mailing list that this is one of the most
> frequently encountered shortcomings of Tapestry.

I don't see this as a failing or shortcoming of Tapestry, I see it as an
opportunity to build a vertical framework on top of Tapestry to provide
specialized services of this type.  I see the future of Tapestry as the
creation of more sophisticated frameworks on top of Tapestry, just as
Tapestry is a layer on top of Servlet API.

>
> Joe
>
>
> >From: "LundakJiri" <[EMAIL PROTECTED]>
> >To: <[EMAIL PROTECTED]>
> >CC: <[EMAIL PROTECTED]>
> >Subject: Re: [Tapestry-developer] Assets stored in database
> >Date: Sat, 6 Jul 2002 10:15:05 +0200
> >
> >Adam Greene wrote:
> > > We are actually working on a Database Asset for a project that we are
> >doing.
> > > I can send you the code when we are done.
> >
> >Hi,
> >
> >I would also be very interested in a database asset.
> >Would you mind contributing the code to the community?
> >
> >Regards
> >
> >Jiri Lundak
> >Switzerland
> >
> >
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>
> Joseph Panico
> [EMAIL PROTECTED]
>
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