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From "James Carman" <ja...@carmanconsulting.com>
Subject Re: comments / questions on hivemind 2.0 branch
Date Tue, 07 Nov 2006 13:50:49 GMT
As long as its kind of hidden behind the scenes, I guess it's not that
bad.  But, too much "magic" can tend to freak some folks out.
However, whenever I present HM to folks and I'm able to make the light
bulb come on, they are usually very impressed with all of the magic
that goes on behind the scenes.


On 11/7/06, Knut Wannheden <knut.wannheden@gmail.com> wrote:
> There is one alternative I can think of. The SchemaRegistry service
> could provided a hardcoded (using Java code) Schema for the "Schemas"
> extension point. Then any <contribution> to the "Schemas"
> configuration could be handled the same way as any other
> <contribution>. But of course the contribution would then have to go
> through the SchemaProcessor to create the Schema...
>
> I think all the magic in the XML implementation of the API actually
> warrants some complexity in its implementation. And I think we should
> try hard to keep as much of this complexity out of the framework. Thus
> I don't think either of these approaches would be that bad.
>
> --knut
>
> On 11/7/06, Achim Hügen <achim.huegen@gmx.de> wrote:
> > It think it can be done this way.
> > But now that you pointed out the consequences I'm no
> > longer sure that this doesn't get too complex.
> >
> > Achim
> >
> >
> > Am Tue, 07 Nov 2006 06:20:30 +0100 schrieb Knut Wannheden
> > <knut.wannheden@gmail.com>:
> >
> > > James,
> > >
> > > Good point. I hadn't thought too hard about that but I think it should
> > > be possible to bootstrap that. What we'd have to do is to:
> > >
> > > - Define the SchemaRegistry service using the Java or Java annotations
> > > implementation of the API (as opposed to the XML implementation).
> > > - Modify the existing XML DescriptorParser to handle <contribution>
> > > elements to the "Schema" configuration the same way it handles
> > > <schema> elements, which is to create the corresponding SchemaImpl
> > > object and create a ContributionDef object for it. This
> > > ContributionDef object would although use a ContributionConstructor
> > > from the Java implementation of the API.
> > >
> > > This way the "Schema" configuration would not have a schema itself and
> > > contributions to it would thus not require the "SchemaRegistry"
> > > service in the ContributionConstructor. Also the "SchemaRegistry"
> > > service can be setup without any schema processing if it's defined
> > > using a Java or Java annotations module.
> > >
> > > Does this make sense?
> > >
> > > --knut
> > >
> > > On 11/6/06, James Carman <james@carmanconsulting.com> wrote:
> > >> Aren't you getting into a chicken/egg scenario here?  You need to
> > >> parse the XML to set up the services, but you need the services to
> > >> parse the XML.  Sorry if I'm just jumping in the middle here with no
> > >> context (I haven't been able to check out the new API yet,
> > >> unfortunately), but this just sounded weird.
> > >>
> > >> On 11/6/06, Knut Wannheden <knut.wannheden@gmail.com> wrote:
> > >> > Achim,
> > >> >
> > >> > I think I see what you're getting at. We could solve the whole problem
> > >> > by defining the whole schema and parsing functionality in terms of
> > >> > HiveMind services and configurations.
> > >> >
> > >> > The XML module could thus define a hivemind.xml.Schemas configuration
> > >> > to which configuration and service points can contribute schemas.
> > >> > Either implicitly by a <schema> element or explicitly with a
normal
> > >> > <contribution> element. I suppose a second configuration (e.g.
> > >> > hivemind.xml.ExtensionSchemas) would be needed to define the linking
> > >> > of a schema to specific configuration or service points. Again, the
> > >> > contributions to this would be explicit or implicit.
> > >> >
> > >> > Now a contribution constructor could access a
> > >> > hivemind.xml.SchemaManager service (having the aforementioned
> > >> > configurations injected) to retrieve the schema and / or parser (or
> > >> > also a "pairing") for its configuration point.
> > >> >
> > >> > Does this correspond to what you were thinking?
> > >> >
> > >> > --knut
> > >> >
> > >> > On 11/6/06, Achim Hügen <achim.huegen@gmx.de> wrote:
> > >> > > Knut,
> > >> > >
> > >> > > you are right, SchemaProcessor should be a service
> > >> > > and I would even make Schemas available via a SchemaManager
> > >> > > service too.
> > >> > > To make the parser based contribution possible as defined
> > >> > > in the contributeToFactoryConfig method in the example
> > >> > > (http://annocon.sourceforge.net/manual/configurations.html)
> > >> > > we need a connection between configuration point, parser
> > >> > > and schema. Otherwise the contributor would always
> > >> > > have to specify which parser to use and I want to have a default.
> > >> > >
> > >> > > Achim
> > >> > >
> > >> > >
> > >> > > Knut Wannheden schrieb:
> > >> > > > Achim,
> > >> > > >
> > >> > > > Instead of adding a new construct I think it would be cleaner
to
> > >> > > > expose the parsers as  normal services. The contribution
> > >> constructor
> > >> > > > would then be given access to the appropriate parser (or
any other
> > >> > > > visible service) using the contextual construction parameter.
I
> > >> > > > believe this would already work in your branch.
> > >> > > >
> > >> > > > So in the XML HiveMind module we'd expose the SchemaProcessor
as a
> > >> > > > service which could be used by contribution constructors.
> > >> > > >
> > >> > > > This also turns out to be how it's solved in Tapestry 5.
See 3rd
> > >> > > > example here:
> > >> > > > http://tapestry.apache.org/tapestry5/ioc/configuration.html.
> > >> > > >
> > >> > > > What do you say?
> > >> > > >
> > >> > > > --knut
> > >> > > >
> > >> > > > On 11/6/06, Achim Hügen <achim.huegen@gmx.de> wrote:
> > >> > > >> Knut Wannheden schrieb:
> > >> > > >> >
> > >> > > >> > Maybe we could also drop the support for contributing
to these
> > >> > > >> > configurations using XML. OK, I know this contradicts
what I
> > >> wrote
> > >> > > >> > about backwards compatibility in the other thread,
but maybe
> > >> that
> > >> > > >> > would be OK. I'd like to point out that Howard
changed how the
> > >> eager
> > >> > > >> > loading works in Tapestry 5 IOC. The ServicePointDef
simply
> > >> has a
> > >> > > >> > boolean getEagerLoad() method. How about that?
> > >> > > >> >
> > >> > > >> I think I've found a better solution (borrowed from
> > >> > > >> http://annocon.sourceforge.net/manual/configurations.html)
> > >> > > >> I will introduce a generic parser interface which is
defined in
> > >> the
> > >> > > >> framework
> > >> > > >> already and which is not xml specific. A configuration
can have
> > >> multiple
> > >> > > >> registered parsers.
> > >> > > >> A parser is responsible for the contribution of data
to a
> > >> configuration
> > >> > > >> which is defined in a textual format (especially file
based
> > >> data).
> > >> > > >> The SchemaProcessor then is one special parser which
can process
> > >> > > >> inline data from a hivemodule.xml.
> > >> > > >>
> > >> > > >> The idea is that the creator of a configuration point
says 'ok,
> > >> here is
> > >> > > >> a parser
> > >> > > >> which can read contributions from files' and the provider
of a
> > >> > > >> contribution
> > >> > > >> just says 'ok, then parse that file please'.
> > >> > > >>
> > >> > > >> Pros:
> > >> > > >> + It solves our 'interface or no interface' dilemma.
Since the
> > >> parser
> > >> > > >> concept
> > >> > > >>   is available in the framework the hivemodule parser
can be
> > >> easily
> > >> > > >>   attached by the xml module afterwards.
> > >> > > >> + Configuration data can be defined in external files
(xml,
> > >> > > >> properties etc.)
> > >> > > >> Either the hivemind parsing is extended so that xml
files can be
> > >> parsed
> > >> > > >> that adhere to a hivemind schema or alternative parsers
(e.g.
> > >> Digester)
> > >> > > >> are used.
> > >> > > >> + Better integration of legacy data files
> > >> > > >> + Annotated modules can provide parsers easily (see
annocon
> > >> examples).
> > >> > > >>
> > >> > > >> What do you think?
> > >> > > >>
> > >> > > >> Achim
> > >> > > >>
> > >> > > >>
> > >> > > >>
> > >> > > >>
> > >> > > >>
> > >> > > >>
> > >> > > >>
> > >> > > >
> > >> > > >
> > >> > >
> > >> > >
> > >> >
> > >>
> > >
> >
> >
> >
>

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