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From "Howard M. Lewis Ship" <hls...@comcast.net>
Subject RE: [HiveMind] Question about HiveMind scope and purpose
Date Tue, 08 Jul 2003 20:03:55 GMT
HiveMind is being very, very actively developed.  I've been putting a lot of info onto my blog:
http://www.freeroller.net/page/hlship/Weblog

I feel HiveMind is entering a more stable stage after its chaotic birth.  I believe it is
just about
at the point where other interested parties might want to join in the fun!

As I've mentioned before, HiveMind is something of an experiment.  A chance for me to learn
Maven,
to establish a project properly within Jakarta and so forth.  Hey, I finally learned some
XSL!

I realize that some aspects of Avalon and HiveMind overlap.

I think our goals are a bit different.  HiveMind is intended to form a lower-layer; Avalon
is a
services container, HiveMind is a services and configuration microkernel.  The majority of
HiveMind
is related to building and contributing configuration elements.  HiveMind expressly does not
have
the same kind of Inversion of Control that Avalon has; IoC or not is left to the developer.
 Avalon
(or at least the Avalon containers I researched) require more explicit connection of services.
 I
did not see anything akin to an Eclipse plugin model for handling configuration ... that's
HiveMind's strong suit ... HiveMind's "assembly" stage occurs dynamically, at runtime.

I know it sounds like "not invented here" syndrome, but I had a short window of opportunity
to put
something together, keep it open-source, but use it in a very large scale project at work.
 In this
situation, it was faster, easier and politcally safer for me to build it myself than it would
be to
take the time to fully grok and adapt Avalon.  Additionally, a key requirement for me is line
precise error reporting [*]; this is a major amount of work to graft into an existing code
base.

Ultimately, I see HiveMind fitting in below Avalon; perhaps it may be adopted as the way in
which
the Avalon container is configured, rather than the way services hosted within the Avalon
container
are configured.

[*] In Tapestry, and now in HiveMind, XML configuration files are read and converted into
"descriptor" objects, which are then used to create runtime objects.  In Tapestry, it's component
specifications used to create components and pages and such.  In HiveMind it is more open-ended.
The line precise bit is: when the XML files are read, the exact location (file, line and column)
for
each descriptor object is recorded as a property of the object.  When the descriptor object
is used
to create a runtime object, this location property is applied to the runtime object.  The
end result
is that exceptions in the runtime objects, long after files have been parsed, can be related
back to
exact locations within the input files.  You don't have to sleuth it out from a stack trace,
a
property of the exception will be the exact location to look.  This works out to be a tremendous
productivity boost ... you spend very little time guessing at problems, instead the framework
directs you to the exact problem.  This is all combined with exceptions that include a location
property, and Tapestry's exception reporting mechanism is capable of displaying those location
properties.

One of the reasons I've been rolling out HiveMind is to seperate this very useful functionality
from
Tapestry.  In fact, Tapestry 3.1 will move a lot of code from Tapestry to HiveMind.

--
Howard M. Lewis Ship
Creator, Tapestry: Java Web Components
http://jakarta.apache.org/tapestry



> -----Original Message-----
> From: Martin Cooper [mailto:martinc@apache.org] 
> Sent: Tuesday, July 08, 2003 3:17 PM
> To: Jakarta Commons Developers List
> Cc: hlship@apache.org
> Subject: Re: [HiveMind] Question about HiveMind scope and purpose
> 
> 
> 
> 
> On Mon, 7 Jul 2003, Berin Loritsch wrote:
> 
> > Berin Loritsch wrote:
> >
> > > Someone pointed out to me that there is a Commons Sandbox project 
> > > called HiveMind, and according to the docs at 
> > > 
> http://cvs.apache.org/viewcvs.cgi/jakarta-commons-sandbox/hive
mind/x
> > docs/index.xml
> >
> > it sounds a *lot* like Avalon.
> >
> > Instead of reinventing the wheel, what about collaborating with the 
> > Avalon team to correct what you feel are deficiencies and work from 
> > there.
> >
> > The Avalon team is in a place where they are evaluating what they 
> > have, and where they want to go from there.
>
> Is HiveMind in active development?  Any interest at all?

It seems to be in development, but only by hlship. I suspect he isn't on this list, so I'm
cc'ing
him to see if we can provoke a response. ;-)

--
Martin Cooper


>
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