10 Oct
2007
10 Oct
'07
12:25 p.m.
Thanks Philippe
yeh i undestand how the meta-descriptions for an object are built.
it makes sense to use the solution you propose, however i dont want to get rid of the
cache, i like the idea of keeping a cache of built descriptions for an object and each
time new code is deployed the cache has to be manually flushed, by calling #flush on the
default instance of MADescriptionBuilder.
Dale is going implement SystemChangeNotifier soon for, so we can always allow
MADescriptionBuilder to subcribe to systemEvents later.
Does that sound reasonable ?
PS: looking at the squeak implementation it seems that MADescriptionBuilder flushes its
cache of description if any method is changed or modified or added in the entire System,
not necessrily an object in the MADescriptionBuilder cache > Date: Wed, 10 Oct 2007
06:48:18 +0200> From: philippe.marschall(a)gmail.com> To: cappadonza(a)hotmail.com>
Subject: Re: [GS/SS Beta] [betaG/S] SystemChangeNotifier> CC:
beta(a)seaside.gemstone.com> > 2007/10/9, isaiah perumalla
<cappadonza@hotmail.com>:> >> > in squeak there is a class
ystemChangeNotifier, what is the equivalent of> > that in Gemstone/S> > I
don't think you necessarily need one. Some background:> To build a metadescription
of an object Magritte per default only> looks a the class side. It collects all the
selectors the class of the> object contains that begin with 'description' and
performs them. This> can take a moment on Squeak so a cache was added that maps classes
to> metadescriptions. This cache will have to be invalidated if a class is> changed
(a method added or removed).> > A solution for this would be to make a
MADescriptionBuilder for use in> production, this one would not be invalidated
automatically. You would> have to invalidate it whenever you deploy code. It might be
that> building metadescriptions of GemStone in fast enough and you don't> need
any cache.> > Cheers> Philippe> > > ________________________________>
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10 Oct
10 Oct
1:34 p.m.
New subject: [GS/SS Beta] SystemChangeNotifier & MADescriptionBuilder
To build a metadescription of an object Magritte per
default only
looks a the class side. It collects all the selectors the class of the
object contains that begin with 'description' and performs them. This
can take a moment on Squeak so a cache was added that maps classes to
metadescriptions. This cache will have to be invalidated if a class is
changed (a method added or removed).
The cache is only useful if you need to traverse a collection of
thousands of objects that mostly share the same descriptions. Like
this, descriptions don't need to be recreated all the time. This
significantly speeds up the traversal.
PS: looking at the squeak implementation it seems
that MADescriptionBuilder
flushes its cache of description if any method is changed or modified or
added in the entire System, not necessrily an object in the
MADescriptionBuilder cache
This is the simplest thing that reliably works. It could be that you
call other methods from the code that builds the descriptions (for
example, if you extract default values to separate methods), that
could affect the settings of the descriptions. In a productive system
the cache fills up pretty fast. Since code changes in a productive
system are rare this is not an issue.
Lukas
--
Lukas Renggli
http://www.lukas-renggli.ch
1:51 p.m.
New subject: [GS/SS Beta] SystemChangeNotifier & MADescriptionBuilder
Thanks Lukas
So for magritte GemStone port, I will let the MADescriptionBuilder build and cache the
description for objects if it doesnt already exist in the cache and since code chages will
be very rare in a production enviorment, i leave out MABuilderDescription subscription to
SystemChangeNotifer for method chages in the System
Cheers
ISaiah> Date: Wed, 10 Oct 2007 13:34:20 +0200> From: renggli(a)gmail.com> To:
smallwiki(a)iam.unibe.ch; beta(a)seaside.gemstone.com> Subject: Re: [GS/SS Beta]
SystemChangeNotifier & MADescriptionBuilder> > > To build a metadescription
of an object Magritte per default only> > looks a the class side. It collects all
the selectors the class of the> > object contains that begin with
'description' and performs them. This> > can take a moment on Squeak so a
cache was added that maps classes to> > metadescriptions. This cache will have to be
invalidated if a class is> > changed (a method added or removed).> > The cache
is only useful if you need to traverse a collection of> thousands of objects that
mostly share the same descriptions. Like> this, descriptions don't need to be
recreated all the time. This> significantly speeds up the traversal.> > > PS:
looking at the squeak implementation it seems that MADescriptionBuilder> > flushes
its cache of description if any method is changed or modified or> > added in the
entire System, not necessrily an object in the> > MADescriptionBuilder cache>
> This is the simplest thing that reliably works. It could be that you> call other
methods from the code that builds the descriptions (for> example, if you extract
default values to separate methods), that> could affect the settings of the
descriptions. In a productive system> the cache fills up pretty fast. Since code
changes in a productive> system are rare this is not an issue.> > Lukas> >
-- > Lukas Renggli> http://www.lukas-renggli.ch> >
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