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From "Daniel S. Haischt" <daniel.hais...@daniel-s-haischt.biz>
Subject AW: [A5:RT] Minimum J2ME Specs and Strategy
Date Mon, 06 Jan 2003 16:07:58 GMT
regarding the 5 - 10 minutes startup time:

 - i did not pay attention that you were asking
   whether it would speed things up if each XML
   descriptor would be compiled into bytecode.

   in that case i would say, that the startup
   time would be something about 0.5 - 1.0 minutes.

   allthough you need to stay within the 100K - 200K
   memory limit (container + app). but that could
   be only figured out by programing a A5 container
   J2ME prototype which could be tested within the
   Sun Wireless Toolkit 2.0.

regards

daniel s. haischt
--

> -----Urspr√ľngliche Nachricht-----
> Von: Berin Loritsch [mailto:bloritsch@citi-us.com]
> Gesendet: Montag, 6. Januar 2003 16:04
> An: 'Daniel S. Haischt'
> Betreff: RE: [A5:RT] Minimum J2ME Specs and Strategy
>
>
>
> > From: Daniel S. Haischt [mailto:daniel.haischt@daniel-s-haischt.biz]
> >
> > hello,
> >
> > > Von: Berin Loritsch [mailto:bloritsch@citi-us.com]
> > >
> > > I am trying to propose something that does not require the
> > > existence of an XML parser.  I.e. the XML descriptors that
> > > you develop with are compiled into bytecode for the J2ME
> > > systems.  With a concrete class that has hard coded return
> > > values, you don't need an XML parser.
> >
> > i am working for a client, that is trying to do exactly the same.
> > they are defining GUI interfaces (SWING/AWT/MIDP) using XML files.
> > the GUI interface will be build dynamically by using the XML file.
> >
> > the problem is - reading XML files on a MIDP (Palm etc.) device is
> > a real performance drawback. so the only solution is to write a parser
> > that reads the XML descriptors and compiles them into Java bytecode.
>
> Right.  That is the solution I am proposing as well.
>
>
> > > >     i am now developing about three years with J2ME and it was
> > > >     allways a challenge to bring both, business logic and the
> > > >     app server, on a MIDP device. for example, if you manage to
> > > >     run both the container and the app on a Palm Pilot (which
> > > >     supports MIDP), there would still be the raimaining problem
> > > >     that it takes about 5 - 10 minutes to start the whole thing.
> > >
> > > That is a problem.  Do you know what it is that causes the 5-10
> > > minute startup time?  If we generate classes from descriptors that
> > > effectively control the component according to the descriptors--
> > > but with the constraint that it cannot be changed, wouldn't that
> > > speed things up tremendously?
> >
> > the proplems are ...
> >
> >  1) omit reading XML files on MIDP devices if possible.
> >     just consider that if you are accessing a SOAP driven
> >     web service using a cell phone, the user has to pay
> >     for the time the app needs to parse the SOAP envelops
> >     which were sent over the wire.
>
> Right.  That is an App specific requirement that the Avalon user
> needs to be aware of.
>
>
> >  2) don't read a XML file at once. instead read each node as
> >     needed. if node A references node B, read node A but not
> >     node B. just store the reference to node B and resolve it
> >     if the app needs to access node B.
>
> Again, this is only if you use XML in the runtime.
>
> >  3) another problems are validating parsers. for example if
> >     you are using XML descriptors that need to be validated
> >     against a DTD/Schema, you will definitly experience some
> >     performance issues.
>
> In a constrained environment, I am sure that more logic will
> be placed on the server to ensure proper validation than on
> the client.  But again this is only if you use XML in the
> runtime--and I want to get away from the misconception that
> it is a requirement in order to use Avalon.
>
>
>
>



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