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From Fedor Karpelevitch <fe...@simpata.com>
Subject RE: Jasper Name Mangling Question - repost
Date Mon, 12 Jun 2000 21:16:54 GMT
is there really a need for class names to be calculated off jsp name. If
this is not required then I would suggest that class files are named  with
sequential numbers. for exaample jsp1.java; jsp2.java;... ;jsp10.java;
jsp11.java etc... . And then have a hash table with jsp name as the key and
the class name as the value. This way file names will stay short enough. I
hope overhead of searching the hashtable is not too bad. Does this make
sense?

WBR, Fedor. 
 
Today: If builders built buildings the way programmers wrote programs, the
first woodpecker that came along would destroy civilization. (Weinberg's
Second Law)


> -----Original Message-----
> From: MANDAR RAJE [mailto:mandar@pathfinder.eng.sun.com]
> Sent: Monday, June 12, 2000 1:40 PM
> To: tomcat-dev@jakarta.apache.org
> Subject: Re: Jasper Name Mangling Question - repost
> 
> 
> Steve Appling wrote:
> > 
> > Jasper's JSP name mangling is causing me some problems, but 
> I don't know if it
> > is operating in this fashion by design or because of a bug. 
>  I'm using the 3.1
> > release.
> > 
> > When compiling a JSP, jasper creates a directory structure 
> under my scratchdir
> > that mimics the path to my jsp (as expected).  It then 
> creates the java source
> > file (and resulting class) in the root of the scratchdir in 
> a mangled form
> > (including substituting the "/" in the path with "_0002f"). 
>  Between mangling
> > the "/" and "_" characters, the resulting file names are 
> often too long to
> > create
> > under Win98 (>256 chars).
> 
>  I have seen this particular problem mentioned before. What we need
> (maybe) is a simple fix -- one that (for example) ignores '/' and
> '-' characters. This will not gurantee a unique class name, but
> probability of having name collisions will still be very low, also
> making the file name relatively smaller. 
> 
> 
> > 
> > Why does jasper create a directory structure under the 
> scratchdir and not use
> > it?  It would seem to be better to put an unmangled file 
> name in the appropriate
> > directory.
> 
>  The main reason is that Jasper needs to compare the time-stamps
> and constructing a proper path name to the class file to find out
> "last-modified time" at runtime is somewhat expensive. Ofcourse
> things can be cached -- maybe one of the to-do things.
> 
> > 
> > It is also not clear to me why the generated classes have 
> the appended version
> > numbers.  Is it necessary to keep multiple versions of the 
> same jsp loaded
> > simultaneously for some reason?  If the generated java file 
> name / class file
> > name / class name were the same, then the 
> ClassFileData.findClassName call
> > wouldn't be so expensive - it wouldn't have to parse the 
> class file data to
> > determine the class name.
> > 
> > This all seems overly complicated - I must be missing 
> something.  I would
> > appreciate any clarifications.
> 
>  This is to support JSP reloading. If you modify a JSP, you use
> a different version number and generate a different 
> class which can then be loaded (A class with the same name can't
> be loaded if its been loaded before).
> 
> Thanks,
> Mandar.
> 
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