XOM API for Processing XML with Java

[Elliotte Rusty Harold <elharo AT metalab.unc.edu>]

At 4:42 PM -0700 9/7/04, Wolfgang Hoschek wrote:


> I'm not convinced either that this is the right API, but do I think 
> that in-memory validation is important and tricky/confusing enought 
> to warrant some built-in help by XOM. How would suggest it should be 
> done? My app would appreciate catching it's own bugs as early as 
> possible, and validating before sending docs onto the network would 
> help here.

Let me also say I'm not convinced it's on the wrong side of 80/20, 
and I'm not convinced your proposal is the wrong API either. Mostly 
right now I'm in feature freeze mode, as I try to get to something 
I'm happy to call 1.0. Something like this I'm not able to see 
immediately whether it's a good thing or not. It requires some 
careful thought and reflection I'm not prepared to do right now. I'll 
put it on the list for further consideration post 1.0.

My initial suspicion is that this shouldn't be part of the core API. 
Instead there should be a separate abstract Schema class in a 
separate package with subclasses for W3C Schemas, RELAX NG schema, 
DTDs, etc. Maybe even a SchemaFactory, but thw whole abstract factory 
design pattern like TrAX and JAXP use just strikes me as insanely 
baroque. This would have a validate method that takes a Document as 
an argument and returns a boolean. I think it should be possible to 
implement this without touching the core of XOM which is why it would 
make a nice third party project. If it couldn't be implemented 
without modifying the XOM core or accessing package private parts of 
nu.xom, then that would indicate a hole in the API somewhere.

Then again, I couldn't be wrong. Serious work on this from me will 
have to wait to post-1.0, but I suspect a third party could implement 
it and publish it as their own extension now. Not everything has to 
go into the core.
--

  Elliotte Rusty Harold
  elharo AT metalab.unc.edu
  Effective XML (Addison-Wesley, 2003)
  http://www.cafeconleche.org/books/effectivexml
  http://www.amazon.com/exec/obidos/ISBN%3D0321150406/ref%3Dnosim/cafeaulaitA