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From "David Bau" <david....@bea.com>
Subject Re: [xmlbeans-dev] RE: Future XMLBeans feature work?
Date Thu, 18 Sep 2003 23:10:31 GMT
Hi Chris,

Yes; unfortunately there is no open-source XQuery implementation I'm aware
of.  The one we're using from BEA was developed in a different part of the
organization from where I sit; i.e., I don't have any say over their code.

I think it would be a very reasonable and useful thing to for us here to
expand the xpath support that is built-into XMLBeans (I'm noting it on the
wiki).  Later, if or when an open-source XQuery implementation becomes
available (e.g., if people rally together and build one), we can revisit the
entire spec there.


On the fast-and-lossy binding and start-from-java, the value I see we can
bring is in unifying the models.

What I'm after is this:  Sometimes people like binding one way; sometimes
people like binding another way, for valid reasons.  It should be possible
to have chosen one or the other or both in the same application without
regretting it.  The various binding styles should be able to coexist and
interrelate to each other in a seamless way.

E.g., we have folks who are dealing with both pojo binding and XMLBeans
binding for the same schema types, and getting confused that the Java is not
the same even though the schema is.  There should be just one Java type.
Elsewhere we have folks who have been asking "can I change the Java code
corresponding to my schema?" (e.g., they sort of want to "start from both
Java and schema") as well as "can I use my XMLBean within a 101 service" or
"101 types within an XMLBean".  And also... "can I do 101-style binding
while also maintaining full fidelity?" (somehow!)

There is some indication that I'm not the only one seeing these kinds of
issues, since JAX-RPC 2.0 and JAXB 2.0 are both proposing that JAX-RPC
binding be done using JAXB 2.0 and that JAXB 2.0 somehow incorporate the
start-from-Java case.

I actually do believe that if we do things right, we can answer "yes, yes,
and yes" to the questions in that previous paragraph, which is something you
cannot say currently in XMLBeans v1, Axis, Castor, or JAXB 1.

Specifically:

(1) Fast-and-lossy vs full-fidelity does not need to correlate with
start-from-java vs start-from-schema.  It is very useful - and quite
possible - to implement all four grid squares.  (Lossy/Java, Lossy/Schema,
Fidelity/Java, Fidelity/Schema).

(2) The choice between fast-lossy and full-fidelity does not need to be a
compiletime decision. It is possible and desirable to make it a runtime
decision.

In other words, you should be able to use the same Java type to bind to a
specific schema type no matter what your performance/fidelity tradeoff is.
When you are writing an instance editing tool, you can load it with a "full
fidelity" option; and when you're writing a high-throughput processor you
can load it with the "fast and lossy" option.  Both tools can use common
utility classes that deal with your bound data once via a single API, rather
than twice, once for a "fast" binding and one for a "full" binding.

The idea is that if there is a unified binding approach, you don't need to
write your app twice just because sometimes you want different performance
or round-tripping characteristics.

(3) The choice between start-from-schema and start-from-java should not be a
global black-and-white decision.  You should be able to mix and nest
start-from-schema types and start-from-java types.  There should be a
mechanism for starting-from-schema and customizing the Java, or starting
from the Java and customizing the schema.


Make any sense?  The value I'm looking for is not in the ability to do
start-from-Java binding itself, but in having it unified with all the other
kinds of bindings that you can do.

David





----- Original Message ----- 
From: "Chris Maeda" <chrismaeda@comcast.net>


I would most interested in seeing XQuery support
added / restored to XMLBeans V2.



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