XML and Objects

[david at megginson.com]

Gregory M. Messner writes:

 > 1) A DTD describes a document which contains content specified by a
 > URL, a local file name, or inline. Documents created using this DTD
 > are assembled and transported across a network. How do you include
 > the content? The 2 ways we have discussed are:
 > 
 >     * Inline using Base64 encoding in a CDATA section

I don't think that you need a CDATA section with Base64 (can someone
confirm that Base64 excludes '<' and '&'?).

 >     * Wrap the document in a multipart/related MIME message
 >       and include the content as attachments

This sounds like a wise choice.  XML packaging is a problem that the
W3C XML Activity has not yet addressed -- experimentation and
implementation experience will be very helpful to them when the time
comes (after all, that's one of XML-DEV's greatest strengths).

 > I am leaning towards multipart/related, but would like to know of
 > others experience in this area.

The key is to use a streaming protocol so that you can start
processing the first files while the rest are arriving.  ZIP is
useless for this purpose, since it keeps the directory information at
the end; TAR is good, as (I think) is CPIO.

 > 2) We desire to provide an API on the client side which exposes a
 > simple mechanism for creating and modifying objects. These objects
 > are serialized using XML and then transported to a server for
 > further processing. The server then responds with another XML
 > document that we then de-serialize into an object and present it to
 > the API user. Here are some basic requirements:
 > 
 >     * Support for both Java and C++
 >     * API must be similar for both Java and C++
 >     * Object members are accessed via get/set methods
 >     * Adhere to JavaBean method naming patterns

The DOM would be a pretty close (and obvious) fit, and has the
advantage of being very close to W3C Recommendation.

 > We are thinking of developing an application which takes a DTD and
 > then generates Java and/or C++ code for each object. We would use a
 > XML helper file to give more control over the generation
 > process. Are we out in left field here? What are some of the other
 > ways to do this? What are you experiences doing something like
 > this?

No, this is a common approach.  Are you going to build the templates
from the DTD itself (I'm not certain that I understand the references
to 'DTD')?


All the best,


David

-- 
David Megginson                 david at megginson.com
           http://www.megginson.com/

xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev at ic.ac.uk
Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/
To (un)subscribe, mailto:majordomo at ic.ac.uk the following message;
(un)subscribe xml-dev
To subscribe to the digests, mailto:majordomo at ic.ac.uk the following message;
subscribe xml-dev-digest
List coordinator, Henry Rzepa (mailto:rzepa at ic.ac.uk)