Java class != XML entity

David G. Durand dgd at cs.bu.edu
Wed Aug 12 19:21:27 BST 1998


At 1:45 PM -0400 8/11/98, David Megginson wrote:
>David G. Durand writes:
>
> [writing about scoping in Java classes]
>
> > The equivalent to this policy for XML would be for the "minimization
> > declarations" to be local to the _entity_.
>
>Reasonable people may disagree: many of us believe (from SGML
>experience, especially) that entities are simply slightly-constrained
>storage units with no other special significance -- if Java had
>#include files, then those would be the equivalents of XML entities.
>As far as I may be allowed to compare tropical and temperate tree
>fruit, the equivalent of a Java class is a complete XML document.

I was writing about Java source files, the relevant scoping region for
package declarations. A Java file is a _compilation_ unit, not a class,
since it is possible (if not favored practice) to put several classes into
one source file. I agree that entities and include files are somewhat
similar, and that explains some of the problems with entities: potential
name clashes or namespace prefix capture by the entity referencing context.

Part of my point is in direct agreement with your point; all such analogies
are hazardous and should be treated like radiactive material -- potentially
useful, and potentially deadly.

People _do_ however, use entities as a mechanism for reuse, and they were
designed for reuse. I think that local scoping can enhance that kind of
reuse by allowing a declaration that only needs limited scope to be tightly
bound to that scope, and also by ensuring that the declaration does not
affect other portions of the document.

>The problem is that we don't have a good name for a collection of XML
>documents working tightly together, the way that a collection of Java
>classes can work in an applet or application -- "web" seems too loose,
>and "docuverse" seems too New-Age.  Any suggestions?

This is an old question. I find the HyTime term "BOS (Bounded Object Set)"
rather opaque. Docuverse is not really correct, since that term was coined
by Nelson to describe the total interlinkined machine readable literature
of the planet. Currently, the Web itself is a nascent docuverse.

Web was the historical term in the HT research community, but its use as
synonym for World Wide Web would cause lasting confusion if we adopted it
in its original sense.

I wasn't able to come up with a good name. I like "nest", or "tangle".

One of the problems is that the notion in question isn't necessarily all
documents linked directly or indirectly from some (set of) starting
point(s). It's a set of documents (including sets of independent links)
that should be processed together, or should at least be simultaneously
available.

I suspect the final term will follow the evolution of an actual authoring
practice.

The term "web site" already hasmuch of the meaning in question, as it does
not _necessarily_ map into a single server or URL, but rather to a set of
documents provided with a single purpose and (usually) having a
well-defined starting point. Personal web sites are often just a
sub-directory on a larger school or ISP server, while corporate web sites
may involve hundreds of servers on many continents.

  -- David


  -- David

_________________________________________
David Durand              dgd at cs.bu.edu  \  david at dynamicDiagrams.com
Boston University Computer Science        \  Sr. Analyst
http://www.cs.bu.edu/students/grads/dgd/   \  Dynamic Diagrams
--------------------------------------------\  http://www.dynamicDiagrams.com/
MAPA: mapping for the WWW                    \__________________________



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