XML and Objects

[David Brownell]

Jonathan A. Borden wrote:
> 
> Now to your specific question, if objects are represented in this fashion,
> you can access members through interfaces (i.e. Java/C++) through get/set
> pairs. A language XML interface layer is needed. This layer is identical to
> COM's dispatch layer which allows COM objects to be used from within
> Javascript and VBScript. COM uses a binary typelibrary as input.

To a first approximation, a type library in COM corresponds to
a Java "Class" object.  Both let you introspect on methods that
are exposed by objects, see interfaces and properties, invoke
methods, and so on.  Used with JNI, you get inter-language calling.
(JNI uses "portable C" -- it's not OS-specific.)


>	 Our
> technique takes the SODL document and
> 
> a) generates a typelibrary from it
> b) employs a custom interface which is driven by the SODL document
> 
>         The advantage of (a) is that it is compatible with existing software
> however the software is limited to Windows.

Building on that correspondence, one could apply this technique with
Java based systems.  A specialized DTD could generate a class file.
Whoops, whoa, don't bother, just use the Java class in the first place...

That is, if you're content to be specific to a given platform (perhaps
Java, perhaps Win32/x86 :-) you can do some very interesting tricks.

BUT ... it may be desirable to design in a platform-neutral way.  Not
to ding any particular platform (certainly not Java!); I just want to
point out that when using XML with Objects, there are lots of tradeoffs.

- Dave


>         XML-DEV would be an excellent place to develop an independent (b) layer
> specification. This spec would certainly need to interface with DOM.

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