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Bob Wyman wrote:
> Just as XML works well in both "schema-based" and
>"schema-free" environments, it is critical that any alternative binary
>encoding do the same. But, it is also useful to recognize that when
>you're working with XML, you are never really in a "schema-free"
>environment... Even if you don't have an application-specific schema,
>you've still got the schema for XML itself -- the InfoSet [5].
> If you have an application-specific schema, you can do all
>sorts of optimizations in the binary encodings and get really great
>compression as well as parsing efficiencies based on your knowledge of
>the schema. When working with the Infoset alone, you can't get quite
>as much benefit from a binary encoding, but for many (not all)
>applications the benefit will still be great enough to justify the
>effort. For instance, you won't get as much compression with an
>Infoset based encoding, but you'll still usually benefit from having
>counted length strings and other benefits that make parsing more
>efficient. (We exploit these efficiencies at PubSub.com, for more
>info see [1] below.)
>
>
I'm well aware of Infoset-based encodings, since my own XBIS project
(http://www.xbis.org) is one of them. I was curious how ASN.1 deals with
data at the Infoset level, rather than schema-specific versions.
I didn't see anything about this in a quick look through the references.
Sun claims both schema and Infoset support for "Fast Web Services" in
the "Binary Interchange of XML Infosets" report
(http://www.idealliance.org/papers/dx_xml03/papers/05-01-02/05-01-02.html)
but doesn't mention the Infoset at all in the paper describing this
(http://java.sun.com/developer/technicalArticles/WebServices/fastWS/). I
find their specific results of dubious use, but don't doubt that when a
specific schema is known it's possible to get better results (in terms
of both data size and processing speed) for an encoding that matches the
schema rather than a general Infoset encoding.
- Dennis
--
Dennis M. Sosnoski
Enterprise Java, XML, and Web Services
Training and Consulting
http://www.sosnoski.com
Redmond, WA 425.885.7197
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