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XML and Web Services In The News - 20 February 2006
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Edited by Robin Cover
This issue of XML.org Daily Newslink is sponsored by SAP
HEADLINES:
XML and Web Services In The News - 20 February 2006
ADL-R: The First Instance of a CORDRA Registry
Henry Jerez, et al., D-Lib Magazine
The Advanced Distributed Learning Registry (ADL-R) is a newly
operational registration system for distributed e-learning content in
the U.S. military. It is the first instance of a registry-based approach
to repository federation resulting from the Content Object Repository
Discovery and Registration/Resolution Architecture (CORDRA) project.
Registry submissions consist of metadata assertions about particular
content objects. These metadata instances are a combination of local
community metadata and global federation or CORDRA level metadata. The
registry must distinguish these metadata layers, therefore the main XML
submission has two main components following two different XML schemas:
(1) The Registry Submission Schema, specifically known in ADL as the
ADL-Reg-T Submission; (2 The Community Metadata Schema, which implements
the LOM approach in ADL-R. Additional characteristics of each metadata
layer are captured by means of business logic modules at both the
Registry/CORDRA level and the Local/Community level. The ADL-R
architecture ensures modularity and scalability by dividing its
operations among several interoperable modules that perform very specific
tasks and present well-defined APIs, and communicate in standard fashion
using XML schema enforced messages. This article provides a brief
overview of CORDRA and detailed information on ADL-R; a related article
in this month's issue of D-Lib Magazine describes FeDCOR, which uses
the same approach to federate DSpace repositories.
FeDCOR: An Institutional CORDRA Registry
Giridhar Manepalli, et al., D-Lib Magazine
FeDCOR (Federation of DSpace using CORDRA),
based on the CORDRA model,is a registry-based federation system for DSpace instances.
DSpace isa repository system designed to capture, store, index, preserve and
redistribute content in various digital formats. Building a federation
of DSpace repositories using a CORDRA compliant registry serves two
purposes: (1) A federation for DSpace repositories; (2) A CORDRA
registry from the library community. The Registry Engine, through its
main programming component, Registry Lib, is the core library that
coordinates the enforcement of business rules, executes operations,
and defines structural components in FeDCOR. The metadata accessed from
institutional repositories is stored inside digital objects held by the
registry. In ADL-R, the validation module validates the entire
submission to check for XML compliance first, and then for adherence
to the registry and community business rules. In FeDCOR, the community
business rules are enforced by the DSpace repositories, so FeDCOR only
needs to validate the registry business rules and does not use the
community business rules validator. The FeDCOR architecture preserves
most of the original ADL-R components, but adds the first implementation
of an Institutional Repository Registry, and an intelligent population
agent and plug-in that make the registration process automatic. The
result is a useful and relatively seamless CORDRA federation of DSpace
repositories that reuses most of the original ADL-R code and provides
a different community registry with a set of basic CORDRA Services.
Newsmaker: Ending Microsoft's Identity Crisis
Ina Fried, CNET News.com
Kim Cameron is the identity expert who leads Microsoft's current
InfoCard development. Microsoft Chairman Bill Gates recently touted
InfoCards as one of the technologies that could finally help cement
the death of the username and password as the means of verifying
identity on the Internet. But before InfoCard can supplant anything,
Microsoft will have to line up Web sites to use it, banks and credit
card companies to support it and then get consumers to buy in, too.
[InfoCard] is built on standards that a lot of companies have adopted,
Web services standards. It's really a precise collection of standards:
WS-Trust, WS-Security, WS-Security Policy... [Cameron says]: "This is
not positioned against Liberty. I am an admirer of Liberty. Liberty
has done a lot of great things around policy, leadership on federation.
This is something that a Liberty-enabled site can use for interacting
with their customers. Now, in terms of WS standards and Liberty,
currently Liberty runs on the SAML (Security Assertion Markup Language)
protocol, and WS standards are slightly different, although they share
components. We're also working to try and align those things. But
those things don't impact InfoCard."
See also:
InfoCard resources.
WikiCalc: Software Pioneer Bricklin Tackles Wikis
Daniel Terdiman, CNET News.com
In 1979, Dan Bricklin released VisiCalc, the first spreadsheet for
personal computers. Now he's close to finishing the beta for WikiCalc,
an open-source, browser-based collaboration tool that mimics the
functionality of a spreadsheet while leveraging the technology of wikis,
which let anyone, anywhere manipulate data across the Web. Currently
in alpha — though a stable beta version is expected by the end of
February 2006 — WikiCalc is a general purpose tool developed with
AJAX that runs either locally or off a server on Windows, Mac OS X,
Unix or Linux. WikiCalc is designed to let people enter, store and
modify data in the tabular format with which so many Excel, Lotus
1-2-3 and, yes, VisiCalc users are familiar. According to Ross
Mayfield, "WikiCalc is the answer to a problem that has been
percolating for some time in the world of IT: that spreadsheets have
traditionally been a single-user application screaming for
functionality that could let multiple people edit data quickly and
easily... How do you track changes on a spreadsheet? What happens
if you don't have just two people going back and forth, (but) have a
finance department of 40 people trying to roll up numbers?" Bricklin's
answer is to make it possible for anyone using WikiCalc to enter data
and for anyone else to edit that data and have those edits be reflected
on everyone's computers instantaneously. You could use it as an
authoring tool without having anything more than a hosting account
from your ISP.
Last Call: for Web Services Addressing WSDL Binding
Martin Gudgin, Marc Hadley, Tony Rogers, Umit Yalcinalp (eds), W3C WD
W3C's Web Services Addressing Working Group has released a Last Call
Working Draft for "Web Services Addressing 1.0 - WSDL Binding. Comments
are welcome through March 31, 2006. The "Web Services Addressing 1.0 -
Core" specification defines a set of abstract properties and an XML
Infoset representation thereof to reference Web service endpoints and
to facilitate end-to-end addressing of endpoints in messages. This
last call draft for "Web Services Addressing 1.0 - WSDL Binding"
defines how the abstract properties defined in Web Services Addressing
1.0 Core are described using WSDL. WS-Addressing is designed to be
able to work with WSDL 2.0 and also, for backwards compatibility, with
WSDL 1.1 described services.
See also:
the W3C news item.
A Step in the Right Direction: VTD-XML Improves XML Processing
Jimmy Zhang, DevX.com
This article describes how a next generation XML processing API goes
beyond DOM and SAX in performance, memory usage, and ease-of-use.
VTD-XML is an open source XML processing API optimizing: (1) Random
Access: VTD-XML is designed to be random-access capable and natively
supports XPath; (2) Performance: VTD-XML's performance is typically
between five to ten times faster than DOM's and one and a half to two
times that of SAX with the Null content handler. On a 3400+ Athlon
machine, the expected performance is 50MB/sec to 60 MB/sec, easily
making it the fastest XML parser in the world; (3) Memory Usage: The
memory that VTD-XML consumes is typically 1.3 to1.5 times the size of
the XML document — a reduction of 30 to 45 percent[3x to 5x] over DOM;
(4) A Simple and Intuitive API: VTD-XML also features an easy-to-
understand, cursor-based API significantly simpler than DOM's
node-based API. The basic concept is simple: VTD-XML tokenizes XML by
recording offsets and lengths according to a binary encoding
specification called Virtual Token Descriptor (VTD), while retaining
the XML document as is in memory (which takes up the one in the 1.3
times memory size of VTD-XML). VTD records are 64-bit integers that
encode the lengths, offsets, nesting depths, and types of XML tokens.
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