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XML and Web Services In The News - 3 October 2006
Provided by OASIS |
Edited by Robin Cover
This issue of XML Daily Newslink is sponsored by SAP
HEADLINES:
The Use of XML Schema for Normative Contributions to W3C Recommendations
John Boyer, IBM Blog
The XML Schema language is a good language for capturing the syntactic
constraints of an XML vocabulary. But let's face it, it is really
designed more for describing data. It's just not powerful enough to be
used for making normative contributions to W3C Recommendations like,
say, XForms. Quite apart from what anyone tells you about the
normativeness of a schema, you can determine that the schema associated
with a recommendation is informative, not normative, if it does not
appear in TR space. This is a subdirectory of the W3 website named 'tr'
and used to publish all technical recommendations of the W3C. In the
case of XForms, the schema lives in the working group space, not TR
space, so it is informative. However, the location of the schema isn't
really the deciding factor for me. Even if a schema did appear in TR
space, it still would only be informative in my opinion because there
are lots of language constraints that you just cannot express in schema
but which are expressed in the recommendation. A number of great
examples of this can be found in XForms, two of which are explained
below. Perhaps the easiest is the use of XPath expressions in XForms.
In the XForms schema, a number of the attributes like calculate and ref
have values that must be XPath expressions... So, in the schema for
XForms, we say that both ref and bind are optional even though that's
not very accurate. Separately, each is optional, but that's only the
half of the story that XML schema can tell. The full story appears in
the normative text of the XForms Recommendation.
See also: on Schema languages
XForms and OpenDocument
J. David Eisenberg, Online Tutorial
This tutorial covers the basic concepts of XForms. You can create form
controls whose data is bound to parts of an XML data instance, and you
can save that data in a local file or send it to a server. The tutorial
provides enough information to start using this new technology. Let's
say you're in charge of a database of chartered clubs for an amateur
sports association. Club directors send you papers like the one in
Appendix A, and you enter the data into an XML file, which is used to
create an online searchable database of the clubs. Clearly, the better
option is to send the club directors a machine-readable document with
form fields that they fill in. The directors send the file back to you,
and, rather than having to decipher their handwriting and re-enter the
data, you run a program to extract the information. The idea of having
a document with user-modifiable fields is not a new one, but
OpenDocument's use of the World Wide Web Consortium's XForms
recommendation is especially noteworthy, because the data that is
stored with the document is in XML format, not in some proprietary
format dependent upon a single vendor's tools. A form in XForms is
described by XML elements. Each form is composed of a model and form
controls. The model contains: (1) Instance data - an XML 'template'
that will be filled in by information in the form controls. (2)
Submission - a description of where the instance data is to be sent and
how it is to be sent. A form can have multiple ways of being submitted;
one to save the data into a file, one to send to a web URL, another to
send to a different URL. (3) Binding - a connection between a node
in the instance data and a form control (text box, drop-down menu, etc),
or a connection between instance data and a constraint in a model item.
XForms is not a stand-alone system; instead, you put the XForms markup
into a document and hand the document to an application that is
XForms aware. Under the guidance of the bindings, the application
handles all the interaction between the controls (which the application
owns) and the instance data.
See also: OpenDocument references
XML Inclusions (XInclude) Version 1.0 (Second Edition)
Jonathan Marsh, David Orchard (et al., eds), W3C Technical Report
W3C's XML Core Working Group has released a Proposed Edited
Recommendation for "XML Inclusions (XInclude) Version 1.0 Second
Edition." Produced as a convenience to readers, the second edition is
intended to correct all known errata in the 2004 XInclude 1.0
Recommendation. Many programming languages provide an inclusion
mechanism to facilitate modularity. Markup languages also often have
need of such a mechanism. The XInclude specification introduces a
generic mechanism for merging XML documents (as represented by their
information sets) for use by applications that need such a facility.
The syntax leverages existing XML constructs: elements, attributes,
and URI references. XInclude differs from the linking features
described in the [XML Linking Language], specifically links with the
attribute value show="embed". Such links provide a media-type
independent syntax for indicating that a resource is to be embedded
graphically within the display of the document. XLink does not specify
a specific processing model, but simply facilitates the detection of
links and recognition of associated metadata by a higher level
application. XInclude, on the other hand, specifies a media-type
specific (XML into XML) transformation. It defines a specific
processing model for merging information sets. XInclude processing
occurs at a low level, often by a generic XInclude processor which
makes the resulting information set available to higher level
applications. Simple information item inclusion as described in this
specification differs from transclusion, which preserves contextual
information such as style.
See also: the W3C news item
XCMTDMW: Element to Element Linking
Eliot Kimber, Blog
What do we mean by "linking" in the context of XML document processing?
[...] Consider a simple XInclude "include" link. This link is
establishing a relationship between itself, the 'xi:include' element,
and the element that is the document element of the XML document named
by the href= attribute. The semantics of the relationship are defined
by the XInclude specification and are "transclude" or "use-by-reference"
... It is also not a link between the document that contains the
xi:include element and the document entity. It is a link from one
element, the xi:include element to another element, the document
element of the document entity named. This is very important and if
you aren't seeing the distinction we need to stop now... XInclude
defines a useful shortcut which is that, by definition (not just by
convention), a reference to a document entity with no explicit XPointer
is a reference to that document entity's document element... During
authoring (that is, during the revision life cycle of the information)
there is a strong requirement for various forms of indirect addressing
in order to avoid the very problem we ran into here: change to a link
target requires changing the link source even though the semantics of
the link were otherwise not affected... Finally, I'll leave you with
one question: what W3C or OASIS or IETF standard provides a mechanism
for doing indirect addressing of XML elements that are not document
elements? I left out ISO because we already know the answer: HyTime
(ISO/IEC 10744:1996).
See also: Dr. Macro's XML Rants Blog series
Nokia Unveils RSS Technology for Phones
Nancy Gohrin, InfoWorld
Web 2.0 is coming to mobile phones, according to Nokia, which has
launched a service that allows Java-enabled phone users to choose
widgets, or small applications, that can be displayed on their phones.
WidSets is a free offering that users can set up on the WidSets Web
site. On the site, customers can choose from many different widgets
that will be displayed on their phones. Widgets usually reside on a
desktop and receive information, such as data delivered via RSS (Really
Simple Syndication). For example, a Google News widget can appear as a
small icon, and when users click on the icon, they can see the latest
headlines that appear on the Google News Web site. Widgets are
considered Web 2.0 applications because they offer an interactive and
customizable service different from more static Web sites. After a
new user signs up, the WidSets site sends an application via text
message to the user's phone. Users must run the WidSets application
and stay connected to the Internet to see the widgets and to allow
the widgets to be updated with new content. The WidSets Web site is
designed to support community input so users can browse for useful
widgets based on community rankings. The service is free for phone
users, although they'll pay associated costs to their mobile operators
for data download. For now, Nokia doesn't have a way to make money
from the offering but in the future the service could support
advertising or Nokia could sell premium content.
IBM Moves to Close Gaps in SOA Offerings
China Martens, InfoWorld
IBM is filling holes in its SOA (service-oriented architecture) product
line-up, notably in the areas of business process management and
industry-specific services. IBM Tuesday made what it billed as its most
extensive rollout of SOA offerings to date, including four new products,
23 enhanced versions of existing software and 11 new services offerings.
IBM positioned the news as demonstrating that the entire company is
focusing its attentions squarely on the SOA space as a revenue driver.
So far, IBM has helped close to 3,000 customers put in place SOA, Mills
said. However, only a "relatively modest percentage" of those users
have been using the SOA approach for a number of years, he added. Mills
stressed IBM's need to be seen by customers as "the" industry provider
of end-to-end SOA capabilities. While there are plenty of small niche
SOA players, IBM mostly competes with Hewlett-Packard when pitching an
SOA portfolio. IBM is investing more than $1 billion in SOA-related
areas this year, he said. One of the four new products IBM unwrapped
Tuesday is WebSphere Business Services Fabric. The software is based on
the technology IBM acquired when it purchased niche SOA player Webify
in August and also draws on services from IBM business partners. The
product includes prebuilt accelerators, tools and frameworks to help
ensure that SOA applications comply with specific industry regulations.
Another new offering is WebSphere Registry and Repository (WSRR) to
help customers manage their Web services and shared business processes.
The software enables users to publish and find SOA services and can
also hook into third-party registries and repositories. The two other
new tools are Tivoli Change and Configuration Management Database and
Tivoli Dynamic Workload Broker.
See also: IBM SOA Resources
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