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XML and Web Services In The News - 25 July 2006
Provided by OASIS |
Edited by Robin Cover
This issue of XML Daily Newslink is sponsored by BEA
HEADLINES:
Power Your Mashups with XQuery
Ning Yan, IBM developerWorks
Web 2.0 applications, which offer users a more dynamic experience,
often use Asynchronous JavaScript and XML (Ajax). Once you load a
master HTML document, you can use Ajax to update Web content without
refreshing the whole Web page. With Ajax, you can treat Web content as
data fragments, pulling in each on demand. In addition, client-side
JavaScript processes can format the data on their own, whether using
data in plain-text, XML, JavaScript Object Notation (JSON) objects, or
HTML fragments. The new paradigm of Web application development goes
far beyond the traditional Model-View-Controller (MVC) model.
Unfortunately, many Ajax Web application frameworks, such as Direct
Web Remoting (DWR) and JavaServer Faces (JSF), can present challenges.
Although Ajax frameworks can simplify application development in many
ways, the mechanism of the framework more or less controls the Web
content. Many existing Ajax frameworks don't provide universal
solutions that can handle real-world complexity, especially with the
increased requirements for data aggregation from XML and content
syndication from RSS feeds. These new requirements dictate the needs
for effective Web service support on the server side. This article
shows how to create a mashup application that uses XQuery, a promising
technology that deals with Web services and XML.
Tsunami Warning Markup Language (TWML)
Renato Iannella and Karen Robinson, NICTA Technical Report
This draft standards-based language for Tsunami Bulletins has been
prepared by members of National ICT Australia (NICTA) and was posted
to the mailing list of the OASIS Emergency Management Technical
Committee. The document seeks to establish structured semantic data
models for tsunami bulletins. It illustrates the use of EDXL-DE
(Emergency Data Exchange Language Distribution Element) as an example
distribution mechanism. The authors anticipate that the language will
be used with EDXL-DE and with the OASIS Common Alerting Protocol (CAP)
Standard. In this draft, selected concepts are also used from the
Open Geospatial Consortium's Geography Markup Language specification.
The TWML schema imports the XML namespace for GML — the Geography
Markup Language [RDDL namespace document], and the editor notes that
additional use of GML in the language is planned for the next release
of TWML.
See also: the OASIS TC
Names and Addresses
Norm Walsh, Blog
The author takes another wack at a permathread in web architecture.
A new URI scheme is not necessary to, nor does it actually, solve the
perceived problem of names and addresses. Time and again, we see
individuals and organizations inventing new URI schemes in order to
tackle the problem of 'names' versus 'addresses'. That is, they want
to provide some sort of a globally unique identifier for 'This Thing'
independent of where representations of that thing might reside.
Almost inevitably, these individuals and organizations fall into the
trap of thinking that an 'HTTP' URI is somehow an address and not a
name and is, therefore, inappropriate for their purpose. They are
mistaken. I used to believe this too and I was wrong. I fear that most
of this essay will recapitulate arguments already presented in URNs,
Namespaces and Registries, a TAG Finding under development by Henry
Thompson and David Orchard, but this misunderstanding about the nature
of URIs is so common, I think it probably bears repeating. URIs are
names. They're all names. There's no technical reason to invent new
URI schemes to address the goal of providing names that can be created
in a distributed fashion, that unambiguously identify a resource, are
persistent, and can be used to retrieve representations.
See also: URNs, Namespaces and Registries
W3C Issues Working Draft on the XHTML Role Attribute Module
Mark Birbeck, Shane McCarron, et al., W3C Working Draft
An initial working draft has been published for the "XHTML Role
Attribute Module: A Module to Support Role Classification of Elements."
The document has been produced by the W3C HTML Working Group as part of
the HTML Activity. The XHTML Role Attribute as defined in this
specification provides XML languages with the ability integrate a "role"
attribute into any markup language based upon "Modularization of XHTML
1.1." The document is the first of a series of XHTML modules designed
to be used to help extend the scope of XHTML-family markup languages
into new environments. It has been developed in conjunction with the
accessibility community and other groups to make it easier to describe
the semantic meaning of XHTML-family document content. XHTML Role
Attribute Module is not a stand-alone document type. It is intended to
be integrated into other host languages such as XHTML. A conforming
XHTML Role Attribute Module document is a document that requires only
the facilities described as mandatory in this specification and the
facilities described as mandatory in its host language.
See also: the W3C news item
NASA's 3D Guide to the Galaxy Lets You Interactively Explore the Milky
Way Galaxy on the Web
StaffWeb3D Consortium News
Using "plug in free" X3D technology in Demicron's WireFusion, NASA's Jet
Propulsion Laboratory's PlanetQuest web site is providing visitors with
a unique opportunity to interactively explore the Milky Way galaxy.
Product Visualization Services worked with NASA to create a
platform-independent interactive 3D visualization and multimedia "3D
Guide to the Galaxy" that can be navigated in real-time over the Web. In
the Hitchhiker's Guide to the Galaxy, Douglas Adams wrote "Space is big.
Really big. You just won't believe how vastly hugely mind-bogglingly big
it is." Mind-bogglingly big is exactly what makes the Milky Way so very
difficult to visualize using photographic means or even using the
traditional "artist's conception" painting. The goal of the "3D Guide to
the Galaxy" project was therefore to use immersive 3D visualization to
help users understand the primary features of the Milky Way, and to
grasp the massive scale of the galaxy relative to our own tiny earth. As
if this wasn't enough of a challenge, NASA wanted the interactive 3D
multimedia content to be web-based and to be accessible using any modern
web browser on any platform.
The Java XPath API: Querying XML from Java Programs
Elliotte Rusty Harold, IBM developerWorks
Among the many query languages, Structured Query Language (SQL) is a
language designed and optimized for querying certain kinds of relational
databases. Other less familiar query languages include Object Query
Language (OQL) and XQuery. However, the subject of this article is XPath,
a query language designed for querying XML documents. XPath expressions
are much easier to write than detailed Document Object Model (DOM)
navigation code. When you need to extract information from an XML
document,
the quickest and simplest way is to embed an XPath expression inside your
Java program. Java 5 introduces the javax.xml.xpath package, an XML
object-model independent library for querying documents with XPath. It
is far, far easier to write queries in declarative languages, like SQL
and XPath, than in imperative languages, like Java and C. It is far, far
easier to write complex logic in Turing complete languages, like Java
and C, than in declarative languages, like SQL and XPath. Fortunately,
it's possible to mix the two using APIs such as Java Database Connectivity
(JDBC) and javax.xml.xpath. As more and more of the world's data moves
to XML, javax.xml.xpath will become as important as java.sql already is.
See also: XML and Query Languages
Load, Save and Filter XML Documents Using the DOM Level 3 API
Deepak Vohra, BEA Dev2Dev
We all use XML for data exchange in enterprise applications. The DOM
Level 3 Load and Save specification provides a standard mechanism for
loading and saving (serializing) an XML document. As specified in the
DOM Level 3 Load and Save specification, "This specification defines
the Document Object Model Load and Save Level 3, a platform- and
language-neutral interface that allows programs and scripts to
dynamically load the content of an XML document into a DOM document
and serialize a DOM document into an XML document." The Java API for
XML Parsing (JAXP) DocumentBuilder class also provides a standard
method to create a parser and load an XML document, but this is specific
to the Java language. The DOM 3 Load and Save API may be implemented in
any language. JAXP also provides the Transformer API to serialize an
XML document. In addition to facilitating the loading and saving of an
XML document, the DOM 3 Load and Save provides event handling and
filtering of XML documents as the document is parsed or serialized.
This article illustrates these new features, which should result in
increased portability of DOM applications.
See also: Open Management Consortium web site
Wiki Start-Up Taps Open Source to Lure New Users
Martin LaMonica, CNET News.com
A wiki software start-up is releasing two products into open source
to help get more developers familiar with its commercial products.
MindTouch, founded by former Microsoft employees, on Tuesday announced
the creation of an open-source project around MindTouch Dream, software
for building distributed Web applications using Microsoft .Net
development tools. The company also intends to release its wiki-based
document-sharing software, called Deki, under an open-source license.
MindTouch's primary business is selling a so-called wiki appliance to
small and medium-size companies. The appliance includes a modified
version of MediaWiki, the software behind Wikipedia, and a server that
can be updated remotely, Bjorg said. MindTouch changed MediaWiki to
make it easier to use for workers sharing Microsoft Office documents.
The first of company's new open-source projects, Deki, will be an open-
source version of the company's wiki software — without the server —
and will be available under the General Public License. By making it
free for download, the company hopes to get people familiar with
MindTouch and its commercial products. Mindtouch Dream software, which
was used to build Deki, is a development framework designed to
accelerate creation of so-called Web 2.0 applications, such as mashups
that combine information from different Web sites. All data is stored
as XML and services can be accessed using simplified, XML-based APIs
called REST (Representational State Transfer).
ODF Notes and Reports from All Over (Installment VI)
Andy Updegrove, Consortiuminfo.org
Last fall, when things were moving quite rapidly in the ODF/OpenXML
(then called "Microsoft XML reference schema") front, I did a weekly
series of blog entries titled as above, pulling together most of what I
thought was worth reading from all manner of sources on this topic.
Today, there are a number of sites that are fulfilling that function
(Bob Sutor's blog is one of the most thoroughly and reliably updated),
so I have not felt that this to be as necessary a task as before.
Recently, however, the volume of news and commentary has risen to the
point that perhaps there is a need for a new service for those
interested in the ODF story: not a gathering, but a winnowing function,
selecting those pieces of information, and those analyses, that are
particularly worthwhile and shuffling them into some sort of coherently
arranged bouquet of contrasting insights. That's what I'll try and do
in this entry, and will continue to do on a periodic basis in the future
if the chore seems to be worthwhile. So here goes...
See also: on Zero Code
Windows Workflow Foundation for Web services
Daniel Rubio, SearchWebServices.com
Workflows lend themselves to the granular nature of services. In other
words, services fulfill a very small unit of work in favor of being
reusable for many different scenarios, this in turn creates the
possibility of stitching together an innumerable number of outcomes as
workflows, so at a very simplistic level a workflow is nothing more than
a series of services glued together to fulfill a particular business
process. In the very specific case of services, many approaches have
emerged to solve this workflow problem: WSFL (Web Services Flow
Language), XLANG (Web Services for Business Process Design) and BPEL
(Business Process Execution Language), to name a few. Among them, the
one with the most traction is without a doubt BPEL, in part due to its
backing not only from major industry vendors, but also from boutique
shops specializing in service-oriented architectures. But while BPEL
provides the semantics and depth to orchestrate elaborate Web services
scenarios, it's still relegated to a niche status confined to the
services world. If you ponder the aspect of creating workflows strictly
from services, you will arrive at the very realistic conclusion that
workflows in many enterprises require the integration of non-serviceable
legacy applications or even non-system human tasks, workflows that would
fall beyond the scope of BPEL or any other orchestration technique
currently applicable to SOA. In light of this last possibility comes
Windows Workflow Foundation (WF) .
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