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XML and Web Services In The News - 7 November 2006
Provided by OASIS |
Edited by Robin Cover
This issue of XML Daily Newslink is sponsored by SAP AG
HEADLINES:
Dynamic XForms Submissions
K. Kelly, J. Kratky, and S. Speicher, IBM developerWorks
Often a single form can be developed to collect standard sets of data
from many different sources. A single one-size-fits-all form for a
specific data collection purpose is ideal because it can constrain data
input values for data integrity and allow for easy correlation and
summarization of data across a wide variety of sources. XForms is a
good choice for this kind of data-driven form because it is an open
standard that can run on a variety of Web-enabled platforms. In order
for the data to be collected, the XForms document must have a submission
target, or someplace for the data to be sent or stored when the input
is complete and the user clicks a submit button. However, each form
filling location may have unique submission requirements, such as
saving a local copy of the form submitted, or submitting a form to a
write-only location or "vault" for recording each submission for
auditing and logging purposes. These unique submission requirements
can erode the value of a single form since a single form cannot
encapsulate each form filling location's unique submission requirements.
The ability to decouple the submission requirements from the standard
form so that each form filling site can have as many specific unique
submission targets as needed can be achieved by using JavaScript for
Document Object Model (DOM) programming and joining the submission
targets with the XForms document at runtime in the browser.
See also: XML and Forms
The Use of Metadata in URIs
Noah Mendelsohn and Stuart Williams, W3C Draft TAG Finding
Members of the W3C Technical Architecture Group (TAG) have released an
updated version of the discussion paper on "The Use of Metadata in
URIs." The paper addresses a number of related concerns, including:
Reliability of URI metadata; Guessing information from a URI; HTML
Forms, and Documenting Metadata Assignment Policies; Authority use of
URI metadata; URIs that are convenient for people to use; Changing
metadata; Hiding metadata for security reasons; Confusing or malicious
metadata. What information about a resource can or should be embedded
in its URI? This question is primarily of concern to URI assignment
authorities, who must choose a suitable URI for each resource they
control. The Draft Finding concludes, for now: (1) It is legitimate for
assignment authorities to encode static identifying properties of a
resource, e.g. author, version, or creation date, within the URIs they
assign. (2) Assignment authorities may publish specifications detailing
the structure and semantics of the URIs they assign; other users of
those URIs may use such specifications to infer information about
resources identified by URI assigned by that authority. (3) Users
therefore benefit from the ability to infer either the nature of the
named resource, or the likely URI of other resources, from inspection
of a URI; such inferences are reliable only when supported by normative
specifications or by documentation from the assignment authorities.
(4) People and software using URIs assigned outside of their own
authority should make as few inferences as possible about a resource
based on its URI. The more dependencies a piece of software has on
particular constraints and inferences, the more fragile it becomes to
change and the lower its generic utility.
See also: W3C TAG Findings
OASIS: Making E-Government Work More Effectively
Stephen Bell Wellington, ComputerWorld
Open standards are crucial to e-government, says Patrick Gannon,
president and chief executive of OASIS (Organisation for the
Advancement of Structured Information Standards). They make the
various government agencies' computer systems interoperable when it
comes to catering to outside companies and citizens, who use a variety
of computer equipment. Gannon spoke to Computerworld last week, while
on a flying visit here en route to an OASIS open standards conference
being held in Sydney. Founded 13 years ago, OASIS aims to both refine
and popularise standard information formats, as well as frameworks for
information transfer. Some of these pertain to the peculiarities of
certain vertical industries and professions. "We have committees focused
on the legal community — how to submit information to court [and] how
to formalise a contract electronically... Other committees are busy
formulating generic document and message formats, based on established
standards such as XML and SGML." Many governments are pretty interested
in establishing such standards, says Gannon. However, they often ask
for a more de jure (based on law) recognition than that conferred by
an unofficial body like OASIS. "[In such cases] we submit the standards
developed by our members to an official body like the International
Standards Organisation." Two of the NZ State Services Commission's
recently developed authentication standards — in security services
and data formats — are, in fact, sub-sets of OASIS standards. Both
OASIS-developed standards have been submitted to the International
Telecommunications Union.
See also: ODF references
Widget Description Exchange Service (WIDEX) Framework
Vlad Stirbu and Dave Raggett (eds), IETF Internet Draft
The Model-View-Controller architectural pattern (MVC) divides an
interactive application into three components. The model contains the
core functionality and data. Views display information to the user.
Controllers handle user input. Views and controllers together comprise
the user interface. A change-propagation mechanism ensures consistency
between the user interface and the model. In the networked MVC
architecture, the View is exported on the remote device while a Virtual
View is maintained on the server. The change- propagation mechanism that
ensures consistency between the user interface and the model is
augmented with methods which keep the View synchronised with the Virtual
View, synchronisation being done via updates. Additionally, user
interactions or gestures are captured by the View copy and passed to
the Controller as events. The Widex framework is handling all network
related issues involved in the networked MVC architecture, e.g.
discovery and matching of Widex Elements, setting up sessions between
Widex Elements, marshaling XML DOM updates or events and exchanging
them over the wire. In the context of Widex working group, the user
interface is understood as XML data describing the user interface.
Typically, the XML data is manipulated as levels 2 and 3 in the W3C
Document Object Model (DOM); style information associated with the
user interface can be manipulated via the DOM. This document defines
a framework used to support XML-based user interfaces, where the user
interface and application logic may be on different machines, and
coupled via an exchange of XML DOM events and update operations.
Adobe Makes ActiveScript Engine Open Source
Andy Patrizio, Internetnews.com
Adobe Systems has announced that it will contribute the source code
for its ActionScript Virtual Machine to the Mozilla Foundation, to be
hosted under a new project called Tamarin. ActionScript is Adobe's
implementation of ECMAScript, the formal name given to JavaScript when
it was turned over to a standards body that almost no one uses.
JavaScript has been forked for some time, with slightly different
implementations in use by different developers. The Mozilla browser,
for example, has its own implementation, called SpiderMonkey.
ActiveScript is used in Adobe's Flash multimedia format, and Microsoft
has its own for Internet Explorer, called JScript. Adobe said its reason
for turning over the ActionScript engine to Mozilla is to create a
single standard for Web-based scripting. Code will be available from
the Tamarin project beginning today. As part of its source code
contribution, Adobe is also giving the Mozilla foundation its Just In
Time compiler, which Deziel said can run up to ten times faster than
SpiderMonkey. Deziel predicts the significant improvement in JavaScript
performance will result in all kinds of new Javascript-based
applications, including those written in Ajax.
See also: the announcement
WS-BPEL 2.0: Not Backward Compatible? Orchestration is a Necessity
David Linthicum, SOA Web Services Journal
WS-BPEL 1.1 was not a great standard, and left so much out that many
end users and vendors found it useless. In response, the vendors put
a ton of proprietary extensions in their BPEL 1.1-based products, thus
diluting its value to the point of "Why bother?" This was a dirty
little secret in the world of SOA. Considering that BPEL 2.0 is on
the horizon, I think it's time we began to talk about what's really
there, how you can fix it, and what you need to do to get from point
A to point B. What's most frustrating about the issues here is that
orchestration is indeed a core feature of SOA...the configuration
component that makes orchestration that part of the architecture
providing agility. Orchestration, at least the notion, is a necessity
if you are building an SOA. It's the layer that creates business
solutions from the vast array of services and information flows found
in new and existing systems. Orchestration is a god-like control
mechanism that's able to put our SOA to work, as well as provide a
point of control. Orchestration layers allow you to change the way
your business functions, as needed, to define or redefine any business
process on-the-fly. This provides the business with the flexibility
and agility needed, and is the core value of SOA. WS-BPEL 2.0 [is]
another opportunity for vendors to get BPEL right; this spec was much
improved, but many issues still remain. For instance, there are
considerable differences in WS-BPEL 2.0 compared to its previous 1.1
version. The major differences include syntax changes to the language,
the inclusion of new features including parallel for-each, and
modifications to the semantics of existing constructions, such as
compensation handling. There are a few more, and I urge you to read
both the 1.1 and 2.0 specs before diving into BPEL, or assessing how
deep you're in already.
See also: BPEL references
Performance, Security, and Run-Time Governance
Eric Knorr and Galen Gruman, InfoWorld
The question of whether or not to use an ESB devolves to the individual
needs and inclinations of each organization. For example, if
orchestration of distributed services is a must-have, that's pretty
tough to do if those services aren't plugged in to an asynchronous
messaging infrastructure. But an ESB does not an SOA make. In an SOA
of any significant size, even a widely deployed ESB would not be the
only game in town. Multiple message buses may need to be bridged and
messages transformed as they travel among them. That's an ideal role
for the new generation of XML appliances — designed to secure, govern,
and boost the performance of an SOA — from the likes of Cisco, Forum
Systems, IBM DataPower, Layer 7, and Reactivity. These companies sell
boxes that route XML messages based on content and rip through XML
transformations, routing, and mapping at blazing speed using special
processors designed for the purpose. Depending on the model, these
boxes incorporate a range of features, many of which overlap with the
capabilities of an ESB. They're particularly adept at virtualizing
services, so that service copies can be created on the fly as
performance demands increase — and so that policies concocted for
services can be enforced at run time using centralized management
software. And most include a range of XML security features as well.
W3C Issues Last Call Review for CSS 2.1
Bert Bos, Tantek Celik, et al (eds), W3C W3C Working Draft
W3C's CSS Working Group has published a Last Call Working Draft for
"Cascading Style Sheets, Level 2 Revision 1 (CSS 2.1 Specification)."
CSS 2.1 is a style sheet language that allows authors and users to
attach style (e.g., fonts and spacing) to structured documents (e.g.,
HTML documents and XML applications). By separating the presentation
style of documents from the content of documents, CSS 2.1 simplifies
Web authoring and site maintenance. CSS 2.1 builds on CSS2 which builds
on CSS1. It supports media-specific style sheets so that authors may
tailor the presentation of their documents to visual browsers, aural
devices, printers, braille devices, handheld devices, etc. It also
supports content positioning, table layout, features for
internationalization and some properties related to user interface.
CSS 2.1 LAO corrects a few errors in CSS2 (the most important being
a new definition of the height/width of absolutely positioned elements,
more influence for HTML's "style" attribute and a new calculation of
the 'clip' property), and adds a few highly requested features which
have already been widely implemented. But most of all CSS 2.1 represents
a "snapshot" of CSS usage: it consists of all CSS features that are
implemented interoperably at the date of publication of the
Recommendation. CSS 2.1 is derived from and is intended to replace
CSS2. Some parts of CSS2 are unchanged in CSS 2.1, some parts have been
altered, and some parts removed. The removed portions may be used in
a future CSS3 specification. Future specs should refer to CSS 2.1
unless they need features from CSS2 which have been dropped in CSS 2.1,
and then they should only reference CSS2 for those features, or
preferably reference such feature(s) in the respective CSS3 Module that
includes those feature(s).
See also: the W3C CSS home page
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