Cover Pages: XML Daily Newslink: Thursday, 10 May 2007

A Cover Pages Publication http://xml.coverpages.org/
Provided by OASIS and Sponsor Members
Edited by Robin Cover

This issue of XML Daily Newslink is sponsored by:
IBM Corporation http://www.ibm.com

Headlines

XML Parser Benchmarks: Part 1
The W3C Technical Architecture Group (TAG)
ebXML Technical Committees Host Week of OASIS ebXML Webinars
Reasonable Principles for Reviewing Open XML and Other Standards
AJAX, JavaServer Faces Ties To Get Stronger
SOA: Inside the Preferred Data Source Pattern
Marc Hadley on WADL: a RESTful API Description Language
On-Demand Vendors Unveil ShareOffice

XML Parser Benchmarks: Part 1
Matthias Farwick and Michael Hafner, XML.com

Five years after the introduction of SOAP 1.0, XML parsing is still the main bottleneck in web service performance. In search of components for a high performance web service security solution, we have executed benchmarks for various XML parsers in Java and C. These benchmarks cover event-driven parser models like SAX and StAX, object model parsers like DOM, and also new breeds of XML parsers like Apache's AXIOM, which only builds parts of the document tree in the memory. Our intention was to find the right components for our high performance web service security gateway, so that it could be run on a small dedicated appliance. The limited resources of such a device brought the C tests into the game, since the Java virtual machine already needs a lot of memory. Object model parsers are the most important parser types in the context of web service security because they can be used to alter a XML document in memory. In this first part of a two-part series, we will present our benchmark results for the event-driven parsers like SAX and StAX, because those are used by the object model parsers, and therefore determine the performance of object model parsers by a large amount. Overall the SAX-like implementation of LIBXML2 in C performs best in all benchmarks. For most document sizes it had one-third to twice as much throughput as its competitors. This is interesting because as we will see in the next part of this series, the LIBXML2 DOM implementation in C uses this parser to read in data and therefore already has a performance advantage over the other object model parsers in Java.

The W3C Technical Architecture Group (TAG)
Henry S. Thompson, UKOLN Ariadne

In this article, the author introduces the W3C Technical Architecture Group (TAG) and its work. The TAG has nine members: the Director ex officio and eight others who serve two- year terms. Of these nine, three are appointed by the Director and five are elected by the W3C membership, although they need not be associated with the W3C themselves. Although the Director is nominally the Chair, in practice he delegates this responsibility to one of the appointees. The mission of the TAG is stewardship of the Web architecture. There are three aspects to this mission: (1) to document and build consensus around principles of Web architecture and to interpret and clarify these principles when necessary; (2) to resolve issues involving general Web architecture brought to the TAG; (3) to help coordinate cross-technology architecture developments inside and outside W3C. In practice this has meant that a lot of the TAG's work has been a kind of industrial archaeology: exploring and analysing the ways in which the technologies which comprise the World Wide Web are used and abused, to try to articulate what is important and what is not, what really underpins the success of the Web so far, what is incidental and what actually threatens the success of the Web going forward. The TAG is currently engaged with a number of issues; in some cases draft findings are available, in others things are still at the preliminary fact-finding and discussion stage: Versioning; (Almost) Always Use http: URIs; Passwords in the Clear; URI Abbreviation; The Self-describing Web; The Future of (X)HTML.

See also: TAG Findings

ebXML Technical Committees Host Week of OASIS ebXML Webinars
Staff, OASIS Announcement

OASIS announced a week of ebXML webinars devoted to the ebXML standards. ebXML (Electronic Business using Extensible Markup Language) is a modular suite of specifications that enables enterprises of any size and in any geographical location to conduct business over the Internet. The Webinars will be held Monday through Thursday, June 4-7, 2007, at 3:00PM GMT. Each day a different ebXML standard will be featured. (1) Monday: OASIS ebXML Registry v3.0 Standard Overview. The ebXML Registry Standard provides the functionality needed for governance and management of electronic artifacts for SOA deployments; it has been adopted and deployed in vertical industries including government, health care, geospatial, telecommunications, banking, and finance. (2) Tuesday: OASIS ebXML Business Process (ebBP) v2.0.4 Standard Overview. The ebBP Standard provides a business process definition for business systems configured to support the execution of business collaborations between partners or collaborating parties. (3) Wednesday: OASIS ebXML Messaging Services (ebMS) TC v3.0 Standard Overview. The ebXML Message Service is one of the most widely used parts of the ebXML framework. Version 3.0 leverages a number of key Web Services technologies such as Web Service Security and Web Services Reliable Messaging, and provides innovative new features to support small and medium size organizations. (4) OASIS ebXML Collaboration Protocol Profile and Agreement (CPPA) Technical Committee v3.0 Standard Overview. ebXML CPPA v 2.0 is already in use in several production communities that are using ebXML Message Service and ebXML Business Process, and will provide support for legacy protocols such as EDIINT, RosettaNet, and emerging SOAP based protocols ("web services").

Reasonable Principles for Reviewing Open XML and Other Standards
Rick Jelliffe, O'Reilly Opinion

The author formulates seven (example) general principles which might be used when reviewing Open XML, ODF, or related specifications. Principle 1: "A schema must allow standard data notations for atomic, embedded data fields, where the standards exists, and may also allow local, common, optimised or legacy notations." Principle 2: "A schema should allow direct representation of data fields, and may allow optimised forms as well." Principle 3: "A schema language for compound documents should support an indirect or over-riding reference mechanism for entities or resource, and may disallow a direct mechanism." [...] When a standard followed the kinds of principles above, it allows both full-fidelity (the main principle behind the design of Open XML) to meet round-tripping/API-replacement/archiving requirements, and it sets the stage for interoperability between different systems: this is where in addition to the broad requirements of the standard, specific limitations are imposed so that all the different kinds of local, legacy, optimized, common-but-non-standard, and platform-dependent notations, media types, scripts and so on are avoided. ODF has just as much need for these kinds of profiles as Open XML does, as far as document interchange goes. It is a kind of paradox: an 'open' data format must be extensible, but the more that extensions are used, the more that a closed range of applications will be able to use the document; a document format that is 'open' in the sense of having a fixed definition that allows guranteed document interchange is actually must be a 'closed' (non-extensible) format.

AJAX, JavaServer Faces Ties To Get Stronger
Paul Krill, InfoWorld

Panelists at the JavaOne conference in San Francisco on Thursday [2007-05-10] discussed the linkage between AJAX (Asynchronous JavaScript and XML) and JSF (JavaServer Faces). AJAX and its attendant JavaScript code work on the client, and JSF resides on the server. Although developer issues remain, such as which AJAX framework to use in Web development, AJAX itself will be better accommodated in version 2.0 of JSF, due in 2008. JSF 2.0 will feature a small JavaScript library. Also to be featured in JSF 2.0 is Comet, which offers a programming technique in which an open socket is leveraged to speed up browser requests to the server. The current version 1.2 of JSF has a small degree of JSF support, with the ability to declare a separate lifecycle for handling AJAX requests; also, a component can be invoked to individually address a row while doing an AJAX transaction. Panelist Ed Burns is a senior staff engineer at Sun Microsystems and specification lead for JSF: "It will allow you, at the very least, from your JSF component or from any old piece of JavaScript in the page, to call back into the JSF lifecycle from JavaScript and have it all run and get back to you. It'll enable partial update of the page." Sun previously has discussed JSF 2.0 as Project Dynamic Faces, noting it would bolster AJAX support. In addition, Sun has revealed an internal effort called Project Flair, which leverages a Web kernel and JavaScript and has been positioned as an alternative to AJAX programming.

SOA: Inside the Preferred Data Source Pattern
Greg Flurry (et al.), IBM developerWorks

The Preferred Data Source Pattern, or Preferred Source Pattern, is a microflow pattern for service aggregation. The pattern allows a client to retrieve information from a group of information sources without the need to understand, at least at a high level, that multiple sources exist. The Preferred Data Source Pattern has the strengths and weaknesses of typical EAI patterns. The Preferred Data Source Pattern works best when the data in multiple sources are relatively consistent, clean, and straightforward, and the returned result sets are small to medium. It provides many advantages, including flexibility, extensibility, implementation simplicity, and cost savings. However, you should be cautious about performance implications, because the Preferred Data Source Pattern doesn't use parallel processing and query optimization. The most common pattern used with the Preferred Data Source Pattern is a wrapper pattern that makes disparate sources of information look the same; it presents the same WSDL port type. In some situations, you can use the Preferred Data Source Pattern recursively. For example, a service in a store may be implemented with the Preferred Data Source Pattern, and one of the alternate sources is a service at the enterprise. You may implement that enterprise service with the Preferred Data Source Pattern. You can use the Requester Side Caching Pattern to implement the On Write policy.

Marc Hadley on WADL: a RESTful API Description Language
Phil Windley, Blog

"WADL is a RESTful description language for Web APIs. WADL comprises resource, method, request, and response descriptions. Marc Hadley gives an example using the Yahoo News Search API. Resources are specified relative to a base URI and can describe parameters that are common to all methods. Methods are the standard HTTP methods and can specify a request and response set for that method. Responses have representations that describe the type of the response. The language can also describe faults as responses. There are tools for turning WADL into Java. wadl2java can be run from the command line or from Ant. He originally used XSLT to generate code, but that didn't work very well. Now he uses the JAXB CodeModel. Thomas Steiner has created REST Describe, a tool for creating WADL from an API. REST Compile, also from Thomas Steiner, will, I think, generate code besides Java, although figuring out what is pretty hard from the site. Personally, I believe that the lack of a description language has held back the use of RESTful APIs. WADL is a good step in the direction of rectifying that."

On-Demand Vendors Unveil ShareOffice
Rutrell Yasin, Government Computer News

A group of software vendors has released an office application based on open standards that allows collaborative teams to easily create, edit and share documents and spreadsheets online. ShareOffice is built on on-demand services from iNetOffice, EditGrid, ShareMethods and SalesForce.com. The application was announced this week at the Software 2007 Conference held in Santa Clara, Calif. ShareOffice is available as part of SalesForce.com's AppExchange or as a standalone service. According to the announement, "OpenSAM is a consortium of software-as-a-service (SaaS) application vendors and a set of AJAX (asynchronous JavaScript and XML) programming recommendations based on open standards that allow multiple online applications to integrate. OpenSAM benefits from an innovation called the "Internet File System" or IFS, which enables an open-standards document repository where multiple applications can read or write documents to a common location even if each application was developed independently by different vendors."

See also: the Opensam.org web site


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