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Does SCA Need a New Java Programming Model?
Sanjay Patil, Blog
"During JavaOne this year, there was a panel discussion on the topic of Service Component Architecture. The panelists were from BEA, IBM, Oracle, SAP, Sun and TIBCO, and I represented SAP on that panel. What about the new SCA programming model? It seems to compete with some of the existing Java technologies like EJB, JAX-WS, etc. BEA and IBM expressed support for the new programming model and one of them also made a point that SCA defines a valuable feature of asynchronous and conversational interactions. Oracle's rep said that they haven't made up their mind yet. I expressed my disagreement with the characterization that SCA defines and requires a new programming model. The main focus of the various language binding specifications in SCA (EJB, Spring, Java, BPEL, etc) is to define mapping of SCA metadata. In order to participate in a SCA composition, an implementation artifact needs to expose metadata declaring the provided services, consumed services (aka references) and configurable business properties that can affect the behavior of that implementation. Exposing such SCA metadata is handled differently by each language. The bulk of what we call as SCA programming model is really about binding SCA metadata. SCA does defines a small set of features that are commonly perceived to be valuable for building service oriented environments such as -- asynchronous invocations, conversational interfaces, bidirectional communications, etc. In that regard, SCA defines the concepts and some language neutral metadata in the assembly specification and then the related mappings in various languages can be found in the individual language binding specifications. One of the main goals of SCA is to enable certain uniformity across different component technologies, and I don't think SCA should define yet another component technology. Different vendors may choose a different starting point for providing SCA support..."
See also: David Chappell's blog
Sun Views SOA Development Through GlassFish
Rich Seeley, SearchWebServices.com
At this month's JavaOne Conference, Sun Microsystems Inc. seemed more focused on consumer applications for everything from cell phones and other mobile devices to television. To make sure Sun hadn't lost its focus of enterprise development and service-oriented architecture (SOA), we sat down with Kevin Schmidt, director for SOA products at Sun Microsystems Inc., to talk about GlassFish, Open ESB, Java SE, JavaFX Script and other things Java-related to SOA and Web services. Schmidt: "We do have the announcement on the preview of Open ESB, which we are going to be rolling into our JavaCAPS offering in the next nine to 12 months. There's enterprise work going on with the GlassFish Community and GlassFish v3, making it much more modular. With the core GlassFish kernel you can deploy things, whether it's EJBs or JRuby or Web applications. Some people perceive an application server being this behemoth, but this much more modular architecture provides what you need, and you don't have to incur overhead by having the entire container deployed." According to the Sun announcement, "Open ESB now includes NetBeans 6.0 IDE Preview release-based tools as well as updated version of the runtimes for JBI, Business Process Execution Language (BPEL) Service Engine, Intelligent Event Processing (IEP) Service Engine, Hypertext Transfer Protocol (HTTP) Binding Component and many other components. This combination of Open ESB, GlassFish V2 and the NetBeans architecture provides Java technology developers with powerful and quick access to building SOA-based composite applications."
Thinking XML: Microformats the XML Way
Uche Ogbuji, IBM developerWorks
Microformats emerged a couple of years ago as a way to tunnel richer semantics into host formats such as HTML/XHTML and Atom. HTML has no direct way to express contact information, but a microformat called hCard allows you to transmogrify workaday HTML divs and spans into constructs to specify contact name, street address, postal code, and so forth. Some of the basic ideas behind microformats are sound, but it has turned into a huge hype machine such that people sometimes don't think about why and where microformats make sense. Microformats should be one tool available for expression of rich content on the Web and should complement, rather than supplant, other such technologies like XML on the Web, and even Ajax. This article looks to bring back some perspective of where microformats make sense and where something else is worth a hard look. Microformats work best where they add a very little bit of nuance to common constructs in a host language such as HTML, XHTML, or Atom. An example is rel-license, which allows you to express that a link is identifying the usage license for the source page's contents. A microformat such as rel-license provides a convention for use of an HTML attribute designed to carry such conventions. It goes no further than providing nuances in such constructs of the host vocabulary, and I call such microformats nuance microformats. Most of these are what microformats designers call elemental microformats, which are those constructed entirely within an element. Certainly nuance microformats are useful, and build on classic respect for rough consensus and running code. They are like formal registries for MIME types, filename extensions, and such, but with less central control. Problems come about when the authors of microformats start to distort host formats rather than just build on them.
W3C and WSRI Workshop to Explore Transparency in eGovernment
Staff, W3C Workshop Announcement
"Toward More Transparent Government: Workshop on eGovernment and the Web" will be held 18-19 June in Washington, D.C., USA, at the U.S. National Academy of Sciences. Attendees, invited speakers and panelists will discuss how the Web works for citizens and governments and how it can best achieve their goals. The first day will be composed of invited talks and panels concentrating on public policy goals of eGovernment strategies, as well as investigation of leading edge eGov Web applications. The second day will explore current best practices that can be gleaned from specific eGov Web applications with the aim of learning about new standardization requirements, as well as identify means to disseminate knowledge about the best practices of successful eGov applications. Co-sponsored by W3C and the Web Science Research Initiative (WSRI), the Workshop is free and open to all but registration is required. The deadline was extended to 22-May-2007 for position papers, which are strongly encouraged.
See also: the PR
Reality Check: ODF vs. OpenXML
Ephraim Schwartz, InfoWorld
At the highest level, ODF (Open Document Format) vs. OpenXML is a battle between two business competitors, IBM and Microsoft, each of which views itself as threatened by the other. IBM and Microsoft have been in a battle for supremacy ever since they parted ways in 1991 over OS/2 and Windows. As unlikely as it sounds, the current battle is over an open file format for saving files, ODF or OpenXML, especially for word processing, spreadsheet, and presentation documents but not limited to those. To see whether I could sort out the differences between these formats, I gave both companies a call. Supported by Big Blue and many other high-tech companies, ODF is a standard both of the ISO and OASIS, which has about 300 members. OpenXML is supported by a smaller European standards group, ECMA International, which has 21 members, 20 of which voted to make it a standard, with only IBM voting no. OpenXML has also been proposed to the ISO and will be voted on in September. If OpenXML adoption is preferred, it closes the door on the opportunity for IBM to create a path to a myriad of IBM/Lotus on-premises and Web 2.0 products for such things as collaboration, unified communications, productivity software ,and even its WebSphere middleware platform. If on the other hand, ODF adoption, especially with government entities, grows over time it could have a viral effect and threaten Microsoft's largest revenue producing product, Office, and help IBM regain market share it lost to Outlook and Exchange Server as well... IBM's Sutor says that, although Microsoft has published all the specs for OpenXML, those specs total 6,000 page (12 reams of paper), which makes it almost impossible for anyone but Microsoft to incorporate the specs in a new productivity suite, thereby crowning Microsoft Office effectually the de facto standard, according to Sutor... Microsoft's Robertson and Jean Paoli, general manager for interoperability and XML architecture at Microsoft, see it quite differently. Robertson says that despite 6,000 pages of documentation there is already an implementation from DataViz for Palm OS, one by a company called Numeric for spreadsheets, that Novell has an implementation of OpenXML for OpenOffice on Suse Linux, and that Corel has announced an implementation for WordPerfect.
Type-consistent Digital Objects
Kostas Saidis and Alex Delis, D-Lib Magazine
"The fundamental element upon which modern Digital Libraries (DLs) are built is that of the digital object. Digital objects can be conceived as compound artifacts that wrap digital material in terms of four elements: its content, its metadata, its relationships with other objects and its behavior. From a digital object encoding perspective, various XML formats, including METS, MPEG-21 DIDL, FOXML, and RDF help encode arbitrary digital object variations through the use of a common XML schema. However, these formats are mainly used to address low-level storage and preservation needs. We argue that, for developing full-fledged, integrated DL systems, we should be able to handle variations in digital object parts at a higher level of abstraction. Digital Object Prototypes (DOPs) provide a domain-specific realization of digital object types and classes in the context of DLs. We gather meta-information about categories or sets of digital objects in a digital object prototype definition and treat individual members of these sets as instances of their prototype, making digital objects conform to their respective prototype specification without user intervention... In this article, we provide an overview of the framework, we highlight its type-conformance capabilities and we show how heterogeneous digital material can be treated in a uniform manner without resorting to custom developments.
Selected from the Cover Pages, by Robin Cover
OASIS announced that members of the Web Services Reliable Exchange (WS-RX) Technical Committee approved "WS-ReliableMessaging Version 1.1" as a Committee Specification and submitted it for consideration as an OASIS Standard. The specification has gone through two Public Review periods, and is being balloted May 16-31, 2007. "WS-ReliableMessaging Version 1.1" is now a three-part specification, each with a prose document, separate XML namespace, and XML schema. The core WS-ReliableMessaging 1.1 document defines a protocol for reliable message exchange between two Web services, even in the presence of network or system failures. For example, the protocol can ensure the resending of messages that have been lost, and can ensure that duplicate messages are not delivered. The protocol allows Web service nodes to implement a variety of delivery assurances, including At Most Once, At Least Once, Exactly Once and In Order delivery of messages. The protocol fundamentally defines a one-way reliable channel (known as a Sequence), but also includes mechanisms to optimize the creation of two-way reliable exchanges. The protocol is designed to compose with other relevant standards such as WS-Security and WS-SecureConversation. The WS-ReliableMessaging Policy 1.1 document defines an XML policy language that enables Web services to advertise their support for the WS-ReliableMessaging specification. The specification is designed for use with the WS-Policy Framework. The language aids the interoperability of nodes that support WS-ReliableMessaging by publishing their support and requirements for aspects of reliable messaging. The WS-MakeConnection 1.0 document defines a protocol that can be used to allow two-way communications when only a transport specific back-channel (such as the HTTP response mechanism) is available.
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