This issue of XML Daily Newslink is sponsored by:
IBM Corporation http://www.ibm.com
- Building Asynchronous Services using Service Component Architecture
- eGovernment and the Web Workshop Report: Toward More Transparent Government
- Sanjiva Weerawarana on Open Source SOA Middleware
- Atomojo Atom Publishing Protocol (APP) Server 0.7.0 Release Available
- Rogue Wave Accelerates SOA Data Services Creation in C++
- Google, NTT and the US GSA Deploy SAML 2.0 for Digital Identity Management
- Russia is Open to Open Protocols
Building Asynchronous Services using Service Component Architecture
Mark Edwards, InfoQueue
Mike Edwards of IBM discusses the need for asynchronous services when you build an application using a service-oriented architecture. Building asynchronous services can get complicated, but is made straightforward using Service Component Architecture (SCA). The steps involved in using SCA to create an asynchronous service and asynchronous service client are described in this article. "Asynchronous services, where responses are returned a long time after an initial request is made, are simply a fact of life—not everything happens immediately! [...] Facilities for writing clients to synchronous services are well provided by most programming models and frameworks. The same can be said for writing synchronous services. The synchronous call-and-return model is the standard form for writing code in most programming languages. As a result, writing a synchronous service or a synchronous service client is usually not much more than a simple extension of the regular programming model. In Java, for example, this usually means that a service is implemented as a method in a class, while the service client is the invocation of a method on a class... Providing Asynchronous service implementations and also providing clients to asynchronous services is made simpler with Service Component Architecture. SCA provides a request followed by callback response model for asynchronous services, allied with the use of callbackID to tie the original request to the callback response. SCA enables this to be done for a variety of underlying communication methods between the client and the service, eliminating the need for the code to be dependent on complex middleware APIs.
See also: the Apache Tuscany Project
eGovernment and the Web Workshop Report: Toward More Transparent Government
Staff, W3C Announcement
W3C has published a Workshop Report: eGovernment and the Web Workshop: "Toward More Transparent Government". On 18-19 June 2007, the World Wide Web Consortium (W3C) and the Web Science Research Initiative held a workshop entitled, Toward More Transparent Government at the US National Academy of Sciences in Washington, DC. The goal of the workshop was to find ways to facilitate the deployment of Web standards across eGovernment sites and help shape the ongoing research agenda in the development of Web technology and public policy in order to realize the potential of the Web for access to and use of government information. The Call for Participation had required participants to submit position papers. Twenty-two (22) position papers were received. The workshop was chaired by Daniel J. Weitzner (MIT/W3C), Ari Schwartz (Center for Democracy and Technology) and Nigel Shadbolt (University of Southampton, UK). The final workshop session considered key lessons learned and identified possible next steps that W3C and WSRI could take together with the eGovernment user, vendor and research communities around the world. After two days of policy and technology presentations, the over-arching theme heard over and over again is the need to take steps, institutional, legal and technical, toward publishing data with re-use in mind. The participants identified several steps to meet this goal...
See also: the position papers
Sanjiva Weerawarana on Open Source SOA Middleware
Stefan Tilkov, InfoQ
In this interview, Stefan Tilkov talks to Sanjiva Weerawarana about web services and REST, about core standards that are essential for web services standards, open source SOA tooling, scripting languages and web services, and the strategy of WSO2 in providing open source middleware. [As to key WS-* specifications:] The most important one from a service oriented perspective, is the thing that is used to describe what the service does. WSDL is the one that people are using for that. There is a whole diversion of the spec that widely deployed, WSDL 1.1. But WSDL 2.0 is a hugely improved spec; it's really not even a WSDL, it's a completely different language in many, many ways. Unfortunately adoption has been slow yet, it just came up this year, and it is going to take some time to major vendors have to got to revisions to get to that point, if they want to get there they have to have a much better way to describe services. The other key spec is of course is the base wire protocol that everybody uses which is SOAP, and there is a series of specs that extend SOAP with security, with reliability, transactions, and so there is WS-Security, WS-SecurePolicy and WS-Secure Conversation and WS-Trust, those are the four security specs that matter. On reliable messaging there is something called WS-ReliableMessaging, in transactions there is something called the WS-AtomicTransaction, WS-BusinessAgreement and WS-Coordination. There are many applications where you never touched reliable messaging or transactions. So a large percentage of the people who built web services would never actually end up invoking these things, and in fact most people who actually use web services shouldn't be knowing about these specs. This is the underneath infrastructure that people like me who build web services should know about...
Atomojo Atom Publishing Protocol (APP) Server 0.7.0 Release Available
Alex Milowski, Software Announcement
This atomojo Google Code project contains both an Atom Publishing Protocol (APP) server and client. While both are intended to be used together, as they implement a standard protocol, they can be used with other APP-enable applications. The client is a Firefox plugin that contains an XPCOM component for interacting with the Atom Publishing Protocol (APP). Atomojo's APP implementation has been coming along quite nicely and release 0.7.0 is quite stable. Here's a short list of some features: full APP implementation; hierarchical feeds; XQuery support; large binary support; full REST interfaces for administration; integration with external authentication services; indexing of Atom category elements; retrieval of entries and feeds via categorization; metadata services for context and query by term and term value. The Atomojo server provides a uniform way to store multiple feeds and manipulate them with the Atom Publishing Protocol (APP). Feeds are organized hierarchically and indexed by their categorization. It provides both metadata feeds for getting context information about feeds as well as pulling a feed for each categorization stored in the database. The server runs on top of a restlet.org engine and uses a rest-style URI architecture for its feeds. Feed are organized hierarchically just like a file system but they are store in an XML database called eXist. In addition to eXist, there is a metadata index that is stored in an embedded Derby database. This index stores information about what feeds contain what entries as well as information about categorization. Once the server is started, you can get the service introspection document by a GET on the server root...
See also: Atom references
Rogue Wave Accelerates SOA Data Services Creation in C++
Staff, Rogue Wave Software Announcement
Rogue Wave has announced the release of Rogue Wave HydraSDO for XML 2.2 and the next edition of HydraSDO for Databases. Rogue Wave HydraSDO data components automate the creation of high-performance, service-oriented data services in Java and C++. The components enable developers to expose any data source as lightweight, independent, and decentralized data services through the Service Data Object (SDO) API, the industry standard data access in SOA. Rogue Wave HydraSDO for XML 2.2 enables XML documents to be read and updated using the SDO API. HydraSDO for XML provides a data access service (DAS) for parsing XML data and populating a DataGraph consisting of DataObjects and a Change Summary. HydraSDO for Databases enables developers to use the SDO API to access relational data in both loosely coupled and traditional tightly coupled application architectures. The component provides read/write capability for relational databases using the SDO API without the need to write SQL statements. HydraSDO for Databases includes support for leading databases including Oracle, SQL Server, MySQL and Sybase databases. Both XML and relational database data sources are made available through the simple XML-style SDO interface, which can be used by multiple applications as a real-time SOA data service. HydraSDO data components work stand-alone or can be seamlessly integrated with Rogue Wave HydraSCA, the first product available for deploying high-performance SOA applications based on the Service Component Architecture (SCA) specification.
Google, NTT and the US GSA Deploy SAML 2.0 for Digital Identity Management
Staff, Liberty Alliance Announcement
Liberty Alliance, the global identity consortium working to build a more trusted internet for consumers, governments and businesses worldwide, today released highlights of SAML 2.0-based digital identity management applications that are delivering real world value to users and organizations around the globe. These applications are among the many public and private sector deployments helping to drive a more secure and privacy-respecting internet identity layer across applications, sectors and regions based on SAML 2.0 standards. With government organizations in The Americas, Asia, Australia and Europe building and deploying SAML 2.0-based identity applications, SAML 2.0 has become the standard of choice in the global eGovernment and public sectors. These governments are relying on SAML 2.0 to deliver a wide variety of new online services to citizens, help meet compliance mandates and to provide business and trading partners with a secure and trusted platform for conducting identity related transactions. A digital map and description of global eGovernment deployments based on SAML 2.0 Liberty Federation is available... Using SAML 2.0 allows Google's customers to treat web-based authentication to Google Apps the same way they treat authentication to their other services... NTT has developed SASSO, a personal Identity Provider that enables users to single-sign-on to a PC and leverage the strong authentication capabilities of the mobile phone to conduct a wide range of secure identity-based transactions. SASSO uses the increasingly ubiquitous mobile phone as an Identity Provider (IdP) to allow users to access a Service Provider (SP). Once authenticated by their own mobile phone, the IdP on the mobile phone issues a SAML assertion signed by a private key and sends that assertion to SPs.
See also: SAML references
Toby Considine, New Daedalus
We now have web services to almost any conceivable control system. We have BACnet-XML and BACREST. We have TAC Web Services. We have LON XML. We have oBIX. So...are we there yet? [...] One of the reasons that I am watching NBIMS so closely from the oBIX vantage point is that the higher semantics will need to be there before oBIX has an enterprise interface. I have a hard time imagining what applying Policy to point services even means. As Enterprise programmers will never be control engineers, we are going to have to wrap up the standard functions into business services. In oBIX if I define a set of functionalities for a given period of time, it is called a contract. For these to be useful, we will need to pre-define several contracts and make each of them discoverable. Discovery will mean that we need to describe each one in terms of the service it provides. The Description/Catalogue will need to be machine readable rather than human readable, which means it will be based on Semantics... I believe that as we all become more familiar with NBIMS, we will be able to discover the Semantics needed to do this. Somewhere in the check list of Services to be Commissioned, in the Systems in the Energy Model, and even in the Function analyzed by the Code Compliance checker are the Semantics needed to create discoverable abstract services. And that XML will be an order of magnitude more useful because it is semantically laden.
Russia is Open to Open Protocols
Andrey Golovin and Ken Sinclair, AutomatedBuildings.com
Golovin (Executive Director BIG-RU—BACnet Interest Group Russia): "I started with BACnet in 2005 when the BIG-RU (BACnet Interest Group Russia) association was founded. Before then I was familiar with the BACnet movement in the US. In my opinion, the Russian market is more similar to the USA market, than the European. The main idea was to bring the latest achievements in open standards to the Russian market and BACnet was the best choice. During the last 2 years the BIG-RU has familiarized an estimated 80% of building owners in Russia with BACnet benefits. In 2007 the KNX Association (ex-EIB protocol) invited me to manage their association in Russia while working with BIG-RU. It is a great experience, because we can say that BACnet grew from HVAC systems, and EIB/KNX grew from lighting and low-voltage systems. Both protocols are relative and part of ISO standard 16484-5. We can now support our customers with a wider field of open building standards applications. Let's say that the joining of BACnet and KNX promotion work is a process of globalization of the market of open standards in Russia... Nobody wants to be locked into a single brand system. The situation is that every open protocol should be implemented where it is practical. Traditionally BACnet is more suitable for integration of large systems, multi-vendor projects and systems which could be expanded in the future. LonWorks is more often applicable in the field level (for products integration) and in middle sized projects. Very often both protocols exist in the same project: BACnet at the management level and automation level, and LonWorks on the field level. A good example of such a system is the 'Federation' Tower project in Moscow..."
See also: BACnet references
Selected from the Cover Pages, by Robin Cover
The Open Geospatial Consortium (OGC) announced that its members have approved version 1.0 of the Observations and Measurements Encoding specification as a final OpenGIS Implementation Standard. The two-part Observations and Measurements Encoding specification "defines an abstract model and an XML schema encoding for observations and measurements. This framework is required for use by other OGC Sensor Web Enablement (SWE) standards as well as for general support for OGC compliant systems dealing in technical measurements in science and engineering. As a new international consensus standard in an era of increasing scientific cooperation, O&M promises to play an important role in Web-based publishing of real-time and archived scientific data across research disciplines and application domains." An 'Observation' is an action with a result which has a value describing some phenomenon. The observation is modelled as a Feature within the context of the General Feature Model. An observation feature binds a result to a feature of interest, upon which the observation was made. The aim of the OpenGIS O&M Standard is to "define terms used for measurements and the relationships between them, mainly to improve the ability of software systems to discover and use live and archived digital data produced by measuring systems. When scientists and engineers encode data in O&M, they can easily publish the data (or live data feeds) in catalogs and registries so others can efficiently discover, access and use the data, using relatively simple software. The scope of the specification covers observations and measurements whose results may be quantities, categories, temporal and geometry values, coverages, and composites and arrays of any of these."
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