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Web standards move forward
UDDI and BPEL4WS
Two meetings of OASIS have moved web services standards forward significantly, writes Peter Abrahams, of Bloor Research.
UDDI V2 was ratified as an OASIS standard. BPEL4WS V1.1 was submitted to an OASIS technical committee, the first step towards ratifying it as a standard.
These standards are two of the five basic pillars of web services, the other three being SOAP, WSDL and WS-transaction.
All these standards are essential if the industry is to be able to implement service oriented architectures (SOA). The SOA will be implemented using services provided by multiple vendors both at the application services and infrastructure services levels.
The Universal Description, Discovery, and Integration (UDDI) project has defined standards for enterprises to publish descriptions of services they offer and for other enterprises, or other parts of the same enterprise, to discover these services.
UDDI V1 defined all the base functions required, so what is new in UDDI V2? Basically extensions to make it more usable in the real and complex world including:
- Modeling support for complex organisations
- More powerful categorisation and identifier support for clients
- Enhanced inquiry
- Internationalisation features
- Peer-based replication
All of these are extensions and improvements. To take one example the modelling support in V1 did not allow the modelling of the relationship between organisations (such as wholly owned subsidiary) so such organisations had to be modelled as if they were totally independent. In V2 the modelling has been improved to enable proper modelling of real life complex organisations.
V2 is also a stepping stone to V3 which has already been drafted. V3 deals with major extensions such as security, improved internationalisation and registry interoperability. V3 is intended to complete the definition of UDDI.
BPEL4WS (Business Process Execution Language for Web Services), also know as BPEL for short, allows the definition of both business processes that make use of Web Services and business processes that externalise their functionality as web services.
The definition is in the form of an XML message with tags to define the partners involved in the business process, the messages flowing between the partners, the links between the partners and their activities.
What is new in V1.1? Mainly changes based on experience of working with V1. These include:
- Some terminology changes (e.g. containers are now called variables)
- A whole range of small feature changes
- Separation of core concepts from usage patterns.
- The executable processes and the business protocol usage patterns had many concepts in common, these have now been extracted and the two usage patterns are now defined as extensions to the core concepts.
Both these standards initiatives are positive moves by key players in the industry and will bring improved operability in the future. Both of them are under the auspices of OASIS but it looks likely, and it is to be hoped, that the W3C and OASIS will cooperate and bring their standards together where there is overlap.