The Object Management Group (OMG) says its new XML Metadata Interchange (XMI) specification will let programmers use the tools they want, while tearing down barriers that obstruct the flow of metadata.
XMI is the long-awaited linking of Extensible Markup Language (XML), a Web-based document sharing standard devised by the World Wide Web Consortium, with Universal Markup Language (UML) and Meta Object Facility (MOF), two OMG initiatives.
UML is a method for specifying, visualizing and documenting the artifacts of an object or system under development. MOF is a repository for abstract information about systems, dealing mostly with construction.
Simply put, XMI allows metadata to be described in UML, stored in MOF and exchanged among tools and repositories via XML. Thus, metadata can be shared regardless of middleware platform, tool or repository.
First proposed in 1997, XMI was developed by a team of OMG members, including Unisys Corp., IBM Corp., Oracle Corp., Platinum Software Inc. and Fujitsu Corp.
Dr. Stephen Brodsky, software architect with IBM, said during a news conference that XMI addresses a long-standing need in the development community.
“We live in an increasingly connected world, and it has become natural to expect that we should…access our most important business assets wherever they’re needed,” he said. “Strangely, this has just begun to happen in the area of software design.”
And XMI has been designed in a way that ensures vendors will have no trouble implementing it into their tools, said Shridhar Iyengar, Unisys fellow at Unisys.
“It’s easy for both system integrators and large vendors to implement, and at the same time the cost for implementing for small vendors is such they will be able to incorporate the technology fairly quickly.”
According to the OMG, XMI will let developers integrate tools from multiple vendors; collaborate on and distribute object-oriented design and database schema information; and enhance the life-cycle of information resources.
Brodsky said on a more practical level, XMI lets developers “mix and match” the tools they want to work with, or which work best in a distributed environment.
Having already passed internal OMG approval, the only thing standing in the way of XMI and developers are the votes of the OMG’s approximately 800 members. At press time, the voting process was one-third complete, and Iyengar expects the approval process to be no more than a formality.
Dr. Richard Mark Soley, the OMG’s chairman and chief executive officer, is already looking ahead to the post XMI world. “Over time, we will see specific meta models for particular uses. Obviously, there’s already UML, and we’re also now working on a data warehouse meta model as well,” he said.
But everything is not rosy at the OMG. One member notable in its lack of support for XMI is Microsoft Corp. The Redmond, Wash.-based company decided to go it alone, developing its own version of XMI, called the XML Interchange Facility, or XIF. Microsoft has since turned that specification over to the Meta Data Coalition.
“We were very surprised that Microsoft did not endorse XMI heartily,” Iyengar said.
As for when developers can expect to see XMI-enabled tools, Soley was cautious. “I can’t give you ship dates from the vendors,” he said. But Brodsky said XMI products are under development, with release dates coming soon.
Unisys’ Iyengar said his company will ship XMI technology, initially for UML, in the first quarter.
