XML Metadata Interchange
|Internet media type||
|Developed by||Object Management Group|
(4 April 2014)
|Type of format||Markup language|
|Standard||MOF 2 XMI Mapping|
It can be used for any metadata whose metamodel can be expressed in Meta-Object Facility (MOF).
The most common use of XMI is as an interchange format for UML models, although it can also be used for serialization of models of other languages (metamodels).
In the OMG vision of modeling, data is split into abstract models and concrete models. The abstract models represent the semantic information, whereas the concrete models represent visual diagrams. Abstract models are instances of arbitrary MOF-based modeling languages such as UML or SysML. For diagrams, the Diagram Interchange (DI, XMI[DI]) standard is used. At the moment there are several incompatibilities between different modeling tool vendor implementations of XMI, even between interchange of abstract model data. The usage of Diagram Interchange is almost nonexistent. Unfortunately this means exchanging files between UML modeling tools using XMI is rarely possible.
One purpose of XML Metadata Interchange (XMI) is to enable easy interchange of metadata between UML-based modeling tools and MOF-based metadata repositories in distributed heterogeneous environments. XMI is also commonly used as the medium by which models are passed from modeling tools to software generation tools as part of model-driven engineering.
Integration of industry standards
XMI integrates four industry standards:
- XML – Extensible Markup Language, a W3C standard.
- UML – Unified Modeling Language, an OMG modeling standard.
- MOF – Meta Object Facility, an OMG language for specifying metamodels.
- MOF – Mapping to XMI
The integration of these four standards into XMI allows tool developers of distributed systems to share object models and other metadata.
Several versions of XMI have been created: 1.0, 1.1, 1.2, 2.0, 2.1, 2.1.1, 2.4, 2.4.1 and 2.4.2. The 2.x versions are radically different from the 1.x series. The version 2.4.2 was issued in April 2014.
There are now other XML standards for representing metadata. One of the most recent is the Web Ontology Language (OWL) (but ontologies are a very specialized kind of metadata, and OWL has no built-in support for most of the information represented in UML). OWL is built upon the Resource Description Framework (RDF).
The Diagram Definition OMG project is another alternative, which can also express the layout and graphical representation.
XMI is now an international standard:
- Common Warehouse Metamodel
- Web Ontology Language
- Generic Modeling Environment (GME)
- Eclipse Modeling Framework (EMF)
- Domain Specific Language (DSL)
- Domain-specific modelling (DSM)
- Meta-Object Facility (MOF)
- OMG (2012-07-01). "Diagram Definition, Version 1.0". Retrieved 2013-02-21.
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