Meta Object Facility
The term Meta Object Facility ( MOF ) was introduced by the Object Management Group (OMG) and describes a special metadata architecture. The core component is a meta-meta model. Furthermore, the MOF specification and associated standards contain ways for model processing, a kind of tool kit. The XMI format ( XML Metadata Interchange ) for the exchange of metadata should be mentioned above all .
MOF bridges the gap between different metamodels by creating a general basis for metamodels. If two different metamodels are MOF-compliant, then models based on them can reside in the same model repository . This then also allows joint processing, for example through model transformation.
Levels
According to the specification, MOF needs at least two levels in order to be able to navigate from classification to instance and back. There are no upper limits.
Examples of different numbers of levels are:
- two levels
- generic, reflexive systems (class - object)
- three levels
- relational database systems (SysTable - Table - Row)
- four levels
- UML 2 infrastructure or MOF 1.4 specification (MOF - UML - User Model - User Object)
The classification of data in four meta-levels:
- M0 level
- Concrete. Pronounced dates.
- M1 level
- Models, for example physical or logical data or process models or specific forms of UML or object models that define the data of the M0 level.
- M2 level
- Meta-models, define how the models are set up and structured. For example, language elements such as classes, associations and attributes of UML 2.0 define how concrete UML models can be structured.
- M3 level
- Meta-meta-models (or MOF level). Abstract plane that is used to define the M2 plane. The definition of the M3 level takes place with the means of the M3 level itself, this represents the conclusion of an otherwise infinite metaization.
Related standards
Other OMG standards closely related to MOF include:
- MOF QVT - a transformation language
- MOF versioning
- MOF Model to Text Transformation Language
- JMI - Java Metadata Interface for programmatic access to model depots in Java
- MOF to IDL Mapping - mapping to CORBA IDL for programmatic access to model depots in any language and distributed systems
EMOF ( Essential MOF ) is a subset of MOF 2.0. Its purpose is to make simple metamodels simple - i. H. without having to understand the entire MOF - to be able to create it. EMOF is also largely compatible with the popular Ecore metamodel , which is used in the Eclipse Modeling Framework . CMOF ( Complete MOF ), on the other hand, covers the entire scope of the language.
Individual evidence
- ↑ Meta Object Facility Core (PDF) Object Management Group (OMG). P. 16f. April 3, 2014. Retrieved September 22, 2014.
