UML（统一建模语言）---介绍

UML is a graphical language for visualizing, specifying, constructing, and documenting the artifacts of a software-intensive system (OMG definition). UML is a language, not a methodology. Methodologies can use it to visualize, specify, construct and document the artifacts they produce. UML defines a notation and a meta-model: Notation – are the graphical elements in models. Meta-model – model that describes another model, are the concepts that define a syntactically correct model. UML metamodel is defined using Meta Object Facility (MOF), a meta-metamodel that is another OMG standard. XML Metadata Interchange (XMI), another OMG standard, provides a mapping from MOF to XML.