Structural Elements

Every element in an OntoUML serialization is built on a small structural backbone: a chain of abstract types that factor out the properties shared across the whole language. Whatever an element ultimately is — a Project, a class, a diagram — it first carries an identity, and (almost always) a name and other descriptive information.

That backbone is the chain OntoumlElement → NamedElement → { Project, ModelElement, Diagram }:

• OntoumlElement is the root of everything. It contributes the identity properties id, created, and modified.
• NamedElement adds the six descriptive properties — name, alternativeNames, description, editorialNotes, creators, and contributors.
• Its concrete/abstract descendants are the Project container, the abstract ModelElement branch (all of the abstract syntax), and the Diagram (part of the concrete syntax).

The pages in this section document the structural types themselves:

• OntoumlElement — abstract; the identity root of every element.
• NamedElement — abstract; adds the descriptive properties.
• Project — concrete; the container that aggregates an entire ontology.

The two other named descendants are documented in their own chapters: ModelElement — the abstract root of the abstract syntax — and the Diagram, part of the concrete syntax.

For a narrative walkthrough of the same material — the type discriminator, references by id, and the required-property rule — see Document Structure.