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Element Roles

Each ElementClass has a role, which defines how the elements are used. These roles decide how the Elements are imported, whether they can be expanded and other behaviour.

Program​

Programs are the roots of expandable Metamodels. They represent the codebase we wish to model and expand.

Programs:

  • Have no parents.
  • Can be found in the model directory.
  • Should always have one or more identifiers.
  • Are expandable.

See Program Models on how to use program ElementClasses

Module​

Modules are reusable models, which can be used by Programs.

Modules:

  • Have no parents.
  • Can be found in the model directory.
  • Should always have one or more identifiers.
  • Are linked to Programs by an aggregation reference
  • Are expandable.

See Module Models on how to use module ElementClasses

Element​

Elements are parts of the model that can be expanded.

Elements:

  • Should have a module, program or element parent, either through composition or extension.
  • Can be found in the model directory.
  • Should have an identifier if it is the target of a Reference.
  • Are expandable.

Nodes​

Nodes are parts of the model that have no function other than adding more information to the model.

Nodes:

  • Should probably have a parent to include it in the model somewhere.
  • Can have an identifier.
  • Are not expandable.

Data​

Data ElementClasses represent the data in DataResources.

Data ElementClasses:

  • Have no parents.
  • Can be found in DataResource files.
  • Should always have one or more identifiers.
  • Can be referenced by association references.
  • Are not expandable.

Config​

Config ElementClasses are Data ElementClasses, but with the added functionality that they can be configured in a settings directory. A settings directory exists next to the model. This can be a way for application developers to define data that would otherwise require a DataResource in an ExpansionResource.

Config ElementClasses:

  • Have no parents.
  • Can be found in settings directories or DataResource files.
  • Should always have one or more identifiers.
  • Can be referenced by association references.
  • Are not expandable.

Taxonomy​

Taxonomy ElementClasses are Data ElementClasses that can be referenced even though they are not defined anywhere. If there is no definition, the element will be stubbed.

Variant​

Variants provide a way to define multiple versions of a program to then select 1 of the versions during expansion.

Variants:

  • Should be the child of a Program through composition.
  • Can be found in the model directory.
  • Should always have one or more identifiers.
  • Are not expandable.

Export​

Export ElementClasses are not regular parts of the model. They are designed to be exported during expansion or other processes. As a result, they get writer support, which is normally only available for Modules and Programs.