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Decorators

Model elements may have arbitrary decorators (aka annotations) placed on them. These are available via API and can be useful for tool vendors to extend the metamodel.

@foo("arg1", 2)
asset Order identified by orderId {
  o String orderId
}

Decorators have an arbitrary number of arguments. They support arguments of type:

  • String
  • Boolean
  • Number
  • Type reference

Resource definitions and properties may be decorated with 0 or more decorations. Note that only a single instance of a decorator is allowed on each element type. I.e. it is invalid to have the @bar decorator listed twice on the same element.

Decorators are accessible at runtime via the ModelManager introspect APIs. This allows tools and utilities to use Concerto to describe a core model, while decorating it with sufficient metadata for their own purposes.

The example below retrieves the 3rd argument to the foo decorator attached to the myField property of a class declaration:

const val = myField.getDecorator('foo').getArguments()[2];