UML Relationship Modelling

Question

Is this UML consistent with the text below?

Instead of trying to either define many subclasses or introduce multiple inheritance, we can instead define a set of roles that the device is meant to play. (It should be noted that this is another reason why the concept of a managed device is a good one – now, we can define a base concept of a managed device, and model its functionality by associating one or more roles to it as appropriate). This solves the mess of having the same generic function (such as routing) assigned to two different types of devices that implement that same generic function in different ways, producing different subsets of functionality.

I believe that the UML specifies that each Device can have 0 or 1 DeviceRoles. A colleague asserts that the UML specifies that each DeviceRole can belong to a maximum of one Device. In either case, the UML seems to not reflect that a Device can aggregate a set of roles.

The UML and text is extracted from TMForum's Information Framework (SID): Physical Resource Business Entities

Information Framework Suite GB922 Physical Resource Release 15.0.1 November 2015

Thanks, Greg

Answer 1

I have worked on this document and created a data model from it. In real world experience a resource, for example a physical resource like a mikrotik router can have roles of a router and firewall at the same time. So the model has to let you fulfill the need of several roles for a single resource. I hope this example will clarify the subject.

Answer 2

The UML diagram is consistent with the text. It clearly says that the device aggregates zero or more device roles and a device role can be played by zero or one device. In UML, multiplicity is notated adjacent to the type it quantifies.

It would help if the property names were written at the ends of the associations.