Composite structure diagram

A composite structure is a set of interconnected elements that collaborate at runtime to achieve some purpose.

The key composite structure entities identified in the UML 2.0 specification are structured classifiers, parts, ports, connectors, and collaborations.

This UML 2.0 composite structure diagram specifies that instances of the 'FibonacciSystem' class are composed of a number of parts.

The fifth part, identified by its classifier Viewer, includes a multiplicity specification.

At runtime the class instances that implement these three roles must provide the services specified by the IVar interface through their var ports.