Partonomic Hierarchies

A computer is an assembly of computer chips. A computer chip is an assembly of gates. A piston is part of an engine. An engine is part of a car. We can use the Composite Design Pattern to represent assemblies and their components:

In this example we use a composite association instead of aggregation. This is done to emphasize the fact that the components of an assembly are not shared and contribute to the overall functioning of the assembly. One might argue that this was also the case for conglomerate organizations.

A more specific example: