Capture aspects of objects that are not part of their identity - aspects that are dynamically changing ways of interacting with their environment.

Participants

• Player - a dynamic object that has multiple dynamic ways of interacting with other objects.
• Role - a mode of interaction between a player and its environment.

People interact with their environment in many different ways. That is, they have numerous roles:

• they are students
• they are employees
• they are customers

None of these roles should be viewed as the identity of a person.

Using inheritance rather than associations to capture roles has the following consequences:

• Players cannot change their roles.
• Players cannot have multiple roles unless the programming language supports multiple inheritance. Even then, you will need a class for each combination of roles that can arise. The combinations cannot be created dynamically.