Functors are objects that model operations that can be performed. Their notation is interesting because of its distinctive combination of other notations already existing: hexagons for classes and dog-eared notes for Code blocks.

An enhancement to a class is an added piece of functionality beyond the core class functionality. Enhancements allow you to manage portions of functionality of a cClass individually while still having all that functionality directly available on instance of the class. For example, you might want your presentation logic to be separate from your true (presentation independent) business domain logic. You could make the ability to create user-readable information an enhancement of your domain class. Since Java doesn’t support enhancements this notation is only useful for conceptual modeling.

A class can be considered to have a public interface that talks to an inner class that manages the state of the object. This means all communication from the public interface will go through private methods to access state information, which allows the object to change its state representation (e.g. delegating to another object) without impacting the public methods.