What is "decorator-pattern"

Decorator or wrapper, is a software design standard that allows you to add behavior to an existing object at runtime, that is, dynamically aggregates additional responsibilities to an object.

Intent

• Add responsibilities to an object dynamically.
• Provide flexible alternative to using subclasses to extend the functionality of a class

Consequences

• More flexibility than inheritance (Adding or removing responsibilities at runtime; Adding the same property more than once).
• Prevents over-functionality in classes.
• Decorator and its component are not identical.
• Results in a design that has several small objects, all similar.

Bibliographic References:

• Using UML and Standards 2nd Edition - Craig Larman.