This chapter covers the decorator pattern.
GoF Definition
Attach additional responsibilities to an object dynamically. Decorators provide a flexible alternative to subclassing for extending functionality.
Concept
This pattern says that the class must be closed for modification but open for extension; that is, a new functionality can be added without disturbing existing functionalities. The concept is very useful when we want to add special functionalities to a specific object instead of the whole class. In this pattern, we try to use the concept of object composition instead of inheritance. ...
