So let's start by seeing how patterns are defined. So
what is the format of the pattern definitions. If we look
at the Gang of Four's book we can see that these
definitions contain a lot of information. In fact, what I'm listing
here is just a subset of this information. In this lesson,
what I want to do is to focus on four essential
elements of a design pattern. It's name, the intent which is
the goal of the pattern. The pattern's applicability which is the
list of situations or context in which the
pattern is applicable. I also want to cover the structure
and participants. Which is the static model that describes
the elements, so normally the classes or the object
involved in the pattern. In addition to that
the structure also describes
the relationships, responsibilities and collaborations
among these classes or objects. Finally what I want
to cover is sample code. So examples that illustrate
the use of patterns.