What is a Pattern?
"Each pattern describes a problem which occurs again
and again in our environment, and then describes the core
of the solution to that problem, in such a way that you
can use this solution a million times, without ever doing
it the same way twice”
In general, a pattern has four essential elements:
1. The pattern name is a handle we can use to
describe a design problem, its solutions, and
consequences.
Naming a pattern immediately increases our design
vocabulary. It lets us design at a higher level of
abstraction. Having a vocabulary for patterns lets us
talk about them with our colleagues, in our
documentation etc. It makes it easier to think about
designs and to communicate them and their trade-
offs to others.
2. The problem describes when to apply the pattern.
It explains the problem and its context. It might
describe specific design problems such as how to
represent algorithms as objects. Sometimes the
problem will include a list of conditions that must
be met before it makes sense to apply the pattern.
