Design Patterns

What Is a Design Pattern?

Christopher Alexander says: “Each pattern describes a problem which occurs over and over 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 over, without ever doing he same thing twice.”

Essential Elements: A pattern has four essential elements:

1. The pattern name that we use to describe a design problem,
2. The problem that describes when to apply the pattern,
3. The solution that describes the elements that make up the design, and
4. The consequences that are the results and trade-offs of applying the pattern.