Quotes from Erich Gamma

A design that doesn't take change into account risks major redesign in the future.

Design patterns should not be applied indiscriminately. Often they achieve flexibility and variability by introducing additional levels of indirection, and that can complicate a design and/or cost you some performance. A design pattern should only be applied when the flexibility it affords is actually needed.

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 it the same way twice

dynamically.

that shows the flow of requests between objects. interface The set of all signatures defined by an object's operations. The interface describes the set of requests to which an object can respond. metaclass Classes are objects in

Naming a pattern immediately

representation. C++ uses the term data member. interaction diagram A diagram that shows the flow of requests between objects. interface The set of all signatures

Provide an interface for creating families of related or dependent objects without specifying their concrete classes.

The best designers will use many design patterns that dovetail and intertwine to produce a greater whole.