Design Pattern Prerequisites

A newly introduced pattern must communicate and integrate with the rest of the software; an isolated, incompatible addition creates more problems than it solves. Patterns must be customized to fit the specific context of a project and not applied verbatim regardless of constraints. Applying a pattern without a clear grasp of the underlying problem will not help and may introduce new issues. Each pattern solves a different class of problem, and using the wrong pattern for a situation produces the wrong result. Four conditions must be met before a design pattern can be applied effectively.