The Rational Unified Process defines a process, notations and hints to guide a project to achieve this goal. In the same book, several quality dimensions are mentioned very briefly such as reliability, function, applicationperformance, systemperformance. However, no process has been presented to explicitly reason and optimize these quality factors. Again, the relations between these quality objectives and the framework design principles are rather implicit. Patterns A pattern is a proven knowledge, which is expressed in a pattern format to solve a given problem.
Patterns generally refer to certain quality factors for motivation.
It is the generation of such emergent behavior that appears to be what is meant by generativity. In this fashion, patterns and pattern languages should guide their users to generate whole architectures that have the quality. Architectures Software systems have to cope with continuously changing requirements. A well-defined architecture can be specified as a set of abstractions and relations, which form a concept. A concept is a fundamental abstraction in a given domain, which is useable and inherently complex.