Jess: SW Arch, Week 8

Chapter 6: From Models to Patterns

This chapter went over patterns and how they represent knowledge and provide a way to convey what’s really going on in a given system. It went over Web 2.0 design patterns as a way to help understand what Web 2.0 really is.

Patterns are recurring solutions to recurring problems. Architectural patterns are generally composed of three main components: the problem (expressed as derived requirements), the context in which the problem occurs, and the generalized solution. Context, problem, and solution.

Context: the set of circumstances or situations in which the problem occurs. A context may be highly generalized or highly specialized. The context helps identify the external sources that may affect the pattern.

Problem: a documentation of issues that arise repeatedly within the context augmented and expressed with a series of opposing forces. An example might be “a large corporation needs to build some kind of system to get all its customers to keep their personal account information up-to-date.”

Solution: solves the recurring business problem and/or indicates how to balance the opposing constraints and forces. The static structure of the generalized solution can be expressed in multiple architectural description langauges (ADLs), including simple drawings.